TECHNICAL SPECIFICATION FOR SELF PROTECTED SINGLE PHASE DISTRIBUTION TRANSFORMERS ( SPECIFICATION NO: DIST/01-N/2004 )

Transcription

1 TECHNICAL SPECIFICATION FOR 11/ 3 KV/250V 15 & 25 KVA OUTDOOR TYPE COMPLETELY SELF PROTECTED SINGLE PHASE DISTRIBUTION TRANSFORMERS ( SPECIFICATION NO: DIST/01-N/2004 ) MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 1 OF 22

2 TECHNICAL SPECIFICATION FOR SUPPLY OF 11/ 3 Kv/ 250V 15 & 25 kva OUTDOOR TYPE COMPLETELY SELF PROTECTED SINGLE PHASE DISTRIBUTION TRANSFORMERS ( SPECIFICATION No: DIST/01-N/2004 ) 1. SCOPE: This specification covers design, engineering, manufacture, assembly, stage testing, inspection & testing before supply and delivery at site of the oil immersed, Oil Natural Air Natural (ONAN) outdoor type 11 kv/ 3 / 250V, 50 Hz, Single phase Distribution Transformers for use in Distribution systems. 1.1 The equipment offered shall be complete with all parts necessary for their effective and trouble-free operation. Such parts will be deemed to be within the scope of the supply irrespective of whether they are specifically indicated in the commercial order or not. 1.2 It is not the intent to specify herein complete details of design and construction. The equipment offered shall conform to the relevant standards and be of high quality, sturdy, robust and of good design and workmanship complete in all respects and capable to perform continuous and satisfactory operations in the actual service conditions at site and shall have sufficiently long life in service as per statutory requirements. The dimensional drawings attached with this specification and the notes thereto are generally of illustrative nature. In actual practice, not withstanding any anomalies, discrepancies, omissions, in-completeness, etc. in these specifications and attached drawings, the design and constructional aspects, including materials and dimensions, will be subject to good engineering practice in conformity with the required quality of the product, and to such tolerances, allowances and requirements for clearances etc. as are necessary by virtue of various stipulations in that respect in the relevant Indian Standards, IEC standards, I.E. Rules, I.E. Act and other statutory provisions. 1.3 The Tenderer/ supplier shall bind himself to abide by these considerations to the entire satisfaction of the employer and will be required to adjust such details at no extra cost to the employer over and above the tendered rates and prices. 1.4 Tolerances: Tolerances on all the dimensions shall be in accordance with provisions made in the relevant Indian/IEC standards and in these specifications. Otherwise the same will be governed by good engineering practice in conformity with required quality of the product. 2. SERVICE CONDITIONS: The Distribution Transformers to be supplied against this Specification shall be suitable for satisfactory continuous operation under the following climatic conditions as per IS 2026 (Part-I) latest revision. i. Max. peak ambient Air temperature : 50 Deg. C ii. Max. relative humidity : 100 % iii. Max. annual rainfall : 1450 mm iv. Max. Wind pressure : 150 kg/sq.m. v. Max. altitude above mean sea level : 1000 mtrs. vi. Seismic level (Horizontal acceleration) : 0.3 g. vii. Reference Ambient Temperature for temperature rise : 50 deg C The equipment shall be for use in moderately hot and humid tropical climate, conducive to rust and fungus growth. MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 2 OF 22

3 3. PRINCIPAL PARAMETERS: The Transformers shall be suitable for outdoor installation with Single phase, 50 c/s 11 kv system in which the neutral is effectively earthed and they should be suitable for service under fluctuations in supply voltage up to plus 10% to minus 15%. The transformer shall conform to the following specific parameters. Sl.No. Item Specifications Continuous rated capacity System voltage (max) Rated voltage HV Rated voltage LV Line current HV Line current LV Frequency No. of Phases Type of cooling Type of Transformer Tap changing Arrangement Over fluxing limit Permissible Temperature rise over ambient under full load condition i) Of top oil measured by thermometer 15 kva 12 kv 11/ 3 kv 250 V 2.52 A 64A 50 c/s Single ONAN Outdoor Not applicable 12.5 % 50 deg. C 25 kva 12 kv 11/ 3 kv 250 V 3.94A 100 A 50 c/s Single ONAN Outdoor Not applicable 12.5 % 50 deg. C 14. ii) Of winding measured by resistance Minimum clearances in air 55 deg. C 55 deg. C a) HV phase to neutral (mm) b) LV phase to neutral (mm) AS per IS latest 140 AS per IS latest DESIGN & CONSTRUCTION: 4.1 WINDING CONNECTION & TERMINAL ARRANGEMENTS: For HV live end should brought out through 12kV bushing and the other end of HV, which is intendent to be earth, shall be brought out on 1.1kV bushing (HV Neutral Bushing) Provision shall be made for connecting the neutral HV terminal to local earth. The secondary (LV) winding shall be connected LV bushings. The HV bushing (live) shall be provided on top cover and the remaining three bushing shall be provided on the sidewall of the tank and below top cover. 4.2 BUSHINGS: The bushings shall conform to the IS: 2099/3347 as amended upto date. Bushings having the creepage distance suitable for highly polluted atmosphere and having type tested as per IS 3347 and IS 2099 latest version shall only be accepted. For HV, 12 kv class bushings and for earth/neutral of HV winding 1.1kV bushing MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 3 OF 22

