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SPEC. No. TI/SPC/PSI/LVCBIN/0120

DRAFT

GOVERNMENT OF INDIA

MINISTRY OF RAILWAYS

SPECFICATIONS FOR

OUTDOOR 22/25 KV SP/DP/POLE MOUNTEDVACUUM CIRCUIT BREAKER & INTERRUPTER

FOR RAILWAY ac TRACTION SUB-STATIONS /SPs /SSPs/2x25KV AT FEEDING SYSTEM

SPECIFICATION No. T I / / SPC/ PSI / LV CB I N / 0 1 2 0

ISSUED BYTraction Installation Directorate

RESEARCH DESIGNS AND STANDARDS ORGANIZATION

Manak Nagar, Lucknow-226011(India)(R.D.S.O.)

GOVERNMENT OF INDIA

MINISTRY OF RAILWAYS

LUCKNOW 226 011

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ANNEXURES & APPENDIX

ANNEXURE-A SCHEDULE OF GUARANTEED PERFORMANCE TECHNICAL ANDOTHER PARTICULARS.

ANNEXURE-B INFORMATION TO BE FURNISHED BY MANUFACTURER /SUPPLIER.

ANNEXURE-I DRAWING FOR GENERAL SCHEME OF POWER SUPPLY FORTRACTION SUB-STATIONS. DRAWING NO.ETI/PSI/702 (MOD.

B)ANNEXURE-II TERMINAL CONNECTOR DRAWING NO. ETI/PSI/11060.(MOD.E)

ANNEXURE-III TERMINAL CONNECTOR DRAWING NO. ETI/PSI/11030.(MOD.C)

ANNEXURE-IV DRAWING NO. ETI/PSI/SK/5214 INTERLOCKING SCHEMEFOR 25kV CB.

ANNEXURE-V DRAWING NO. ETI/PSI/ 5212 (MOD. B) (FOR 132KvINTERLOCKING SCHEME).

ANNEXURE-VI DRAWING NO. ETI/PSI/SK/334 LOCK & KEYFOR 25kV CB.

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22/25 KV OUTDOOR VACUUM CIRCUIT BREAKER & INTERRUPTER

For RAILWAY ac TRACTION SUB-STATION/SPs /SSPs/

2x25KV AT FEEDING SYSTEM

1. Scope

1.1 This specification applies to Outdoor Type Single Pole, Double Pole & PoleMounted Vacuum Circuit Breakers and Interrupters for use in Unattended /attended Railway Traction Sub- Stations / SPs / SSPs in any part of India forcontrolling Power Supply to the 25kV ac 50 Hz Single Phase/ 2 X 25kV ATFeeding System for Traction Overhead Equipment (OHE).The followingSpecification supersedes:-

Sl.No. Specification No Description

(i)ETI / PSI /167 ( 9/ 97 ) withA&C Slip 1-2

25kV, SP Outdoor Interrupter

(ii)TI/SPC/PSI /CB/0000 withA&C Slip 1-5

Outdoor Circuit Breakers

(iii)TI /SPC / PSI/ ACINT/0040 25KV,SP Outdoor Vacuum

Interrupter with MagneticActuated Operating Mechanism

(iv) TI /PSI/93(5/94) 25kV, SP SF6 Circuit Breaker

(v) ETI/PSI/46(9/94 25kV, SP Vacuum Circuit Breaker

(vi)

ETI PSI 131(8/89) 25KV,DP, Outdoor SF6 Circuit

Breaker for 2x25 KV AT FeedingSystem

(vii)ETI/PSI/132 (8/ 89) 25KV, DP Outdoor Vacuum

Interrupter for 2x25 KV ATFeeding System

(viii)ETI /PSI /139 (12/89)withA&C Slip No.1-4

25KV,DP, Outdoor SF6Interrupter for 2x25 KV ATFeeding System

(ix)ETI / PSI /159 ( 10 / 94 25KV, SP Outdoor Pole Mounted

Vacuum Interrupter

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This specification shall also apply for 2 X 22 kV two poles VCB for MumbaiArea of Central and Western Railway ac Traction System.

1.2 The Circuit Breaker / Interrupter shall be complete with all parts, fittings,Vacuum Bottle and accessories necessary for its efficient operation,including Mounting Frame work of steel. All such parts, fittings andaccessories shall be deemed to be within the scope of this specification,whether specifically Mentioned or not. The CB /Interrupter shall be proven

design.1.3 The Circuit Breaker / Interrupter shall be erected by the Purchaser / Indian

Railways. However, in case a defect / deficiency are noticed, themanufacturer / successful tenderer will have to depute his Engineer fornecessary remedial action without any cost to the Railways. In all the casesin which an order is placed either on new Manufacturer or for a new type/design of the Circuit Breaker / Interrupter , the services of ManufacturesEngineer shall be made available free of cost during the erection andproving / pre-commissioning test for the first order of their Circuit Breaker /Interrupter. For this purpose, prior intimation regarding the date and thelocation shall be given by the purchaser to the successful tenderer /manufacturer.

2.0 Governing Specification

2.1 The CB / Interrupter shall unless otherwise specified herein, conform tothe IEC 62271-100, IEC600694, IEC 600265-II High Voltage ac CircuitBreaker / Interrupter and the Indian Electricity Rules, wherever applicable.

2.1.1 In the preparation of this specification, assistance has been derived from thefollowing Standards:

SL.No. IS/IEC/RDSOSpecification

Description

(1) IEC: 62271-100 High voltage alternating current circuitbreakers

(2) IEC: 60694(1980) Common clauses for high voltageSwitchgear and Control gear Standards.

(3) IS: 456(1978) Code of Practice for plain and reinforcedConcrete.

(4) IS: 996(1979 Specification for single phase small ac andUniversal Electric Motors.

(5) IS: 2099(1973) Specification for bushing for alternatingVoltages above 1000V

(6) IS: 2544(1979) Specification for Porcelain Post Insulatorsfor System with nominal voltages greater

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Than 1000V.(7) IS: 5561(1978) Specification for Electric Power

Connectors.

(8) IS: 5621(1980) Specification for hollow insulators forUse In Electric equipment.

(9) IS:6875(Pt.I-1973) Specification for Control Switches(Switching Device Control and AuxiliaryCircuits including contactor Relay) forVoltages up to and including 1000V ac and1200dc-General requirements and Tests

(10) IS: 7906(Pt. I-1976) Specification for Helical Extension Springs

(11) IS: 7907(Pt. I-1976) Specification for Helical Extension springs(12) IS: 13118(1991) Specification for high voltage alternatingCurrent Circuit Breakers.

(13)

IS: 1554(Pt. V-1988 Specification for PVC Insulated (heavy

duty)Electrical Cables for workingVoltage Up to including 1100V.

14) IS: 808(1989) Dimension for hot rolled steel beam,Column Channel and angle sections.

(15) IS: 2147(1962) Degree of protection provided byEnclosures for low voltage switchgear

(16) RDSO SpecificationNO.ETI/OHE/13(4/84)

For Hot Dip Galvanization

(17) RDSO SpecificationNo.ETI/OHE/18(4/84)

For Steel and Stainless Steel Bolts,Nutsand Washers

(18) RDSO SpecificationNo. M&C/PCN-102/86

For Epoxy Bases Zinc Phosphate Primer(Two Pack)

(19) RDSO SpecificationNo. M&C/PCN-110/88

For Aluminum paints based onPolyurethane

(20) IEC:265-II High Voltage Switches for rated voltage of

52 kV and above

(21) IS 9920 Specification for alternating currentSwitches above 1000 V

(22) IS 2633 (1972 Method of Testing uniformity of ZincCoated articles

(23) AC Traction manual (Issued in 1994)

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2.2 Any deviation from this specification as proposed by the tendererto improve upon the performance, utility and efficiency of theEquipment will be given due consideration, provided full particulars ofthe deviation with justification thereof are furnished; subject to approval ofRDSO. In case of any contradiction between the provision of the IndianStandards Specification/ IEC standards and this specification, the lattershall prevail.

2.3 This Specification is framed merging the four RDSO Specification areas under:

Sl.No. Specification No. Description

(i) ETI / PSI /167 ( 9/ 97 ) with

A&C Slip 1-2

25kV, SP Outdoor Interrupter

(ii) TI/SPC/PSI /CB/0000 with A&CSlip 1-5

Outdoor Circuit Breakers ( only25kV, SP /DP portion )

(iii) ETI/PSI/ 132 (8/89) with A&CSlip 1-4

25 kV, DP Vacuum Interrupter

(iv) ETI/PSI/ 159 (10 /94) withA&C Slip No.1

25 kV Single Pole Outdoor PoleMounted Vacuum Interrupter

Hence the firms approved as per any of the above specifications (four),shall be considered as approved as per this specification also. The

changes are with respect to merging of the above mentioned fourspecifications, elimination of SF6 CBs and Interrupters in 25 kV class,updation of certain clauses as required in line with the relevant RDSOspecifications, A&C slips of the above specification, relevant clauses ofIS and IEC and modifications wherever required for standardising thespecification of Low Voltage Switchgear, viz. Outdoor Type 25kVVacuum SP /DP / Pole Mounted versions of CBs and Interrupters.

