rps 6-10 rec specifications for materials & equipments for t(1)

Power Finance Corporation Ltd.

(A Govt. of India Undertaking)

Space for Institution Logo

Rural Power Supply and Participatory ModelsDistribution Reform, Upgrades and Management (DRUM) Training Program

REC SPECIFICATIONS FOR MATERIALS & EQUIPMENTS FOR THE POWER DISTRIBUTION SYSTEM

Compiled by CIRE, REC Ltd.

Prior to creation of Rural Electrification Corporation (REC), various State Electricity Boards (SEBs) were following different practices with regard to type of materials, equipments and construction practices. As an apex organization, REC realized the need for standardization of the materials as well as construction practices. Systematic efforts made have resulted into more than 300 standards which include specifications and construction practices.

The standards are evolved in close consultation with State Electricity Boards, Power Utilities, Bureau of Indian Standards, and Manufacturers etc. For this purpose periodical standardization meetings are convened by REC for discussions and final decisions. The existing standards also are reviewed on the basis of feed back from SEBs as well as manufacturers.

Along with efforts in the field of standardization the REC is also making endeavours to keep pace with the advances in technology. Over the years, many materials and improved construction practices have been introduced.

Benefits from standardization

The importance of standardization becomes apparent from the fact that 70% of the cost of equipment and materials go into it.

Standardization of major items and materials by REC reduced the variety of materials which resulted into minimum inventories cost to the SEBs. Bulk production of equipment and materials of uniform ratings and designs not only optimizes the production cost but also ensures quicker deliveries by the suppliers.

Adoption of uniform and efficient construction practices has increased the pace of work and improved the quality of construction.

The enclosed annexure gives the brief particulars of REC specification in respect of materials and equipment to be used on overhead lines upto 33 KV, 33/11 KV Sub-station and distribution transformer centres.

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REC Specifications for Materials/Equipment

1. Support for Over Head Lines/Distribution Transformers Centres

1. 15/1979 PCC Poles (Solid Rectangular Poles

Length/Working Loads1) 7.5 Mt/140; 200 Kg

For 11 KV without earth wire and LT Lines with horizontal configurations

2) 8.0 Mt/140; 200 Kg For 11 KV lines with earth wire and LT lines with vertical configuration

3) 9.00 Mt/140; 200 Kg For DTCs/special locations on 11 KV/LV lines

2. 24/1983(R-1987)

i) PCC (Virendeel poles)

1) 9.0 Mt/300; 400 Kg

2) 9.5 Mt/200; 300 & 400 Kg

At tangent locations of 33 KV linesSpecial locations of 33 KV lines such as road crossings

ii) PCC (Solid Rectangular Poles)

1) 9.0/200; 300; 400 Kg

2) 9.5 /200; 300; 400 Kg

At tangent locations of 33 KV linesSpecial locations of 33 KV lines such as road crossings

Note : The earthing shall be provided by using 8 Swg GI wire embeded in concrete during manufacture and the ends of wire left projecting from the pole to a length of 50 mm at 250 mm from top and 150 mm below ground level.

3. 47/1987 PCC Spun Concrete PolesHollow Circular

1) 7.5 Mt/140 & 200 Kgs2) 8.0 Mt/140 & 200 Kgs

11 KV & LT Lines

3) 9.0 Mt/200 Kg 1) Special location of 11 KV and LT lines(Road crossings)2) 33 KV lines in wind pressure zone of 50 Kg M2

4) 9.0 Mt/300 Kg 33 KV lines with W.P. of 75 kg/M2

5) 9.0 Mt/400 Kg 33 KV lines with W.P. of 100 Kg/M2

6) 9.5 Mt/200, 300 & 400 Kg

For special locations of 33 KV lines

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4) 41/1985 Rectangular 1)7.5 Mt/140kg Shall be used at tangentHallow 2)7.50 Mt/200 kg locations of 11KV andSteel Poles 3)8.00/140 kg LT lines in wind pressure

4)8.00/200 kg zone upto 100 kg/M2

1) The planting depth shall be 1.5 Mt.2) The factor of safety for design of the poles shall not be less than 1.5 as per

provisions of IE Rules.