4 shall be used and for LV, 1.1 kv class bushings shall be used. iii) iv) The terminal arrangement shall not require a separate oil chamber. The HV bushings shall be mounted on top cover and LV bushings shall be mounted on sides of tank.the bushing rods and nuts shall be of brass. v) The HV bushings shall not have arcing horns. 4.3 CORE, WINDINGS AND OIL: CORE MATERIAL: Transformer core shall be shell type or core type, wound core construction using prime quality CRGO steel with heat resistant insulating coating. The core shall be properly stress relieved by annealing in inert atmosphere. The transformer shall be suitable for over fluxing (due to combined effect of voltage and frequency) up to 12.5% without injurious heating FLUX DENSITY: Flux density should not be more than 1.55 Tesla at the rated voltage and frequency. Transformer core should be designed in such a way that it will not get saturated for any value of V/f (Voltage/frequency) ratio to the extent of 112.5% of rated value of V/f ratio (i.e /50 & 33000/50). Actual core design alongwith calculations in support of it should be submitted by successful tenderer. Material to be used for the transformer core shall be made of prime grade (M-4 or better) imported COLD ROLLED GRAIN ORIENTED (CRGO) laminations and not from second grade steel laminations. Only those suppliers who directly imported CRGO either from the manufacturer or through their accredited marketing organization of repute (and not through any agent) shall be considered. In support of this requirement the supplier should give an undertaking in the form of affidavit on Rs. 100/- stamp paper, duly notarised, in the specified format. Test reports for specific loss, chemical analysis, and surface insulation resistance has to be submitted during stage inspection WINDING: HV and LV windings shall be wound from Aluminum conductors with DPC/ Polyesterimide enamel (Class H) insulation. The enamel covering shall conform to Grade-II of Part-8 or IEC Part-8. The windings shall be progressively wound in LV-HV coil design for better voltage regulation and mechanical strength. The inner layer insulation shall be of Epoxy dotted paper. The type of winding shall be indicated in the tender whether LV windings are of conventional type or foil wound. Winding must be done in cleanest possible atmosphere to prevent possible accumulation of dust particles. The coil shall be further processed for dimensional control, improved bonding and for improving short circuit withstand capability. The current density of the winding shall not be more than 1.2 A/mm 2 for Aluminium and 2.8 A/mm 2 for Copper. Test reports for material characteristics like density, tensile strength, and elongation moisture content, ash content, dielectric strength, thickness of resin etc. for epoxy dotted paper shall be submitted during stage inspection CORE COIL ASSEMBLY: Core coil assembly shall be further processed in oven for removal of moisture. MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 4 OF 22