3.0 Traction Power Supply

3.1 General Scheme

3.1.1 The Single Phase 50Hz Power Supply for Railway Traction at 25kV isobtained from 220/132/110/100/66/22kV three phase grid system

through a step down/ step up single phase Power Transformer, theprimary winding of which is connected to two of the phase of the threephase effectively earthed transmission line network of the StateElectricity Board. The primary voltage of the Traction Transformer being220kV or 132kV or 110kV or 100kV or 66kV or 22kV and no loadsecondary voltage being 27kV. In order to reduce the imbalance on thethree-phase grid system, the two phases of the three phase transmissionline are tapped in a cyclic order for feeding the successive traction sub-

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stations (TSS). The distance between adjacent TSS is normally between50km and 80km depending upon density of traffic, gradients in thesections and other factors.

3.1.2 One terminal of the 25 kV secondary winding of the traction transformeris connected to the OHE through circuit breaker/interrupters and theother terminal is solidly earthed and connected to the appropriatetraction rail(s).The current flows through the OHE, to the locomotives

and returns through the rails and earth to the TSS .In sections wherebooster transformers and return conductors are provided the currentreturns through Booster Transformers; the Traction Rail(s)and partlythrough earth in the vicinity of TSS. Approximately midway between twoTSS a dead zone known as Neutral Section or Phase break is provided tseparate the two sections of OHE fed by different phases. The power fedto the OHE on one side of the TSS is controlled by feeder circuit breakerswhile the power fed to the OHE of each track is controlled by aninterrupter. Incase of a fault on the OHE, the feeder circuit breaker tripsto isolate the faulty OHE.A schematic diagram No.ETI/PSI/702 (Mod. B)Showing the general arrangement at a TSS is at appendix 1.

3.2 TRACTION POWER SUPPLY SYSTEMS (2x25kV AT Feeding System)

3.2.1 General Scheme

The electric power for railway traction is supplied in ac 50Hz, single phase

through 2x25kV AT feeding system, which has a feeding voltage form the

substation two times as high (2x25kV) as catenary voltage (25kV) this

high voltage power supply from the traction substation through catenary

wire and feeder wire is step down to the catenary voltage by use of

autotransformers installed about every 13 to 17 km along the tract and

then fed to the locomotives. In other words both the catenary voltage

and feeder voltage are 25kV against the rail, although the substation

feeding voltage between the catenary voltage and feeder is 50kV.

Therefore the catenary voltage is same is that of the conventional 25kV

system.

Since the power is supplied in two times higher voltage, 2x25kV AT

feeding system is suitable for a large power supply, and it has the

following advantages compared with conventional feeding systems:

a) Less voltage drops in feeder circuit.

b) Large spacing of traction substation.

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c) Less telecommunication interference by use of AT Installed with

adequate spacing.

The power is obtained from 220/2x25 kV Scott connected traction

transformer or 132/2x25kv single phase transformers. The primary

windings of the single phase transformers are connected to 2 or 3 phases

of 132kv three phase effectively earthed transmission network of the

electricity board, in case of a single phase transformer or in case of the

single phase transformers connected in V, respectively. On the other

hand, the primary windings of the Scott connected transformers areconnected to the three phases of 220kv Three phase, effectively earthed

transmission network of the electricity board .The Scott-connected

transformer and V-connected single phase Transformers are effective in

reducing voltage unbalance on the transmission network of the electricity

board. The spacing between the adjacent substations is normally between

70-100kms.

One outer side terminal of the secondary windings of traction transformer

is connected to the catenary, the other outer side terminal being

connected to the feeder. Two inner side terminals are, via seriescapacitors or directly, connected to each other, and their joint is solidly

earthed and connected to the running rails.

The load current from the substations flows through the catenary and

returns to the substation through the feeder. Between two adjacent ATs,

the load current fed from catenary to the locomotive flows in the rail and

is boosted up to the feeder through the neutral tap of ATs at left and

right sides of the locomotive.

At the points of the substations and sectioning posts, a dead zone knownas neutral section is provided in OHE to avoid a wrong phase coupling.

The power to the catenary and feeder on one side of the substation is fed

by one feeder circuit breaker, even if there exists two breakers for one

side, and each track is controlled by an interrupter. The two breakers are

used as a standby for each other. For maintenance work and keeping the

voltage drop within limits, one or more sub sectioning or paralleling

posts(known as SSP) are introduced between the traction substations and

a sectioning and paralleling post(Known as SP).A SSP on a double track

section normally has four sectioning interrupters for each feeder circuit

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and one paralleling interrupter. In case of fault , feeder circuit breaker ofthe substation isolates it.

A figure showing the principle of AT feeding system and a typical power

supply diagram showing the general feeding arrangement at a traction

substation and sections of the OHE are given in the sketch at the

appendix-1and appendix-11.

3.3 Nature of Faults on the OHE

3.3.1 OHE is prone to frequent earth faults caused by failure of insulation or bysnapping and touching the rail/earth or by a piece of wire dropped bybirds which connects the OHE to earth at over line structures/supports orby miscreant activities.

3.3.2 The sections of OHE fed by different phases are sometimes ininadvertently bridged causing wrong phase coupling.

3.4 Protection Scheme

3.4.1 The faults in the OHE are isolated by the feeder circuit beaker whichoperates through either one or more of the following relays:

(i) Distance mho relay(ii) Instantaneous overcurrent relay(iii) Wrong phase coupling relay and(iv) High speed inter tripping relay

3.4.2 The faults in the traction transformer are isolated by one of theFollowing relays:

(i) Differential relay(ii)

IDMT over current relays for the primary (HV) as well as for thesecondary (LV) side

.(iii) Instantaneous earth leakage relays on the primary (HV) as well

as for the secondary (LV) side.

(iv) Auxiliary relays for transformer faults ie.Buchholz,excessivewinding and oil temperature trip and alarm and low oil levelalarm

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3.4.3 The faults in the shunt capacitor bank are isolated by one of thefollowing Relays:

(i) Over current relay

(ii) Over voltage relay

(ii) Under voltage relay

(iv) Neutral current relay

3.4.4 In the event of the 25kV feeder as well as Transformer Circuit BreakersFailing to operate under fault conditions, the Circuit Breakers on thePrimary side of the Transformer operates to Isolate the fault.

3.5 Short circuit level

3.5.1 The fault level for different grid Supply Voltages based on a threePhase symmetrical short circuit fault is between 1000 MVA and10,000 MVA Depending upon the proximity of the Traction Sub- Stationto the Generating Station. The fault level is 550 MVA at 25kV & 1000MVA at 22KV at the Vicinity of Traction Sub- Station.

3.6 Nature of load on 25 kV systems

3.6.1 The traction load is of frequent and rapidly varying nature and fluctuatesbetween no load and over loads. The load cycle varies from day to daydue to non-uniform pattern of traffic.

3.6.2 An AC electric locomotive is fitted with single phase bridge connectedsilicon Rectifier with smoothening reactor for conversion of ac to dc forfeeding the dc traction motors. The ripple content is in the region of 25to 40% which introduces harmonics in the 25kV power supply. Thetypical percentages of harmonics present in the traction current are as

follows:

Sl. No Detail WithRectifier

WithThyristor

WithGTOs

(i) 3rd harmonic (150 Hz) 15 % 23 % 3%

(ii) 5th harmonic (250Hz) 6 % 14 % 2%

(iii) 7th harmonic (350 Hz) 4% 10 % 0.5%

(iv) 9th harmonic (450 Hz) --- 4% 0.35%

(v) 11th harmonic (550Hz)

--- 3% 0.40%

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Total harmonicdistortion

16.64%

29.15% 3.68%

3.6.3 The average power factor of electric locomotive and multiple units Trainsgenerally vary between 0.7 and 0.8 lagging without Compensation.

3.6.4 In big yards and loco sheds large number of locomotives / ElectricalMultiple units (Emus) stand idle with only the load of their auxiliariesDrawing higher reactive power. Therefore these are drawing power atLow Power Factor.

3.6.5 For improving power factor fixed shunt capacitor bank with 13% SeriesReactor is also installed at some traction sub-stations, the Net KVAR

Rating of which is generally in the range of 2000- 3500kVAR.

3.7 Electrical parameters

3.7.1 OHE is made up of a stranded cadmium copper catenary of 65 Sq.mmCross section or stranded aluminum alloy catenary of 116sq mm crossSection and a grooved copper contact wire of 107sq.mm cross section,

Making up a total of 150sq.mm copper equivalent. For 2 x 25 AT feedingsystems, as a feeder wire, a stranded aluminum alloy catenary of 240sq.mm is used. The calculated OHE impedance value of AT Feeding circuit

(OHE: Al 116 or Cu 107 sq.mm & feeder wire: Al 240sq.mm) for singleTrack line is 0.0601 + J 0.1419 ohm/km (at 25kV system impedance).The OHE impedance values for conventional 25kV system are generallytaken as under:

Sl.No.

Description Impedancevalues

(i) Single track OHE without BT and ReturnConductor

0.41 < 70 ohm/km

(ii) Double Track OHE without BT andReturn Conductor

0.24 < 70 ohm/km

(iii) Single Track OHE with BT and ReturnConductor

0.70 < 70 ohm/km

(iv) Double Track OHE with BT and returnconductor

0.70 < 70 ohm/km

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(v) Add Booster Transformer impedance @ 0.15 ohms perBooster Transformerwhere these areProvided.

(vi) Percentage impedance of TractionTransformer

(12+/ -0.5)% for21.6 MVA at 27kV.

3.8 Duties of the Circuit breaker

3.8.1 The Circuit Breaker is used at the following locations in the 25kV AC,50Hz single phase traction system.

(i) As transformer circuit breaker on the secondary side of tractionTransformer for voltage of 25kV.