The maximum weight of the different varieties of poles shall be as under

S l No

Length Working Load Combined weight of two sections (Excluding nuts & bolts)

Maximum weight of individual poles

1. 7.5 Mt 140 Kg 55 – 65 Kg 45 Kg2. 7.5 Mt 200 Kg 70 – 80 Kg 50 Kg3. 8.0 Mt 140 Kg 60 – 70 Kg 50 Kg4. 9.0 Mt 200 Kg 90 – 100 Kg 60 Kg

2. Conductors for Overhead Lines

S. No.

Specification Number

Conductor Size Application

1 1/1971 i) AAC 1) 7/2.21 mm (25 mm2 Al. Area) For use on LT lines2) 7/3.10 mm (50 mm2 Al. Area) -do-

ii) ACSR 1) 7/2.11 mm (20 mm2 Al. Area) For use on LT and 11 KV lines

2) 7/2.59 mm (30 mm2 Al. Area) -do-3) 7/3.35 mm (50 mm2 Al. Area) -do-1) 7/3.35 mm (50 mm2 Al. Area) For use of 33 KV

lines2) 7/4.09 mm (80 mm2 Al. Area) -do-3) 6/4.72 mm + 7/1.57 (100 mm2

Al. Area)-do-

2 33/1984(R-1991)

All Aluminum Alloy Stranded Conductor(AAAC)

1) 3/2.50 mm (14 mm2 Al. Area) For street lights only.

2) 7/2.00 mm (20 mm2 Al. Area) For 11 KV & LT Lines3) 7/2.50 mm (30 mm2 Al. Area)

4) 7/3.15 mm (50 mm2 Al. Area)1) 7/3.15 mm (50 mm2 Al. Area) For 33 KV Lines2) 7/3.81 mm (80 mm2 Al. Area)3) 7/4.26 mm (100 mm2 Al. Area)

The Aluminum Alloy Stranded Conductors have lower resistance resulting in superior electrical performance of lines i.e. lower voltage drop and reduced power losses. Because

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of lesser weighty, spans can be increased which means lesser supports. These are corrosion resistant and hence suitable in coastal areas. Another advantage is elimination of theft of conductors.

3. Aerial Bunched Cables (ABC System) for LT Over Head Lines

In ABC System, the insulated Aluminum Alloy Conductors (3 or 4 numbers as required) are twisted around high strength aluminium alloy bearer wire which carries the main weight and also serves as the earth-cum-neutral wire. The phase conductors are not under tension. The advantages of system are: 1) The system is very safe and LT faults are practically eliminated, interruptions of supply are minimized and the life of the transformers is increased. 2) The problem of tree cutting is minimized. 3) Due to reduction of height of poles, elimination of insulators and associated hardware. The sizes specified are:

A) For Phase and Street Lighting :

Sl No

Nominal Sectional Area

No of Strands

Diameter of compacted conductor

Approximate MassKg/.Km

Maximum DC Resistance at 200 C/KM

1. 16 mm2 1 4.4 42 1.912. 25 7 5.5 65 1.203. 35 7 6.8 95 0.8684. 50 7 7.9 127 0.641

B) Messenger Wire

1. 25 mm2 55 1.8302. 25 mm2 7 6.8

C) Composition and Designation of Finished Cables

S. No.

Designation Complete Bunched CablesOverall dia Approx Total mass

(mm) (Approx Kg/Km1. 3 x 16 + 25 mm2 19 2502. 3 x 16 + 16 + 25 19 3103. 3 + 25 + 25 22 3304. 3 x 25+ 16 + 25 22 3905. 3 x 35 + 16 + 25 24 4306. 3 x 35 + 16 + 25 24 4907. 3 x 50 + 35 32 5808. 3 x 50 + 16 + 35 32 640