5 4.3.5 OIL: The insulating oil shall comply with the requirements of IS 335 / 1993.Oil shall be filled under vacuum only. 4.4 BUSHING TERMINALS: HV terminal shall be designed to directly receive ACSR conductor up to 7/2.59 mm (without requiring the use of lug) and the LV terminals shall be suitable for directly receiving LT cables (aluminum) ranging from 50 Sq.mm to 70 Sq.mm both in vertical and horizontal position and the arrangements should be such as to avoid bimetallic corrosion. Terminal connectors must have type tested as per IS: TANK: The oil volume inside the tank shall be such that even under the extreme operating conditions, the pressure generated inside the tank does not exceed 0.4 kg/sq.cm positive or negative. There must be sufficient space from the core to the top cover to take care of oil expansion. The tank cover shall have plasticised surface at the top to guard against bird faults. Alternatively, suitable insulating shrouds shall be provided on the bushing terminals (a) The Transformer tank shall be of robust construction round in shape and shall be built up of tested CRCA / MS Sheet of the following thickness. (b) i) Main tank : 2.0 mm (min.) ii) Top Cover : 2.5 mm (min.) iii) Bottom cover : 2.5 mm (min.) The tank without oil is subjected to an air pressure of 80 Kpa above atmosphere for 30 minutes and 70KPA for 30 min in vacuum as per IS : 1180 part 2. Permanent deflection should not be more than the limits specified in IS: 1180 part 2. Pressure test shall be performed carefully at the time of 1 st stage inspection only to confirm the adequacy of the tank strength and to be certified by employer s representative. The long seam joint and other welds shall be oil tight and no deflection / bulging should occur during service. Manufacturer should carry out the all-welding operations as per he relevant ASME standards and submit a copy of the welding procedure qualifications and welder performance qualification certificates to the Employer. The bottom of the tank should be 25 mm above the Transformer bottom and welded with channel as shown in the drawings. Tank shall have permanent lugs for lifting the Transformer bodily and there shall be facilities for lifting the core coil assembly separately. The Transformer tank and the top cover shall be designed in such a manner as to leave no external pockets in which water can lodge. The Transformer shall be provided with two mounting lugs suitable for fixing the transformer to a single pole by means of 2 bolts of 20 mm diameter as per ANSI C Both mounting lugs are made with steel of min. 5 mm thickness. Minimum Oil level mark shall be embossed inside the tank. Jump proof lips shall be provided for upper mounting lug. Mounting lugs faces shall be in one plane. MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 5 OF 22

6 The top cover shall be fixed to the tank by proper arrangement to avoid ingress of moisture. Design of top cover shall be such that no water can lodge on the top cover so as to eliminate ingression of moisture and water. HV bushing pocket shall be embossed to topside of the top cover so as to eliminate ingression of moisture and water. The edges of the top cover shall be formed, so as to cover the top end of the tank and gasket. Nitrile/Neoprene rubber gaskets conform ing to latest IS 4253 Part- II shall be provided between tank and top cover. 5. TANK SEALING: The space on the top of the oil shall be filled with dry air or nitrogen. The dry air of nitrogen plus oil volume inside the tank shall be such that even under extreme operating conditions, the pressure generated inside the tank does not exceed 0.4 kg/sq. cm positive or negative. The nitrogen shall conform to commercial grade of the relevant standard. 5.1 OIL LEAKAGE TEST: The oil leakage test shall be conducted on one unit selected from the offered lot of each rating. Transformer complete in all respects shall be subjected to the Pressure of 0.4 kg/cm² and maintained for 10 minutes. No leakage should occur. 6. SURFACE PROTECTION: The transformer tanks should be powder coated, with light cream colour paint ( Shade : RAL 7053). Steel surface of the tank shall be prepared by sand / shot blast or chemical cleaning including phosphating as per IS Heat resistance paint ( Hot oil proof) shall be provided inside the tank. On external surface one quote of thermosetting powder paint 7. RATING AND TERMINAL PLATES: Rating & terminal marking plate : Each transformer shall be provided with non- detachable name, rating and terminal marking plate fitted in a visible position. All details shall be given on one plate. Material of the plate shall be stainless steel only. Thickness shall be 0.9 mm (with a tolerance of ± 0.1 mm). The plate shall be made absolutely undetectable either through welding or riveting or through any other approved method. There shall be a rating plate on the transformer containing the information given in the relevant Indian Standard. The HV winding terminals shall be marked 1U and 1N. The corresponding secondary terminal shall be marked as 2u and 2n. Besides other particulars, following details shall also be given on the nameplate: Order No. Month & year Sr. No. of Transformer Date of Manufacturing Month & year Date of expiry of guarantee period month & year Maximum Guaranteed No Load & Load loss Figures Name & Full address of the manufacturer. Capacity Rating MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 6 OF 22

