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by Schneider
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Improved monitoring and protectionRCD-based protection plan
COMBT13FR-11/02
COMBT13FR-11/02 2
Contents
Protection of life and property 3 standard IEC 60479-1 standard IEC 60364 fire protection Disturbances on distribution systems 23 earth-leakage currents non-linear loads overvoltage disturbances Vigirex 27 four mesurement features protection on disturbed distribution systems Applications 36 EMC tests and voltage-dip immunity measurement of fault currents with a DC component RCD coordination protection plans for different system earthing arrangements load leakage currents Vigirex - installation of toroids protection of property
COMBT13FR-11/02 3
Impedance of the human body ZT UC = ZT ID
ZT depends on:
the frequency the touch voltage the path through the body
Protection of life and propertyStandard IEC 60479-1
Internalresistance = ZT
UCZT ID
E92
455
Skin(hand)
Skin(foot)
COMBT13FR-11/02 4
Impedance of the human body ZT UC = ZT ID
ZT depends on:
the frequency the touch voltage the path through the body
The level of danger depends on: the current ID
the duration of current flow
Protection of life and property Standard IEC 60479-1
UCZT
ID
ID
E92
456
Internalresistance = ZT
Skin(hand)
Skin(foot)
COMBT13FR-11/02 5
T(ms)
5000
(mA)0.230 mA
0.1
20001000500
200100
50
2010
10 000
1 2 5 10 50005000.5 mA
100
4321
c3b c2c1
20001000
Time/current zones defining the effects of AC current(15 Hz to 100 Hz)
Protection of life and propertyStandard IEC 60479-1
Zone 1 : perception
Zone 2 : unpleasant sensation
Zone 3 : muscular contractionsb (10 mA) let-go threshold
Zone 4 : risk of ventricular fibrillation(cardiac arrest)c1 (30 mA)
b - c1 : probability 0 %
c1 - c2 : probability ~ 5 %
c2 - c3 : probability ~ 50 %
> c3 : probability > 50 %
E92
444
Duration of current flow
Current flowing through the body
COMBT13FR-11/02 6
Critical current thresholds
Protection of life and propertyStandard IEC 60479-1
Cardiac arrest
Irreversible cardiacfibrillation
Breathing arrest
Muscular contraction
Tingling
1 A
75 mA
30 mA
10mA
0.5 mA
mAE
9245
0
COMBT13FR-11/02 7
Effect of frequency
Protection of life and propertyStandard IEC 60479-1
The human body is most sensitive to frequenciesin the 50 Hz / 60 Hz range
Current-sensitivity thresholds(mA)
E92
451
(f)30
100
500
50 100 1000DC
COMBT13FR-11/02 8
50 V < Uo 120 V 120 V < Uo 230 V 230 V < Uo 400 V Uo 400 V
Disconnecting time (s) AC DC AC DC AC DC AC DC
TN or IT system 0.8 5 0.4 5 0.2 0.4 0.1 0.1
TT system 0.3 5 0.2 0.4 0.07 0.2 0.04 0.1
Standard IEC 60364 converts the current/exposure-time curves ofstandard IEC 60479-1 into tables presenting the disconnecting-time versus the nominal AC-voltage (Uo)
From table 41A of standard IEC 60364
Protection of life and propertyStandard IEC 60364
COMBT13FR-11/02 9
Direct contact "Contact of persons or livestock with live parts of the installation"
Protection of life and propertyStandard IEC 60364
E92
458
Uc
E92
459
Equivalent electrical circuit
COMBT13FR-11/02 10
Out of reachInsulation
IP2X or IPXXB ELV < 25 V 30 mA
Direct contact
Protection of life and propertyStandard IEC 60364
E95
155
COMBT13FR-11/02 11
Indirect contact “Contact of persons or livestock with exposed conductive parts in case
of a fault”
Protection of life and property
E92
454
Standard IEC 60364
Uc
E92
460
Equivalent electrical circuit
COMBT13FR-11/02 12
Standard IEC 60364 defines three system earthing arrangementsto ensure:
Protection of persons against indirect contactProtection against fire hazards
TT system TN system IT system
RCD protection is a fundamental part of the TT system
E568
87
Protection of life and propertyStandard IEC 60364
COMBT13FR-11/02 13
