6670062 Indian Standard Specification for Power Transformers

7/31/2019 6670062 Indian Standard Specification for Power Transformers

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STANDARDS, SPCIFICATION OF

POWER TRANSFORMERSI.S2026 (Part I ) - 1977

The test basis for all characteristics, other than insulation, is the rated condition,

unless the test clause states otherwise.

Where it is required, test results shall be corrected to a reference temperature of 75C.

16.1.1 Type Tests The following shall constitute the type tests:

a) Measurement of winding resistance (16.2);

b) Measurement of voltage rafio and check of voltage vectorrelationship (16.3);

c) Measurement of impedance voltage/short-circuit impedance(principal tapping) and load loss (16.4);

d) Measurement of no-load loss and current (16.5);e) . '*f) Measurement of insulation resistance (16.6);

Dielectric tests (16.7);

g) Temperature-rise (16.8); and

Tests on on-load tap-changers, where appropriate (16.9).

16.1.2 Routine Tests The following shall constitute the routine tests:

a) Measurement of winding resistance (16.2);

b) Measurement of voltage ratio and check' of voltage vectorrelationship (16,3);

c) Measurement of impedance volt age/short-circuitimpedance (principaltapping) and load loss (16.4);

d) Measurement of no-load loss and current (16.5 );e) Measurement of insulation resistance (16.6);

Dielectric tests (16.7); andf) Tests on on-load tap-changers, where appropriate (16.9).

16.1.3 Special Tests The following tests shall be carried out by mutualagreement between the purchaser and the supplier:


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a) Dielectric tests (16.7);

b) Measurement of zero-sequence impedance of three-phase transformers (16.10);

c) Short-circuit test (16.11);

d) Measurement of acoustic noise level (16.12);Measurement of the harmonics of the no-load current (16.13);

e) andf) Measurement of the power taken by the fans and oil pumps

(16.14).16.1.3.1 If special tests other than those listed in 16.1.3 are required the test method

shall be subject to agreement between the manufacturer and thepurchaser.


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IS:2026 (Part I )-1977

If there is doubt or disagreement with regard to the result of tests or the

inspection of the untanked transformer, a detailed examination, including completedismantling of the unit is necessary. For category 1 transformers the complete

dismantling is necessary when the reactance measured after the tests differs more

than 2 percent from that measured in the original state. For the interpretation ofthis difference (if any ) with regard to transformers of categories 2 and 3

agreement between the manufacturer and the purchaser is needed.

16.11.6 Evaluation of the Results of Short-Circuit Tests The transformershall bedeemed to have withstood the short-circuit tests if the measurements and

inspections (untanked or dismantled) show no apparent defects (displacements,

deformations of windings, connections or supporting structures, or traces ofdischarge).

16.12 Measurement of Acoustic Noise Level The method of test and criteriafor conformity shall be agreed between the manufacturer and the purchaser.

16.13 Measurement of tbe Harmonics of the No-Load Current

The harmonics of the no-load current in all the phases are measured by rneans of

harmonic analyzer and the magnitude of the harmonics is expressed as a percentage

of the fundamental component.

16.14 Measurement of Power Taken by the Fans and Oil-Pumps

The method of test shall be agreed between the manufacturer and the purchaser the

Purchaser [see also 4.7 of IS: 2026 ( Part II )-1977* ].


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A P P E N D I X A

( Clause 12.1)

INFORMATION REQUIRED WITH ENQUIRY AND ORDER

A-l. RATING AND GENERAL DATA

A-l.l Two-Winding Transformers

A-l.1.1 Normal The following information should be given in all cases:

a) Particulars of the specification to be complied with;

b) Type of transformer, for example, separate winding transformer;autotransformer or booster transformer;

c) Single or polyphase unit;

'Specification for power transformers: Part II Temperature-rise (firstrevision ).

d) Number of phases in system;

e) Frequency;f) Dry-type or oil-immersed type. If oil-immersed, whether mineral

oil or synthetic insulating liquid;g) Indoor or outdoor type;h) Type of cooling;i) Rated power (in kVA) and, for tapping ranges exceeding 5

percent required power on extreme tappings; ^If-the transformer is to have different values of rated power for different typesof cooling, these should be stated.

j) Rated voltages ( for each winding);

k) State if tappings are required and if on-load or off-circuit tap-changers, orlinks are required. Give the information required as detailed in IS: 2026 (PartIV)-1977*;

l) Highest voltage for equipment (for each winding) [see alsoAppendix Cof IS: 2026 ( Part III )-1977f ];

m) Method of system earthing (for each winding );n) Insulation level (for each winding), power frequency -test level/ impulse level

[ see IS : 2026 (Part III )-1977f ];

o) Connection symbol; 'p) Neutral terminals, if required (for each winding) and their insulation

level to earth;q) Special requirements of installation, assembly, transport

and handling;

r) Details of auxiliary supply voltage (for fans, tap-changer,alarms, etc);s) Fittings required and an indication of the side from which meters,

rating plates, oil-level indicator, etc, may be readable.