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First Part : Phase conductorsSecond Part : Street light phaseThird Part : Bare messenger wire

D) ABC for 11 KV OH Lines

64/1993 Aerial Bunched Cables for 11 KV Lines

The specification covers XLPE insulated 11 KV Aerial Bunched Cables for OH lines. Nominal size of the conductors are 35 mm2 and 70 mm2. Nominal section area of messenger wire 70 mm2

Designation Complete Bunched Cable Overall dia Total mass (Appx.) mm (Appx.) Kg/Km3 x 35 + 70 53 14503 x 70 + 70 59 1900

3. Distribution Transformers (3 Phase & Single Phase)

Specification Item Ratingsi) 2/1971 Outdoor type 3 phase DT

upto and including 100 KVA (Conventional Type)

11 KV/433-250 V for 16,25,63 & 100 KVA10.450 KV/433-250 V for 100 KVA only

ii) 11/1976(R-1988)

Outdoor type 3 phase sealed distribution transformer upto and including 100 KVA

11 KV/433-250 V for 16, 25, 63 & 100 KVA10.450 KV/433-250 V for 100 KVA only (wherever specified)

iii) 23/1983 Outdoor type 3 phase Completely Self Protected (CSP) upto and including 100 KVA

11 KV/433-250 V for 16,25,63 & 100 KVA10.450 KV/433-250 V for 100 KVA only (wherever specified)These transformers have built in LT Circuit breakers, 11 KV fuses and 11 KV LA

iv) 56/1988 Outdoor type 3 phase Fail-Safe Distribution Transformers

11 KV/433-250 V for 16,25,63 & 100 KVA10.450 KV/433-250 V for 100 KVA only (wherever specified)

These transformers have built in LTCB which is controlled by special electronic device to provide fool-proof protection against excessive overloads, system faults and low oil level. A signal light will indicate that the transformer is being overloaded so that necessary action can be taken to either relieve load or to augment the transformers capacity. However, pending this action, transformer will not get damaged. Another special feature is the provision of automatic closing of the circuit breaker. This will result in automatic restoration of supply following temporary faults. Even in case of tripping due to excessive overloading, supply will be automatically restored after a short interval to allow for cooling of oil by 50C. The work load of maintenance staff will be resulted and ensure more reliable power supply to consumers.

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Specification No.

Item Rating

v) 30/1983 Outdoor type 3 phase 11 KV/433 – 250 V Cast Resin Dry Type DT upto and including 100 KVA

11 KV/433-250 V for 25,63 & 100 KVA ratings

vi) 70/1993 Amorphous Metal Core Transformers

Amorphous metal core transformers offer substantially lower no load losses compared to CRGO. Initial cost is about 35% higher, but considering the savings in energy, additional cost will be recovered in few years. KVA Rating No Load loss No Load loss AMDT CRGO 25 25 watts 100 watts 63 45 watts 180 watts 100 60 watts 260 watts

These transformers have the advantage of being practically maintenance free. These have better short circuit withstand capability and longer life compared to conventional transformers.

vii) 49/1987 Single Phase Resin Encapsulated Dry Type distribution transformers10 KVA & 16 KVA

11/ √3 / 0-250 V KV (Phase to Neutral) 11 KV/0-250 V (Phase to Phase)

viii) 50/1987 Single Phase Oil filled distribution transformers

11/√3 / 0-250 V KV (Phase to neutral) 11 KV/0-250 V (Phase to Phase)

ix) 7/1984 3 Phase 33/11 KV Step down Power transformer

Standard ratings shall be 630, 1600, 3150 KVA and 5000 KVA

x) 17/1981 On load tap changer for 33/11 KV transformer

For 3150 KVA and 5000 KVA transformers + 5% to – 15% @ 2.5% on HV side

4. Insulators

Specification No Item Brief Particularsi) 3/1971 (R-1988)