TT system The neutral point of the LV transformer is directly connected to an earth electrode The exposed conductive parts
of the installation are connected to a separate earth electrode
Protection of life and propertyStandard IEC 60364
E95
152
L1L2L3N
RuRn
PE
COMBT13FR-11/02 14
TT systemEarth fault protectionValue of fault currentId = Uo / (Rn + Ru)
= 230 / (10 + 10)= 11.5 A
Ud = Ru x Id= 10 x 11.5= 115 V > UL = 50 V
The fault current createsa dangerous touch voltage
The SCPD is not capableof clearing this type of fault
Protection of life and propertyStandard IEC 60364
E95
153
Load
L1L2L3N
Uo = 230 V
400/230 V
Ru10 Ω
Rn10 Ω
Ud =115 V
Metal exposed conductive partId = 11.5 A
COMBT13FR-11/02 15
TT system Earth fault protectionSolution The SCPD is not capable of
clearing this type of fault (ST setting = 25 A) The solution is a residual-current
device (RCD) designed for the protection of persons
Tripping conditions UCmax UL
Ru x In < UL
(In is the setting for the RCD) In = UL / Ru
= 50 /10= 5 A
SCPD 25 A
400/230 V
Load
L1L2L3N
Ru10 Ω
Rn10 Ω
Uo = 230 V
In = 5A
Protection of life and propertyStandard IEC 60364
E95
154
Metal exposed conductive part
COMBT13FR-11/02 16
At A
I1 + I2 + I3 + IN = IPE Well designed network IPE = 0
Protection of life and propertyStandard IEC 60364
L1L2L3NPE
E92
457
I1 + I2 + I3 + IN = 0
IPE = 0
A
Current in the neutral does not depend on current IPE equal to unbalanced load
currents and/or 3rd orderharmonics (3 k)
IN = Iunbalance + I3 k
TT system
RuRn
COMBT13FR-11/02 17
Measurement of current IPE can be used for protection of persons(values depend on the earthing arrangement) and protection against fire hazards. However, it is necessary to detect the true IPE
Faulty distribution system IPE 0
Protection of life and propertyStandard IEC 60364
L1L2L3NPE
E94
409
I1 + I2 + I3 + IN 0
IPE 0
A
Current in the neutral does not depend on current IPE equal to unbalanced load
currents and/or 3rd orderharmonics (3 k) IN = Iunbalance + I3 k
TT system
RuRn
COMBT13FR-11/02 18
"Deep" earth the earth does not act as an insulator
Protection of life and propertyStandard IEC 60364
"Deep" earth
E92
452
E92
453
Equivalent electrical circuit "Deep" earth is equipotential in nature…
1000 km
1 Ω 15 Ω 10 Ω 10 Ω 5 Ω
"Deep" earth
11 Ω
… whatever the distance!
COMBT13FR-11/02 19
Study carried out in Germany between 1980 and 1990
41% of fires are electrical in origin this risk is far from negligible it can be eliminated
Protection of life and property
Risk analysis - the origins of fires in buildings
E92
446
Fire 37%
Accidents 7%
Lightning 1% Explosions 1%
Electricity 41%Cigarettes 6% Other 7%
Fire protection
COMBT13FR-11/02 20
Ageing of the installation results in: less effective insulation the risk of very small leakage currents Presence of humidity
There is a real risk of fire starting at leakage currents of 300 mA
Main cause
Leakagecurrents
Smalldischarges
Carbonisationof insulation
(dust)
E92
462
E92
461
Protection of life and propertyFire protection
COMBT13FR-11/02 21
Standard IEC 60364, section 3-32, defines premises presenting arisk of fire (BE2) or explosion (BE3)
Standard IEC 60364, section 4-48, deals with premises where there is a risk of fire
imposes use of a 500 mA RCD device recommends use of a TT or IT system for the electrical installation
in such premises prohibits use of a TN-C system
In TT, IT and TN-S systems, a 300 mA RCD eliminates the risk of fire
Standard IEC 60364
IEC 60364
E94
550
Protection of life and propertyFire protection
COMBT13FR-11/02 22
The National Electrical Code (NEC) defines a TN-S system the neutral conductor is not interrupted the PE protective conductor is created by connecting the metal parts
of the equipment The NEC considers that the TN-S system cannot control
the impedance of the insulation-fault loop
