Specification No. CSC- XXIX/DH/UH/P&D/

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1 UTTAR & DAKSHIN HARYANA BIJLI VITRAN NIGAM Specification No. CSC- XXIX/DH/UH/P&D/ TECHNICALSPECIFICATION FOR PORCELAIN INSULATROS AND INSULATORS FITTINGS FOR 11 KV OVERHEAD POWER LINES Issue of the Month: Common Specifications Committee UHBVN & DHBVN Page 1 of 11

2 TECHNICAL SPECIFICATIONS FOR PORCELAIN INSULATORS AND INSULATORS FITTINGS FOR 11 KV OVERHEAD LINES: 1. SCOPE : This specification covers the details of the porcelain insulators and insulator fittings for use on 11 KV overhead power lines met with in rural Electric distribution systems. 2. APPLICABLE STANDARDS : Except when they conflict with the specific requirements of this specification, the insulators shall comply with the Indian Standard Specification IS: or the latest version thereof and the insulator fittings shall comply with the Indian Standard Specification IS: 2486 (Part-I), IS 2486 (Part-II) 1974 & IS: 3188 or the latest version thereof or equivalent international standards. 3. CLIMATIC CONDITIONS : The equipment is required to operate satisfactory under the following site conditions: 1. Max. ambient air temperature 60 0 C 2. Min. ambient air temperature (-)5 0 C 3. Average Daily Max. ambient temperature 40 0 C 4. Max. yearly weighted average ambient temperature 32 0 C 5. Max. altitude above mean sea level (Meters) Minimum Relative Humidity (%age) Max. Relative Humidity (%age) Avg. No. of Rainy days/year Avg. annual rainfall 900 mm 10. Maximum wind pressure 195 Kg./m Sq. 4. GENERAL REQUIREMENT : 4.1 The porcelain shall be sound free from defects thoroughly vitrified and smoothly glazed. 4.2 Unless otherwise specified, the glaze shall be brown in colours. The glaze shall cover all the porcelain parts of the insulator except those areas which serve as support during firing or are left unglazed for the purpose of assembly. 4.3 The design of the insulator shall be such that stresses due to expansion and contraction in any part of the insulator shall not lead to deterioration. The porcelain shall not engage directly with hard metal. Page 2 of 11

3 4.4 Cement used in the construction of the insulator shall not cause fracture kby expansion or loosing by contraction and proper care shall be taken to locate the individual parts correctly during cementing. The cement shall not give rise to chemical reaction with metal fittings and its thickness shall be as uniform as possible. 4.5 The insulators should preferably be manufactured in automatic temperature controlled kilns to obtain uniform baking and better electrical & mechanical properties. 5. CLASSIFICATION AND DIMENSIONS : 5.1 Both pin & strain insulators shall conform to type B of IS: The dimension of pin insulators shall be as shown in the drawings. 5.3 The strain insulators shall be ball & socket type or Tongue & clevis type, as required by the purchaser. The dimensions of these insulators shall be as per IS: 2486 (Part-II). 6. TEST VOLTAGES : Highest system voltage The test voltages of insulators shall be as under: Visible discharge test Wet power frequency withstand test. Power frequency puncture withstand test (Pin Insulators) Power frequency puncture withstand test (Strain Insulators) Impulse voltage withstand test. KV 12 (rms) KV (rms) 9 KV (rms) 35 KV 105 (rms) KV (rms) 1.3 times the actual dry flash over voltage of insulator KV 75 (Peak) 7. FAILING LOAD : 7.1 Electro mechanical failing load (for Pin Insulators only). The insulators shall be suitable for a minimum failing load of 5 KN applied in transverse direction. 7.2 Electro mechanical failing load (for strain insulators only). The insulators shall be suitable for a minimum failing load of 45 KN applied in axially. Page 3 of 11

4 8. CREEPAGE DISTANCE : The maximum creepage distance shall be as under: Highest voltage system Normal & Heavily polluted Atmosphere moderately polluted atmosphere Pin Insulator strain insulator 12 KV 230 mm 320 mm 400 mm Higher value of creepage distance has been specified for strain insulators as these are normally used in horizontal position in 11 KV lines. 9. TESTS: The insulators shall comply with the following tests as per IS 731 or equivalent international standards. 9.1 TYPE TESTS : The following shall constitute the type tests: A) Visual examination. B) Verification of dimensions. C) Impulse voltage withstand test. D) Wet power frequency voltage withstand test. E) Temperature cycles test. F) Electro mechanical failing load test. (for strain insulator only). G) Mechanical failing load test. (for Pin Insulator only). H) Puncture test. I) Porosity test. J) Galvanizing test. K) Visible discharge test. L) 24 hours mechanical strength test. (for strain insulators only). 9.2 ACCEPTANCE TESTS : The test samples after having withstood the routine test shall be subjected to the following acceptance tests in the order indicated below: Page 4 of 11

