HARYANA VIDYUT PRASARAN NIGAM LTD.

Transcription

1 HARYANA VIDYUT PRASARAN NIGAM LTD. TECHNICAL SPECIFICATION FOR 420kV CT, 245kV, 145kV, 72.5kV & 36kV CTs & NCTs & 12kV NCTs SPECIFICATION HPD/S-122/HPM-465/Vol.-II (September, 2018) Chief Engineer/MM Design Directorate, HVPNL, Shakti Bhawan, Sec-6, Panchkula (Haryana) Tel./Fax E:\2. Tech. Specf. of Sub Station Wise \Latest Tech. Spec. JULY 2018\Spec September 2018\Final September Chapter - 1 CT-NCT Spec CT-1

2 CONTENTS CLAUSE NO. TITLE PAGE NO. 1.0 SCOPE STANDARDS SERVICE CONDITIONS PRINCIPAL PARAMETERS GENERAL TECHNICAL REQUIREMENTS TESTS DOCUMENTATION 10 ANNEXURES I. COREWISE DETAILS FOR A-(i) 420kV CT ( /1-1A, /1-1-1A) 12 B-(i) 245kV TRANSFORMER CTs ( / A) 12 B-(ii/a) 245kV LINE CUM BUS COUPLER CTs ( / A) FOR 220KV S/STNS. 13 B-(ii/b) 245kV LINE CTs ( / A) FOR 220KV S/STNS. 14 B-(iii) 245kV B/C CT ( / A) FOR 400KV S/STNS. 15 B-(iv) 245kV T/F I/C CT ( / A) 16 B-(v) 245kV NCTs ( /1A) 16 C-(i) 145kV T/F I/C CTs ( / A) 17 C-(ii) 145kV TRANSFORMER CTs WITH METERING CORE ( / A) 17 C-(iii) 145kV LINE CT AND 145kV B/C CTs for 132kV S/Stns. ( /1-1-1A) 18 C-(iv) 145kV NCTs ( /1A) 18 C-(v) 145kV BUS COUPLER CT ( /1-1A) for 160MVA 220/132kV T/Fs 19 C-(vi) 145kV Metering CT (100-50/1-1A) 19 D-(i) 72.5kV T/F I/C CTs ( / A) 20 D-(ii) 72.5kV T/F CTs ( / A) FOR 66/11kV T/Fs 20 D-(iii) 72.5kV LINE CT AND 72.5kV B/C CTs ( /1-1-1A) for 66kV S/Stns. 21 D-(iv) 72.5kV TRANSFORMER INCOMER NCTs ( /1A) 21 D-(v) 72.5kV NCTs ( /1A) FOR 66/11kV T/Fs 22 D-(vi) 72.5kV BUS COUPLER CT ( /1-1A) for 160MVA 220/66kV T/Fs 22 D-(vii) 72.5kV Metering CT (75/1-1 Amp) 23 D-(viii) 72.5kV Metering CT (200/1-1 Amp) 23 E-(i) 36 kv T/F I/C CTs FOR 132/33KV T/F WITH 25/31.5KA STC ( / A) 24 E-(ii) 36kV T/F I/C CTs FOR 220/33KV T/F WITH 25/31.5KA STC ( / A) 24 E-(iii) 36kV LINE CUM CAPACITOR CTs WITH 25/31.5KA STC ( /5-1A) 25 E-(iv) 36kV T/F I/C NCTs ( /5A) FOR 132/33KV T/F WITH 25/31.5KA STC 25 E-(v) 36kV T/F I/C NCTs ( /5A) FOR 220/33KV T/F WITH 25/31.5KA STC 25 E-(vi) 36kV Bus Coupler CTs ( /5A) FOR 220/33KV T/F WITH 25/31.5KA STC 26 E-(vii) 36kV TRANSFORMER CTs(100-50/5-5A) FOR 4 MVA 33/11KV T/F WITH 25/31.5KA STC 26 E-(viii) 36kV T/F NCT (100-50/5A) FOR 4 MVA 33/11KV T/F WITH 25/31.5KA STC 26 F-(i) 12kV NCTs ( /5A) FOR 25/31.5 MVA 27 F-(ii) 12kV NCTs ( /5A) FOR 12.5/16 MVA & 16/20 MVA 27 F-(iii) 12kV NCTs ( /5A) FOR 4 MVA 33/11KV T/F 27 II. GUARANTEED TECHNICAL PARTICULARS E:\2. Tech. Specf. of Sub Station Wise \Latest Tech. Spec. JULY 2018\Spec September 2018\Final September Chapter - 1 CT-NCT Spec CT-2