The NEC requires specific ground fault protection) (GFP) to protect against fire hazards (maximum setting of 1200 A)
N
In the USA
E92
447
Protection of life and propertyFire protection
COMBT13FR-11/02 23
Cable leakage capacitance continuous leakage current
called "natural leakage current"
Disturbances on distribution systemsEarth-leakage currents
E92
463
Load leakage capacitance continuous leakage current
called "intentional leakage current"
E92
449
N
L1
COMBT13FR-11/02 24
0
20
80
40
60
%
100
1 3 5 7 9 11 13
Harmonic currents non-linear loads cause harmonic currents, as a result, the intentional leakage currents are "amplified"
Disturbances on distribution systemsNon-linear loads
Amplitude
HarmonicorderE
9246
4
IH E94
410
VSD
COMBT13FR-11/02 25
E92
465
- E92
499
Fault currents fault currents have DC components
Disturbances on distribution systemsNon-linear loads
PEUPS
COMBT13FR-11/02 26
Lightning and switching overvoltages cause high transient currentsin distribution-system leakage capacitances
Current in the PE
Disturbances on distribution systemsOvervoltages (surges)
E94
167
Ir1
A
0
2
4
6
-2
-4
-6
T(s)0,02 0,040
10
E94
412
COMBT13FR-11/02 27
Vigirex implements four functions to: analyse leakage currents to avoid nuisance tripping trip immediately when required for the protection of persons
VigirexFour mesurement features
Reduced tolerances
Rmsmeasurement
Inverse time
Frequency filtering
E94
411
COMBT13FR-11/02 28
2
15 x30 mA
5 x30 mA
1 x30 mA
In
50/60 Hz 1000 Hz 10 KHz
1
2
Filtering of harmonic frequencies frequency converters create leakage currents
with high harmonic components
Vigirex
Analyse leakage currents
E94
414
E94
413
Eliminatenuisance tripping
a /a
M
ihfPE
Ich ihf = ihf
Ich = 0
ihf
3
the RCD must not trip 3
these currents are not dangerous 1
Four mesurement features
COMBT13FR-11/02 29
2
RMS measurement non-linear loads can cause leakage currents with high
form factors 1
E94
415
2
RMS measurement is the means to react only to dangerous currents
Eliminatenuisance tripping
1
T (ms)
I
+ In
In
Vigirex
Analyse leakage currents
Four mesurement features
COMBT13FR-11/02 30
Reduced tolerances RCDs never operate below 50% of In RCDs always operate at 100% of In
E94
416
Vigirex has a non-operating current equal to 80% of In,i.e. better immunity to both natural and intentional leakage currents
I faultStandard RCD
Vigirex
OperationNon-operation
0.8 In InIn2
Eliminatenuisance tripping
Vigirex
Analyse leakage currents
Four mesurement features
COMBT13FR-11/02 31
10
T (s)
I
1
2 5
0,3
0,15
0,04
0,1
0,01
1
2
31
1
these currents must not tripthe RCD
Inverse time
energisation of loadswith filters can create major
inrush currents
E94
417
Eliminatenuisance tripping
Vigirex
Analyse leakage currents
2
Four mesurement features
Vigirex does not trip 3
COMBT13FR-11/02 32
10
T (s)
I
1
2 5
0,3
0,15
0,04
0,1
0,01
1
1
Inverse time
dangerous faults can occur 1
Vigirex
E94
418
Schneider guarantees the break time for a Vigirex combined with circuit breakers rated up to 630 A, even for the 30 mA threshold
Ensureeffectiveprotectionof persons
2
Four mesurement features
Vigirex, combinedwith a Compact NS, has an
instantaneous total break time that complies with table B1 of standard IEC 60947-2, appendix B 2
COMBT13FR-11/02 33
Test standard Standardised test as per IEC 60947-2 Vigirex testsElectrostatic-discharge 8 kV contact 8 kV contactimmunity test 8 kV in air 15 kV in airRadiated EM-field 10 V/m 12 V/mimmunity test 80 to 1000 MHz modulated at 1 kHz 80 to 1000 MHz modulated at 1 kHzSurge immunity test - On supply > 100 V AC - For all supplies (*)
