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POWER SYSTEM COMMISSIONING AND MAINTENANCE PRACTICE
DET 310
CHAPTER 7
UNDERGROUND CABLES
70 INTRODUCTION
A considerable amount of transmission and distribution of electrical energy especially in densely populated urban areas is carried out by means of underground cable
The underground cable are rugged in construction and provide greater service reliability increased safety better appearance and trouble free service under a variety of environmental conditions
71 Applications Of Underground Cables
Underground cables are necessary for supply connection in the electrical plants in generating stations transmission system and distribution systems utilization plants and so on List of example of underground cable application for connecting one apparatus with the others for the following
- Supply power to the individual machine apparatus in electrical plants- Connection between switchgear and individual load group load- Connection between auxiliary transformer and switchgear- Subtransmission line between receiving substation and distribution substation
72 Underground Distribution System Vs Overhead Line
Safety Reliability of supply Interference Disturbance Maintenance Environment impact Economics
73 Cable Constructions
A cable consists of three main components-bull Conductorbull Insulationbull Sheath
External protection is provided by the sheath against
mechanical damage chemical reaction moisture an so on
73 Cable Constructions
bull Conductorndash An element design to
transmit electricityndash A single core has one
conductor while a three-core has 3 conductors
ndash A cable may be has single core 3 core or multiple conductor
041923
6
ETE503 Underground Cable
73 Cable Constructions
bull Insulationndash Is a material that reduces
or prevents the transmission of electricity
ndash Each conductor is covered by insulation
ndash Insulation is phase to ground and phase to phase
XLPE
PAPER
041923
7
ETE503 Underground Cable
74 Cable Constructions
bull Sheathndash Cable protective covering ndash Metallic or nonmetallic
protective covering over the conductor insulation shield
ndash External protection is provided by the sheath against mechanical damage chemical reaction moisture an so on
041923
8
ETE503 Underground Cable
75 Types of Underground Cables
bullThe identification of the cable are based on the several items
bull Insulationbull Voltage Systembull Cable Sizing And Corebull Technical Specification Characteristics Of The
Cable
041923
9
ETE503 Underground Cable
75 Types of Underground Cables
bullUsually the operating voltage decides the types of insulation and cable placed in various categories depending upon the voltage for which they are designed
ndashLow Voltage Cable (LV) 11kVndashHigh Voltage Cable (HV) 11 kV
041923
10
ETE503 Underground Cable
76 High Voltage Cable Categories
bullPaper Insulationndash3 core belted 11kV PILC cablendashSingle core screened 11 kV PILC cable
bullPolymer Insulationndash3 core XLPE 11 kV cablendashSingle core XLPE 11 kV cable
041923
11
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
70 INTRODUCTION
A considerable amount of transmission and distribution of electrical energy especially in densely populated urban areas is carried out by means of underground cable
The underground cable are rugged in construction and provide greater service reliability increased safety better appearance and trouble free service under a variety of environmental conditions
71 Applications Of Underground Cables
Underground cables are necessary for supply connection in the electrical plants in generating stations transmission system and distribution systems utilization plants and so on List of example of underground cable application for connecting one apparatus with the others for the following
- Supply power to the individual machine apparatus in electrical plants- Connection between switchgear and individual load group load- Connection between auxiliary transformer and switchgear- Subtransmission line between receiving substation and distribution substation
72 Underground Distribution System Vs Overhead Line
Safety Reliability of supply Interference Disturbance Maintenance Environment impact Economics
73 Cable Constructions
A cable consists of three main components-bull Conductorbull Insulationbull Sheath
External protection is provided by the sheath against
mechanical damage chemical reaction moisture an so on
73 Cable Constructions
bull Conductorndash An element design to
transmit electricityndash A single core has one
conductor while a three-core has 3 conductors
ndash A cable may be has single core 3 core or multiple conductor
041923
6
ETE503 Underground Cable
73 Cable Constructions
bull Insulationndash Is a material that reduces
or prevents the transmission of electricity
ndash Each conductor is covered by insulation
ndash Insulation is phase to ground and phase to phase
XLPE
PAPER
041923
7
ETE503 Underground Cable
74 Cable Constructions
bull Sheathndash Cable protective covering ndash Metallic or nonmetallic
protective covering over the conductor insulation shield