3 1.0 SCOPE 1.1 This specification provides for design, engineering, manufacture, testing of out-door instrument transformers alongwith terminal connectors for protection and metering services in different 400/220/132/66kV S/Stns. in the state of Haryana. 1.2 It is not the intent to specify herein complete / all details of the design and construction of equipment. However the equipment shall conform in all respects to high standards of engineering design and workmanship and shall be acceptable to the purchaser, who will interpret the meanings of drawings and specifications and shall have the power to reject any work or material, which in his judgement is not in accordance therewith. The equipment offered shall be complete with all components necessary for its effective and trouble free operation. Such components shall deemed to be within the scope of supply irrespective of whether those are specifically brought out in this specification and or the commercial order or not. 2.0 STANDARDS Unless otherwise specified elsewhere in this specification the rating as well formance and testing of the instrument transformers shall conform but not limited to the latest revisions and amendments available at the time of placement of order of all the relevant standards as listed hereunder. 2.1 INSTRUMENT TRANSFORMERS : Sr. Standard Title 1. IS:2165 Insulation Co-ordination for equipment of 100kV and above. 2. IS:2705 Transformers. (I to IV) 3. IS:2099 Bushings for alternating voltages above 1000Volts. 4. IS:3347 Dimensions of porcelain transformer bushings. 5. IS:2071 Method of High Voltage Testing. 6. IS:335 Insulating oil for transformers Switchgears. 7. IS:2147 Degree of protection provided by enclosures for low voltage switchgear and control. 8. IS:2633 Method of testing hot dipped galvanized articles. 9. IS:4800 Enameled round winding wires. 10. IS:5561 Terminal connectors. 11. IS:11065 Drawings. 12. IEC 44-1 Transformers. 13. IEC-270 Partial Discharge Measurement (or IS:11322) 14. IEC-44(4) Instrument Transformer measurement of PDs. 15. IEC-171 Insulation co-ordination. 16. IEC-60 High voltage testing techniques. 17. IEC-8263 Method for RIV test on high voltage insulators. 18. Indian Electricity Rules IS:5621 Hollow porcelain insulators. E:\2. Tech. Specf. of Sub Station Wise \Latest Tech. Spec. JULY 2018\Spec September 2018\Final September Chapter - 1 CT-NCT Spec CT-3

4 Sr. 2.2 Equipment meeting with the requirements of other authoritative standards, which ensure equal or better performance than the standards mentioned above, shall also be considered. When the equipment offered by the supplier conforms to other standards salient points of difference between standards adopted and the standards specified in this specification shall be clearly brought out in the relevant schedule. Four copies of such standards with authentic translation in English shall be furnished alongwith the offer. 3.0 SERVICE CONDITIONS: 3.1 Equipment to be supplied against this specification shall be suitable for satisfactory continuous operation under the following tropical conditions:- 1. Location IN THE STATE OF HARYANA 2. Max. ambient air temp( O C) Min. ambient air temp ( 0 C) Relative humidity (%) Minimum Relative humidity (%) Average annual rainfall (mm) Max. wind pressure (Kg/sq.m.) Max. altitude above mean sea level 1000 (meters) 9. Isoceraunic level (days/year) Seismic level (horizontal 0.3g acceleration) Note : Moderately hot and humid tropical climate conducive to rust and fungus growth. The climatic conditions are also prone to wide variations in ambient conditions. Smoke is also present in the atmosphere. Heavy lightening also occurs during June to October. 4.0 PRINCIPAL PARAMETERS: The current transformers covered in this specification shall meet the technical requirements listed hereunder. PRINCIPAL TECHNICAL PARAMETERS: Item 420kV 245kV 145kV 72.5kV 36kV 12kV 1. Type of C.T./ installation. Single phase, dead/live tank, oil filled, Hermetically sealed, outdoor type. 2. Type of Mounting Steel Structures 3. Suitable for system Frequency 50 Hz 4. Highest system Voltage (KV rms) 5. Minimum Neutral CT Insulating Voltage 6. Ratio A/A a. Line CT / / / / / , / b. Transformer CT / / / / /5-5 - E:\2. Tech. Specf. of Sub Station Wise \Latest Tech. Spec. JULY 2018\Spec September 2018\Final September Chapter - 1 CT-NCT Spec CT-4

5 Sr. Item 400kV 245kV 145kV 72.5kV 36kV 12kV c. Transformer Incomer CT / / / / , / d. Capacitor CT /5-1A - e. NCT / /1 f. Bus Coupler/Tie CT / / , / /1-1A, / /1, / /1-1A, / /5, /5, / /5, /5, / /5-7. Method of Earthing the System Solidly Earthed 8. Rated Continuous Thermal current 125% for all taps 9. Ratio taps The tapings shall be only on secondary winding. 10. Acceptable limit of temperature rise above the specified ambient temperature for continuous operation at rated current. As per IS:2705 or equivalent IEC 11. Acceptance partial discharge level at 1.1 times the rated voltage. As per IS: or equivalent IEC /50 microsecond lightning impulse withstand voltage (kvp) a. CTs b. NCTs minute dry & wet power frequency withstand Voltage primary (kv rms) a. CTs b. NCTs Power frequency over voltage withstand requirement for secondary winding (kv rms) (for 1 minute) 15. Min. creepage distance of porcelain housing (mm) a. CTs b. NCTs Rated short time withstand current (karms) for 1 Second Rated Dynamic withstand current (kap) 18. Creepage Factor /31.5* 62.5/78.75* * i. 31.5kA & 78.75kAp for 33 kv CTs to be installed / provided on new 220kv substations. ii. 25kA & 62.5kAp for 33 kv CTs to be installed / provided on 66 kv, 132 kv and existing 220kv substations E:\2. Tech. Specf. of Sub Station Wise \Latest Tech. Spec. JULY 2018\Spec September 2018\Final September Chapter - 1 CT- NCT Spec CT-5