5 A) Verification of dimensions. B) Temperature cycle tests. C) Electro mechanical failing load test (for strain insulator only). D) Puncture test (for strain insulator only). E) Porosity test and. F) Galvanizing test. 9.3 ROUTINE TESTS : 10. MARKING: The following test shall be carried out as routine tests: A) Visual examination. B) Mechanical routine test (for strain insulator only). C) Electrical routine test. (for strain insulator only) Each insulator shall be legibly and indelibly marked to show the following: A) Name or trade mark of the manufacturer. B) Month and year of manufacture. C) Min. failing load in KN. D) ISI certification mark, if any Marking on porcelain shall be printed and shall be applied before firing. 11. PACKING : All insulators (without fittings) shall be packed in wooden crates suitable for easy and rough handling land acceptable for rail transport, where more than one insulator is packed in a crate wooden separators shall be fixed between the insulators to keep individual insulator in position without movement within the crate. 12. SCOPE : PART-B INSULATOR FITTINGS : This specification covers details and test requirements for: 1) Pins for 11 KV Pin Insulators. 2) Fittings for strain insulators. Page 5 of 11

6 13. APPLICABLE STANDARD : Pins shall comply with the requirements of IS: 2486 (Part I & II) with latest amendments. Fitting for strain insulator shall comply with the requirements of IS: 2486, Part-I to IV with latest amendments or equivalent international standards Pins for Pin Insulators General requirements : The pins shall be a single piece obtained preferably by the process of forging. They shall not be made by joining, welding, shrink fitting or any other process from more than one piece of material. They shall be of good finish, free from flaws and other defects. The finish of the cellar shall be such that a sharp angle between the cellar and the shank is avoided. All ferrous pins, nuts & washer except those made of stainless steel shall be galvanized. The threads of nuts & tapped holes shall be cut after galvanizing and shall be well oiled or greased DIMENSIONS : Pins shall be of small steel head type S-I as per IS : 3486 (Part II) having stalk length of 165 mm and shank length of 150mm with minimum failing load of 5 KN TEST : Insulator pins shall comply with the following test as per IS: 2486 (Part-I) or equivalent international standards ACCEPTANCE TEST : a) Checking of threads on heads. b) Galvanizing test. c) Mechanical test ROUTINE TEST : Visual examination test TYPE TEST : a) Checking of threads on heads. b) Galvanizing test. c) Mechanical test. d) Visual examination test. Page 6 of 11

7 15. STRAIN INSULATORS SETS : 15.1 GENERAL REQUIREMENTS : All forging and casting shall be of good finish and free from laws and other defects. All edges on the outside of fittings such as at the eye, clevis & holes, shall be rounded. All parts of different fittings which provide for interconnection shall be made such that sufficient clearance is provided at the connection point to ensure free movement and suspension of the insulator string assembly. All eye and clevis connections shall be free but the care shall be taken that too much clearance between eye & the tongues of the clevis is avoided. All ferrous fittings and the parts other than those stain less steel, shall be galvanized, small fittings like spring washers, nuts etc. may be electroplated with zinc TYPE : Clevis and tongue type insulator set shall be supplied, the nominal dimensions of the clevis and tongue type insulator set shall be as given in IS: TESTS : Strain insulator sets shall comply with the following tests as per IS: 2486 (Part I) TYPE TESTS : A) Mechanical test. B) Electrical resistance test (for tension clamps only). C) Heating cycles test (for tension clamps only) SAMPLE TEST : A) Dimensional. B) Galvanizing check electroplating test ROUTINE TEST : A) Visual check. B) Mechanical test STRAIN CLAMPS : Suitable aluminum alloys clamps shall be provided alongwith the fittings to suit ACSR conductors 7/2. 11 mm 7/3. 35mm. The ultimate strength of clamps should not be less than 3000 Kgs. Page 7 of 11