Porcelain Insulators and insulator fittings for 11 KV overhead power lines (OH)

The specification includes pin/strain insulators and the associate ed fittings. The revised specification incorporates dimension of 11 KV pin insulators

ii) 4/1972 Porcelain Insulators and insulator fittings for 11 KV overhead power lines (OH) for 415 V/240 V OH lines

The specification covers porcelain insulators (Pin/Shackle) and fittings for 415/240 V lines

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iii) 13/1979 Porcelain Insulators and insulator fittings for 11 KV overhead power lines (OH)for 33 OH lines

The specification covers porcelain insulators and insulators fittings for 33 KV OH lines

iv) 21/1981 Guy strain insulators for OH lines

The specification covers porcelainguy strain insulator for use on 415/240 V, 11000 V and 33000 V OH lines

5. Energy Meters

1. 5/1974 Single/Three phase whole current AC electricity meters (240 volts)

Single Phase meters 2.5 – 5 Amps and 10 – 20 Amps3 Phase meters 10, 30, 50 Amps ratingsVoltage ratingSingle Phase = 240 Volts3 phase = 3 x 240 V

Some of the recommendations in the specification are as follows:1) 2 sealing screws for 1 phase meters and 3 sealing screws in case of 3 phase meters

2) The sealing screws shall have two independent sealing holes

3) The sealing screws used shall be fixed upside down

4) The maximum power loss in potential coil shall be 1.5 watts

5) 8 mm clearance between window glass and disc

6) The current/potential coils shall be made of enameled copper wire

7) All electrically alive screws shall be electroplated.

6. Lightning Arresters

Specification No. Item Featuresi) 10/1976 11 KV LA Voltage rating = 9 KV

Normal discharge current = 5 KA

ii) 16/1981 33 KV LA Voltage rating = 30 KV Normal discharge current = 10 KA

iii) 55/1987 11 KV and 33 KV Metal Oxide LA

The metal oxide LA has gapless constructions. MOLA have higher life expectancy/higher energy handling capacity1) Voltage ratings : 9 KV/30 KV2) Discharge current : 5 KA/10 KA ratings

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7. Circuit Breaker

Specification No. Items Ratings

i) 8/1975 11 KV Oil Circuit Breaker

3 Pole, 50 HZ, 11 KV OBC for both indoor/outdoor instruments1) The rated voltage : 12 KV2) Normal current : 400 A3) SC breaking current : 8 & 12.5 KA4)Standard DC voltage : 24 V5) CT Ratio 50 – 25/5, 200-100/5 A and 300 – 150 A/5A 6) VT : 11 KV/110 Volts

ii) 18/1981 (R-1983)

LT Circuit Breaker The specification for current setting/ minimum breaking unit for Transformer are Current Breaking current 16 KVA 22 A 2.5 KA25 KVA 35 2.5 KA63 KVA 90 3.0 KA 100 KVA 140 5.0 KA

iii) 22/1983 11 KV Vacuum Circuit Breaker

1) The rated voltage : 12 KV2) Normal current : 400 A3) SC breaking current : 8 & 12.5 KA 4) DC Voltage : 24 V5) PT Ratio : 11000/116) CT Ratio : 50-25/5A, 200 – 100/5 A and 300-150 A/5AMetering on Incoming/Outgoing feedersProtection =i) O/C = 2 Relaysii) E/P = 1 Relay

iv) 12/1979 (R-1993)

33 KV Vacuum/SF6

Circuit Breakers3 Phase, 50 Hz, Outdoor installation in 33/11 KV S/S of 2 x 5 MVA capacity1) Rated Voltage : 36 V2) Normal Current : 630 A3) SC Breaking Current : 12.5 KA (750 MVA)4) CT Ratio : 200/100/5 A5) PT : 11 KV/100 V

v) 20/1981 (R-1993)