6 5.0 GENERAL TECHNICAL REQUIREMENTS : 5.1 The insulation of the instrument transformer shall be so designed that the internal insulation shall have higher electrical withstand capability than the external insulation. The designed dielectrics withstand values of external and internal insulation's shall be clearly brought out in the guaranteed technical particulars. The dielectric withstand values specified in this specification are meant for fully assembled instrument transformers. 5.2 PORCELAIN HOUSING: The details of location and type of joint, if provided on the porcelain, shall be furnished by the Supplier alongwith the offer. The housing shall be made of homogeneous, vitreous porcelain of high mechanical and dielectric strength, glazing of porcelain shall be uniform brown or dark brown colour with a smooth surface arranged to shed away rain water or condensed water particles (fog) Details of attachment of metallic flanges to the porcelain shall be brought out in the offer. Nuts and bolts or screws used for fixation of the interfacing porcelain bushings for taking out terminals shall be provided on flanges cemented to the bushings and not on the porcelain. 5.3 METAL TANK: The metal tanks shall have bare minimum number of welded joints so as to minimize possible locations of oil leakage. The metal tanks shall be made out of mild steel/stainless steel/aluminum alloy, depending on the requirement. Welding in horizontal plane is to be avoided as welding at this location may give way due to vibrations during transport resulting in oil leakage. Supplier has to obtain specific approval from purchaser for any horizontal welding used in the bottom tank. The castings of base, collar etc, shall be diecast and tested before assembly to detect cracks and voids if any. 5.4 SURFACE FINISH : The ferrous parts exposed to atmosphere shall be hot dip galvanized or shall be coated with atleast two coats of Zinc Rich Epoxy painting. All nuts, Bolts and washers shall be of stainless steel. 5.5 INSULATING OIL: Insulating oil required for first filling of the instrument transformer shall be covered in Supplier's scope of supply. The oil shall meet the requirements of latest edition IS:335 or equivalent IEC. 5.6 PREVENTION OF OIL LEAKAGE & ENTRY OF MOISTURE: The supplier shall ensure that the sealing of instrument transformer is properly achieved. In this connection the arrangement provided by the Supplier at various locations including the following ones shall be described, supported by sectional drawings. i) Locations of emergence of primary and secondary terminals. ii) Interface between porcelain housing and metal tank/s. iii) Cover of the secondary terminal box. 5.7 GASKETS: For gasketed joints, wherever used nitrile butyl rubber gaskets shall be used. The gasket shall be fitted in properly machined groove with adequate space for accommodating the gasket under compression. 5.8 OIL LEVEL INDICATORS: Instrument transformers shall be provided with oil sight window (Prismatic Type) at suitable location so that the oil level is clearly visible with naked eye to an observer standing at ground level. CT-6

7 5.9 EARTHING: Metal tank of instrument transformer shall be provided with two separate earthing terminals for bolted connection to 50x8mm MS flat to be provided by the Purchaser for connection to station earth mat LIFITING AND TRANSPORTATION ARRANGEMENTS: Instrument transformer shall be provided with suitable lifting arrangement to lift the entire unit. The lifting arrangement shall be clearly shown in the general arrangement drawing. Lifting arrangement (lifting eye) shall be positioned in such a way as to avoid any damage to the porcelain housing or the tanks during lifting for installation/transport. Necessary string guides, if required shall be offered which shall be removable type. The CT/NCT shall be so constructed that it can be easily transported to site within the allowable transport limitation and in horizontal position, if the transport limitations so demand NAME PLATE: The instrument transformer shall be provided with non-corrosive, legible name plate with the information specified in relevant standards, duly engraved/punched on it. In addition to these the following specific points shall also be marked on the name plate. i) P.O. with date and (item No, if any) ii) Connection diagram. iii) iv) Rated continuous thermal current. General knee point voltage formula. The size of nameplate and its location on the equipment should be such that it is clearly readable with naked eyes while standing on ground TERMINAL CONNECTORS: Suitable terminal connectors of type 4 IPS Aluminium tube for 400kV CTs (Rigid type for one side and expansion type for other side) and suitable terminal connectors for connecting twin tarantulla for 220kV T/F I/C CTs, 220kV B/C CT ( / A),220kV Line CT ( / A), 33kV B/C CTs, 33kV T/F I/C CT ( / A), 33kV T/F I/C NCT ( /5A), 132kV B/C CT( /1-1A), 66kV B/C CT( /1-1A), 66kV T/F I/C CT, 66kV T/F I/C NCT & single Tarantulla conductor for 220kV T/F, Line/B.C CTs, 220kV NCTs, 132kV T/F I/C CT, 33kV Line cum Capacitor CT ( /5-1A) meant for 220/33kV T/F, twin ACSR Zebra for 33kV T/F I/C CT ( / A), 33kV T/F I/C NCT ( /5A) meant for 40/50MVA 132/33kV T/F & for Single ACSR Zebra for remaining CTs/NCTs shall be supplied. Suitable terminal earth connectors for earthing connections shall also be provided The terminal connectors shall meet the following requirements: 1) Terminal connectors shall be manufactured and tested IS:5561 or equivalent IEC. 2) All castings shall be free from blowholes, surface blisters, cracks and cavities. All sharp edges and corners shall be blurred and rounded off. 3) No part of a clamp shall be less than 10mm thick. 4) All ferrous parts shall be hot dip galvanized conforming to IS:2633 or equivalent IEC. 5) For bimetallic connectors, copper alloy liner of minimum 2mm thickness shall be cast integral with aluminium body. 6) Flexible connectors shall be made from tinned copper/ aluminium sheets. 7) All current carrying parts shall be designed and manufactured to have minimum contact resistance. 8) Connectors shall be designed to be corona free in accordance with the requirements stipulated in IS:5561 or equivalent IEC INTERNAL INSULATION: Enamel, if used for conductor insulation, shall be polyvinyl acetate type and shall meet the requirements of IS:4800 or equivalent IEC. Polyester enamel shall not be used. Double cotton cover, CT-7