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A-l.1.2 Special The following additional informationmay be required to be given:

a) If a lightning impulse voltage test is required, whether or not thetest is to include chopped waves [see IS : 2026 (Part III)-1977fJ;

b) Whether a stabilizing winding is required and, if so, the method of

earthing;c) Impedance voltage at rated current, if specific value is required;

'Specification for power transformers: Part IV Terminal markings, tapping andconnections (first revision ).

tSpccification for power transformers: Part III Insulation levels and dielectrictests (first revision J

d) Whether transformer is to be connected to a generator directly orthrough switchgear and whether it may be subjected to load &

rejection conditions;

e) Altitude above mean sea-level, if in excess of 1 000 m;

f) Special cooling conditions, for example, temperature of coolingmediumif above or below values given in 3, or restrictions to circulation ofcooling air;

g) Whether unbalanced loading is anticipated, and if so details;

h) Whether transformers will be subjected to frequent over currents, forexample, furnace transformers and traction feeding trans-formers ( see

8);i) Details of intended regular cyclic overloading other than coveredby 4.1

( to enable the ratings of the transformer auxiliary equipment to beestablished };

j) Any other exceptional service conditions;

k) Connections required, ex-works, in the case of the transformer havingalternative winding connections;

l) Val e of load and no-load losses, if specific values are required;m) Short-circuit characteristics of the system (see 8 and 9);

Whether noise level measurement is to be carried out;

n) Vacuum withstand of the transformer tank, if a specific value is required;

Type of tap-changer controls required;o) Water analysis in case of OFWF cooled transformers; and

p) Any other appropriate information, including reference to any specialtests not referred to above which may be required.


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A-1.2 Multi-Winding Transformers Generally as in A-l.l, butinformation in respect of the additional windings is required, and also:

a) required loading combinations, stating, when necessary, the activeand reactive outputs separately, especially in the case of multi-winding

auto-transformer; andb) any impedance voltages that are specified for particular pairs of windings.

A-2. PARALLEL OPERATION

A-2.1 If parallel operation with existing transformers is required, thisshouldbe stated and the following information given:

a) Rated kVA of existing transformers,

b) Rated voltage ratio,

c) Voltage ratios corresponding to tappings other than the principal tapping,

d) Load loss at rated current and rated voltage on the principal tappingcorrected to the appropriate reference temperature,

e) Impedance voltage at rated current (on the principal tapping),

f) Short-circuit impedances at least on the extreme tappings if the tappingrange of the tapped winding exceeds 5 percent, and

g) Diagram of connections and connection symbol.


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A P P E N D I X B

(Clause 13.1)

Schedule of technical particulars to be furnished by the manufacturer

B-L> STANDARDFORMOFTECHNICALPARTICULARS

1. Name of the manufacturer 2. Service

3. kVA rating:

a) HV winding kVA

b) IV winding kVA

c) LV winding kVA

4. Rated voltage:

a) HV winding kV

b) IV winding kV

c) LV winding

5. Rated frequency Hz

6.Number of phases7. Connections:

a)HV winding

bIV winding

c)LV winding18:2026 (Part I) -1977

8. Connection symbol [ see IS : 2026 ( Part IV )-1977*]:

a) HV-IVb) HV-LV

9. Tappings:a) Rangeb) Number of stepsc) For high voltage variation/For intermediate oltage variation/For

low voltage variation10. Reference ambient temperatures: .

a) Maximum ambient air temperature Cb) Maximum daily average ambient air C

temperaturec) Maximum yearly weighted average ambient C

temperatured) Minimum ambient air temperature C

, e) Maximum cooling water temperature C

11. Type of cooling [see IS: 2026 (Part II )-l&77f]

12. Temperature-rise [see IS: 2026 (Part II )-I977fJ:a) Top oil Cb) Windings C


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13. Total loss at rated voltage at principal tapping kWand rated frequency

14. Component losses:

a) No load loss at rated voltage on principal kWtapping and at rated frequency

b) Load loss at rated current at Principal kWtapping at 75C

15. Impedance voltage at rated current for the principaltapping:

a) HV-IV . percent

b) HV-LV , percent

c) IV-LV percent

Note Item 11 to 15 are guaranteed particulars and are subject to

tolerancet as specified in Table 7.

*Specification for power transformers: Part IV Terminal markingl, tappingsand connections (first revision ).

f Specification for power transformers: Part II Temperature rise (first revision ).