7 ALL DETAILS ON THE RATING AND DIAGRAM PLATE SHALL BE INDELIGIBLY MARKED i.e. BY ENGRAVING OR PUNCHING. 8. PRESSURE RELEASE DEVICE: The transformer shall be equipped with a self-sealing pressure release device design to operate at a minimum pressure of 8-PSI (0.564-kg/ cm 2 ). 9. PROTECTION : The transformer shall have the following additional fittings as its integral part: 9.1 The transformer shall have the following CSP features: a) INTERNAL HV FUSES ON THE HT SIDE OF TRANSFORMER: Specification for the HT fuses: Expulsion / any other suitable fuse placed in series with primary winding. This fuse is mounted normally inside of the primary bushing and is connected to the high voltage winding through a terminal block. This has to protect that part of the electrical distribution system which is ahead of the Distribution Transformers from faults which occur inside the Distribution Transformers i.e., either the windings or some other part of the transformer. It shall be ensured that this fuse does not blow for faults on the secondary side (LT side) of the transformer i.e., the blowing characteristic of the fuse and LT breaker shall be so coordinated that the fuse shall not blow for any faults on the secondary side of the transformer and these faults shall be cleared by the LT breaker only. b) INTERNALLY MOUNTED OIL IMMERSED LT BREAKER ON THE LV SIDE OF THE TRANSFORMER: LT CIRCUIT BREAKER : All LT faults after the breaker shall be cleared by this breaker. As such, it shall be designed for perfect coordination with the HT fuse link. The supplier shall furnish the time/current characteristics of LT circuit breaker and 11kV fuses for various current multiples. The two characteristics shall be drawn on the same sheet to indicate coordination between the circuit breaker and fuse. This shall be based on the type test carried out on one of the transformers. In addition, the supplier shall carry out coordination test as indicated above, and this forms one of the tests for acceptance. The breaker is to be mounted on the secondary side of the transformer under oil to minimise premature operations from primary surges as would be with undersized line fuses. Two single pole elements is preferred. THE BREAKER SHALL BE COORDINATED THERMALLY WITH THE TRANSFORMER RATING TO FOLLOW CLOSELY THE VARIATIONS OF COIL TEMPERATURE DUE TO FLUCTUATIONS IN LOADS AND AMBIENT TEMPERATURES. This is to be accomplished by connecting the breaker in series between the secondary winding and the load current. The breaker shall be located in the same oil as the core and coil assembly so that the bimetal are sensitive to the temperature of oil as well as the load current. The circuit breaker may be an electro-mechanical device with three elements viz. (a) temperature sensing (b) latching and tripping and (c) current interrupting. The temperature sensing function might be accomplished through the use of bimetallic strips which would be built into the breaker, such that load current of the transformer flows through them. In addition to this, a magnetic tripping device is to be provided for increasing the opening speed MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 7 OF 22

8 of the breaker under high fault conditions. The circuit breaker shall be mounted inside of the transformer so that these bimetallic strips are within the top oil layer of the transformer. The latching and tripping functions of the circuit breaker may be carried out within assembly similar to those used in industrial type air circuit breaker. The circuit breaker shall also be closed and opened manually standing on ground and with a magnetic trip device also. The current interruption element shall consist of copper current carrying parts plus a set of copper tungsten current interrupting contacts. The magnetic element shall increase the opening speed of the circuit breaker under high fault current conditions. The response of circuit breaker to the activity shall remain unchanged by the addition of the magnetic trip element. The specification to which the breakers conform shall be indicated. LOAD MANAGEMENT SIGNAL LIGHT: A signal light, controlled by a bimetal in the breaker shall switch on when the transformer load reaches a predetermined level indicating that the transformer has been over-loaded. The load management signal light shall perform two functions. It shall show visually when the particular transformer has been operating in an overload condition and shall provide knowledge that for good system management, the economical change out point for the transformer is fast approaching. The signal light need not indicate temporary overloads and shall turn on only when the overload condition has existed at a given level for a certain length of time. The LT circuit breaker shall have a set of auxiliary contacts built-in for signal light operation. These, normally open contact, shall form part of the signal light circuit. The signal light circuit shall consist of an auxiliary transformer winding (one or two turns) which generates about 4V, for the signal light contact set within the circuit breaker, and the signal light is to be mounted on the transformer tank. The signal light contact set is mechanically connected to the main circuit breaker latching and bimetal system. The signal light mechanism is adjusted so that the signal light contacts will close at a pre-set thermal condition which occurs before the main latching system opens the main contact. The net result is a visual external indication that a pre-set load condition has reached by the transformer. The signal light mechanism does not reset itself when the load drops off, the signal light remains lighted once the signal light contact closes and can only be turned off by manually operating the external circuit breaker handle. ALTERNATIVE FOR (b) b) EXTERNALLY MOUNTED MCCB FOR LV SIDE: Single pole MCCB is to be provided on LV side with thermal trip release with inverse time current characteristics for overload protection and magnetic trip release for instantaneous tripping in the wake of short circuits. Application Outdoor (enclosed) Utilization category A (IS 13947) Type Thermal and magnetic trip free mechanism Number of poles One Reference ambient temperature 40 Deg.C. Rated insulation level 600 V. Impulse withstand 8 kv peak. Rated operational voltage 250 V. Continuous current rating 100 A for 25 KVA and 64 A for 15 KVA Breaking capacity 10 KA at 240 V. MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 8 OF 22