4 kV line-to-earth, 4 kV line-to-line 4 kV line-to-earth, 4 kV line-to-line - On supply < 100 V AC - On supply < 100 V AC2 kV line-to-earth, 1 kV line-to-line 4 kV line-to-earth, 4 kV line-to-line - On DC supply - On DC supply 0.5 kV line-to-earth, 0.5 kV line-to-line 2 kV line-to-earth, 1 kV line-to-line - On input/output (I/O) - On input/output (I/O) 2 kV line-to-earth, 1 kV line-to-line 2 kV line-to-earth, 1 kV line-to-line 1.2/50 s wave, open circuit 1.2/50 s wave, open circuit 8/20 s short circuit 8/20 s short circuit
Voltage-dip Single-phase supply: Us 85 V Single-phase supply: Us 85 Vimmunity test Three-phase supply: Us 70%
Vigirex goes beyond the maximum requirements of standard IEC 60947-2 for EMC immunity
Protection on disturbed distribution systemsEMC tests and voltage-dip immunity
(*) for V AC < 48 V, the Vigirex relay does not have a supply transformer
COMBT13FR-11/02 34
T
I IfFault
Loads Linear - frequent Non-linear - frequent Non-linear - rare
Examples Lamps Dimmers, soft starters (*) Variable-speed drives AC motors Variable-speed drives with accessible
Capacitors braking resistors
RCD Type AC Type A Type B
Classification of faults and types of RCDs
Measurement of fault currents with a DC component
For power distribution, a type A RCD is required for effective protection against insulation fault
T
I If
T
I If
E94
419
Protection on disturbed distribution systems
(*) Type ACis sufficient
COMBT13FR-11/02 35
Combination of different types of RCDs
Measurement of fault currents with a DC component
Different types of RCDs may be combined as long as noneof the devices are blocked by the fault current
E94
441
Class IIinsulation
type ARCD2
type BRCD2
type A ortype AC RCD
type ARCD
type AVigirexRCD1
300 mAinst
type AVigirexRCD1
300 mA60 ms
Protection on disturbed distribution systems
COMBT13FR-11/02 36
Discrimination rules
two conditions: In (RCD1) > 2 In (RCD2)t (RCD1) > t (RCD2) + t (CB2)(including the interrupting time)
To implement condition , it is necessary to know the total break time guaranteed for the CB2 + RCD2 combination or to run tests on the combination
ApplicationsRCD coordination
CB1RCD1
CB2RCD2
E94
442
2
1
2
COMBT13FR-11/02 37
2
1
Condition is automatically obtained for (RCD2) +1 if RCD2is combined with a circuit breaker/switch disconnector fromthe Multi 9 or Compact ranges
Discrimination rules
two conditions: In (RCD1) > 2 In (RCD2)setting (RCD1) setting (RCD2) +1
ApplicationsCoordination of RCDs
CB1
RCD1
CB2
RCD2
E94
442
2
COMBT13FR-11/02 38
Discrimination rules with a Vigirex upstream
two conditions: In (RCD1) > 1.5 Insetting (RCD1) setting (RCD2) +1
ApplicationsCoordination of RCDs
CB1
RCD1
CB2
RCD2
E94
442
Vigirex2
1
Condition is automatically obtained for (RCD2) +1 if RCD2is combined with a circuit breaker/switch disconnector fromthe Multi 9 or Compact ranges
2
COMBT13FR-11/02 39
RCD1
Protection plans for different system earthing arrangements
In current setting on upstream RCD
E94
479
CB1
CB2
RCD2
E94
478
2,5 A 5 A 1 s
standardised rules (maximum): In = 5 A t = 1 sUL = 50 VRT = 10
In t
Applications
TT system
COMBT13FR-11/02 40
CB1RCD1
CB2
E94
478
In current setting on upstream RCD standardised rules (maximum): In = 5 A t = 1 s
E94
479
ProcessILA
Example. NS250 Vigi 3 A
BA
20 VSDsILB
leakage-current IL withstand (min.):
In t
310150
60
0
0,03 (t = 0)
1
0,3
t(ms)
In(A)
10
HS
T R3 vigi MH
200 / 440 V - 5
vigiNS 250
2 4 6
1 3 5N
Vigi 3 ANS250
Protection plans for different system earthing arrangementsApplications
TT system
In 2 IL = 1.1 A In = 3 AILA = 150 mAILB = 400 mAIL = 550 mA
3 A1,5 A0,55
IL
5 A 1 s
COMBT13FR-11/02 41
2,5 A 5 A 1 s
Vigirex
CB1RCD1
E94
478
In current setting on upstream RCD
standardised rules (maximum): In = 5 A t = 1 s
E94
479
ProcessILA
BA
20 VSDsILB leakage-current IL withstand (min.):
In tMERLIN GERIN
RH99 1ANS250
Example. Vigirex RH99
Protection plans for different system earthing arrangementsApplications
TT system
In 1.5 IL = 825 mA In = 1 AILA = 150 mAILB = 400 mAIL = 550 mA
1 A0,7 A0,55
IL
5 A 1 s
COMBT13FR-11/02 42
?