16. Reactance at rated current and rated frequency:a) HV IV Percentb) HV LV Percent

c) IV LV Percent

17. No load current at rated voltage and rated frequency Percent

18. Input to cooling plant kW

19. Insulation level [see IS: 2026 (Part III )-1977*]:

a) Separate source power-frequency voltage withstand:i) HV winding kV rms

ii) IV winding kV rmsiii) LV winding kV rms

b) Induced overvoltage withstand:i) HV winding kV rmsii) IV winding kV rms

iii) LV winding kV rms

c) Full wave lightning impulse withstand voltage:

i) HV winding kV peak

ii) IV winding kV Peak

iii) LV winding kV Peak


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d) Switching impulse withstand voltage:

i) HV winding kV peakii) IV winding kV peak

iii) LV winding kV peak

20. Stabilizing/Tertiary winding:a) Rated voltage kVb) Normal rating kVA

c)Normal rating (expressed main winding rating in thecase of stabilizing winding)

Percent

d) Delta closed inside/outside (In the case of stabilizing winding)

21. Efficiencies at 75G at unity power factor:a) At full load percentb) At 3/4 full load percentc) At 1/2 full load percent

22. Regulation at full load at 75"G:a) At unity power factor percentb) At 0'8 power factor lagging percent

23. Equipment for ONAN or ONAF/ONAN Cooling: ,a) State:

i) Radiators on main tankii) Separate cooler bank

b) State ON AN rating in case of mixed cooling

24. Equipment for OFAF/ODAF cooling:a) State:

i) Radiator bank * . . . . . .ii) Separate enclosed type coolers

b) State OFAN/ODAN, ONAF, ONAN rating (kVA) whichever is/areapplicable in case of mixed cooling:i) OFAN/ODAN ii) ONAF iii) ONAN

25. Number of coolers or cooler banks per transformer.

26. Rating of each cooler or cooler bank

27. In case of OFF circuit voltage variation, state (a) or (b):a) Off circuit tap switchb) Off circuit links

28. Details of on-load tap-changer:a) Make


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b) Typec) Rating:

i) Rated voltageii) Rated current - !Siii) Step voltageiv) Number of steps

d) Controle) Auxiliary supply detailsf) Voltage controlg) Parallel operationh) Protective devicesj) Approximate overall weightk) Approximate overall dimensions

m) Approximate overall quantity of oil

note The information against (j), (k) and (m) is required in case of separatelymounted and handled tap-changers.

29. Terminal arrangement:

a) High voltageb) Intermediate voltage .c) Low voltage ..d) Neutral

30. Approximate masses:

a) Gore and windings kgb) Tank, fittings and accessoriesc) Oild) Total mass

31. Approximate quantity of oil required for firstfilling

32. Approximate overall demensions:

a) Length mmb) Breadth mmc) Height mm

33. Despatch details:

a) Approximate mass of heaviest package kg

b) Approximate dimensions of largest package:

i) Length mm

ii) Breadth mmiii) Height mm

34. Untanking height mm

35. Reference standards

kgm

kgkgkglitre


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A P P E N D I X C( Clause 14.1 )

FITTINGS

C-l. The fittings as given below shall be provided:

SI No. Item

1. Inspection cover

2. Rating plate

3. Terminal-marking plate

4. Two earthing terminals5. Lifting lugs

Transformers to Which Fitted

Above 1 600 kVA All

All

All

All

6. Drain valve with plug or cover plate 25 kVA andabove

7. Dehydrating breather

8. Oil-level indicator with

minimum9. Marking

10.Thermometer pocket

11. Oil-filling bole wi ih cover

12.Conservator

13.Air release device

14.Jacking lugs ,,15.Filter valve

When filter valves are required,the drain valve should be usedas one of these


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25 kVA and above for ratedvoltage 11 kV and below,and all ratings above 11 kV

All

All

All

50 kVA and above for ratedvoltage 11 kV and below,and all ratings above 11 kV

All transformers fitted withconservators

Above 1 600 kVA

Above 1 600 kVA


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C-2. The additional fittings as given below may beprovided, if ordered:

St ,Vo. Item1. Filter valves

2. Rollers

3. Thermometer

4. Additional thermometer pockets

5. Winding temperature indicator

6. Explosion vent

7. Gas- and oil-actuated relay

8. Skids

9. Inspection cover

RemarksI 600 WA and below

Details of rollers to be stated withenquiry or order

Type to be stated with enquiryor order

To be stated with enquiry ororder

Details of requirments to be statedwith enquiry or order

Details to be stated

Type to be stated

1 600 kVA and below


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IS : 2026 (Part II) - 1977

1. SCOPE

1.1 This standard (Part II) covers temperature-rise requirements of. power transformers.

2. IDENTIFICATION ACCORDING TO COOLING METHOD2.1 Identification Symbols Transformers shall be identified accordingto the cooling method employed. Letter symbols for use inconnection with each cooling method shall be as given in Table 1.