(ii) As feeder circuit breaker for controlling power supply to OHE throughInterrupters for voltage of 25kV.

(iii) As Shunt Capacitor Bank circuit breaker for controlling power Supply toshunt capacitor bank for voltage of 25kV.

(iv) For controlling Power Supply to major yard or loco sheds for voltage of

25kV.

3.8.2 Special Duty to be performed by 25kV CIRCUIT BREAKER

3.8.2.1 The 25kV Circuit Breaker shall be called upon to trip under short- circuitConditions. On an average, the number of fault tripping seen by the

Feeder Circuit Breaker per month is about 40 Nos, but in exceptionalCases the number of fault trappings per month may go as high as 120Numbers. The magnitude of short circuit current interrupted generallyRanges from 2kA to 8kA. The Circuit Breaker shall also be called upon toClear wrong phase coupling on the OHE when two sections of the OHE fed

By different phases from adjacent Sub-Stations are accidentally shorted.

3.8.2.2 The design and construction of the 25kV Circuit Breaker shall be suchThat it is capable of a cumulative duty (nI where n is the number Of C-O Operations at a current of I kA rms) of 20,000 kA in service withoutAdjustment/ change of any part/ contacts of vacuum Bottle. Lubricationsand tightening of moving parts in the Operating mechanism and cleaningof Porcelain Insulators can However be done as per Manufacturersrecommendations.

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3.8.2.3 The Manufacturer shall supply graphs in support of suitability of offeredCircuit Breaker to perform above duties at the tender stage, Indicatingthe cumulative duty which can be performed by offered CB Without anymaintenance/ replacement of any components.

3.8.2.4 The 25kV circuit breaker is also required to interrupt the line chargingand magnetizing current of locomotive transformers without restrike.Values of line charging current are of the order of 10A and values of

Magnetizing current for locomotive/ EMU are likely to be as under:

(a) Locomotive - 6.38 A

(b) EMU - 6.0 A

3.8.2.5 The 25kV Circuit Breakers are normally operated through RemoteControl. A single shot auto re-closing scheme provided the RemoteControl System to facilitate the re-closing of the circuit breakerAutomatically once within the preset dead time after the tripping of theCircuit Breaker on an OHE faults. This feature helps in quick Restorationof Power Supply to the OHE if the fault is of a transient Nature. The deadtime is the periods taken by the Auto re-close Mechanism to close theCircuit Breaker after the same has tripped on fault is set at 0.5sec.

3.9 Duties of Interrupter

3.9.1 The Interrupter is used at the following locations in the 25kV AC 50 Hz,Single Phase Traction Systems

(i) As sectioning Interrupter at Sub Sectioning and Paralleling Posts(SSP)

(ii) As Paralleling Interrupter at Sectioning Post (SP) and SubSectioning and Paralleling Post (SSP)

(iii) As Bridging Interrupter at Sectioning Post (SP) and(iv) As feeding Interrupter at Feeding post (FP)(v)

As Bus Coupler Interrupter at TSS(vi) For controlling Power Supply to Major Yards / Loco Sheds

3.9.2 The Interrupter is called up on to perform the following duties: -

(i) Making short circuit current

(ii) Making and Breaking Traction load currents from very lowCapacitive or Inductive Current to Rated Normal Current.

(iii) Carrying normal rated current continuously and

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(iv) Carrying short circuit current until the fault is cleared by the CircuitBreaker up- stream

3.10 The design and construction of the Circuit Breaker/ Interrupter shall besuch that it is capable of performing 20000 Close-Open operations forSpring-Spring Mechanism and Magnetically Actuated Mechanism inservice without adjustment/change of any part/contacts or vacuum

bottle. Lubrication and tightening of moving parts in the operatingmechanism and cleaning of porcelain insulators can be done as permanufacturers recommendation.

4.0 Environmental Conditions

4.1 The CB shall be suitable for outdoor use in moist tropical climate and inareas subject to heavy rainfall, pollution due to industry and salineatmosphere and severe lightening. The limited weather conditions forwhich the equipment has to withstand in service are indicated below:

SL.NO. Description Requirements

1. Maximum ambient air temperature 50 C

2. Minimum ambient air temperature 0 C

3. Average ambient temperature over a periodof 24 h

40 C

4. Maximum relative humidity 100%

5. Annual rainfall Ranging Rangingbetween1750mm& 6250mm

6. Number of thunderstorm days per annum 85(Max)

7. Number of dust storm days per annum 35(Max)8. Number of rainy days per annum 120 days (Max)

9. Maximum basic wind pressure 200kgf/m

10. Altitude NotExceeding1000meters

11 Pollution Level Heavily polluted

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4.2 The CB/Interrupter would be subjected to vibrations on account of trainsrunning on nearby Railway Tracks. The amplitude of these vibrationswhich occur with rapidly varying time periods in the range of 15ms to70ms lie in the range of 30 to150 microns at present, with theinstantaneous peak going up to 350 microns.

5.0 Technical specification

5.1 The rating and other particulars

The circuit breakers shall be designed for the following rating and otherparticulars:

S.No.

Particulars

RATED SYSTEM VOLTAGE (kV)

Circuit Breaker Interrupter

25kVSP

25 DP &22 kV DP

25kVSinglePole

Mounted

25kV SP 25kV DP

25kVPole

Mounted

1 2 3 4 5 6 7 8

(i)

Nominal system

voltage(kV)

25kV

subjectto

variation from19kV to27.5kVoccasionally

touching 30kV

25kV

subjectto

variationfrom

19kV to27.5kV

occasionally

touching30kV

25kV

subjectto

variationfrom

19kV to27.5kV

occasionally

touching30kV

25kV

subjectto

variationfrom

19kV to27.5kV

occasionally

touching30kV

25kV

subjectto

variation from19kV to27.5kV

occasionally

touching30kV

25kV

subjectto

variation from19kVto

27.5kVoccasionally

touching 30kV

(ii) Ratedvoltage(kV)

52 52 52 52 52 52

(iii)

Rated insulation

level(a)Rated1minwet powerfrequencywithstandvoltage(b)Rated impulse

(1.2/50s)

95kV(rms)

250 kV

95kV(rms)

250 kV

95kV(rms)

250 kV

95kV(rms)

250 kV

95kV(rms)

250 kV

95kV(rms)

250 kV

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withstandvoltage

(peak) (peak) (peak) (peak) (peak) (peak)

(v) Rated frequency------------------------50Hz 3%----------------------

1 2 3 4 5 6 7 8

(vi)

Rated breaking

capacity(symmetrical)(i) Single pole

(ii) Two pole

550MVA

550MVA

550MVA

550/600MVA

550MVA

550MVA

NA

NA

NA

344MVA

NA

NA

(vii)Out of phase

breaking current5 kA(rms)

5 kA(rms)

5 kA(rms) NA

3.125kA

NA

(vii)

Rated singlecapacitor bank

breaking current 150A 150A 150A NA NA NA

(ix)

Rated linecharging

breaking current10A 10A 10A 10A 10A 10A

(x)Rated smallinductivebreaking current

------------------------ 10A ---------------------------

(xi)Rated makingcurrent

50A(peak

50A(peak)

50A(peak

20 kA31.25

kA20 kA

(xii) Rated operatingsequence

O - 0.3s CO 15 sec CO CO 15 sec- CO

(xiii)Total beak

Time

Notmorethan60ms

Not morethan60ms

Not morethan60ms

Not morethan80ms

Notmorethan80ms

Notmorethan80ms

(xiv)Rated shorttime current

20kA for3sec

20kA for3sec

20kA for3sec

8kAfor 3 sec

12.5kAfor3sec

8kAfor 3sec

(xv) First pole to NA ---1.5 NA NA -----1.5 NA

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clear factor for 2parameters-------

for 2parameters----

(xvi)CoronaExtinctionVoltage NA NA NA NA NA NA

(xvii)

Rating ofauxiliary switchcontacts

(a) Rated voltage

(b) Rated current(continuous)

(c)Ratedbreaking current

---------------------------- 110V dc -----------------------------

----------------------------- 10A -----------------------------

--------- 2A at 220V dc with 20ms circuit time constant ------

5.2 ClearancesThe design of the CB shall be such that when it is erected on theSupporting Structure, the following clearances / distance of lowest livePart of the circuit breaker from the ground level or earth is achieved:

S. No. Clearance/distance 22/25KV

1Minimum height of lowest live part of the CBfrom ground level 3800 mm

2

From a point where a man may be required

to stand for operation or for attending thebreaker (sectional clearance).

3000 mm

3

Minimum height of the bottom most part ofany insulator from the ground level. 2500 mm

4Minimum clearance between live part andearth part.

500 mm

5 Distance between pole centers for 2 poles 1500 mm

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6.0 Type and General Construction

6.1 The design and construction of the Circuit Breaker/ Interrupter shall besuch that it is capable of performing 20000 Close-Open operations forSpring-Spring Mechanism and Magnetically Actuated Mechanism inservice without adjustment/change of any part/contacts or vacuumbottle. Lubrication and tightening of moving parts in the operating

mechanism and cleaning of porcelain insulators can be done as permanufacturers recommendation.