8 if used, shall be suitably covered to ensure that it does not come in contact with oil TEMPERATURE RISE: The temperature rise on any part of equipment shall not exceed maximum temperature rise specified in IS:2705 or equivalent IEC. However, the permissible temperature rise is for a maximum ambient temperature of 50 o C PRESSURE RELIEF DEVICE: Suitable arrangement shall be made for compensation of variation in the oil volume due to ambient variation and to take care of internal abnormal pressures. The pressure variation shall be kept within limits, which do not impair the tightness of the instrument transformer. A pressure relief device capable of releasing abnormal internal pressure shall be provided SECONDARY TERMINAL BOXES: The CT secondary terminals except for CTs with metering core having accuracy class 0.2S shall be brought out in a weather proof terminal box. The terminal box shall be provided with removable gland plate. In case of CTs, with metering core having accuracy class 0.2S, CT secondary terminals shall be brought out in two separate weatherproof terminal boxes. In case of metering CTs having 2 metering cores, CT secondary terminals shall be brought out in two separate weatherproof terminal boxes with proper sealing facility. In the first box, all the terminals of cores of CTs except metering core having accuracy class 0.2S shall be brought out. The terminal box shall be provided with removable gland plate. The terminal of metering core having accuracy class 0.2S CTs, shall be brought out in the second terminal box. This shall also be provided with a removable gland plate. This terminal box shall be provided with proper sealing facility. The terminal box/boxes shall be dust and vermin proof. The dimensions of the terminal box/boxes and its/their openings shall be adequate to enable easy access and working space with use of normal tools POLARITY : Polarity shall be indelibly marked on each primary and secondary terminal. Facility shall be provided for short-circuiting and grounding of the secondary terminals inside the terminal box OIL FILLING AND DRAIN VALVES: The instrument transformers shall be vacuum filled with oil after processing and thereafter hermetically sealed to eliminate breathing and to prevent air and moisture from entering the tanks. Sealing type oil filling and/or oil sampling cocks shall be provided with facility to reseal the same. The method adopted for hermetic sealing shall be described in the offer INSTRUMENT SECURITY FACTOR: For all type of CTs, the instrument security factor at all ratios shall be less than 5 for metering core. If any, auxiliary CTs / reactor are used in the CTs then all the parameters specified shall have to be met treating auxiliary CTs as integral part of the current transformer PRIMARY WINDING: The design density for short circuit current as well as conductivity of the metal used for primary winding shall meet the requirement of IS:2705 or equivalent IEC. The supplier shall in his offer furnish detailed calculations for selection of winding cross-sections. CT-8

9 5.21 SECONDARY WINDING: Suitably insulated wire of electrolytic grade shall be used for secondary windings. Type of insulation used shall be described in the offer. For multi ratio design, suitable tapping shall be provided on secondary winding only. Ratio tap selection through primary side shall not be acceptable CORE: The exciting current of the CT shall be as low as possible. The supplier shall furnish alongwith his offer the magnetization curve/s for all the core/s. The cores shall be of high grade, non-ageing electrical silicon laminated steel of low hysterisis loss and high permeability to ensure high accuracy at both normal and over current PRIMARY TERMINALS: For 400kV CT, 220 kv Line CT ( / A), 220kV Bus Coupler CT ( / A), 66kV T/F I/C CT ( / A), 66kV T/F I/C NCT ( /1A), 66kV B/C CT ( /1-1A), 33kV T/F I/C CT ( / A & / A), 33kV T/F I/C NCT ( /5A & /5A) & 33kV Bus Coupler CT the primary terminal shall be made out of rods of not less than 40mm dia. copper or equivalent IS/IEC and for remaining CTs/NCTs the primary terminals shall be made out of rods not less than 30mm dia. copper or equivalent ISS\IEC DEVIATION FROM SPECIFICATION: Any deviation from the specification shall be clearly brought out separately. In the absence of any specific mention, it shall be implied that the equipment offered is entirely according to this specification TEST TAP: The 72.5 kv and above voltage level, instrument transformers shall be provided with suitable test tap for measurement of tests such as partial discharges etc. in factory as well as at site. Provision shall be made of a screw on cap for solid and secured earthing of the test tap connection, when not in use. A suitable caution plate shall be provided duly fixed on the cover of the secondary terminal box indicating the purpose of the test tap and necessity of its solid earthing prescribed method before energizing the equipment. NOTE:- The Overall Tolerance for dimensions, Quantity of Oil, Weight, etc should be +5% max. The General Tolerance should be ISS. Tolerance for Mounting Dimension should be +5mm. 6.0 TESTS: 6.1 TYPE TESTS The equipment offered should be fully type tested. In case, the equipment of the type and design offered has already been type tested, the supplier shall furnish 4 sets of type test reports alongwith the offer. The type test reports should not be more than seven years old, reckoned from the date of bid opening and the type test should have been carried out in accordance with ISS- 2705(1992)/equivalent IEC from Govt./ Govt. approved test house. However, temperature rise test although covered under type tests will be got conducted by the supplier on one piece of total ordered quantity of each type, at his premises in the presence of the inspecting officer of the purchaser, without any extra charges. The purchaser reserves the right to demand repetition of some or all the type tests in the presence of purchaser's representative. 6.2 ACCEPTANCE AND ROUTINE TESTS: i) All acceptance including Tan Delta test and routine tests as stipulated in the relevant standards shall be carried out by the Supplier in presence of purchaser's representative, unless dispensed with in writing by the Purchaser. CT-9