NOTE In transformers with forced directed oil circulation a certain proportion ofthe forced oil flow is channelled so as to pass through the windings. Certainwindings, however, may have a non-directed oil flow, for instance, separatetapping windings,auxiliary windings and stabilizing windings.

TABLE 1 LETTER SYMBOLS

(Clause 2.1)

i) Kind of Cooling Medium Symbola)Mineral oil or equivalent flammahle synthetic O. insulating liquid

-, b)Non-flammable synthetic insulating liquid L

c)Gas : Gd) Water We) Air A

ii) Kind of Circulationa) Natural Nb) Forced (oil not directed) F

c) Forced (directed oil) D

2.2 Arrangement of Symbols Transformers shall be identified by foursymbols for each cooling method for which a rating is assigned by themanufacturer.

2.2.1 Dry-type transformers without protective enclosures are identified by twosymbols only for the cooling medium that is in contact with the windings of thesurface "coating of windings with an overall coating (for example, epoxy resin).

2.2.2 The order in which the symbols are used shall" be as given in Table 2.Oblique strokes shall be used to separate the group symbols * for differentcooling methods.|

2.2.3 For example, an oil-immersed transformer with forced directed oilcirculation and forced air circulation shall be designated ODAF.

2.2.4 For oil-immersed transformers in which the alternatives of natural orforced cooling with non-directed oil flow are possible, typical designations are :

ONAN/ONAF ONAN/OFAF


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2.2.5 The cooling method of a dry-type transformer without a protectiveenclosure or with a ventilated enclosure and with natural air cooling isdesignated by :

AN2.2.6 For a dry-type transformer in a non-ventilated protectiveenclosure with natural air cooling inside and outside the enclosure thedesignation is :

ANAN

TABLE 2 ORDER OF SYMBOLS

(Clause 2.2.2)

Ist Letter 2nd Letter 3rd Letter 4th Letter

Kind of coolingmediumindicating thecooling mediumthat is in contactwith the winding

Kind of circulation

Kind of coolingmediumindicating thecooling mediumthat is in contactwith the externalcooling systems

Kind of circulation

3. LIMITS OF TEMPERATURE-RISE

3.1 Normal Temperature-Rise Limits The temperature-rises of the

windings, cores and oil, of transformers designed for operation at" altitudes not exceeding those given in 3 of IS : 2026 (Part I)-1977* and9 with cooling medium temperatures as described in 3 of IS : 2026 (Part I)-1977* shall not exceed the limits specified in Tables 3 and 4when tested in accordance with 4.

3.1.1 The method of verification of the forced directed oil flow shall be subject toagreement between the manufacturer and the purchaser,normally at the time of tender.

3.1.2 The temperature-rises of transformers immersed in non-flammable synthetic insulating liquids and using insulating materialswhose temperature classes are different from A may be raised by an amount

to be agreed by manufacturer and purchaser.3.1.3 In certain types of transformers with concentric windings andvertical axes of core and windings two or more windings can be arrangedone above the other. If these windings are identical, thearithmetic mean value of their temperature-rises shall not exceed thepermissible temperature-rises given in Tables 3 and 4. If the windings

*Specification for power transformers: Part I General


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INSTRUMENT TRANSFORMERS

Instrument Transformers are primarily used to provideisolation between the main Primary Circuit and theSecondary Control and measuring Devices.Secondarily they reduce levels in magnitudes to saferlimits

The isolation between the two is achieved bymagnetically coupling the two circuits

Instrument transformers are divided in toa) Voltage transformers OR Potential transformersb) Current transformers

Voltage transformer ratingsThe Voltage ratios aregenerally

Primary Voltage/ 3110V /3

Specified I.S is IS 3156 different Voltage transformersa) Single Phase Voltage Transformerb) Three Phase Voltage Transformerc) Residual Voltage Transformerd) Capacitor Voltage Transformer


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TERMINOLOGY

3.0 For the purpose of this standard, the following definitions shall apply.

3.1 Instrument Transformer

A transformer intended to supply measuring instruments, meters, relaysand other similar apparatus.

3.2 Current Transformer

An instrument transformer in which the secondary current, in normalconditions of use, is substantially proportional to the primary current anddiffers in phase from it by an angle which is approximately zero for anappropriate direction of the connections.

3.2.1 Current Transformer ( Wound Type )

A current transformer having a primary winding of more than one full turnwound on the core (s).

3.2.2 Current Transformer ( Bar Type )

A current transformer in which the primary winding consists of a bar ofsuitable size and material forming an integral part of the current transformer.

3.2.3 Current Transformer ( Dry Type )

A current transformer which does not require the use of any liquid or semi-liquid material.

3.2.4 Current Transformer ( Liquid Immersed )

A current transformer which requires the use of oil or other suitable liquid ofsuitable characteristics as insulating and/or cooling medium.