6.2 The CB / Interrupter shall be of outdoor type suitable for mounting onsteel structure / Pole. The 25kV CB shall be of single pole or double poleidentical to single pole unit operated through common / two operatingmechanisms electrically paralleled. The CB shall comprise of-

(i) The pole (interrupting chamber and support insulators)(ii) Operating mechanism cubicle / cubicles and(iii) Mounting steel frame suitable for mounting on foundation / pole

6.2.1 Interrupting chamber

6.2.1.1 Vacuum Circuit Breaker / Vacuum Interrupter

The operating mechanism ( spring-spring and magnetic actuator ), thepole assembly and supporting structure of vacuum CB shall be separateand capable of being packed and handled individually and erected insequence. The pole shall comprise the interrupting chamber and thesupport insulator. The interrupting chamber shall consist of vacuumbottle contained in porcelain hollow insulator. The vacuum bottle shallcomprise a vessel sealed for life time with insulating side walls and metalends containing the fixed and moving contacts. The movement of themoving contact in the vacuum enclosure shall be guided by means of

metal bellows. Suitable metallic shields shall be provided for preventingheat and metal vapor from arcing zone affecting the insulating envelope.These shields will also control the electric field when contacts are openand voltage is appearing across the CB contacts. This will mask highinternal stress points and produce an almost linear axial grading of theexternal insulating surfaces. A shield shall also be provided to protect thebellows. The design and construction of vacuum bottle of the CB shall besuch that the current chopping level is kept to the minimum and shall notproduce any appreciable switching over voltages.

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6.2.2 Porcelain hollow insulator and terminal connector

6.2.2.1 Porcelain hollow insulator

The porcelain hollow insulators used as the support insulators andinterrupting chamber insulator for the CB shall be outdoor typeconforming to IS: 5621 (1980). The porcelain hollow insulator shall be of

single piece construction ie, there shall be no joint with in the porcelain..The shed profile shall have a lip at the extremity but free from ribs onthe under side so as to avoid accumulation of dust and pollutants andpermit easy cleaning. These insulators shall be procured from RDSOsapproved sources only. Both the porcelain insulators for the support andinterrupting chamber shall have a minimum creepage distance of not lessthan 1300mm.

6.2.3 Terminal Connectors

6.2.3.1 The CB/ Interrupter shall have aluminum terminal pads and shall beSupplied with the flexible terminal connectors as per RDSO DrawingNo.ETI/PSI/11060 (Appendix-II) and ETI / PSI / P / 6570 Mod F(Appendix II ) suitable for connection to 50 mm / 36 mm outsideDiameter aluminum tubular bus bars for 25kV CB / Interrupter

Respectively.

6.2.3.2 The connectors shall conform to IS:5561 (1978) and design shall besuch, so as to be connected to the equipment terminal pads withminimum four 12mm diameter bolts, nuts,lock-nuts of stainless steelconforming to IS:1570 (Pt.V) (1978) grade 04Cr,17Ni and Mo2 each ofthese bolts shall have two flat washers.

6.2.4 Contacts for both Vacuum CB / Interrupter

6.2.4.1 Main contacts

The main, fixed and moving contacts of the CB shall have ample cross-section and contact pressure for carrying the rated current and shorttime current without excessive temperature rise, pitting and welding.Internal arcing contacts of vacuum bottle shall be made up of suitablematerial. Indication for contact wear condition shall be provided.

6.2.4.2 Auxiliary Switch Contacts

Apart from the auxiliary switch contacts required exclusively by themanufacturer for the functioning of the CB at least 6 pairs of normally

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open (NO) contacts and 6 pairs of normally closed (NC) contacts shall beprovided additionally for the exclusive use of the purchaser. The auxiliarycontacts which are operated in conjunction with the main contacts shallbe positively driven in both the directions.

6.2.5 Operating Mechanism for spring

6.2.5.1 The CB shall be operated by a motor charged spring stored energy

mechanism. Both opening and closing operations shall be done by thestored energy of spring (S). The motor shall be so rated that the timerequired for fully charging the closing spring is not more than 15seconds. The closing action of the CB shall charge the opening spring sothat the CB is ready for opening any time thereafter. The spring shall beof robust design. Using tested steel as per IS: 7906 or IS: 7907 (1976).the ends of the compression springs if used, shall be flattened to enableproper fixing and shall minimize the possibility of misalignment.

6.2.5.2 The motor for spring charging shall be suitable for operation from a 110Vdc power from a battery. The voltage at motor terminals is likely to varybetween 110% and 85% of the normal value. The carbon brushesprovided shall have copper pigtails for carrying motor current. Aminiature circuit breaker of adequate ratings and of reputed make shall

be provided in the motor circuit for protection of the motor against overcurrent and earth faults.

6.2.5.3 Operating Mechanism (Magnetic Actuator)

The magnetic actuator mechanism shall be provided with two welldesigned magnetic coils /solenoids; one for closing and other for thetripping operations. The latching of mechanism in its two end positionsshall be ensured by specially designed, permanent magnets designed tooperate with minimum hysteresis loss. The tenderer shall indicate the

maximum service temperature ie, the max.temperature to which themagnet may be exposed with no significant long range instability orstructural changes and Curie temperature ie, the transition temperatureabove which material losses its magnetic properties. The temperaturerises expected to be attained by the magnets during service shall beindicating by the tenderer. Suppliers catalogs / test certificate for thishave to be furnished. The Circuit breaker shall be provided witharrangement s for trip and close circuits to be compatible with either 110Volt DC potential or potential free contacts from control and relay panel.This feature shall enable use of this circuit breaker in place of existingcircuit breaker Interrupter, where potential free contact do not exists.

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6.2.5.4 The operating mechanism shall be designed so that the CB can beoperated from the operating mechanism cubicle itself as well as remotelyfrom the control panel in the TSS and also from the remote controlCentre (RCC) which is situated away from the CB. For his purposeLOCAL/REMOTE Two way selector switches which shall be provided in theoperating Mechanism cubicle. When the Switch is in the LOCALposition, the CB can be operated locally and when it is in the REMOE

position the CB can be operated from the control panel or from the RCC.The selector switch shall be spring loaded in order that it automaticallyreturns to the LOCAL/ REMOTE Position. For closing and opening the CBfrom the Operating Mechanism cubicle itself, the switch shall be of thepush Button type or Knob type.

6.2.5.5 The operating mechanism shall also be provided with a suitableemergency device to manually open the CB in the failure of any part ofDC control circuit including the opening coil in the operating Mechanism.

6.2.5.6 The operating mechanism, shall also be provided with a suitable device tomanually close the CB (mainly for maintenance Purposes). In addition, adetachable handle/ crank shall be provided for manually charging theclosing spring. The height from ground/ platform level at which thehandle / crank is to be inserted in the operating mechanism shall be

between 1500mm and 2000mm so as to enable its operation convenientlyby the operator standing on the round/Platform. The height of otherdevices like interlock, ON-OF switches, selector switches etc. to beoperated from ground/ Platform Platform shall also be at a heightbetween 1500mm and 2000mm.

6.2.5.7 In addition to the manually operated local mechanical opening andClosing devices as indicated in clause 6.1.44 & 6.1.45 above,Provision shall also be made by means of a suitable crank or handlefor slow closing and slow opening of the circuit breaker forMaintenance purposes.

6.2.5.8 The closing coil and opening coil in the operating mechanismShall be suitable for operation from 110V dc power supplyFrom a battery. The closing coil shall be suitable for operating at avoltage variation of +10% to -15%, while the opening coil shall besuitable for operating at a voltage variation of +10% to -30%.

6.2.5.9 The circuit breaker shall be fitted with an electrical anti-Pumping device,to give priority to tripping command in case of a persisting losingcommand being simultaneously present.

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6.2.5.10 The circuit breaker shall be trip-free.

6.2.5.11 Facility for trip circuit supervision shall be provided in Circuit Breaker.

6.2.5.12 An operation counter having five digit recording mechanism for thenumber of tripping operation shall be provided at a suitable as to beconveniently read by the operator standing on the Ground. The operationcounter shall be of lock type and shall not be of resettable type.

6.1.5.13 Mechanical indicators clearly visible from ground, shall be provided forCLOSED and OPEN conditions of the CB /VI.

6.1.5.14 All working parts of the operating mechanism shall be of corrosionexisting material, bearings, if any, shall be sealed type. Bearing pins,bolts, nuts and other parts shall be adequately locked to preventloosening.

6.1.5.15 In case operation of closing device when CB is already in CLOSEDcondition shall not cause damage to any part of the CB or endanger theoperator standing near the CB. The average Power requirement fortripping coil or closing coil shall not Exceed 200W and power requirementat any time including Spring Charging shall not exceed 1000W.

6.1.5.16 In the event of 110V battery supply voltage dropping below 85V which isthe minimum voltage prescribed for operation of Tripping coil to trip thecircuit breaker, the circuit breaker should Trip automatically by means ofa suitable arrangement/ Device (CTD).

6.1.5.17 Shock absorbers used (if any) shall not require any maintenance duringthe entire life of the CB / Interrupter

.6.1.5.18 The operating mechanism and associated accessories shall be enclosed in

weather, dust and vermin proof cabinet or cubicle. The cubicle made of atleast 2mm thick sheet steel (of tested quality) with provision for pad

locking. The cubicle shall be tested for dust and water proofing as perIP55 as per IS: 2147(1962)

6.1.5.19 Suitable heaters(s) shall be provided in operating mechanism cubicle tooperate at 240V ac, 50Hz single phase supply to prevent condensation ofmoisture during monsoon / winter. A 240V ac, 5A, 3 pin socket outlet foran inspection lamp shall also be provided. Miniature circuit breaker /Switch with thermostat of reputed make & of adequate rating shall beused for protection of heater circuit for overload and earth fault.