10 ii) Immediately after finalisation of the programme of routine /acceptance testing, the Supplier shall give sufficient advance intimation to the Purchaser to enable him to depute his representative for witnessing the testing. 7.0 DOCUMENTATION: 7.1 All drawings shall conform to international standards organisation (ISO) `A' series of drawing sheet/indian Standards Specification IS: All drawings shall be in ink and suitable for microfilming. If drawings are computerized than all drawings shall be nicely printed. All dimensions and data shall be in S.I. Units. 7.2 List of drawings: a) General outline and assembly drawings of the equipment. b) Graphs showing the performance of equipment's in regard to magnetisation characteristics; ratio & phase angle curves, ratio correction factor curves. c) Sectional views showing: i) General Constructional Features. ii) Materials/Gaskets/Sealing used. iii) The insulation & the winding arrangements, method of connection of the primary / secondary winding to the primary/ secondary terminals etc. iv) of Turns, Cross-Sectional Area, density of Primary and secondary windings. v) Porcelain used and its dimensions. d) Arrangement of terminals and details of connection studs provided. e) Name plate. f) Schematic drawing. g) Detailed drawing of pressure release device with detailed literature. h) Terminal connector drawing. NOTE:- All above drawings should bear a minimum space (14X10cm) for stamping the approval of drawings by the purchaser. 7.3 The bidder shall submit four sets of final versions of complete and correct equipment drawings except 7.2 (b) above (actual of which shall be supplied at the time of inspection) for purchaser s approval alongwith bid in a sealed envelope. The purchaser shall communicate his comments/approval on the drawings to the supplier within 21 days from the date of issue of LOI. The submission of complete and correct readable drawings for approval is the responsibility of the bidder/supplier. The supplier shall, if so required by the purchaser, modify the drawings and resubmit four copies of the modified drawings for purchaser s approval within two weeks from the date of purchaser s comments. Then, the purchaser shall approve the revised drawings within two weeks from the date of its receipt. 7.4 The manufacturing of the equipment shall be strictly in accordance with the approved drawings and no deviation shall be permitted without the written approval of the purchaser. All manufacturing and fabrication work in connection with the equipment prior to the approval of the drawing shall be at the supplier's risk. 7.5 The successful bidder shall also supply one set of nicely bound all the approved drawings & instruction manual containing handling, installation, testing and commissioning of equipment at the time of despatch of material to the consignee with each equipment for our field staff without which the supply will not be considered as complete supply. In addition, 5 sets of such bound manuals and final approved drawings shall be supplied for reference & record in our design office alongwith one good quality soft copy (CD) of approved drawings and instruction manuals, if computerized. CT-10

11 7.6 Approval of drawings / work by Purchaser shall not relieve the Supplier of his responsibility and liability for ensuring correctness and correct interpretation of the latest revision of applicable standards, rules and codes of practices. The equipment shall conform in all respects to high standards of engineering, design, workmanship and latest revisions of relevant standards at the time of ordering and purchaser shall have the power to reject any work or material which in his judgement is not in full accordance therewith. NOTE :- (i) In case the equipment offered by the Supplier does not meet with the requirement of technical specification the offer of the firm shall not be considered. (ii) Supplier shall provide special label on the LIVE Tank CTs and its packing for caution in handling the CTs carefully. CT-11

12 ratio COREWISE DETAILS OF 420 kv CTs ( / A) NUMBER OF CORES 5 class Min. knee Pt. Voltage Vk Max. CT sec. wdg. Resistance (ohms) ANNEXURE I-A(i) Max. Excitation current at Vk (in ma) LINE PROTN. 5 TRANS. DIFF/ LINE PROTN. 1 BUS DIFF MAIN 1000 /1 2 BUS DIFF CHECK 1000/1 3 METERING /1 4 TRANS BACKUP/ / /1 - PS 2000/ /5 30 on 2000/1 Tap; 60 on 1000/1 Tap - PS 2000/ /5 30 on 2000/1 Tap; 60 on 1000/1 Tap S PS 4000/2000/ PS 4000/2000/ 1000 COREWISE DETAILS OF 245kV Transformer CTs ( / A) NUMBER OF CORES - 5 class knee-point voltage At CT Secondary resistance at 75 0 C at 300A tap (Volt) 10/5/ on 2000/1 Tap;60 on 1000/1 Tap; 120 on 500/1 Tap 10/5/ on 2000/1 Tap;60 on 1000/1 Tap; 120 on 500/1 Tap ANNEXURE I-B(i) 1 DIFFERENTIAL / - PS 40 (RCT+2) 2 REF /1 - PS 14 (RCT+2) OVER CURRENT / BUS BAR 4 BUSBAR (FOR LOW IMPEDANCE SCHEME) A.L.F /1 - PS 40 (RCT+4) - PS 40 (RCT+4) METERING / S NOTE : 4th core for bus bar protection has been kept in view of general design being followed in HVPNL. In case this CT is used on a sub station having high impedance bus bar protection scheme or no bus bar protection scheme then this core shall be short-circuited at site. CT-12