11 KV CB for Controlling Capacitors

3 Phase, 50 Hz, 11 KV Vacuum /SF6 CBBoth for indoor and outdoor use. To control 11 KV shunt capacitors Bank of 1200 KVAR, 2400 KVAR & 3600 KVAR at 33/11 KV S/S.1) The rated voltage : 12 KV2) Rated Current : 400 A3) Bus bar rating (indoor type) : 800 A

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4) Standard rating for capacitive breaking current = 300 Amps5) Breaking capacity : 12.5 KA6) Rated voltage for operating devices : 24 V DC/240 V AC7) CT Ratio : 300 –150/5A (for 2400 and 3600 KVAR Bank)8) Metering and protection shall be provided

8. Cables

SpecificationNo.

Item Size Type Use

i) 26/1983 (R-1987)

PVC InsulatorLT Cables

2.5 mm2 Twin core(unarmoured)

Single Phase S/C upto 2 KW CL3 Phase S/C 3 HP

4.0 mm2 Twin core(unarmoured)

Single Phase S/C 2 & 4 KW3 Phase S/C 3 HP – 5 HP

6.0 mm2 4 Core(unarmoured)

3 Phase S/C 5 HP – 10 HP



16.0 mm2

10.0 mm24 Core(unarmoured)Single core(Unarmoured)

25 KVA DT

70 mm2

50 mm2

3 Core(armoured) or 4 Core(unarmoured)Single Core(unarmoured)

63 KVA DT

63 KVA DT

120 mm2

95 mm2

3 Core(armoured) or 4 Core(unarmoured)Single Core(unarmoured)

100 KVA DT

ii) 27/1983 PVC Insulated LT Service Cab les with

These cables are especially intended for use in coastal areas.

Size Type Use

2.5 mm2 Twin core (unarmoured)

Single Phase S/C upto 2 KW3 Phase S/C upto 3 HP

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Embedded bearer wire

4.0 mm2 Twin core (unarmoured)

1 Phase S/C 2 KW- 4 KW3 Phase 3 HP – 5 HP


3 Phase S/C 5 HP - 10 HP



iii) 63/1993 11 KV cross linked Poly Ethylene Al. Cables for 33/11 KV SS

A) Transformer Cables

33/11 KV Transformer (KVA)

3- Core Cables (nominal area ofcross section)mm2

3 Single Core Cables (nominal area of cross section) mm2

1) 1600 35 252) 3150 120 953) 5000 240 100B) Feeder Cables1) 20 mm2 ACSR 35 252) 30 mm2 ACSR 70 503) 50 mm2 ACSR 120 95

9. Rubber Hand Gloves

9/1975 Rubber hand gloves 1) For working on live low and medium lines and equipment

2) For operation of 11 KV and 33 KV AB Switch operating handles

9. Rewirable Fuses

28/1973 LT Rewirable Fuses(415 V AC)

A) Single Phase S/C with load 1) Upto 2 KW = 16 A2) 2 KW – 4 KW = 32 AB) 3 Phase S/CUpto 7.5 HP = 16 A7.5 HP - 15 HP = 32 A 15 HP - 30 HP = 63 A 30 HP - 50 HP = 100 A C) 16 KVA = 32 Amps 25 KVA = 63 Amps 63 KVA = 100 Amps

11. LT Spacers

29/1983(R-1987)

1) Spiral Spacers (PVC)2) Composite Spacers (Poly Propylene)

The spacers shall be suitable with ambient air temperature of 500 C; humidity of 100% and wind pressure of 150 Kg/ M2

31/1084 Earth knobs for LT Lines Cast iron earth knobs for supporting neutral cum

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earth wire used for earthing of metal pares or supporting structures of OH lines with voltage upto 1000 V