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6.1.5.20 The entry of all cables into the operating mechanism cubicle shall be onlythrough suitable cable glands which shall not allow ingress of vermin,insects, etc. into the cubicle. The cable glands shall be supplied with theCB Five cable glands shall be provided of which three shall be of 16.5mmoutside diameter while the Balance two glands shall be for cable of14mm outside diameter.

6.1.5.21 The wiring inside the operating mechanism cubicle shall be with

1100V grade PVC insulated single core cable conforming to IS: 1554(Pt.I- 1988), with stranded copper conductors of adequate cross-section(with min 2.5 sq.mm strand copper) so proportioned as to reduce voltagedrop and IR losses to minimum. The ends of wires shall be terminatedwith crimped eye type lugs. The wiring of 110V dc control circuit and240V ac circuit shall be segregated and properly identified. The positiveand negative wires of dc circuits shall also be segregated. The length ofthe cables used shall be kept to the minimum. Wire inside the cubicleshall be properly laid on trays and Anchored to avoid breakage duringvibration.

6.1.5.22 The terminal end of all wires shall be provided with numbered interlocktype Ferrules which shall be of PVC or other durable material withmarking (numbers) either engraved or punched so as to be indelible. Theferrules shall be of white color with lettering thereon black. All wiring

shall be properly supported and suitably protected to avoid rubbingagainst any Metallic part.

6.1.5.23 Terminal blocks of standard type shall be provided in the operatingmechanism. There shall be insulating barriers between adjacentterminals. The terminals shall be stud type with spring washers. Suitabledust proof shrouds of unbreakable transparent material shall be providedon each terminal block. The terminal blocks used for DC and AC circuitsshall be clearly distinguished and separated from each other. Similarlypositive and negative Terminations of the wiring of the dc circuit shall besegregated and Separated by insulating barriers.

6.1.5..24 For earthling of the operating mechanism cubicle, two earthing terminalsof adequate capacity to carry the rated short circuit current shall beprovided with 17.5 + 1.5/-0. Diameter stud/hole for fixing the EarthlingFlat.

7.0 Steel supporting frame

7.1 The steel supporting frame for CB / Interrupter shall be designed with afactor of safety not less than 2.5 with respect to the yield point underconditions of maximum loading for a basic wind pressure of 200kg/m on

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1.5 times the projected area of each member of one face and taking intoaccount to IS:808 (1989) and test certificate shall be furnished to RDSO.The fixing distance for steel supporting frame on the foundation for singlepole 25kV CB shall be 650 x 725 mm.

7.2 Typical design calculations for the steel supporting frame shall befurnished by the manufacturer to the RDSO during design approval stage

for checking the safety of the supporting frame proposed to be used.

7.3 For earthling at least 2 legs of the steel supporting frame shall beprovided with stud/hole type earthing terminals of adequate capacity tocarry the rated short circuit current safely. The earthing shall be providedwith 50 x 8 mm MS flat. The terminal shall be provided with 17.5 +0.5/0.0mm diameter stud/hole for fixing the earthling flat.

8.0 Foundations

Gravity foundation of plain mass concrete to M 10 mix as per IS: 456(1978) shall be designed considering the normal impact loading inopening/closing operations. The basic wind pressure shall be taken as200 kgf/m. Two alternative design of foundations one for a normal soil

of bearing capacity 5500 kgf/m and other for black-cotton soil ofbearing capacity 16500 kgf/m shall be furnished by the manufacturer.The foundation block design shall give complete details of its size andsize of pockets provided for grouting the fixing bolts. Detailed designcalculation for proposed foundation shall be submitted to DG (TI) RDSOfor scrutiny and approval.

9.0 Foot prints and foundation

The dimension of steel frame has to match with the sketch no.TI/DRG/PSI/25 kV CB INT/COMFDN/00365/Rev.0. This is to facilitate

common foundation and interchangeability of interrupters of differentmakes.

10. Pole (mast) for Pole Mounted VCB/VI

10.1 The pole (mast) for mounting the Interrupter shall be either steelMast or a round tapered prestressed spun concrete mast. The detail ofpole (mast) for mounting the Interrupter shall be supplied by thepurchase/DG(TI) RDSO Lucknow.

10.2 Typical design calculations shall be furnished by the manufacturer

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for checking the safety of the pole (mast) proposed to be used. Thedesign calculation for steel mast shall be based on a factor of safety ofnot less than 1.67 with respect to the yield point under conditions ofmaximum loading allowing for a basic Wind pressure of 200kgf/m2on 1.5times the projected area of each member of one face and taking intoaccount the dead and impact loads of Interrupter/Circuit Breaker.

11.0 Corrosion prevention system

11.1 Galvanizing

The operating mechanism cubicle and steel supporting frame shallbe hot dip galvanized in accordance with RDSO Specification No.ETI/OHE/13 (4/84) and the weight of zinc coating shall not be less than1000 gm/m.

11.2 Painting

If the successful tenderer/manufacturer is not able to hot dipGalvanize the operating mechanism cubicle and the steel supportingFrame as per Clause 9.1, it shall be painted conforming to RDSOsSpecification No. M & C/PCN-110/88.

11.3 Fasteners

All fasteners of 12 mm diameter and less exposed to atmosphere Shallbe of stainless steel and those above 12 mm diameter shall be ofpreferably stainless steel or of mild steel hot dip galvanized, to RDSOsspecification No. ETI/OHE/18(4/84).

12.0 Interlocking arrangements

12.1 The CB Interrupter shall be provided with a suitable interlocking devicefor electrical and mechanical interlocking with its associated

isolator(s), such that (i) the isolator(s) can be operated only whenthe CB / Interrupter is locked in open condition and (ii) the CB /Interrupter cannot be operated both manually and electrically eitheron LOCAL or REMOTE unless the isolator(s) is Locked in the CLOSE orOPEN condition.

12.2 Interlocking Scheme for 25kV CB

12.2.1. Three types of isolator interlocking schemes shall be utilized. The detailsof these schemes are indicated below:

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a) Single isolator interlocking (SI)

Under this scheme, the circuit breaker shall be interlocked with its singleassociated isolator. This interlocking scheme shall be provided on thecircuit breaker to be installed as transformer breakers and circuit breakerfor controlling feed to the shunt capacitor. In this scheme the key shallbe trapped in the lock mounted on the circuit breaker mechanism whenthe circuit breaker is in closed position. The key can be released from the

operating mechanism when the circuit breaker is in the open positiononly. Any attempt to forcibly withdraw the key when the circuit breaker sin the closed position shall result in tripping of the circuit breaker. Thekey thus released from circuit breaker shall be utilized to operate thelock mounted on the isolator. It shall be possible to release this key fromisolator lock only when the isolator is locked in open or closed position.Once the key has been removed from the circuit breaker operatingmechanism, it shall not be possible to operate the circuit breaker eithermanually or electrically by local/remote control.

(b) Double isolator interlocking (DI)

The scheme is identical to the SI scheme but in this the circuit breakershall be interlocked with its two numbers associated isolators. Thisinterlocking shall be provided on circuit breaker to be installed as feeder

breakers.

(c) Bus Coupler Isolator Interlocking (BCI)

Under this scheme the Circuit Breakers of adjacent bay shall beinterlocked with the bus coupler /interrupter. The operation of the BusCoupler Isolator/Interrupter. The operation of the Bus Coupler

/Interrupter shall not be possible unless both the circuit breakers ofadjacent Circuit are locked in open position. In this scheme the twokeys so released from the circuit breakers shall be inserted in a keyexchange box (which shall be supplied loose) for releasing a third key

which shall be used for operating the Bus Coupler Isolator/ Interrupter.The details of all these schemes indicated above are given I drawingNo. ETI/PSI/SK/5124 enclosed as Appendix (IV).

12.2.2 SI Interlocking scheme shall include supply of 2 locks along with theCommon interlocking key, out of which one lock shall be duly mountedon the Circuit Breaker Operating Mechanism and the other, shall besupplied loose for mounting by Purchaser on the associated isolator.

12.2.3 DI Interlocking scheme shall include supply of 3 locks along with thecommon interlocking key out of which one lock shall be duly Mounted

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on the Circuit Breaker operating mechanism and 2 locks shall be suppliedloose for mounting by Purchaser n the associated Isolators.

12.2.4 BCI Interlocking scheme shall include supply of a Key exchange boxwhich can be operated by the two keys released from the CircuitBreakers of adjacent circuits and one loose lock operated by the keyreleased from the key exchange box. The loose lock shall be Suitablefor directly mounting on the bus coupler (Supply of locks fitted on the

circuit breakers operating Mechanism shall be covered under SI/DIInterlocking Schemes).

12.2.5 The Interlocks provided on the Circuit Breakers installed at a tractionSub- Station shall have non-interchangeable key codes to safeguardagainst an mal-operation.

12.2.6 The lock meant for mounting on the associated isolator(s) and Buscoupler isolator shall be a bolt type lock of approved design. Theinternal mechanism of the lock shall be made of non-ferrous metal andthe outer housing hall be of steel hot dip Galvanized. RDSO drawing No.ETI/PSI/SK/334 showing the Interlocks is attached with this specificationas Appendix VI. The key when trapped inside the lock shall remainproperly secured so to safeguard against its working loose due tovibrations.

12.2.7 One spare duplicate key shall be supplied with each of the three types ofInterlocking schemes.

12.2.8 In order to facilitate the ordering of Interlocks, the tender shallseparately furnish prices for SI, DI, and BCI interlocking schemes. Therequirements of interlocks and the key codes to be adopted shall beascertained by the successful tenderer from the respective Consignee.