3.2.5 Hermetically Sealed Current Transformer

A liquid immersed current transformer which is sealed and does notcommunicate with atmospheric air.

3.2.6 Current Transformer (Ring Type )

A current transformer which has an opening in the center to accommodate aprimary conductor through it.

3.2.7 Multi-Core Current Transformers

A current transformer having more than one secondary core and winding with

a common primary winding.3.2.8 Multi-Ratio Current Transformer

A current transformer in which more than one ratio is obtainable byreconnection, or tappings, in primary or secondary windings.

3.3 Measuring Current Transformer

A current transformer intended to supply indicating instruments, integratingmeters and similar apparatus.


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3.4 Protective Current Transformer

A current transformer intended to supply protective relays and similarapparatus.

3.5 Dual Purpose Current Transformer

A current transformer intended to serve the dual purposes of measuring andprotection.

3.6 Primary Winding

The winding through which flows the current to be transformed.

3.7 Secondary Winding

The winding which supplies the current circuits of measuring instruments,meters, relays or similar apparatus.

3.8 Secondary Circuit

The external circuit supplied by the secondary winding of a currenttransformer.

3.9 Rated Primary Current

The value of the primary current which appears in the designation of thetransformer and on which the performance of the current transformer isbased.

3.10 Rated Secondary Current

The value of the secondary current which appears in the designation of thetransformer and on which the performance of the transformer is based.

3.11 Actual Transformation RatioThe ratio of the actual primary current to theactual secondary current.

3.12 Rated Transformation Ratio

The ratio of the rated primary current to the rated secondary current.


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3.13 Current Error (Ratio Error)

The error with a transformer introduces into the measurement of a current andwhich arises from the fact that the actual transformation ratio is not equal to therated transformation ratio.

The current error expressed in percent is given by the formula:

Current error, Percent = ( K a . Is - Ip ) x 100 / Ip

whereKa = rated transformation ratio,Ip = actual primary current, and

/s = actual secondary current when Ip is flowing under the conditions of

measurement.3.14 Phase Displacement

The difference in phase between the primary and secondary current vectors, thedirection of the vectors being so chosen that the angle is zero for a perfecttransformer. The phase displacement is said to be positive when the secondarycurrent vector leads the primary current vector. It is usually expressed in minutes.

NOTE This definition is strictly correct for sinusoidal currents only.

3.15 Accuracy Class

A designation assigned to a current transformer the errors of which remain withinspecified limits under prescribed conditions of use.


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Table 1A Rated Insulation Levels for Highest System Voltages Up to andIncluding 72.5 Kv

NominalSystemVoltage

HighestSystemVoltage

PowerFrequencyWithstandVoltage

Lightning Impulse withstandVoltage

(1) (2) (3) (4) (5)

kV( rms) kV( rms) kV( rms) kV( rms) kV( peak)

List 1 List 2

Up to

0.6 0.66 3

3.3 3.6 10 20 406.6 7.2 20 40 60

11 12.0 28 60 75

15 17.5 38 75 95

22 24.0 50 95 125

33 36.0 70 145 170

45 52.0 95 250 250

66 72.5 140 325 325

Notes

1 Underlined values are preferred.2 The choice between Lists 1 and 2 should be made by considering the degreeof exposure to lightning and switching overvoltages, the type of system neutralearthing and the kind of the overvoltage protection. Some guidance is given inIS 2165 (Part 1): 1977.


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Table 2 Limits of Temperature-Rise of Windings

( Clauses 7.2.1, 7.2.1.1, 7.2.1.2 and7.2,4 )

Class of Insulation Maximum Temperature - Rise

(1) (2)

(k)

All Classes immersed in oil 55

All classes immersed in oil andhermetically sealed

60

All classes immersed in bituminous

compound

45

Classes not immersed in oil orbituminous compound

Y 40

A 55

E 70

B 80

F 105

H 130

NOTE For some materials (such as epoxy resin) the manufacturer shouldspecify the relevant insulation class.


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9 TESTS

9.1 Classification of Tests9.1.1 Type Tests ''*The following shall constitute the type tests:

a) Short-time current tests

b) Temperature-rise test.

c) Lightning impulse test for current transformers for service in electricallyexposed installation

d) Switching impulse voltage tests for current transformers of 420 kV andabove

e) High voltage power-frequency wet withstand voltage tests on outdoor

current transformers up to and including 245 kVNOTE If the porcelain weather casing/bushing has been subjected tothis test separately, the requirements of this test shall be deemed to havebeen complied with.

f) Determination of errors or other characteristics according to therequirements of the appropriate designation or accuracy class

NOTES

1 The dielectric type tests in (c), (d) and (e) shall all be carried out on thesame transformer unless otherwise agreed.


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9.1.2 Routine Tests

The following shall constitute the routine tests:a) Verification of terminal marking and polarity ( see 9.2 ).

b) Power frequency dry withstand tests on primary windings ( see 9.3 ).

c) Power frequency dry withstand tests on secondary windings ( see 9.4 ).

d) Over-voltage inter-turn test ( see 9.5 ),

e) Partial discharge tests in accordance with IS 11322 :1985.