12. Helically Formed Fittings

25/1983 Helically formed fittings For use on 11 KV & LT OH lines covering the following -1) Conductor dead end fitting2) Distribution ties, side ties and double ties3) Conductor splices4) Guy grid dead ends5) Tap connectors6) Service grip dead ends

13. Fibre Glass Reinforced Plastic (FRP) Cross Arms

40/1985(R-1987)

Fibre glass cross arms for 11 KV lines

1) Shall be either channel or rectangular hollow section with an over all length of 1150 mm

and a top width of 45 mm2) The cross arm shall have two holes of 22 mm dia for fixing of pin insulator3) Centre to centre distance between two holes shall be 1070 mm

42/1985(R-1987)

Fibre glass cross arms for 33 KV lines

1) Shall be either channel or rectangular hollow section with an over all length of 1605 mm and a top width of 50 mm2) The X -cross arm shall have two holes of 26 mm dia for fixing of pin insulators3) Centre to centre distance between two holes shall be 1525 mm

14. Nicad Battery with Charger

34/1984(R-1987)

24 V Nicad Battery with charger

24V 110 V1) 33/11 KV SS 66/11 KV SS2) 1.2 V x 20 1.2 V x 90 Cells3) 15 AH 15 AHThe capacity at room temperature (32ºC) 1) 3 Amps for 5 hours to end voltage not less than 1.0 V per Cell2) 100 Amps for 0.5 Sec to end voltage not less than 1.0 V per cell

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These batteries have much longer life and less maintenance requirement compared to lead acid batteries; besides better stability of voltage under severe cyclic loads; fast recovery on trickle change, more compact size.

15. Capacitors

SpecificationNo

Item Features of Specifications

i) 6/1974 415 V 3 Phase Shunt Capacitors

1) 415 v, 3 Phase 50 HZ outdoor type capacitor for PF improvement upto and including 10 HP induction motors2) Ratio voltage : 415 V3) Recommended ratings for Motor & Capacitor 3 HP 1 KVAR 5 HP 2 KVAR 7.5 HP 3 KVAR 10 HP 4 KVAR

68/1983 LT Switched Capacitors (415 V)

The specification coves outdoor type automatically switched LT capacitors banks for use on the second side of the distribution transformers. The equipment covered in the specification comprises (i) Capacitor bank and

(ii) Automatic control panelDT rating Capacitor Bank rating25 KVA 9 KVAR 1 x 9 KVAR63 KVA 27 KVAR 3 x 9 KVAR100 KVA 36 KVAR 4 x 9 KVAR

iii) 35/1984 (R-1993)

11 KV Pole Mounted Switched Capacitor

11 KV 50 HZ pole mounted switched capacitor comprising of (i) 11 KV Automatic capacitor switches and (ii) 11 KV switched capacitor bank of 600 KVAR rating1) Rated voltage : 12 V2) Rated normal current : 200 A3) The capacitor shall be self powered for the 11 KV, no AC or DC control supply shall be required for its operation 4) The control parameters for switching operation shall be line current at the point of installation of switches. The maximum value of the line current shall be 150 A and accordingly CT of 150/5A shall be supplied to monitor current in one of the phases for control5) The switch shall have adjustable values of current at which capacitor bank shall be switched “On” and “Off”.

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ii) 19/1981(R-1993)

11 KV Capacitor Banks for 33/11 KV SS

1) The rated output of Capacitor Bank shall be 12 KV (Phase to Phase) and individual capacitors shall be rated for 12/13 KVii) Standard output of Capacitor Bank shall be 1200, 2400 and 3600 KVAR at 12 KV voltage. The bank shall comprise of single phase units of 200 KVAR each connected in single/double star (with floating neutral).