60 ms
t1 > t2 + break time CB2
5 A3 A0,55
IL
1 s1,5 A
leakage-current IL withstand (min.): In 2 IL = 1.1 A In = 3 A discrimination rules
CB1RCD1
CB2
RCD2
E94
478
In current setting on upstream RCD standardised rules (maximum): In = 5 A t = 1 s
E94
479
In t
Protection plans for different system earthing arrangementsApplications
TT system
In1 In2 x 2 = 600 mA In = 1 A
RCD2300 mA - s
300 mA
In2
COMBT13FR-11/02 43
setting RCD1 setting RCD2 + 1
150 ms
60 ms
310150
60
0
0,03 (t = 0)
1
0,3
t(ms)
In(A)
10
HS
T R150
vigi MH200 / 440 V - 5
vigiNS 250
2 4 6
1 3 5N3
NS250 Vigi3 A - 150 ms 5 A3 A0,55
IL
1 s1,5 A
leakage-current IL withstand (min.): In 1,5 IL = 825 mA In = 3 A discrimination rules (Schneider)
CB1RCD1
CB2
RCD2
E94
478
In current setting on upstream RCD standardised rules (maximum): In = 5 A t = 1 s
E94
479
In t
Protection plans for different system earthing arrangementsApplications
TT system
In1 In2 x 2 = 600 mA In = 1 A
300 mA
In2
RCD2C60 Vigi if s 300 mA
RCD1NS250Vigi
COMBT13FR-11/02 44
150 ms
60 ms
setting RCD1 setting RCD2 + 1
MERLIN GERIN
1 A - 150 msRH99
5 A1 A0,55
IL
1 s0,7 A0,3
discrimination rules
CB1RCD1
CB2
RCD2
E94
478
In current setting on upstream RCD standardised rules (maximum): In = 5 A t = 1 s leakage-current IL withstand (min.): In 1.5 IL = 825 mA In = 1A
E94
479
Vigirex In t
Protection plans for different system earthing arrangementsApplications
TT system
300 mA
In2
In In x 1.5 = 450 mA In = 0.5 A
C60 VigiIf s 300 mA
COMBT13FR-11/02 45
In < 5 A
In < 10 A In < 5 A
Implementation In3 < = 5 A, In2 < = 10 A, In1 < min , = 5 A50 V10
50 V 5
5010
50 V 5
Standardised rule An RCD must be installed at the head of the installation and at thehead of each group of separately earthed exposed conductive parts Settings: current setting In < UL/RT
delay T < 1s
RCD 1RCD 2 RCD 3
RT RT RT
UL
Protection plans for different system earthing arrangementsApplications
RCD at the head
Basic principle
1 5 10
UL = 50 V
COMBT13FR-11/02 46
System leakage capacitance (µF) First-fault current1 70 mA5 360 mA30 2.17 A
Typical leakage currents following a first fault
Standardised ruleIEC 60364-5-53: The RCD current settings must be greater than twice the first-fault current
In setting300 mA1 A5 A
Protection plans for different system earthing arrangementsApplications
TT system
COMBT13FR-11/02 47
Leakage currents IL are due to the natural or intentional capacitances installed between the phases and earth cable leakage currents
Applications
E94
472
Differential-mode capacitance Common-mode capacitanceStandard cable (not shielded) 20 pF/m 150 pF/mShielded cable 30 pF/m 200 pF/m
leakage currents of computer equipment
requirement for RCD protection - an RCD must not trip for these natural currents, yet must protect life and property
Computer equipment Standard IEC 60950 Maximum leakage current (mA)All equipment 0.25
PC Type A fixed or mobile 3.5Computer room Type B fixed 3.5 or 5% In
Equipment
Load leakage currents
COMBT13FR-11/02 48
Implementation of RCDs
for RCDs protecting power outlets, In = 30 mA, IL must therefore not exceed 15 mA
Example. Maximum of 4 PCs per set of outlets
ID6330 mA
IL = 3.5 mAPC
E94
473
for RCDs upstream of a set of loads on a TT system
calculate current IL
RCD current setting In must be greater than 2 IL
check that In < UL / RT
E94
474
IL2 IL1
IL = m IL2 + n IL
xnxm
In?