13 COREWISE DETAILS OF 245kV LINE CUM BUS-COUPLER CTs ( / A) NUMBER OF CORES 5 class knee point voltage At CT Secondary resistance at 75 0 C at 800Atap (Volt) ANNEXURE I-B(ii/a) MAIN I DISTANCE /1 - PS 80(RCT+9) Vk 2. MAIN II DISTANCE 3. BUS DIFFERENTIAL MAIN 4. BUS DIFFERENTIAL CHECK / / /1 5. METERING /1 - PS 80(RCT+9) Vk - PS 100(RCT+4) Vk/2 - PS 100(RCT+4) Vk/ S - - NOTE : 1. 5 cores of 245kV line CT have been kept in view of general design being followed in HVPNL. 2. In case this CT is used exclusively for bus bar protection purpose on a transformer circuit at sub station having high impedance bus bar protection scheme then core no 1, 2 & 5 shall be short circuited at site. 3. In case this CT is used for feeder circuit on a sub station having low impedance bus bar protection scheme then core no. 4 shall be short circuited at site and where there is no bus bar protection scheme core no. 3 & 4 shall be short circuited at site. CT-13

14 ANNEXURE I-B(ii/b) COREWISE DETAILS OF 245kV LINE CTs ( / A) NUMBER OF CORES 5 class knee point voltage At CT Secondary resistance at 75 0 C at 1000A tap (Volt) MAIN I DISTANCE /1 - PS MAIN II DISTANCE 3. BUS DIFFERENTIAL MAIN 4. BUS DIFFERENTIAL CHECK / / /1 5. METERING /1 - PS PS PS S - - NOTE : 1. 5 cores of 245kV line CT have been kept in view of general design being followed in HVPNL. 2. In case this CT is used exclusively for bus bar protection purpose on a transformer circuit at sub station having high impedance bus bar protection scheme then core no 1, 2 & 5 shall be short circuited at site. 3. In case this CT is used for feeder circuit on a sub station having low impedance bus bar protection scheme then core no. 4 shall be short circuited at site and where there is no bus bar protection scheme core no. 3 & 4 shall be short circuited at site. CT-14

15 COREWISE DETAILS OF 245 kv BUS COUPLER CTs FOR 400KV S/STNS. ( / A) ANNEXURE I-B(iii) NUMBER OF CORES - 4 class Formula for minimum knee point voltage At CT Secondary resistance at 75 0 C at 2400Atap (Volt) 1. O/C & E/F /1 15 5P ALF 2. BUS DIFFERENTIAL /1 - PS 100(RCT+4) Vk/2-3. BUS /1 - PS 100(RCT+4) Vk/2 - DIFFERENTIAL CHECK 4. METERING / CT-15

16 ANNEXURE I-B(iv) COREWISE DETAILS OF 245 kv Transformer INCOMER CTs ( / A) NUMBER OF CORES - 5 class Formula for minimum knee-point voltage At CT Secondary resistance at 75 0 C at 900Atap (Volt) A.L.F 1 DIFFERENTIAL /1 - PS 40 (RCT+2) OVER CURRENT & /1 15 5P EARTH FAULT 3 METERING / S BUSBAR MAIN DIFF /1 - PS 40 (RCT+4) BUSBAR CHECK DIFF /1 - PS 40 (RCT+4) - ANNEXURE I-B (v) COREWISE DETAILS OF 245kV NEUTRAL CTs ( /1A) NUMBER OF CORE - 1 class knee-point voltage at CT Secondary resistance at 75 0 C at 300Atap(Volt) Minimum Insulation Voltage (kv) REF /1 PS 14(RCT+2) V K/2 33 CT-16

17 COREWISE DETAILS OF 145kV TRANSFORMER INCOMER CT ( / A) NUMBER OF CORES 4 Class knee-point voltage At CT Secondary resistance at 75 0 C at 500Atap (Volt) ANNEXURE I-C(i) 1. DIFFERENTIAL / - PS 40 (RCT+2) Vk/ REF /1 - PS 90 (RCT+2) Vk/2-3. OVER CURRENT AND /1 15 5P EARTH FAULT 4. METERING / S - - COREWISE DETAILS OF 145kV TRANSFORMER CT ( / A) OF CORES = 4 class as per IEC 185 knee-point voltage At CT Secondary resistance at 75 0 C at 100A tap (Volt) A.L.F. ANNEXURE I-C(ii) A.L.F. 1. DIFFERENTIAL PS 40 (RCT+1) Vk/4-100/ REF PS 20 (RCT+1) Vk/2-100/1 3. OVER P CURRENT 100/1 4. METERING / S CT-17

18 ANNEXURE I-C(iii) COREWISE DETAILS OF 145kV LINE CT AND 145kV BUS COUPLER CT for 132kV S/STNS. ( /1-1-1A) OF CORES = 3 Accurac y class knee-point voltage At CT Secondary resistance at 75 0 C at 300Atap (Volt) A.L.F. 1 DISTANCE /1 - PS 120 (RCT+4.5) VKP - 2 OVER-CURRENT & EARTH FAULT /1 15 5P METERING / S COREWISE DETAILS OF 145kV NEUTRAL CT ( /1A) OF CORE= 1 Accurac y class knee-point voltage At CT Secondary resistance at 75 0 C at 100A tap (Volt) ANNEXURE I-C(iv) Minimum Insulatio n Voltage (kv) 1 REF /1 - PS 20 (RCT+1) VK/2 15 CT-18

19 ANNEXURE I-C(v) COREWISE DETAILS OF 145kV BUS COUPLER CT for 160MVA 220/132kV T/Fs. ( /1-1A) OF CORES = 2 class A.L.F OVER-CURRENT & EARTH /1 15 5P 10 FAULT 3 METERING / COREWISE DETAILS OF 145kV Metering CT (100-50/1-1A) OF CORES = 2 class knee-point voltage At CT Secondary resistance at 75 0 C at 300Atap (Volt) ANNEXURE I-C(vi) 1 MAIN METERING /1A S - - ISF<5 2 CHECK METERING /1A S - - ISF<5 I.S.F. CT-19