12.3 Interlocking Scheme for 25kV VCB at Sub Station of Mumbai Area underDC-AC conversion

12.3.1 Normally, both incoming and lines circuit breakers CB 1& 2 shallRemain closed and 110kV bus coupling circuit breakers CB-3 will be inopen position.

12.3.2 The power supply to Traction Over Head Equipment shall be fed throughany one of the to transformers by closing its respective HV and LVTransformer Circuit Breakers. At a time, only one Transformer will be inservice. Other transformer, not on load, can be kept as

a) Hot standby, by closing its HV side Transformer Circuit Breaker and

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keeping LV transformer Circuit Breaker open.OR

b) Dead, by keeping both HV and LV Transformer Circuit Breakers in openposition However, each transformer shall Feed load periodically at regularintervals.

12.3.3 Bus coupler is provided on 25 kV side with Circuit Breaker CB-8. Thisshall normally be closed for feeding the OHE in either side of IGL from

any of the transformers.

12.3.4 In case of outage of one feeder and Transformers on other bay at aParticulars time power supply can be restored through healthyTransformer from other feeder by operation of 110KV bus coupler CircuitBreaker CB-3.

12.3.5 Extension of 25KV supply in case of outage of one complete TSS.

(a) In the event of failure of any TSS, supply from adjoining TSS may beextended up to the IOL of failed TSS by closing the bridging the SP oneither side of failed TSS. Bus coupler CB no.8 at the failed TSS shall bekept in open position along with LV Transformer CB 6&7 at the failed TSSin open position. However, this will necessitate lower panto/raise pantoof the trains in front of failed TSS, if it is not provided with neutral

sections.

(b) Otherwise, supply may be extended over complete zone of failed TSSfrom any of the adjoining TSS. i.e from SP to SP. Bus coupler CB no.8at the failed TSS shall be kept in close position along with LVtransformer CB 6& 7 at the failed TSS in open position. In this case nolower panto/raise panto is required, however the OHE voltage and loadhas to be closely monitored.

12.3.6 For paralleling of nominated Traction Sub Stations

Energize the OHEs of concerned TSS zone up to SP locations and thenclose the bridging CBs at SP location.Energize the OHE of one TSS zone.Extend the supply by closing bridging CB at SP and feeder CB and buscoupler CB at the next TSS. Then clause LV transformers Circuit Breakerat other Traction Sub-Station to make parallel operation of the TwoTSSs.

Details of interlocking scheme indicated above are given in the drawingno. TI/DRG/PSI/INTERLOCK/RDSO/00001/06/0 as appendix VII.

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13.0 Parts, fittings and accessories

13.1 The following parts, fittings and accessories shall be provided for eachCB:

(i) Contact wear indication.

(ii) Operating mechanism cubicle door padlocking arrangement with padlock.

(iii) Local operated mechanical opening and closing device.

(iv) Spring loaded local/remote selector switch.

(v) Local operated electrical closing and opening device (push or knob).

(vi) Operation counter.

(vii) Interlocking device (as required)

(viii) Terminal connectors.

(ix) Earthing terminals

(x) Name/ rating plate.

(xi) Mechanical ON and OFF position indicators.

(xii) Handle/crank for slow closing and slow opening of CB.

(xiii) Supporting frame work.

(xiv) Tripping device in case of 82 V D failure (CTD) for VCB

(xv) Anti-pumping device.

(xvi) Foundation Bolts.

(xvii) Handle/crank for charging the closing spring manually.

13.2 The name/ rating plate shall contain the following particulars

Each CB / Interrupter shall be provided with rating plates (Hindi /English)of weatherproof material fitted in a visible position showing the itemsindicated below. The letters/numbers on the plate shall be indelibly

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marked by etching/engraving.

(i)Manufacturers name and country of origin.

(ii) Type designation and no: of pole.(iii) Serial number(iv) Rated voltage(v) Rated normal current(vi) Rated frequency(vii) Rated short circuit breaking current.

(viii) Rated short circuit peak making current(ix) Rated single capacitor bank breaking current(x) Rated out of phase breaking current.(xi) Rated short time withstand current and its duration.(xii) Rated insulation level.

(xiii) Rated operating sequence.(xiv) Control circuit voltage with permissible variation for

(a) Closing coil(b) Opening coil(c) Motor voltage

(xv) Total weight of CB

(xvi) Specification conforming to IEC/RDSO.

(xvii) Vacuum level in Torr (for vacuum CB).

(xviii) Order reference

(xiv) Month/Year of manufacture

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14.0 Testing

14.1 General

14.1.1 After all the designs and drawings have been approved and clearanceGiven to this effect by RDSO, the manufacturer shall take upManufacture of the prototype for inspection/testing by RDSO. It is to beClearly understood that any changes to be done on the prototype as

required by RDSO, the same shall be done expeditiously.

14.1.2 Prior to giving a call to the Purchaser/Director General Tractioninstallations, Research Designs and Standards Organization, Lucknow(DG/TI/RDSO,Lucknow) for inspection and testing of the prototype, thesuccessful tenderer/manufacturer shall submit a detailed test scheduleconsisting of test procedures, schematic circuit diagrams,items/parameters to be checked and values required as per specificationfor each of the tests and the number of days required to complete all thetests at one stretch. The schedule shall also indicate the venue of each ofthe test. Once the schedule is approved, the test shall invariably be doneaccordingly. However, during the process of type testing or even later,the Purchaser /DG/TI/RDSO, Lucknow reserves the right to conduct anyadditional test(s), besides those specified herein, on any equipment/item so as to test the equipment/ item to his satisfaction or for gaining

additional information and knowledge. Incase any dispute or disagreement arises between the successful tenderer/ manufacturer andthe representative of the Purchaser/DG/TI/RDSO, Lucknow during theprocess of testing as regards the procedure for type tests and for theinterpretation and acceptability of the results of type tests. It shall bebrought to the notice of the Purchaser /DG/TI/ RDSO, Lucknow as thecase may be whose decision shall be final and binding. Only after theprototype of the equipment is manufactured and ready in all respects,shall the successful tenderer/manufacturer give the actual call for theinspection and testing with at least 15 days notice for the purpose.

14.1.3 In the event of the test not being carried through to completion at onestretch for any reason attributable to the successful tenderer/manufacturer and it is required for the representative of the Purchaser/DG/TI/ RDSO to go again or more numbers of times to the works of thesuccessful tenderer/manufacturer or to any reputed testinghouse/laboratory where tests are being done for continuing and/ orcompleting the tests on the prototype(s) of the equipment, thesuccessful tenderer/manufacturer shall reimburse to the Purchaser

/DG/TI/ RDSO the cost for the representative(s) having to visit the worksor other place(s) for the tests more than once. The cost as claimed bythe Purchaser /DG/TI/ RDSO ,Lucknow shall be paid thorough a Demand

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Draft to the concerned Accounts Officer of the Purchaser/ Purchaser/DG/TI/ RDSO,Lucknow as shall be advised to the successfultenderer/manufacturer.

14.1.4 The tests shall be conducted on the prototype of the CB / Interrupter atthe works of the successful tenderer/ manufacturer or at any reputedtesting house of laboratory in the presence of Purchaser /DG/TI/ RDSO,Luck bow or his authorized representative. He prototype shall be

complete in all respects, including the terminal connectors as would besupplied if it had passed the tests. The tests shall be conducted as perrelevant governing specification and as modified or amplified herein.Incase of test being conducted at government test house, the presenceof Purchasers representative for witnessing the test may be waived offsubject to the discretion of the Purchaser /DG/TI/ RDSO, Luck now.

14.1.5 For the tests which are conducted in the laboratories of Central PowerResearch Institute, Bhopal/Bangalore, Electrical Research DevelopmentAssociation, Vadodara or any such testing house or laboratory a clearcertificate to the effect that the equipment has passed the tests as perthe specification shall be obtained by the manufacturer and submitted tothe Purchaser/DI(TI)/RDSO, Lucknow. Full details of the tests and thetest parameters shall be furnished along with the test reports.

The type tests comprises of:

(i) Mechanical operation test as per clause 13.2.1 for VCB and Interrupter.(ii) Mechanical Endurance Test of Operating Mechanism(Magnetic Actuator)

(iii) Temperature rise tests as per the clause 13.2.2 for VCB and Interrupter(iv) Dielectric tests as per the clause 13.2.3 for VCB and Interrupter

(a)Rated lightning impulse voltage withstand test as per clause 13.2.3.1

(b) Rated one minute power frequency wet withstand voltage test

(v) Rated short circuit making and breaking capacity test (basic shortcircuit test duties) for VCB.

(vi) Making and breaking test for Interrupter

TD-1 Making and breaking test at 100 % of mainly active load.

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TD-2 Closed loop make break test.

TD-2a Transmission circuit closed loop make break operation test.

TD-2b Parallel transformer circuit makes break operation test.

TD-3 Making and breaking test at 5% of mainly active load.

TD-4b Line charging make break operation test and

TD-6 Short circuit making current.

(vii) Rated short time withstand current & peak withstand current testas per clause 13.2.5As per clause 13.2.3.2 for VCB and Interrupter

(viii) Line charging breaking current test as per clause 13.2.6 for VCB

(ix) Test to prove the rated transient recovery voltage (TRV) and rateof recovery Voltage (RRRV)

(x) Out of phase making and breaking current as per clause 13.2.9 forVCB,

(xi) Capacitor current switching test as per clause 13.2.10 for VCB.