NOTE This test is applicable only for current transformers with solid

insulation for highest system voltages 7.2 kV and above and currenttransformers with liquid immersed insulation for highest system voltages of

72.5 kV and above.

f) Determination of errors or other characteristics according to the

requirements of the appropriate designation or accuracy class ( see

individual parts of this standard ).

NOTES

1 The determination of errors or other characteristics in (e) shall be carried outafter the tests (b), (c) and (d). The order or possible combination of other tests is

not standardized.

2 Repeated power frequency tests on the primary

windings shall be performed at 80 percent of the

specified test voltage, except when the method of 9.3.2.2

is used.


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Limits of Voltage Errors and Phase Displacement

Class Percentage Voltage

(Ratio Errors

Phase Displacement

( Minutes)(1) (2) (3)0-1 0.1 50-2 0.2 100-5 0.5 201-0 1.0 403 3.0 -


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LIMITS OF VOLTAGE ERROR AND PHASE DISPLACEMENT FORPROTECTIVE VOLTAGE TRANSFORMERS

5.1 The Voltage error and phase displacement at rated frequency shall notexceed the values in Table 1 at 5% rated voltage, and at rated voltagemultiplied by the rated voltage factor (1.2, 1.5 or 1.9) with burdens ofbetween 25% and 100% of rated burded at a power factor of 0.8lagging.

5.2 At present of the rated voltage, the limits of error and phasedisplacement with burdens of between 25% and 100% of ratedburded at a power factor of 0.8 lagging shall be twice as high asthose given in Table

Limits of Voltage error and phase displacement

Accuracy Class Percentage VoltageError

Phase Displacement

(1) (2) (3)

3P 3.0 120

6P 6.0 240

Table 2 Limits of Voltage Error and Phase


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Displacement for Residual VoltageTransformers

( Clauses &.2 and10.2.1.1 )

Accuracy Class Voltage Error Phase Displacement

(1) (2) (3)

Percent minutes

5 PR 5-0 200

10 PR IO'0 600


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Schedule Of Guaranteed Technical Particulars Of ,12Kv, 12Kv ,800/1250, 25KA Indoor Metalclad Vacuum Circuit Breaker

S.NO DESCRIPTION DETAILS

i Manufacturer's type designation WMS 12/1250

2 Applicable technical standards I.E.C 62271-100, I.E.C

3 Type of breaker offered Indoor Draw out typeMetal clad VCB

4 Rated voltage(kV) 12

5 Rated frequency(Hz) 50

6 Number of poles Three

7 Class(indoor/outdoor) Indoor

8 Rated normal current

(a) Under site conditions(Amps) 800/1250

(b) Rated current (Amps) 800/1250

9 Rated short circuit breaking current(a) rms value of A.C. component of ratedshort circuit current (kA)

25

(b) percentage of D.C. component 45

10 Rated short circuit making current (kAp) 62.5

11 First pole to clear factor 1.5

12 Rated operating sequence O-0.3sec-CO-3min-CO

13 Rated duration of short circuit(sec) Upto3

14 Rated out of phase breaking current (kA) 6.25


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15 Opening tune (ms) 35 +/- 5

16 Short time current rating for 3 seconds 25 kA rms with 62.5

17 Arcing tune (ms)

(a) At 100% rated breaking current(ms) 8-11

(b)At 50% rated breaking current (ms) 9-10

(c) At 25% rated breaking current (ms) 6-8

(d) At 10% rated breaking current(ms) 5-6

18 Total Break Time(ms)

(a) At 100% rated breaking current (ms) 47-49

(b)At 50% rated breaking current (ms) 50

(c) At 25% rated breaking current (ms) 48

(d) At 10% rated breaking current (ms) 45

19 Closing time (ms) 45 +/- 5

20 Minimum reclosing time at ratedinterruption capacity from the instant of tripcoil energisation (ms)

300

21 Minimum dead time for reclosing (ms) 250

22 Elated shunt capacitor bank switching capacity(single bank) in Amps

400

23 Max. Rise of temperature over ambient (C) 58

24 Length of contact travel (mm) 6-8

25 Rate of contact travel

a) At tripping(meters/sec) 0.8 to 1


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(b) At closing (meters/sec): 0.7 to 0.9

26 Type of main contact Butt type

27 Material of the contact

(a), main contacts Copper-Chromium

(b). whether contacts are silver coated No

(c). Contact pressure (Kg/sq.mm) 230

28 Insulation level of the breaker

(a) 1 minute power frequency withstand

voltage

28

(b) Impulse withstand test voltage (kV peak) 75

29 Minimum clearances

(a) Between phases(live parts) (mm) 130

(b) Between live parts and Earth (mm) 120

(c) Centre to centre distance between

phases (mm)