ndash External protection is provided by the sheath against mechanical damage chemical reaction moisture an so on
041923
8
ETE503 Underground Cable
75 Types of Underground Cables
bullThe identification of the cable are based on the several items
bull Insulationbull Voltage Systembull Cable Sizing And Corebull Technical Specification Characteristics Of The
Cable
041923
9
ETE503 Underground Cable
75 Types of Underground Cables
bullUsually the operating voltage decides the types of insulation and cable placed in various categories depending upon the voltage for which they are designed
ndashLow Voltage Cable (LV) 11kVndashHigh Voltage Cable (HV) 11 kV
041923
10
ETE503 Underground Cable
76 High Voltage Cable Categories
bullPaper Insulationndash3 core belted 11kV PILC cablendashSingle core screened 11 kV PILC cable
bullPolymer Insulationndash3 core XLPE 11 kV cablendashSingle core XLPE 11 kV cable
041923
11
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
71 Applications Of Underground Cables
Underground cables are necessary for supply connection in the electrical plants in generating stations transmission system and distribution systems utilization plants and so on List of example of underground cable application for connecting one apparatus with the others for the following
- Supply power to the individual machine apparatus in electrical plants- Connection between switchgear and individual load group load- Connection between auxiliary transformer and switchgear- Subtransmission line between receiving substation and distribution substation
72 Underground Distribution System Vs Overhead Line
Safety Reliability of supply Interference Disturbance Maintenance Environment impact Economics
73 Cable Constructions
A cable consists of three main components-bull Conductorbull Insulationbull Sheath
External protection is provided by the sheath against
mechanical damage chemical reaction moisture an so on
73 Cable Constructions
bull Conductorndash An element design to
transmit electricityndash A single core has one
conductor while a three-core has 3 conductors
ndash A cable may be has single core 3 core or multiple conductor
041923
6
ETE503 Underground Cable
73 Cable Constructions
bull Insulationndash Is a material that reduces
or prevents the transmission of electricity
ndash Each conductor is covered by insulation
ndash Insulation is phase to ground and phase to phase
XLPE
PAPER
041923
7
ETE503 Underground Cable
74 Cable Constructions
bull Sheathndash Cable protective covering ndash Metallic or nonmetallic
protective covering over the conductor insulation shield
ndash External protection is provided by the sheath against mechanical damage chemical reaction moisture an so on
041923
8
ETE503 Underground Cable
75 Types of Underground Cables
bullThe identification of the cable are based on the several items
bull Insulationbull Voltage Systembull Cable Sizing And Corebull Technical Specification Characteristics Of The
Cable
041923
9
ETE503 Underground Cable
75 Types of Underground Cables
bullUsually the operating voltage decides the types of insulation and cable placed in various categories depending upon the voltage for which they are designed
ndashLow Voltage Cable (LV) 11kVndashHigh Voltage Cable (HV) 11 kV
041923
10
ETE503 Underground Cable
76 High Voltage Cable Categories
bullPaper Insulationndash3 core belted 11kV PILC cablendashSingle core screened 11 kV PILC cable
bullPolymer Insulationndash3 core XLPE 11 kV cablendashSingle core XLPE 11 kV cable
041923
11
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
72 Underground Distribution System Vs Overhead Line
Safety Reliability of supply Interference Disturbance Maintenance Environment impact Economics
73 Cable Constructions
A cable consists of three main components-bull Conductorbull Insulationbull Sheath
External protection is provided by the sheath against
mechanical damage chemical reaction moisture an so on
73 Cable Constructions
bull Conductorndash An element design to
transmit electricityndash A single core has one
conductor while a three-core has 3 conductors
ndash A cable may be has single core 3 core or multiple conductor
041923
6
ETE503 Underground Cable
73 Cable Constructions
bull Insulationndash Is a material that reduces
or prevents the transmission of electricity
ndash Each conductor is covered by insulation
ndash Insulation is phase to ground and phase to phase
XLPE
PAPER
041923
7
ETE503 Underground Cable
74 Cable Constructions
bull Sheathndash Cable protective covering ndash Metallic or nonmetallic
protective covering over the conductor insulation shield
ndash External protection is provided by the sheath against mechanical damage chemical reaction moisture an so on
041923
8
ETE503 Underground Cable
75 Types of Underground Cables
bullThe identification of the cable are based on the several items
bull Insulationbull Voltage Systembull Cable Sizing And Corebull Technical Specification Characteristics Of The
Cable
041923
9
ETE503 Underground Cable
75 Types of Underground Cables
bullUsually the operating voltage decides the types of insulation and cable placed in various categories depending upon the voltage for which they are designed