(xii) Special electrical test applicable for 25kV circuit breaker only as perclause 13.2.12

(xiii) Selected EMC(Electro Magnetic Compatibility) preliminary tests as perIEC 61000 and IEC 60694-1996 for Magnetic Actuated VCB andInterrupter

(a) EM radiated field immunity test

(b) Fast transient immunity test

(c) Surge immunity test

(d) Radio frequency conducted immunity test

(e) HF disturbances: damped oscillatory wave 1 MHz-100 kHz immunitytest

(g) Radiated emission test

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14.2.1 Mechanical Operation test

14.2.1.1 The test shall be conducted in accordance with clause 6.101 ofIEC 62271-100 but the number of operations shall be 10,000 in case of25kV VCB / Interrupter instead of 2000specified therein for 25 kV VCB

/ Interrupter with spring Spring Mechanism and 20,000 for VCB/Interrupter with Magnetic Actuator Mechanism. For this purpose, VCB/ Interrupter shall be tested in accordance with Table XII of IEC 62271-100 However, the sequence shall be repeated 5 times to complete10, 000 operations in case of 25kV VCB / Interrupter with spring complete 20,000 operations for VCB / Interrupter with Magnetic ActuatorMechanism. Following checks/ tests shall be done before thecommencement of

Mechanical operation test.

(i) General visual inspection of the equipment to check its conformity withthe approved drawings.

(ii) Operation of various circuits and devices of the CB.(iii) Measurement of dimensions of components liable to wear, dimension of

opening, closing and wipe springs, lift of tripping and closing coil plunger,and clearances of opening and closing coil armatures.

(iv) Measurement of insulation resistance of auxiliary and motor circuits with500V meter.

(v) Measurement of contact resistance of main circuit by dc voltage drop.(vi) Mechanical operation comprising 5 closing and 5 opening operations at

the specified, normal, minimum and maximum control voltages.

(vii) Closing and opening travel characteristics of contacts to record theFollowing at the specified, normal, minimum and maximum controlVoltages.

Opening speed & time Closing speed & time Contact bounce & Contact travel

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14.2.1.3 The measurement of items (v) & (vii) above shall be repeated after every5000 operations for 22KV/25kV VCB and observations made/ resultsobtained shall be evaluated by comparing with the figures and thetolerances given by the successful tenderer/manufacturer in the SOGP.

14.2.1.4 After completion of 10,000 operations in case of 25kV CB / Interrupterwith spring spring and 20,000 for magnetic VCB / Interrupter beforedismantling the CB for internal inspection, the following checks/tests

shall be performed.

(i) Dielectric tests on control and auxiliary circuit (110Vdc) by applying 2kV(rms) for 1 min. after disconnecting the motor

(ii) Spring charging motor shall be tested at 1kV (rms) for 1 min.

(iii) Power frequency dry withstand voltage test on complete CB /Interrupter for 1 minute.

(iv) Temperature rise test on opening and closing coils as 13.2.2.2

(v) Closing and Opening Travel characteristics of contacts to record theFollowing at the specified normal , minimum and maximum controlvoltages

Opening speed & time Closing speed & time Contact bounce & Contact travelThe above parameters shall be within the specified limits declared bythe manufacturer in SOGP.

14.2.2 Mechanical Endurance of Operating Mechanism (MagneticActuator)

14.2.2.1 Mechanical endurance for operating mechanism without Vacuum bottleshall be tested for 1,00,000 operation for VCB / interrupter with MagneticActuator Mechanism.

The test shall be performed on the prototype unit in accordance with IEC62271-100, clause 6.101.1.2 (component tests) & as per 6.101.2.4(extended mechanical endurance tests) for special service requirements.

At the beginning of the design test, the characteristics of the magneticactuator shall be established as the reference characteristics for the

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actuator. The purpose of this reference is to characterize the behavior ofthe magnetic actuator. The following characteristics shall be measuredand recorded before and after the tests:

a. Resistance of the coils (Both closing & opening coils in the case ofdouble coil magnetic actuators)

b. Ambient temperature at the time of measurement of resistance of thecoil.

c. Insulation level of the coils, i.e, 2kV (rms) frequency voltage applied onto the coils across the body of the actuator.

Since the parts of auxiliary and control equipments which have beenmanufactured in accordance with relevant standard and also test alongwith the operating mechanisms of conformance to these standards, theproper functions of such parts in connection with the functions of theother parts of the magnetic actuator need not be verified separately.

14.2.2.2 Condition of the magnetic actuator during and after the tests during andafter the tests, the actuator shall be in such a condition that it is capableof operating at the rated voltage as per clause 5.0 of the specification.In general, these requirements are fulfilled, if

(a) During the test, the actuator operates on command and does not operatewithout command

(b) After the test, all parts do not show undue wear.(c) During and after the tests, any distortion of the mechanical part is not

such that it adversely affects the operation of the actuator

(d) After the tests, the insulating properties of the actuator coils shall be inessentially in same condition as before the tests. Visual inspection of theactuator after the test is usually sufficient for verification of the insulatingproperties

14.2.2.3 Procedure

The mechanical operation tests on magnetic actuator shall be made atthe ambient air temperature of the test location. The ambienttemperature should be recorded in the test reports. Auxiliaryequipments, forming parts of the operating devices are being tested withthe equipment, shall be included as a part of evaluation for this test. Theactuator for the test shall be mounted on its own support. Any springsmounting arrangement required to simulate the tripping condition of thebreaker shall be made part of the mounting arrangement.

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The mechanical operation test shall consist of l00000 operatingsequence

Operating sequence: C ta O - ta

Supply voltage / operatingpressure

No. of operating sequence

Minimum 10000

Rated 90000

O= Opening, C = Closing

ta= Time between two operation which is necessary to re storethe initial condition and /or to prevent undue heating of parts ofthe actuator(this time can be different according to the type of

operation and shall not exceed 15 second)

Between the test series specified, some maintenance such aslubrication and mechanical adjustment, is allowed, and shall beperformed in accordance with the manufacturers instructions.Change of parts is not permitted.

The programme of maintenance during the tests shall bedefined by the manufacturer before the tests and recorded in

the test report.

14.2.3 Temperature rise test for VCB / Interrupter

14.2.3.1 On main contact

The temperature rise test on the main circuit (contacts) andterminal connectors of VCB / Interrupter shall be carried out asper clause 6.3 IEC 694(1980) or latest. Contact resistance ofthe main circuit shall be determined by dc voltage drop andrecorded before and after this test.

14.2.3.1.1 Procedure

Unless otherwise specified, temperature rise on the main circuitshall be made on a new CB in closed position with cleancontacts. The test shall be mad with rated normal current. Thetest shall be done in indoor environment substantially free fromair currents, except those generated by heat from the CB beingtested. Temporary connections to the CB terminals shallbe such that no significant amount of heat is conducted awayfrom, or conveyed to the CB / Interrupter during the test.

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The temperature rise at the terminal of main circuit and thetemporary connections at a distance of 1m from the terminalshall be measured. The difference of temperature rise shall notexceed 5C. The type and sizes of temporary connections shallbe recorded in the test report.

14.2.3.1.2 The maximum temperature rise of contacts, terminals forConnection to external conductors by bolts, material used

as Insulation and metal parts in contact with insulation shallNot exceed the values given in Table below when carryingRated Normal current continuously. These values shall beConforming to IEC 694(1984) or latest.

Table

Sl.No Nature of faults/components Maximumtemperature rise at

an ambienttemperature notexceeding 50C

1. CONTACTS

i) Bare copper and bare copper alloy in SF6gas.ii) Silver contacts in SF6 gas.

25C55C

2. Terminal for external connection by bolts 40C3. Insulator (Porcelain) 130C

14.2.3.1.3 In case a layer of coating of silver over the contact area isnot maintained at the end of any tests the contacts shall beregarded as bare for the purpose of temperature rise limits.

14.2.3.2 On Auxiliary equipment (Closing & Opening coils)

The temperature rise test on the coils shall be carried out asper clause 6.3 of IEC 694(1980) or latest.

14.2.3.2.1 Procedure

The temperature rise on auxiliary equipment (Closing and

Opening coils) shall be made by the method of measuringVariation of resistance before and after energisation at 110Vdc. For this purpose the coil(s) shall be energized 10 times for

1 second, the interval between the instant of each energizingbeing 2 second. The resistance of the coil shall be measuredImmediately before and after such energisation. The value ofTemperature rise, over the ambient shall be computed.

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14.2.3.2.2 The maximum temperature rise shall be as per table V of IEC694(1980) or latest considering the insulating material of theCoil. The temperature rise shall not exceed the value asGuaranteed by the manufacturer in SOGP.

14.2.4 Dielectric tests VCB / Interrupter

Dielectric tests shall be carried out generally in accordance withClause 6.1 of IEC 694 (1980) or latest. Humidity and air densityCorrection factor if less than 1.0 shall not be applied.

14.2.4.1 Rated Impulse withstand voltage test

The CB / Interrupter shall withstand its rated impulse voltage250 kV (peak) of 1.2/50s wave shape.

14.2.4.2 Rated one minute wet power frequency voltage withstandtest for VCB / Interrupter

The CB / Interrupter shall withstand rated one minute wet powerfrequency withstand voltage of 95 kV .

14.2.5 Basic short circuit test duties for VCB

The basic short circuit test duties 1 to 5 shall being accordance toClause 6.106 of IEC 62271-100. The Power Frequency RecoveryVoltage shall be as per clause 6.104.7 of IEC -62271-100.