8 16. MARKING : 16.1 The caps and clamps shall have mark on them with the following information : a) Name or trade mark of the manufacture. b) Country of manufacture. 17. PACKING : 17.1 For packing of GI pins, strain clamps & related hardware, double gunny bags or wooden cases if deemed necessary shall be employed. The heads & threads portions of pins & the fittings shall be properly protected against damage. The gross weight of the packing shall not normally exceed 50 Kg. Different fittings shall be packed in different bags or cases and shall be complete with their minor accessories fitted in place. All nuts shall be hand tightened over the bolts & screwed up to the farthest point The packages containing fittings may also be marked with the ISI certification mark. 18. TEST & TEST CERTIFICATES : The tenderers shall submit Photostat copies of all the tests including type test as prescribed in the relevant ISS from any accredited laboratory 19. GUARANTEED & OTHER TECHNICAL PARTICULARS : These particulars shall be furnished strictly as per Annexure A in duplicate. Any deviation from this specification shall be clearly brought out separately. 20. PLACE OF MANUFACTURE : The tender shall state the place of manufacturer, testing and name of the manufacturer of the various items included in his Tender. 21. INSPECTION : Inspection of material and supervision of test in accordance with the relevant standards as mentioned in clause 2 & 13 above and supporting drawing and schedules, and approved manufacturer specification shall be carried out by the purchaser or his duly authorized representative. The material shall be inspected and tested before dispatch by an authorized representative of the DHBVN in respect of quality. The manufacturer shall provide to the Page 8 of 11

9 inspecting officer all reasonable facilities without charge to satisfy him that the material is being furnished in accordance with the specification. The purchaser or his authorized representative shall have access to all reasonable time to manufacturer s works to inspect and witness the test of the equipment manufactured. The purchaser has the right to have the tests carried out at the cost of supplier by an independent Govt. agency wherever there is a dispute regarding the quality of material supplied. The manufacturer shall be responsible to pay penalty of Rs 20,000/- for each occasion at which the fake inspection call has been made or the material is rejected during testing/inspection by the authorized agency/representative of the Nigam. This penalty would be in addition to the expenses incurred by the Nigam in deputing the Inspecting Officer, carrying out such inspection. 22. Challenge Clause:- The material offered/received after the inspection by the authorized inspecting officer may again be subjected to the test for or any parameter from any testing house/in-house technique of the Nigam & the results if found deviating un-acceptable or not complying to approved GTPs the bidder shall arrange to supply the replacement within thirty (30) days of such detection at his cost including to & fro transportation. In addition, of cost of the inspected lot of material shall be imposed. 23. Warranty Period:- The supplier shall be responsible to replace, free of cost, with no transportation or insurance cost to the purchaser, up to destination, the whole or any part to the material which in normal and proper use proves the defective in quality or workmanship, subject to the condition that the defect is noticed within 18 months from the date of receipt of material in stores or 12 months from the date of commissioning whichever period may expire earlier. The consignee or nay other officer of Nigam actually using the material will give Page 9 of 11

10 prompt notice of each such defect to the supplier. The replacement shall be effected by the supplier within a reasonable time, but not, in any case, exceeding 45 days. The supplier shall, also, arrange to remove the defective within a reasonable period, but not exceeding 45 days from the date of issue of notice in respect thereof, failing which, the purchaser reserve the right to dispose of defective material in any manner considered fit by him (purchaser), at the sole risk and cost of the supplier. Any sale proceeds of the defective material after meeting the expenses incurred on its custody, disposal handling etc., shall however be credited to the supplier s account and set off against any outstanding dues of the purchaser against the supplier. The warranty for 12/18 months shall be one time. Director/Technical-I, UHBNV, Panchkula Director/Project, DHBVN, Hisar CGM/PD&C, UHBVN, Panchkula CGM/P&D, DHBVN, Hisar. FA & CAO/MM, UHBNV, Panchkula FA & CAO/MM, DHBVN, Hisar GM/P&D, UHBNV, Panchkula GM/P&D, DHBVN, Hisar Page 10 of 11

11 ANNEXURE A GURANTEED TECHNICAL PARTICULARS OF PORCELAIN INSULATORS FOR 11 KV OVERHEAD POWER LINE : 1. Maker s name and country. 2. Nominal voltage. 3. Highest voltage. 4. Dry one minute power frequencies withstand voltage. 5. Wet Dry one minute power frequencies withstand voltage. 6. Power frequencies withstand voltage. 7. Impulse withstand voltage (1/50 second positive waves ). 8. Visible discharge test voltage. 9. Impulse flashover voltage (1/50 micro second positive waves). 10. Impulse flashover voltage (1/50 micro second negative waves). 11. Dry flashover voltage. 12. Wet flashover voltage. 13. Min. failing load. 14. Minimum creepage distance. 15. Weight per unit. 16. Size of insulators. 17. Standard to which the insulator shall be manufactured and tested. 18. Tolerance in dimensions, if any. Page 11 of 11