ApplicationsLoad leakage currents
COMBT13FR-11/02 49
ApplicationsVigirex - installation of toroids
Recommendations centre the conductors respect the operational current In of the toroid, corresponding to a 30 mA operating threshold, on a 6 In overload
E94
484
Improve immunity to disturbances use a toroid with a larger diameter delay the protection function (< 1s) install a magnetic sleeveE
9452
3E
9452
4
< 15 mA
6 In
Toroid mounting on multi-conductor cable with PE run the PE back down through the toroid
COMBT13FR-11/02 50
Protection of motors (TN-S system)
a low insulation fault can cause a short-circuit an RCD with a current setting between 3 and 30 A avoids this risk
ApplicationsProtection of property
R
M
E94
458
MERLIN GERINVigirex
COMBT13FR-11/02 51
PEPEN
A
N
Monitored system
T
PEN
E94
481
N
PE PEPEN
A
N
Monitored system
T
PE
PEN
A
N
Monitored system
T
Toroid T measures all the fault currents downstream of A the neutral is not earthed downstream of A the system earthing arrangement is TT or TN-S TT/ RCD - MS a few A
TN-S RCD - BS / RS-type GFP a few 100 A Protection of life and property
Protecting downstream
ApplicationsProtection of property
COMBT13FR-11/02 52
E94
482PE source
NPEN
PE
ApplicationsProtection of property
Protecting upstream
COMBT13FR-11/02 53
PE amont
PEN amontN amont
PE
E94
482
Toroid T measures all the fault currents upstream of A the neutral is not earthed upstream of A the downstream system earthing arrangement is TN-S, the upstream
system earthing arrangement is TN-C
Monitored system
T
A
PE source
NPEN
PE
ApplicationsProtection of property
Protecting upstream
COMBT13FR-11/02 54
PE amont
PEN amontN amont
PE
E94
482
Monitored system
PEN
PE
T
A
ApplicationsProtection of property
Protecting upstream
COMBT13FR-11/02 55
E94
482
Monitored system
PE source
PEN
PE
T
A
RCD - BS / RS-type GFP The fault current is a few 100 A
ApplicationsProtection of property
Protecting upstream
COMBT13FR-11/02 56
PE amont
PEN amontN amont
PE
E94
482
Monitored system
PE source PE
T
A
2nd source
Protection and/or decoupling of sources
ApplicationsProtection of property
Protecting upstream
COMBT13FR-11/02 57
E94
482PE source
PEN
PET
AMonitored system
SGR
ApplicationsProtection of property
Protecting upstream
COMBT13FR-11/02 58
PE amont
PEN amontN amont
PE
E94
482
PEN
PET
AMonitored system
N
SGR
Note. SGR-type GFP measures the upstream and downstream currents
ApplicationsProtection of property
Protecting upstream
COMBT13FR-11/02 59
PE amont
PEN amontN amont
PE
E94
482
Toroid T measures all the fault currents upstream of A the neutral is not earthed upstream of A the downstream system earthing arrangement is TN-S, the upstream is TN-C
Monitored system
T
A
PE source
NPEN
PE
RCD - BS / RS-type GFPThe fault current is a few 100 A Nota : GFP de type SGR mesure les
courants amont et aval Protection and/or decoupling of sourcesNote. SGR-type GFP measures the upstream and downstream currents
ApplicationsProtection of property
Protecting upstream
COMBT13FR-11/02 60
Upstream system earthing arrangement is TN-C
L
N
PE
PENPE
R
Purpose protection of generators
Restricted Earth Fault (REF)
Unprotectedzone
Protectedzone
E94
483
Generator
Generatorshutdown
RS-type GFP or RCD - BS
ApplicationsProtection of property
COMBT13FR-11/02 61
L
N
PE
PENPE
R
PENPE
R
Generator no. 1
Purpose continuity of service (parallel-connected generators) elimination of a generator if an insulation fault occurs
E94
384
Unprotectedzone
Protectedzone
Generator no. 2
RS-type GFP or RCD - BS
Restricted Earth Fault (REF) - Multisource diagram
ApplicationsProtection of property