9 Terminal capacity Applicable Standard Time current characteristics 2 x 25 sq.mm. Aluminium cable. IS Part-2 latest. To co-ordinate with HV fuse The time current characteristics and co-ordination with HV fuse shall be submitted alongwith the offer. MCCB is to be fixed in an enclosure (IP 55) in ready to be used condition and to be mounted on the transformer before installation on the pole. The enclosure shall be made with sheet steel of thickness not less than 1.6 mm. It shall be painted both inside and outside with powder coating. Enclosure shall have provision for pad locking arrangement. Detachable gland plate shall be provided for taking connections from MCCB and transformer bushing terminal. SIGNAL LIGHT (LED INDICATING LAMP): The MCCB enclosure shall be provided with LED indicating lamp to indicate tripping of MCCB. An auxiliary relay with changeover contacts can be used to connect LED indicating lamp to the transformer secondary terminals if MCCB is not having auxiliary contacts. In case the MCCB trips or switched OFF, the relay contacts are closed which turns ON the LEDindicating lamp. When the MCCB is reset and switched ON, the indicating lamp switches OFF. Signal light shall be arranged to avoid damages while handling the MCCB enclosure at site KV LIGHTNING ARRESTERS: High surge capacity 9 KV 5 KA Lightning Arresters (disconnector type) conforming to IS; 3070/1974 shall be mounted on the transformer, clamped securely to the tank, to protect the transformer and associated line equipment from the occasional high voltage surges resulting from lighting or switching operations. The earthing terminal of the lightning arresters shall be connected solidly to the transformer tank earthing in terminal. 10. FITTINGS: The following standard fittings shall be provided. a) Two earthing terminals. b) Two lifting lugs. c) Rating and terminal marking plates. d) Metal oxide lightning surge arrester with Disconnector. e) Pressure relief device. f) HV bushings. g) LV bushings. h) HV & LV terminal connectors. i) Top cover-fixing clamps. j) Mounting lugs - 2 Nos. k) LV earthing arrangement. l) Protection cover (Plasticised cover on live parts) m) Circuit Breaker, Operating mechanism n) Signal light o) Five year guarantee plate p) HV Fuse. q) Any other fitting necessary for satisfactory performance MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 9 OF 22

10 11. FASTENERS: All bolts, studs, screw threads, pipe threads, bolt heads and nuts shall comply with the appropriate Indian standards for metric threads or the technical equivalent. Bolts or studs shall not be less than 6 mm in diameter except when used for small wiring terminals. All nuts and pins shall be adequately locked. Wherever possible bolts shall be fitted in such a manner that in the event of failure of locking resulting in the nuts working loose and falling off, the bolt will remain in position. All ferrous bolts, nuts and washers placed in outdoor positions shall be treated to prevent corrosion by hot dip galvanizing except high tensile steel bolts and spring washers, which shall be Electro, galvanized. Appropriate precautions shall be taken to prevent electrolytic action between dissimilar materials. Each bolt or stud shall project at least one thread but not more than three threads through the nut, except when otherwise approved for terminal board studs or relay stems. If bolts are provided at inaccessible places for ordinary spanners, special spanners shall be provided. The length of screwed portion of the bolts shall be such that no screw thread may form part of a sheer plane between members. Taper washers may be provided where necessary. Protective washers of suitable material shall be provided front and back of the securing screws. 12. LOSSES: The no load and load losses shall not exceed the following values: Voltage Ratio Rating KVA No load loss watts Load loss at 75 Deg.C watts 11/ 3/250 V / 3/250 V These losses are maximum allowable and there would not be any positive tolerance. Transformers with higher losses than the above-specified losses would be rejected. 13. IMPEDANCE: The recommended percentage impedance at rated frequency and at 75 deg. C is 4.0 % with tolerance as per IS Bids not conforming to the limits indicated above will be treated as non-responsive 14. TEMPERATURE RISE: The temperature rise over ambient shall not exceed the limits described below. Top oil temperature rise measured by thermometer : 50 deg. C Winding temperature rise measured by resistance : 55 deg. C non- Bids not conforming to the above limits of temperature rise will be treated as responsive. MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 10 OF 22