14.2.6 Making and breaking test for Vacuum Interrupter

These tests shall be conducted in accordance with IEC-265-2 asModified or amplified here. The test set up shall be for single phase

System with earthed neutral. Only the following test duties shall bePerformed in any convenient order without any adjustment orChange of part of lubrication or re-conditioning of the interrupter.

14.2.6.1 Making and breaking test at 100% mainly active load (Test dutyNo.1.0)

Five hundred make-break operations shall be conducted at 80A (rms) ata test voltage of not less than 27.5 kV. The supply circuit shall have apower factor not exceeding 0.2 and the load circuit shall have a powerfactor between 0.65 and 0.75. Prospetive TRV Parameters shall be set in

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accordance with Table III of IEC-265-2 The test may be interrupted afterevery 10 operations, if necessary, to enable the components to cooldown to the ambient temperature

14.2.6.2 Closed loop make break operations (Test Duty No.2a & 2b)

If TRV parameters achieved in test duty 1 are equal or more severe thenthe TRV parameters prescribed in Table IV-A of IEC 265-2 for test duty

2a and 2b then test duty 2a and 2b need not be performed, otherwisetests comprising test duties 2a and 2b described as under shall beperformed:

i) Transmission circuit closed loop make-break operation test (Test DutyNo.2a)-10 make-break operations shall be performed at 800 A.

ii) Parallel transformer circuit make-break operation (Test Duty No.2b)-10make break operation shall be performed at 800 A.

14.2.6.3 Making and breaking test at 5 % of mainly active load (Test DutyNo.3).

Twenty make break operations shall be performed at 5 % of the ratednormal current with a test voltage of not less than 27.5 kV.

14.2.6.4 Line charging make-break operation(Test Duty No.4b)

Test shall be made at 100% and from 20% to 40% of rated line chargingcurrent. 12 make-break operations at each current shall be performedwith contact separation distributed at intervals of approximately 30electrical degrees. If this is not possible then 30 make break operationsshall be performed at random contact separation. The over voltagesproduced during switching shall not exceed 77.7kV(peak) at single phasetest voltage of 27.5 kV(rms) with earthed neutral.

14.2.6.5 Short circuit making current test (Test Duty No.6)

Twenty close operations at 20 kA (peak) shall be performed.Opening of the interrupter shall be done with supply disconnected.

14.2.7 All the making and breaking tests shall be done on a singleInterrupter and no maintenance or reconditioning of the contactsshall be permitted during the above test series.

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14.2.8 Condition of the interrupter during make-break tests andshort time withstand current test:

14.2.8.1 During the test the interrupter shall neither show signs of excessivedistress nor endanger the operator. No disruptive discharge betweenenergized parts and earth shall occur during the tests. Their shall be noindication of significant leakage current to the interrupter earthedstructure or screens whenever fitted during the tests. The earthed parts

should be connected to earth through a fuse consisting of a copper wireof 0.1mm diameter and 5 cm length. The fuse wire shall be intact afterthe tests.

14.2.8.2 Condition of the interrupter after make-break tests andShort time withstand current test:

The mechanical functions and the insulation of the interruptershall be essentially in the same condition as before the tests. Thewear of the contacts shall not be disproportional. The interruptershall be capable of carrying rated normal current and also capable ofperforming assigned duty provided in the Clause 3.5 and 3.7 of thespecification. The interrupter should withstand 95kV (rms) for 1 min indry conditions

14.2.9 Rated short time withstand current & peak current withstand test

This test shall be conducted as per clause 6.5 of IEC 694 (1980) orlatest. Ie, 20kA (rms) for 3 seconds and 50 kA (peak) for VCB, 8kA(rms) and 20 kA (peak) for interrupter.

14.2.10 Line charging current switching test for VCB

This test shall be conducted as per clause 6.111.5.1 of IEC62271-100 test values shall conform as given in SOGP.

14.2.11 Test to prove rated transient recovery voltage (TRV) forVCB

The measurement shall be done as per clause 6.104.5 of IEC62271

14.2.12 Out of phase making and breaking test for VCB

This test shall be conducted as per clause 6.110 of IEC 62271-100) at its rated out of phase breaking current.

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14.2.13 Capacitor bank breaking current test for VCB

The test shall be carried out at rated single capacitor bank breakingcurrent generally as per clause 6.111 of IEC 62271-100 . No restrikeshall occur during the test. The breaking current shall conform to theguaranteed value.

14.2.14 Special Electrical Test (applicable for 25kV CB only)

CB shall be subjected to short circuit making and breaking capacity testat a current of 6.25kA for duty cycle CO-15s-CO for 200 close-openoperations. During this test no part of CB shall require anyinspection/maintenance, change of SF6 gas or vacuum bottle or any otherpart. The standard value of prospective TRV shall be taken as 64kV.Other conditions shall be similar to short circuit test duties specified inIEC 56 (1987). The test may be interrupted once after every 10 COoperations if need arises to enable the components to cooled down toambient temperature.

14.2.15 Condition of CB during the tests conducted as per clause no. 14.2.5,14.2.9, 14.2.10, 14.2.11, 14.2.12, 14.2.13, and 14.2.14 of thisspecification shall conform as under:

14.2.15.1 During these tests the CB shall neither show signs of excessive distressnor endanger the operator. No disruptive discharge between energizedparts and earth shall occur during the test. There shall be no indication ofsignificant leakage current to the earth structure or screens wheneverfitted during the test. The earthed part shall be connected to earththrough a fuse consisting of copper wire of 0.11mm diameter and 5cmlength. The fuse wire shall be intact after the test.

14.2.16 Condition of CB during the tests conducted as per clause No.14.2.5,14.2.9, 14.2.10, 14.2.11, 14.2.12, 14.2.13,and 14.2.14 of this

specification shall conform as under :

14.2.16.1 The mechanical functions and insulation of CB shall be essentially inthe same condition as before the test. The wear of the contacts shallnot be disproportionate to its original shape and size. The CB shall becapable of carrying its rated normal current and also capable ofperforming its assigned duty provided in clause 3.7 of thespecification The CB shall withstand for 1 minute dry power frequencywithstand voltage 95KV rms.

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14.2.17 Selected EMC preliminary test

14.2.17.1 EM radiated field immunity test(80-10000 MHz) according to IEC/EN61000-4-3 Criteria for successful passing of the test are as follows:

(a) No unwanted trip in all frequency range with both open and closeposition of the circuit breaker

(b) Correct trip at stepped frequency 80-100-120-180-240-320-480-

40-960 MHz for following operation: C/O;C/Auxiliary O;C/Protection Trip O;C/OpenLock;c/Under voltage O; Reclosefunction.

14.2.17.2 Fast transients immunity tests according to IEC/EN 61000-4-4 test shallbe done for severity level 4 for AC main(+/- 4 kV) and BinaryInput/Output (+/- 2kV) of different modes. Criteria for successful passingof test are as follows:

(a) No unwanted trip during disturbance injection with both open andclose position of circuit breaker.

(b) Correct trip(absence of anomalies) with open circuit breaker forC/O operations.

14.2.17.3 Surge immunity test according to IEC/EN 61000-4-5 Test shall be

done for different severity levels from 1 to 4 for AC Main (+/- 4 kV)and Binary Input/Output(+/- 2 kV) of different modes. No degradation ofperformance shall occur during the injection of disturbances.

14.2.17.4 Radio frequency conducted immunity tests according to IEC/EN 61000-4-6 Criteria for successful passing of the tests are as follows:

No unwanted trip during disturbance injection with both open and closeposition of circuit breaker. Correct trip (absence of anomalism)with openCircuit Breaker for C/O operations.

14.2.17.5 HF disturbances: damped oscillatory wave 1 MHz 100 kHz immunitytests according to IEC/EN61000-4-10 Criteria for successful passing ofthe tests are as follows:

No unwanted trip during disturbance injection with both open and closeposition of circuit breaker. Correct trip(absence of anomalism)with openCircuit Breaker for C/O operations.

14.2.17.6 Radiated emission test according to EN 55011/CISPR 11. Test settingshall be as per sub clause.

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14.3 The tenderer may quote separately the charges for short circuit testduties, short time withstand current and peak current withstand test, linecharging breaking current tests, test to prove rated TRV, short line faulttests, out of phase making and breaking tests, capacitor bank breakingcurrent test, measurement of RIV level and special electrical tests as perclause 14.2.4,14.2.5, 14.2.6,14.2.7, 14.2.8, 14.2.9, 14.2.10, 14.2.11,14.2.12 . No test charge shall be payable for any other test.

14.4 If the prototype of the CB / Interrupter conforming to the specificationhas been approved for earlier supplies to Indian Railways, testing ofprototype again may be waived provided that no changes in the designand/ or materials used have been made. For this purpose the successfultenderer/manufacturer shall approach Purchaser/DG(TI), RDSO Lucknowwith complete documents to ascertain whether the equipment is identicalto the prototype approved earlier. Once prototype approval is accordedafter conducting all or part of the type tests by RDSO, the prototypeapproval shall normally be valid for five years subject to the no change ofdesign, material and the process adopted for prototype.

14.5 Only after clear written approval of the prototype is communicated byPurchaser/DG/TI/, RDSO Lucknow to the successfultenderer/manufacturer, they shall take up bulk manufacture of the CBwhich shall be strictly with the same design, material and process as

adopted for the prototype. In no circumstances the mate

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LVCBINd_0120_ Rev.1 (1)