190

30 Whether circuit breaker is fixed trip or tripfree

Trip free

31 Method of closing

(a) Normal Shunt release

(b) Emergency Manual

32 Type of closing mechanism Motor wound spring33 Normal voltage of closing pick up range 220/110/48/30

34 (a)Power at normal voltage of closingmechanism (watt)

200


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35 (b)Power at 85% of normal voltage,(watts) 144.5

36 Type of tripping mechanism Toggle trip

37 Normal voltage of tripping coils (volts) 220/110/48/30

(a)Power at normal voltage for trippingcoils(watts) (b)Power at 70% normalvoltage for tripping coil(watt)

200 98

38 Recovery voltage when circuit breakerstested at 100% rated

6.9

39 Rate of rise of restriking voltage at breaking

(a) for 30% breaking capacity,( kV/Micro 1.7

(b) for 100% breaking capacity, (kV/Micro 0.34

40 No. of openings circuit breakers is capableof performing without inspection,replacement of contacts or other mainparts

^a) at 50% rated current >20000

(b) at 100% rated current 10000

^c) at current corresponding to 50% ratedbreaking capacity

200 to 400

(d) at current corresponding to 100% ratedbreaking capacity

100

41 Weight of complete circuit breaker(kg) 850

42 [mpact loading for foundation design toinclude dead load plus impact value onopening at maximum interrupting ratings,in terms of equivalent static load (kg)

1700


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43 Overall dimensions

a) Height (mm) 1253

(b) Width (mm) 630

c) Length (mm) 1562

44 Spring charging motor rating 220 V, AC/DC,250watts

45 Busbar material Copper

46 Busbar cross sectional area (a) For 800Amps b) For 1250 Amps

80x8 2 bars of 80x8

47 Busbar insulation Heat shrinkable PVC

48 Power required for heater(watts) 80

49 Whether heater is continuously rated yes

Specifications Of Vacuum Interrupter

Type VS12014 (B14) HELICOIL

Electrical data:

1 Rated voltage (50/60Hz) 12 kVrms

2 Rated normal current 2000 kArms3 Rated short circuit breaking current 26.3 kArms

4 Rated peak short circuit making current 67 kApeak

5 Rated peak withstand current 67 kApeak

6 Rated short time withstand current 26.3 Arms


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7 Single capacitor Breaking currentca abilit

400 Arms

8 Applicable standard IEC 62271-100(2001)

Rated insulation level:1 Rated power frequency withstand

voltage- 1 min36 kVrms

2 Rated lightning impulse withstandvoltage

95 kVpeak

Thermal data:

1 Resistance at min closing force(newcondition)

17+/-20%

Micro ohms

2 Max temperature at movablestem(terminal) 105 C

Electrical life:

1 At rated normal current 20000 operations

2 At rated short circuit current 100 operations

Mechanical data:

1 Contact stroke 6+1-1 mm

2 Max over travel 2 mm

3 Average opening speed ( 0 to 60% 0.7 to 1.2 m/s

4 Average closing speed (40% to 0.4 to 0.8 m/s

5 Max. bouncing duration 2 ms

6 Min closing force 2000 N

7 Max closing force 2600 N

8 Closing force due to bellows andatmosphere

100 N

9 Force required to hold contact open atfull stroke 110+/-10% N

10 Mass of moving contact 1.3 Kg

11 Mass of interrupter 3.8 Kg

12 Contact erosion limit 3 mm


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13 Mechanical life 30000 operations

Schedule Of Guaranteed Technical Particulars Of 12 KV,800/1250,25KA Outdoor Porcelain Clad Vacuum Circuit Breaker

S.NO Description Details

i Manufacturer's type designation WPS 12/1250

2 Applicable technical standards I.E.C 62271-100 &

3 Type of breaker offered Outdoor fixed Type

4 Rated voltage(kV) 12

5 Rated frequency(Hz) 50

6 Number of poles Three

7 Class(indoor/outdoor) Outdoor

8 Rated normal current

(a) Under site conditions(Amps) 800/1250

(c) Rated current (Amps) 800/1250

9 Rated short circuit breaking current

(a) rms value of A.C. component of rated shortcircuit current (kA)

25

(b) percentage of D.C, component 45

10 Rated short circuit making current (kA) 62.5

11 First pole to clear factor 1.5

12 Rated operating sequence O - 0.3sec - CO -13 Rated duration of short circuit(sec) Up to 3

14 Rated out of phase breaking current (kA) 6.25

15 Opening time (ms) 35 +/- 5


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16 Short time current rating for 3 seconds 25 kA rms with 62.5kA