11 15. TESTS: All the equipment offered shall be fully type tested by the manufacturer as per the relevant standards as mentioned at clause ROUTINE TESTS: The following routine tests have to be conducted on each transformer (at the cost of the supplier) 1. Ratio, polarity tests. 2. No load current and losses at rated voltage and normal frequency. 3. Load losses at rated current and normal frequency. 4. Impedance Voltage test. 5. Resistance of windings cold (at or near the test bed temp.) 6. Insulation resistance. 7. Induced over voltage withstand test. 8. Separate source voltage withstand test. 9. Measurement of voltage ratio and check of voltage vector relationship 10. Co-ordination test 11. Oil Break down voltage test 15.2 Type tests & special tests: In addition to routine tests as above, the transformers offered in the bid should have been successfully type tested for the following type tests, within the last five years prior to the date of opening of the tender, at laboratories accredited by National Accreditation Board for Testing and Calibration Laboratories (NABL) in accordance with IS-2026/1977 as amended from time to time. i. Impulse voltage withstands test as per Clause No.13 of IS-2026 (Part-III)/81. Impulse voltage withstand test shall be for 75 kvp for 11 kv Class transformers respectively. ii. Dynamic Short circuit withstand test In case the tenderer does not possess the type test reports for any or all the tests as indicated above, the tenderer shall have to carry out these type tests at his cost before commencement of supply Temperature rise test and air pressure test shall be carried out at manufacturer s works in the presence of MSEDCL s representative at the time of inspection of first lot. The copies of type test reports shall be submitted to Chief Engineer (Distt/Infra) for approval before commencement of supply. 16. DRAWING & DOCUMENTS: One copy of the dimensional drawing and internal construction drawing of each transformer shall be submitted with the tender. As per the tender condition No. XV of tender form these drawings shall be A3 (420x297 mm) size only. Guaranteed and other technical particulars of the transformers as per the A/T should also be submitted in A-4 size for our approval The following documents shall invariably be submitted with the offer : 1. All the relevant information in Schedule `A' & `A-1 i.e. Guaranteed Technical Particular (GTP). Drawings required as per clause number 2. Heat dissipation calculations. (Heat dissipation by tank walls MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 11 OF 22

12 excluding top and bottom should be 500 W/sq.m.) 17. DOCUMENTARY SERVICES : The tenderer will have to produce documentary evidence for the purchase of CRGO Sheet, oil and copper wire/aluminium wire. Test reports for properties/parameters of copper wire, Insulating materials, bushings, mild steel, and gaskets to be submitted during 1st stage inspection. 18. TESTING FACILITY: The manufacturer should have in-house testing facility for all routine and acceptance tests and also arrangement for measurement of losses, resistance, etc. details of which will be enumerated in the tender. 19. SUBMISSION OF ROUTINE TEST CERTIFICATE: The manufacturer shall submit the routine test certificate along with documentary evidence for having paid the Excise Duty for the following raw materials viz. Oil, Copper/Aluminium for conductors, insulating materials, core materials, bushings at the time of routine testing of the fully assembled transformer. 20. INSPECTION: In respect of raw materials such as core stamping, winding conductor, insulating paper and oil, you shall use these materials manufactured/supplied by the standard manufacturers and furnish the manufacturers' test certificates as well as the proof of purchase from these manufacturers (documentary evidence for having paid the Excise Duty and/or Customs Duty etc.) for information of the employer. The successful tenderer will give 15 days advance intimation to the employer to organize for stage inspection of the transformer in which the assembly of core and the winding could be inspected. 21. INSPECTION & TESTING OF TRANSFORMER OIL : To ascertain the quality of the transformer oil, the original manufacturer's test report should be submitted at the time of inspection. Also arrangements should be made for testing of transformer oil, after taking out the sample from the manufactured transformers and tested in the presence of employer's representative or in an independent laboratory. 22. LOADING OF TRANSFORMER: The transformer shall be suitable for loading as per IS 6600/1972. The tenderer should state clearly the percentage overload the transformer can take for a continuous period of one hour. 23. SCHEDULES: 23.1 The tenderer shall fill in the following schedules, which form part of the tender specification and offer. In schedule A & A -1 the specific values shall be furnished and only quoting of IS reference or writing, as per drawing enclosed, as per MSEDCL s requirement is not sufficient. If the schedules are not submitted duly filled in with the offer, the offer shall be liable for rejection. MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 12 OF 22