ndashLow Voltage Cable (LV) 11kVndashHigh Voltage Cable (HV) 11 kV
041923
10
ETE503 Underground Cable
76 High Voltage Cable Categories
bullPaper Insulationndash3 core belted 11kV PILC cablendashSingle core screened 11 kV PILC cable
bullPolymer Insulationndash3 core XLPE 11 kV cablendashSingle core XLPE 11 kV cable
041923
11
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
73 Cable Constructions
A cable consists of three main components-bull Conductorbull Insulationbull Sheath
External protection is provided by the sheath against
mechanical damage chemical reaction moisture an so on
73 Cable Constructions
bull Conductorndash An element design to
transmit electricityndash A single core has one
conductor while a three-core has 3 conductors
ndash A cable may be has single core 3 core or multiple conductor
041923
6
ETE503 Underground Cable
73 Cable Constructions
bull Insulationndash Is a material that reduces
or prevents the transmission of electricity
ndash Each conductor is covered by insulation
ndash Insulation is phase to ground and phase to phase
XLPE
PAPER
041923
7
ETE503 Underground Cable
74 Cable Constructions
bull Sheathndash Cable protective covering ndash Metallic or nonmetallic
protective covering over the conductor insulation shield
ndash External protection is provided by the sheath against mechanical damage chemical reaction moisture an so on
041923
8
ETE503 Underground Cable
75 Types of Underground Cables
bullThe identification of the cable are based on the several items
bull Insulationbull Voltage Systembull Cable Sizing And Corebull Technical Specification Characteristics Of The
Cable
041923
9
ETE503 Underground Cable
75 Types of Underground Cables
bullUsually the operating voltage decides the types of insulation and cable placed in various categories depending upon the voltage for which they are designed
ndashLow Voltage Cable (LV) 11kVndashHigh Voltage Cable (HV) 11 kV
041923
10
ETE503 Underground Cable
76 High Voltage Cable Categories
bullPaper Insulationndash3 core belted 11kV PILC cablendashSingle core screened 11 kV PILC cable
bullPolymer Insulationndash3 core XLPE 11 kV cablendashSingle core XLPE 11 kV cable
041923
11
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
73 Cable Constructions
bull Conductorndash An element design to
transmit electricityndash A single core has one
conductor while a three-core has 3 conductors
ndash A cable may be has single core 3 core or multiple conductor
041923
6
ETE503 Underground Cable
73 Cable Constructions
bull Insulationndash Is a material that reduces
or prevents the transmission of electricity
ndash Each conductor is covered by insulation
ndash Insulation is phase to ground and phase to phase
XLPE
PAPER
041923
7
ETE503 Underground Cable
74 Cable Constructions
bull Sheathndash Cable protective covering ndash Metallic or nonmetallic
protective covering over the conductor insulation shield
ndash External protection is provided by the sheath against mechanical damage chemical reaction moisture an so on
041923
8
ETE503 Underground Cable
75 Types of Underground Cables
bullThe identification of the cable are based on the several items
bull Insulationbull Voltage Systembull Cable Sizing And Corebull Technical Specification Characteristics Of The
Cable
041923
9
ETE503 Underground Cable
75 Types of Underground Cables
bullUsually the operating voltage decides the types of insulation and cable placed in various categories depending upon the voltage for which they are designed
ndashLow Voltage Cable (LV) 11kVndashHigh Voltage Cable (HV) 11 kV
041923
10
ETE503 Underground Cable
76 High Voltage Cable Categories
bullPaper Insulationndash3 core belted 11kV PILC cablendashSingle core screened 11 kV PILC cable
bullPolymer Insulationndash3 core XLPE 11 kV cablendashSingle core XLPE 11 kV cable
041923
11
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
73 Cable Constructions
bull Insulationndash Is a material that reduces
or prevents the transmission of electricity
ndash Each conductor is covered by insulation
ndash Insulation is phase to ground and phase to phase
XLPE
PAPER
041923
7
ETE503 Underground Cable
74 Cable Constructions
bull Sheathndash Cable protective covering ndash Metallic or nonmetallic
protective covering over the conductor insulation shield
ndash External protection is provided by the sheath against mechanical damage chemical reaction moisture an so on
041923
8
ETE503 Underground Cable
75 Types of Underground Cables
bullThe identification of the cable are based on the several items
bull Insulationbull Voltage Systembull Cable Sizing And Corebull Technical Specification Characteristics Of The
Cable
041923
9
ETE503 Underground Cable
75 Types of Underground Cables
bullUsually the operating voltage decides the types of insulation and cable placed in various categories depending upon the voltage for which they are designed
ndashLow Voltage Cable (LV) 11kVndashHigh Voltage Cable (HV) 11 kV
041923
10
ETE503 Underground Cable
76 High Voltage Cable Categories