69/1993 11 KV Automatically Switched Capacitor Banks at S/S

The specification covers capacitor bank, automatic control unit, capacitor switches and auxiliary equipment. This bank is to be installed at 33/11 KV and 66/11 KV Sub-Station. Switching “on” and “off” capacitor banks depend on load KVAR.PT capacity Capacitor Bank size 1x3.15 MVA PTR 2 x 600 KVAR1x5.00 MVA PTR 1 x 600 + 1 x 1200 KVAR

16. Automatic Transformer Disconnection Switch

36/1984 Automatic transformer disconnection switch (for 11/04 KV 3 phase DT upto 100 KVA rating)

To reduce no load losses in the distribution transformer and to prevent tubewell consumes typing to run 3 phase motors on two phase supply, these switches have been developed. The specification covers 11 KV, single core, 50 HZ pole mounted for 11/0.4 KV 3 phase DT upto 100 KVA

17. Automatic Voltage Boosters/ Regulators

37/1984 (R-1990)

11 KV AVB/Regulators

1) Standard continuous current rating : 100 A2)Standard automatic voltage regulation will be (-) 10%); (0%) Boost only (-) 15%); (0%) Boost only (-) 15%); (+5%) Boost and Buck only Equipment shall provide boost or buck in steps of 2.5% eachEquipment can be in single or 3 phase.The equipment shall be designed to give normal current of 11,250 V on load side’s terminals.The percentage sensibility for automatic tap change operation shall be 80% of step voltage on either side of nominal voltage of 11,250 volts

18. Auto Reclosers

38/1984 (R-1987)

11 KV Autorecloser

3 Phase 50 HZ, 11 KV Autorecloser for outdoor/indoor installation

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Rated voltage : 12 KVNormal current : 400 ASC Breaking capacity at 12 KV = 6 KA1) The air shall be useful to control major T-oft lines

there by providing discrimination of faulty section and ensuring uninterrupted supply to healthy network and

2) To set up low cost unattended 33/11 KV SS

19. Line Sectionalisers

44/1987 (R-1993)

11 KV Line Sectionalisers (Vacuum/SF-6)

3 Phase, 11 KV 50 HZ Pole mounted automatic line sectionalisers for outdoor installations- Can be voltage sensing/current sensing type- Rated voltage: 12 KV- Normal current : 200 Amps- The sectionalisers work in coordination with 11 KV CB/AR controlling the main line- Serve for purpose of load break and fault make switches

20. Air Break Switches

43/1985 11 KV Air Break Switches

11 KV, 50 HZ, AB switches for outdoor installation - suitable for operation under off load condition only- for use on DTCs and tapping/sectionalizing points Can be voltage sensing/current sensing type- Rated voltage: 12 KV- Normal current : 400 Amps

21. GI Wire

45/1987 GI Wire 1) Bearer wire 3.15mm for single phase service for service cables2) Earth of 4 mm for 3 phase services transformer3) Continuous 4 mm earthwire for 11 KV line 4) Protective guarding at 3.15, 4 and 5 mm crossings (Road/Railway)

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22. GI Stay Wire

46/1987 GI Stay Wire 7/2.5 mm )7/3.15 mm ) For OH lines and DTCs7/4.0 mm )

23. Batteries for Solar Street Lightings

48/1987 12 Volts Batteries for solar street lightings

The specification is for NICAD or Lead Acid batteriesNICAD : 1.2 v/Cell x 10 cells = 12 V orLead acid : 2 V/cell x 6 cells/12 VNICAD or 5 Amps for 5 hrs = 25 AmpsLead acid 6 Amps for 10 hours

24. Switch Isolators

52/1987 33 KV Switch Isolators

33 KV 50 HZ, AC switch isolators for outdoor installations for use at 33/11 KV SSRated voltage = 36 VNormal current = 630 Amps

25. Drop Out Fuse

53/1987 11 KV DO Fuse Cutouts

11 KV, 50 HZ, type DO fuse cutout for installation in 11 KV Distribution System Rated voltage = 12 KVRated normal current = 100 Amps