13 Schedule A & A Guaranteed Technical Particulars. Schedule B - Schedule of Deviations from Specification. Schedule C - Schedule of Tenderer s Experience. Schedule D - Schedule of Deviations from specified standards. Schedule E - Schedule of Deviations from specified Test requirements All deviations from the specification shall be brought out in the schedules of deviation (Schedules B, D & E ). The discrepancies between the specification and the catalogues, Literatures and indicative drawings which are subject to change, submitted as part of the offer, shall not be considered and representation in this regard will not be entertained The deviation brought out in the schedule shall be supported by authentic documents and clarifications; otherwise the offer may be liable for rejection. 2.4 The tenderer shall submit the list of orders for similar type of equipment, executed of under execution during the last three years, with full details in the schedule of Tenderer s experience (Schedule `C') to enable the employer to evaluate the tender. MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 13 OF 22

14 STANDARDS Indian Standard Title International & Internationally recognized ISS-2026 Specification for Power Transformer IEC-76 (Part-I to IV) ISS-1180 Outdoor Three Phase Distribution Transformer DIN 42531,2,3 ISS-3347/1967 Specification for Porcelain Transformer DIN 42531,2,3 Bushings ISS-7421/1974 Specification for Low Voltage Bushings ISS Specification for copper wire rods ASTM B 49 ISS 5484 Specification for Aluminum wire rods ASTM B 233 ISS-335/1983 Specification for Transformer Oil BS 148/ASTM D1275, D1533, IEC Pub ISS-6600/1972 Guide for loading of oil immersed transformers IEC 76 ISS-2099/1973 High Voltage Porcelain Bushings IEC 137 ISS 9335 Specification for Insulating Kraft Paper IEC 554 ISS 1576 Specification for Insulating Press Board IEC 641 IS: 5/1961 Specification for Colours Material conforming to other internationally accepted standards, which ensure equal or higher quality than the standards mentioned above would also be acceptable. In case the Bidders who wish to offer material conforming to the other standards, salient points of difference between the standards adopted and the specific standards shall be clearly brought out in relevant schedule. Four copies of such standards with authentic English Translations shall be furnished along with the offer. MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 14 OF 22

15 SCHEDULE-A GUARANTEED TECHNICAL PARTICULARS OF SINGLE PHASE DISTRIBUTION TRANSFORMER Sl.No. Description 15 KVA 25 KVA 1. Name of the manufacturer and place of manufacturer 2. Continuous max. rating as per this specification kva Normal ratio of transformer kv 11/(3 kv /250 V 11/(3 kv / 250 V 4. Method of Connection HV / LV 5. Max. Current density in Windings. a) Higher voltage Amps/sq.cm b) Lower voltage Amps/sq.cm Al/Cu Al/Cu 1.2 / / / / Max. Hot Spot Temp. Deg. C. (Ambient air temp. on which above is based) 7. a) Max. observable Oil temp. Deg.C.(Ambient air temp on which above is based) b) Max. Winding Temperature Deg.C (Ambient air temp. on which above is based) 8. Fixed losses at normal voltage and frequency (watts) Maximum 9. Load losses at rated current and 75 C reference temperature (watts) Maximum Total losses at normal voltage 10. ratio,frequency and emperature (watts) Maximum MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 15 OF 22

16 Sl.No. Description 15 KVA 25 KVA Efficiency at normal voltage i) Unity Power Factor a) At 50% Load b) At 75% Load c) At full Load ii) 0.8 Power Factor a) At 50% Load b) At 75% Load c) At full Load Regulation as percentage of normal voltage. a) At unity power factor % b) At 0.8 Power factor lagging % 13. % Impedance voltage at normal ratio between HV & LV Windings 14. Type of transformers, shell type / core type wound core 15. Type of Insulation used in a) HV Windings b) LV Windings 16. Type of insulation used in a) Core bolts b) Core bolt washers c) End plates d) Core lamination 17. Impulse test voltage level HV Windings LV Windings 18. Characteristics of transformer oil As per IS 335 Latest Version 19. Total content of oil in liters 20. i) Approx. overall dimensions a) Height mm b) Breadth mm c) Width mm ii) Tank dimensions a) Diameter mm b) Height mm MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 16 OF 22