20 COREWISE DETAILS OF 72.5kV TRANSFORMER INCOMER CT ( / A) NUMBER OF CORES - 4 class knee-point voltage At CT Secondary resistance at 75 0 C at 1000A tap (Volt) ANNEXURE I-D(i) A.L.F. 1 DIFFERENTIAL / PS 40 (RCT+2) VK/4-2 REF /1 - PS 14 (RCT+2) VK/2-3 OVER CURRENT & EARTH FAULT /1 15 5P METERING / S COREWISE DETAILS OF 72.5kV TRANSFORMER CT FOR 66/11kV T/Fs ( / ) OF CORES = 3 ANNEXURE I-D(ii) Formula for A.L.F class minimum kneepoint voltage At CT Secondary resistance at 75 0 C at 300A tap (Volt) 1 DIFFERENTIAL / PS 40(RCT+4) VK/2-2 REF /1 - PS 40(RCT+4) VK/2-3 OVER CURRENT /1 15 5P CT-20

21 ANNEXURE I-D(iii) COREWISE DETAILS OF 72.5kV LINE CT AND 72.5kV BUS COUPLER CT for 66kV S/STNS. ( /1-1-1A) OF CORES = 3 class Formula for min knee point voltage At CT Secondary res. at 75 0 C at 600A tap (Volt) A.L.F. 1 DISTANCE /1 - PS 80(RCT+4) OVER CURRENT & EARTH FAULT /1 15 5P METERING / S COREWISE DETAILS OF 72.5kV TRANSFORMER INCOMER NCT ( /1A) OF CORES= 1 class Formula for min knee point voltage At CT Secondary res. at 75 0 C at 1000A tap (Volt) ANNEXURE I-D(iv) Minimum Insulation Voltage (kv) 1 REF /1 - PS 14 VK/2 15 (RCT+2) CT-21

22 COREWISE DETAILS OF 72.5 kv NEURAL CT FOR 66/11kV T/Fs ( /1) OF CORE = 1 ANNEXURE-I D(v) Formula for Minimum class as minimum knee exciting Insulation per IEC point voltage at current voltage 185 CT secondary (kv) resistance at 75 0 at 300A tap (Volt) 1. REF /1 - PS 20 (RCT+1) Vk/2 15 ANNEXURE I-D(vi) COREWISE DETAILS OF 72.5kV BUS COUPLER CT for 160MVA 220/66kV T/Fs. ( /1-1A) OF CORES = 2 class A.L.F OVER-CURRENT & EARTH /1 15 5P 10 FAULT 3 METERING / CT-22

23 COREWISE DETAILS OF 72.5kV Metering CT (75/1-1A) of CORES = 2 ANNEXURE I-D(vii) class as per IEC 185 knee-point voltage At CT Secondary resistance at 75 0 C at A tap (Volt) I.S.F. 1 METERING 75/1A S - - ISF<5 2 METERING 75/1A S - - ISF<5 ANNEXURE I-D(viii) COREWISE DETAILS OF 72.5kV Metering CT (200/1-1A) of CORES = 2 class as per IEC 185 knee-point voltage At CT Secondary resistance at 75 0 C at A tap (Volt) I.S.F. 1 METERING 200/1A S - - ISF<5 2 METERING 200/1A S - - ISF<5 Note:- As primary current of CT is dependent upon load so secondary parameters i.e. secondary current,, accuracy class, ISF etc. for each will remain same for metering CTs with different primary current. CT-23

24 ANNEXURE I-E(i) COREWISE DETAILS OF 36kV TRANSFORMER INCOMER CT FOR 40/50MVA 132/33kV T/F AND OTHER RATINGS OF 132/33KV T/Fs WITH 25/31.5*KA STC ( / ) OF CORES = 4 Formula for A.L.F. class as minimum knee point Per IEC voltage At CT 185 Secondary resistance at 75 0 C at 400A tap (Volt) (ma) 1 DIFFERENTIAL /0.577 PS 40 (RCT+1) 30@VK/4-2 REF /5 - PS 100(RCT+1) 75@VK/2-3 OVER CURRENT & EARTH FAULT /5 15 5P MAIN METERING / S ANNEXURE-I-E(ii) COREWISE DETAILS OF 36kV TRANSFORMER INCOMER CT FOR 220/33KV WITH 25/31.5*KA STC ( / ) Burden OF CORES = 4 class knee-point voltage At CT Secondary resistance at 75 0 C at 2000A tap (Volt) 1 DIFFERENTIAL / - PS 40 (RCT+1) 30@ V K/ REF. PROT / 5 - PS 100 (RCT+1) 75@ V K/2-3 OVER CURRENT & EARTH FAULT PROT /5 15 5P MAIN METERING / S A.L.F. CT-24