17 Arcing tune (ms)

(a) At 100% rated breaking current(ms) 8-11(b)At 50% rated breaking current imsl 7-8

(c) At 25% rated breaking current (ms) 6-7

(d) At 10% rated breaking current(ms) 5-6

18 Total Break Time(ms)

(a) At 100% rated breaking current (ms) 48

(b)At 50% rated breaking current (ms) 46-47

(c) At 25% rated breaking current (ms) 45

(d) At 10% rated breaking current (ms) 44

19 Closing tune (ms) 45 +/- 5

20 Minimum reclosing time at rated interruptioncapacity from the instant of trip coil energisation

300

21 Minimum dead time for reclosing (ms) 250

22 Rated shunt capacitor bank switching capacity 400

23 Max. Rise of temperature over ambient (C) 55

24 Length of contact travel (mm) 6-8

25 Rate of contact travel

(a) At tripping(meters/sec) 0.8 to 1

(b) At closing (meters/sec): 0.7 to 0.9

26 Tvpe of main contact Butt type

27 Material of the contact

(a), main contacts Copper-Chromium

(b). whether contacts are silver coated No

(c). Contact pressure (Kg/sq.mm) 230

28 Insulation level of the breaker

(a) 1 minute power frequency withstand voltage(kVrms)

28


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(b) Impulse withstand test voltage (kV peak) 75

29 Minimum clearances

(a) Between phasesdive parts) ( mm) 300

(b) Between live parts and Earth (mm)(c) Centre to centre distance betweeirphases 500

30 Whether circuit breaker is fixed trip or trip free Trip free

31 Method of closing

(a) Normal Shunt release

(b) Emergency Manual

32 Type of closing mechanism Motor wound spring

33 Normal voltage of closing pick up range (volts) 220/110/48/30

34 (a)Power at normal voltage of closing mechanism(watt)

200

35 (bJPower at 85% of normal voltage,(watts) 144.5

36 Type of tripping mechanism Toggle trip

37 Normal voltage of tripping coils (volts) 220/110/48/30

(a)Power at normal voltage for tripping coils(watts)(b)Power at 70% normal voltage for tripping

coil(watt)

200 98

38 Recovery voltage when circuit breakers tested at100%

6.9

39 Rate of rise of restriking voltage at breaking

(a) for 30% breaking capacity,( kV/Microsecs) 1.7

(b) for 100% breaking capacity, ( kV/Microsecs) 0.34

40 No. of openings circuit breakers is capable of

performing without inspection, replacement ofcontacts or other main parts (a) at 50% ratedcurrent

>20000

(b) at 100% rated current 10000


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(c) at current corresponding to 50% rated breaking 200 to 400

(d) at current corresponding to 100% ratedbreaking

100

41 Weight of complete circuit breaker(kg) 80042 tmpact loading for foundation design to include

dead load plus impact value on opening atmaximum interrupting ratings, in terms ofequivalent static load (kg)

1600

43 Overall dimensions

(a) Height (mm) 3350 +/-5

(b) Width (mm) 380 +/-5(c) Length (mm) 1360+/-10

44 Spring charging motor rating 220V, AC/DC,

Specifications Of Vacuum Interrupter TypeVS 12014 (B14) HELICOIL

Electrical data:

1 Rated voltage (50/60Hz) 12 kVrms

2 Rated normal current 2000 kArms

3 Rated short circuit breaking current 26.3 kArms


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4 Rated peak short circuit making current 67 kApeak

5 Rated peak withstand current 67 kApeak

6 Rated short time withstand current 26.3 Arms

7 Single capacitor Breaking currentcapability 400 Arms

8 Applicable standard IEC 62271-100(2001)

Rated insulation level:

1 Rated power frequency withstand voltage-1 min

36 kVrms

2 Rated lightning impulse withstand voltage 95 kVpeak

Thermal data:

1 Resistance at min closingjbrce(newcondition^

17+7-20% Microohms

2 Max temperature at movablestem(terminal)

105 C

Electrical life:

1 At rated normal current 20000 operations

2 At rated short circuit current 100 OperationsMechanical data:

1 Contact stroke 6+7- 1 mm

2 Max over travel 2 mm

3 Average opening speed ( 0 to 60% stroke) 0.7 to 1.2 m/s

4 Averace closine soeed (40% to contact 0.4 to 0.8 m/s

5 Max. bouncing duration 2 ms

6 Min closing force 2000 N7 Max closing force 2600 N

8 Closing force due to bellows andatmosphere

100 N

9 Force required to hold contact open at full 110+7- N


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10 Mass of moving contact 1.3 Kg

11 Mass of interrupter 3.8 Kg

12 Contact erosion limit 3 mm

13 Mechanical life 30000 operations

Documents

6670062 Indian Standard Specification for Power Transformers