bullPaper Insulationndash3 core belted 11kV PILC cablendashSingle core screened 11 kV PILC cable
bullPolymer Insulationndash3 core XLPE 11 kV cablendashSingle core XLPE 11 kV cable
041923
11
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
74 Cable Constructions
bull Sheathndash Cable protective covering ndash Metallic or nonmetallic
protective covering over the conductor insulation shield
ndash External protection is provided by the sheath against mechanical damage chemical reaction moisture an so on
041923
8
ETE503 Underground Cable
75 Types of Underground Cables
bullThe identification of the cable are based on the several items
bull Insulationbull Voltage Systembull Cable Sizing And Corebull Technical Specification Characteristics Of The
Cable
041923
9
ETE503 Underground Cable
75 Types of Underground Cables
bullUsually the operating voltage decides the types of insulation and cable placed in various categories depending upon the voltage for which they are designed
ndashLow Voltage Cable (LV) 11kVndashHigh Voltage Cable (HV) 11 kV
041923
10
ETE503 Underground Cable
76 High Voltage Cable Categories
bullPaper Insulationndash3 core belted 11kV PILC cablendashSingle core screened 11 kV PILC cable
bullPolymer Insulationndash3 core XLPE 11 kV cablendashSingle core XLPE 11 kV cable
041923
11
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
75 Types of Underground Cables
bullThe identification of the cable are based on the several items
bull Insulationbull Voltage Systembull Cable Sizing And Corebull Technical Specification Characteristics Of The
Cable
041923
9
ETE503 Underground Cable
75 Types of Underground Cables
bullUsually the operating voltage decides the types of insulation and cable placed in various categories depending upon the voltage for which they are designed
ndashLow Voltage Cable (LV) 11kVndashHigh Voltage Cable (HV) 11 kV
041923
10
ETE503 Underground Cable
76 High Voltage Cable Categories
bullPaper Insulationndash3 core belted 11kV PILC cablendashSingle core screened 11 kV PILC cable
bullPolymer Insulationndash3 core XLPE 11 kV cablendashSingle core XLPE 11 kV cable
041923
11
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
75 Types of Underground Cables
bullUsually the operating voltage decides the types of insulation and cable placed in various categories depending upon the voltage for which they are designed
ndashLow Voltage Cable (LV) 11kVndashHigh Voltage Cable (HV) 11 kV
041923
10
ETE503 Underground Cable
76 High Voltage Cable Categories
bullPaper Insulationndash3 core belted 11kV PILC cablendashSingle core screened 11 kV PILC cable
bullPolymer Insulationndash3 core XLPE 11 kV cablendashSingle core XLPE 11 kV cable
041923
11
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
76 High Voltage Cable Categories
bullPaper Insulationndash3 core belted 11kV PILC cablendashSingle core screened 11 kV PILC cable
bullPolymer Insulationndash3 core XLPE 11 kV cablendashSingle core XLPE 11 kV cable
041923
11
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (carbon black paper )bull C = Insulation (Paper)bull D = Insulation Screen
(carbon black paper)bull E = Sheath (copper
lead)bull F = Jacket Example of Single core
screened 11 kV PILC cable041923
12
ETE503 Underground Cable
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
77 High Voltage Cable Categories
bull A = Conductor (Aluminum)
bull B = Strand Screen (extruded
semiconducting)bull C = Insulation (XLPE)bull D = Insulation Screen (extruded
semiconducting)bull E = Shield (copper
tape)bull F = Jacket
Example of Single core XLPE 11 kV cable
041923
13
ETE503 Underground Cable
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
78 Why XLPE Cable
ndash Excellent Electrical amp Physical Properties
ndash Capable Of Carrying Large Current At High Temperaturebull Normal ~ 90ocbull Emergency ~ 130ocbull Short Circuit Conditions
~250ocndash Easy To Install ndash XLPE Easier
To Jointndash No Need For Metallic Sheath
041923
14
ETE503 Underground Cable
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
79 Cable Accessories
bull A cable network must be capable of supplying electric power without interruption
bull If a failure does occur it is usually the junction points on the network that are at fault rarely the cable
bull So it pays to choose cable accessories with care
041923
15
ETE503 Underground Cable
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
bull Cable accessories can be divided into 3 major categories-ndash JointSplice
ndash Termination
ndash Connector
79 Cable Accessories
JointSplice
TerminationConnector
041923
16
ETE503 Underground Cable
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
710 Examples of Cable JointSplice
Examples Of LVMVHV Cable Joint-
1LV Heat Shrink Joint
2LV Heat Shrink (Branch Joint)
3MV Heat Shrink Joint
4MV Heat Shrink Joint (Transition Joint Paper To Polymeric)
5 HV Heat Shrink Joint Up To 72KV
6HV Heat Shrink Joint Up To 170kv
1
2
3
4
5
6
041923
17
ETE503 Underground Cable
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
bull Cable termination is one of the important components in the electrical power system