26. Load Break Switches

54/1987 33 KV load break switches

33 KV 50 HZ, AC load break switches for outdoor installation for use on sectionalizing and tapping points of 33 KV linesRated voltage = 36 KVRated normal current = 400 Amps

27. Current Transformers

59/1993 Current Transformers Two standard ratings of CTs for use at 33/11 KV Sub-stations300m - 150/5-5 A200m - 100/5-5 A100m - 50/5-5 A 50m - 25/5-5 A

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28. Voltage/Potential Transformers

60/1993 Voltage/Potential Transformers

The rating of the voltage transformer for use at 33/11 KV substation is 11 KV/110 volts

29. Miniature Circuit Breakers

61/1993 Miniature Circuit Breakers for Service Connections

The specification covers 1-pole and 3-pole LT Miniature Circuit Breaker suitable single phase and 3 phase service connection.

Single Phase MCBs Connected load Rated CurrentUpto 0.5 KW 4 Amps0.6 to 1 KW 8 Amps1.1 to 2 KW 16 Amps2.1 to 3 KW 25 Amps3.1 to 4 KW 32 Amps

3 Phase MCBs 2.2 KW (3 HP) 6 Amps3.7 KW (5 HP) 8 Amps5.5 KW (7.5 HP) 16 Amps7.5 KW (10 HP) 20 Amps11 KW (15 HP) 32 Amps

30. Cross Linked Poly Ethylene Cables (XLPE)

63/1993 11 KV XLPE Cables

This specification covers 11 KV XLPE insulated and PVC sheathed aluminum cables for 33/11 KV sub-stationApplication Size of cable (nominal

cross section) mm2

a) For 33/11 KV transformers(KVA capacity)

Three Core Single Core

1600 35 253150 120 955000 240 185b) For 11 KV Outgoing Feeders (Conductor size in

nominal aluminum area) 20 mm2 ACSR(7/2.11 mm) or AAAC (7/2.0 mm)

35 25

30 mm2 ACSR(7/2.59 mm) or AAAC (7/5.0 mm)

70 50

50 mm2 ACSR(7/3.35 mm) or AAAC (7/3.15 mm)

120 95

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31. Residual Current Operated Circuit Breaker (RCCB)

66/1993 Residual Current Operated Circuit Breaker

Specification covers 2 pole, and 4 pole RCCBs for use in single phase and 3 phase installations/service connections respectively. Rated current shall be 30 milli amps. Rated voltage shall be 240 V for single phase 415 C for 3 phase.

32. Remote Controlled Load Management

71/1993 Remote Controlled Load Management

This specification covers design, survey, manufacture, inspection, installation, commissioning, operation and maintenance of the following load management scheme.i) Remote controlled circuit breakersii) Master control unit at 33/11 KV S/S/iii) Communication system

This scheme will ensure round the clock supply to the villages for domestic, commercial and industries load whereas agricultural load can be subjected to load rostering. This will reduce peak demand on the system and also the losses.

38. Low Cost Unattended 33/11 KV S/S

In this layout, maintenance free vacuum/SF-6 11 KV auto-reclosures are used on 11 KV feeders in the place of CBs. As 80% of the line faults are temporary nature, these 11 KV auto reclosers clear the faults in 1 or 2 trials, thus eliminating the need for an operator. As the auto-enclosures are designed to function automatically, the provision of maintenance staff (sub-station operators) is either fully or partially dispensed with and also there is no need for costly civil works including control room and staff quarters, etc. Due to simple layout and elimination of civil works, the sub-station can be set up at practically half the cost of a conventional attended type station. The requirement of land is also considerably reduced and sub-station can be commissioned much faster. At the discretion of SEBs, skelton maintenance staff can be stationed at the sub-station for attending consumer’s complaints and also to carry out required switching operations in connection with periodical load rostering. The standard lay out of low cost unattended 33/11 KV sub-station is attached separately.

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rps 6-10 rec specifications for materials & equipments for t(1)

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