17 Sl.No. Description 15 KVA 25 KVA 21. Weight of insulated conductor a) HV (min.) kg. b) LV (min.) kg 22. Weight of core (min.)kg(crgo) 23. Weight of complete transformer Arranged for transport ( kg.) 24. Resistance at rated current & frequency. a) HV Ohms. b) LV Ohms. 25. Resistance of windings at 75 Deg. C per phase a) HV Ohms. b) LV Ohms. 26. Bushings 12KV (Normal Voltage Rating) 1.1KV(Normal Voltage Rating) Dry withstand(kv) Wet withstand (kv) Impulse withstand(kv) 27. Material of bushing rod/ nuts & Bushing caps HV LV Brass Brass 28. Make, type and technical details of LV breakers 29. Make and rating of LA 30. Make, rating and type of HT fuses. MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 17 OF 22

18 SCHEDULE `A -1 ADDITIONAL GUARANTEED TECHNICAL PARTICULARS Sr. No DESCRIPTION 1 Core Grade 2 Core diameter mm 3 Gross core area mm 4 Net core area mm 5 Flux density 6 Weight of core 7 Loss per Kg. Core at the specified flux density 8 Core window height 9 Center to center distance 10 No. of LV turns 11 No. of HV turns 12 Size of LV conductor bare covered mm 13 Size of HV conductor bare covered mm 14 No. of parallels 15 Current density of LV winding A/Sq.mm 16 Current density of HV winding A/Sq.mm Weight of LV winding copper/aluminium for 17 transformer (Kg) Weight of HV winding copper/aluminium for transformer (Kg) No. of LV coil per phase 20 No. of HV coil per phase 21 Height of LV winding mm 22 Height of HV winding mm 23 ID/DD of LV winding mm 24 ID/DD of HV winding mm 25 Size of the duct in LV winding mm 26 Size of the duct in HV winding mm 27 Size of the duct between HV & LV mm 28 HV winding to LV clearance mm 29 HV winding to tank clearance mm 30 Calculated impedance 31 HV to earth creepage distance 32 LV to earth creepage distance PARTICULARS (15 KVA) (25 KVA) MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 18 OF 22

19 SCHEDULE - B DEVIATIONS FROM SPECIFICATION SR.NO. CLAUSE NO. DETAILS OF DEVIATION NAME OF FIRM NAME & SIGNATURE OF TENDERER DESIGNATION DATE MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 19 OF 22

20 SCHEDULE - C SCHEDULE OF TENDERER'S EXPERIENCE Tenderer shall furnish here a list of similar orders executed/under execution by him to whom a reference may be made by employer in case he considers such a reference necessary Sr. Name of client Value Period of supply Name & Address to No. & Description Of Order & commissioning whom reference may of material (alongwith be made cap. of T/F) NAME OF FIRM NAME & SIGNATURE OF TENDERER DESIGNATION DATE MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 20 OF 22

21 SCHEDULE - D SCHEDULE OF DEVIATIONS FROM SPECIFIED STANDARDS Sr. Particulars Stipulation of Stipulation of Remarks No. specified standard adopted Standards By tenderer Standard Stipulations. Standard Stipulations Ref. Ref NAME OF FIRM NAME & SIGNATURE OF TENDERER DESIGNATION DATE MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 21 OF 22

22 SCHEDULE - E DEVIATIONS FROM SPECIFIED TEST REQUIREMENTS SPECIFIED IN RELEVANT AND PRESENT SPECIFICATIONS Sr. Name of Test Standard Requirement Proposed Reasons No. No. & Cl. No. of standards deviation for deviation TYPE TEST 2. ADDL. TEST 3. ACCPTANCE 4. TEST. 5. ROUTINE 6. TEST. NAME OF FIRM NAME & SIGNATURE OF TENDERER DESIGNATION DATE MAHARASHTRA STATE ELECTRICITY DISTRIBUTION COMPANY LTD. PAGE 22 OF 22