25 ANNEXURE I-E(iii) COREWISE DETAILS OF 36kV LINE CUM CAPACITOR CT for 33kV LINE BAY AND FOR 20MVAR & 10MVAR CAPACITOR BANKS ON 220/33KV T/F & 40/50MVA 132/33kV T/F WITH 25/31.5*KA STC ( /5-1) OF CORES = 2 Ratio (A) Burden Class as A.L.F. per IEC OVER CURRENT & EARTH /5 15 5P 10 FAULT 2. METERING / S 75 ANNEXURE I-E(iv) COREWISE DETAILS OF 36kV TRANSFORMER INCOMER NCT FOR 40/50MVA 132/33kV T/F AND OTHER RATINGS OF 132/33KV T/Fs WITH 25/31.5*KA STC ( /5) OF CORES = 1 class as Per IEC 185 knee point voltage At CT Secondary resistance at 75 0 C at 400A tap (Volt) Minimum Insulation Voltage (kv) 1 REF /5 - PS 100 (RCT+1) 75@ VK/2 15 ANNEXURE-I-E(v) COREWISE DETAILS OF 36kV TRANSFORMER INCOMER NCT FOR 220/33KV T/F WITH 25/31.5*KA STC ( /5) OF CORES = 1 Burden class knee-point voltage At CT Secondary resistance at 75 0 C at 2000A tap (Volt) Minimum Insulatio n Voltage (kv) 1 REF /5 - PS 100 (RCT+1) 75@ VK/2 15 CT-25

26 ANNEXURE-I-E(vi) COREWISE DETAILS OF 36kV BUS COUPLER CT FOR 220/33KV WITH 25/31.5*KA STC ( /5A) OF CORES = 1 Burden class IEC 185 A.L.F OVER CURRENT & EARTH FAULT / 5A 15 5P 10 COREWISE DETAILS OF 36kV TRANSFORMER CT WITH 25/31.5*KA STC FOR 4 MVA 33/11kV T/F (100-50/5-5) OF CORES = 2 class as Per IEC 185 knee point voltage At CT Secondary resistance at 75 0 C at 100A tap (Volt) ANNEXURE I-E(vii) Minimum Insulation Voltage (kv) 1 REF /5 - PS 100 (RCT+1) 75@ VK/2-2 OVER CURRENT /5 15 5P COREWISE DETAILS OF 36kV TRANSFORMER NCT WITH 25/31.5*KA STC FOR 4 MVA 33/11kV T/F (100-50/5) OF CORE = 1 class knee-point voltage At CT Secondary resistance at 75 0 C at 100A tap (Volt) ANNEXURE I-E(viii) Minimum Insulation Voltage (kv) REF /5 PS 100 (RCT+1) 75@ VK/2 15 * i. 31.5kA for 33 kv CTs to be installed / provided on new 220kv substations. ii. 25kA for 33 kv CTs to be installed / provided on 66 kv, 132 kv and existing 220kv substations. CT-26

27 COREWISE DETAILS OF 12 kv NEUTRAL CT FOR 31.5 MVA T/F ( /5) OF CORE = 1 ANNEXURE-I F(i) Minimum class as knee point voltage at exciting Insulation per IEC CT secondary current voltage 185 resistance at 75 0 at (kv) 1800A tap (Volt) REF /5 PS 95 (RCT+1) 75@ Vk/ ANNEXURE I-F(ii) COREWISE DETAILS OF 12kV NEUTRAL CT FOR 12.5/16 MVA & 16/20 MVA T/F class ( /5) OF CORE = 1 knee-point voltage At CT Secondary resistance at 75 0 C at 1200A tap (Volt) Minimum Insulatio n Voltage (kv) REF /5 PS 95 (RCT+1) 75@ VK/ COREWISE DETAILS OF 12kV NEUTRAL CT for 4MVA 33/11kV T/F class ( /5) OF CORE = 1 knee-point voltage At CT Secondary resistance at 75 0 C at 300A tap (Volt) ANNEXURE I-F(iii) Minimum Insulatio n Voltage (kv) REF /5 PS 95 (RCT+1) 75@ VK/ CT-27

28 ANNEXURE-II GUARANTEED TECHNICAL PARTICULARS (To be filled in by the Supplier separately for each type and voltage rating). 1. Manufacturer's Name 2. Type/Installation. 3. Conforming to standard. 4. Rated voltage. 5. Rated frequency. 6. Detail of cores. * I II III IV V 6.1 Purpose of cores. 6.2 Rated Secondary. 6.3 Class of accuracy. 6.4 limit factor. 6.5 Formula governing minimum knee point voltage at CT Secondary resistance corrected to 75 C. 6.6 Instrument security factor. 6.7 Secondary limiting voltage. 6.8 Secondary resistance corrected to 75 C. 6.9 Rated current for Distance protection core at Vk, for Bus Bar protection core & REF at CT-28

29 Vk/2. and for differential protection at Vk/4 * of cores applicability for a particular type of current 7. Rated primary current. 8. Rated short time withstand current (ka rms) for 1 second duration. 9. Rated dynamic withstand current (ka peak). 10. Rated continuous thermal current (pu). 11. One minute power frequency withstand voltage (kv rms) a) Dry b) Wet /50 micro-second impulse withstand voltage (kv peak) 13. One minute power frequency withstand voltage of secondary winding (kv rms) 14. Minimum creepage distance (mm) 15. creepage factor. 16. Winding a) of primary turns b) Primary amp. turns CT-29

30 (Dynamic condition) c) density d) Area of Cross-section & material i) Primary turns ii) Secondary turns 17. I.S. to which the oil conforms. 18. Weight of oil (kg). 19. Quantity of oil (Ltrs) 20. Total weight (kg). 21. shipping weight (kg) 22. Overall dimension. 23. Mounting details. 24. permissible temperature rise of winding when referred to maximum ambient temperature of 50 C in terms of clause 7.2 (Table 2 of IS:2705 Part ) or Equivalent IEC CT-30