bull A failure of it can cause a long interruption costly repair and loss of revenue
bull A cable termination is a way of preparing the end of a cable to provide adequate electrical and mechanical properties
710 Cable Accessories ndashTermination
041923
18
ETE503 Underground Cable
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
711 Examples of Cable Connector
Examples Of LVMVHV Cable Connector-
1 MV Heat Shrink Straight Bushing Boot
2MV Heat Shrink Right Angle Bushing Boot
3MV Push On connector with surge arrestor
4MV Push On Connector separable 3 Core
5 MV Push On Connector 1 Core
6MV Push On Straight Bushing Boot
1 2 3 4 5 6
041923
19
ETE503 Underground Cable
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
7120 (CABLE FAULT) INTRODUCTION
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
1048707 Cable faults are undesirable causes because-
1 Power supply is interrupted
2 Locating fault in a long underground cable is difficult and time consuming
3 Repairing faulty cable is difficult and time consuming aging is a natural process
1048707 Cable insulation gets deterioration with time1048707 Preventive Maintenance periodic monitoring is necessary to prevent failure
7121 CAUSES OF CABLE FAULT (CONTINUE)
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
71221 MECHANICAL
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
7122 CAUSES OF UNDERGROUND CABLE FAILURE
Major factors that cause failure of a cable are-
bull Damaged accidentally by external mechanical means
bull Damage caused as a results of mishandling the cable
during layout
bull Poor workmanship in cable jointing
bull Natural causes due to aging
of cable
bull Damaged caused by movement
of soil and erosion
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
71222 MISHANDLING
Mishandling of cable may be occurred during installation
Some of the examples are
1 Excessive pull
2 Sharp bend
3 Accident crush
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
71223 Poor workmanship During Cable Jointing
The cable are jointed together with poor workmanship can lead to cable fault after a period of time
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
71224 NATURAL CAUSES DUE TO AGING OF CABLE
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
CONTINUE-
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
CONTINUE-
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
CONTINUE-
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
CONTINUE-
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
713 TYPES OF CABLE FAULT
GENERAL
bull Series (open circuit) Fault
- Failure of continuity (conductor (s) or cable)
bull Shunt (short circuit) fault
- failure of insulation
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
713 TYPES OF FAULT (CONTINUE)-
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
713 TYPES OF FAULT (CONTINUE)-
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
7131 SERIES AND SHUNT FAULT
Are subsided into the following categories
Low Resistance Fault of ZR 10
Where Zo= cable surge impedance
=10 ndash 100 ohm
Usually happens in series fault
High Resistance Fault
Where ZoR f 10
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
7132 INTERMITTENT OR FLASH FAULT
-Usually not apparent to insulation resistance measuring
instrument
-Does not manifest itself at lower voltages or a surge
-Breakdown will appear under application of high voltage
dc or DC pressure test
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
714 FAULT LOCATION PROCEDURE
The proper sequence of cable fault location are as follows
a) Analysis of fault
b) Pre-location
c) Pin Pointing
d) Confirmation and re-test
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
714 FAULT LOCATION PROCEDURE (cont-)
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
714 FAULT LOCATION PROCEDURE (cont-)
Continuity Test - With the cable conductor shorted or looped at the remote end perform continuity test on the cable
- Measure and record the results in ohm
- Three measurements are to be carried out between R-Y Y-B B-R
- The test will determine whether any of cable is open circuited - The resistance per-conductor per km is provided in Table VI VII VIII and IX (refer appendix A)
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
714 FAULT LOCATION PROCEDURE (cont-)
if the continuity of the cable is sound insulation resistance from one end are sufficient
If continuity is broken IR test should be carried out at both ends of the cable
7141 BURNING A FAULT
-The continuity and IR test may indicate that burning of fault by means of HT pressure test set is required
-
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first
7141 BURNING A FAULT (continue-)
-Burning a fault is achieve by passing current from a DC HT test set through the fault
-Other conductors not under test should be earthed
-HT is applied for about 5 to 10 minutes to burn the fault
- HT test is used to determine which fault location equipment is suitable to be used
-HT is the last resort often used because it sometimes produce ambiguous and unpredictable results
-Therefore fault location equipment should be attempted first