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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