General Electricity Company of Libya

Transcription

1 GES Technical Specification of GECOL 11/0.4kV Oil Immersed Ground Mounted Three Phase Sealed Type Distribution Transformers (Revision history) Issued on: Jan. 01, 2007 General Electricity Company of Libya

2 Contents 1 SCOPE AND SERVICE CONDITIONS SCOPE SERVICE CONDITIONS Normal service conditions Unusual service conditions NORMATIVE REFERENCES DEFINITIONS OIL-IMMERSED TYPE TRANSFORMER HIGH-VOLTAGE WINDING LOW-VOLTAGE WINDING RATED VOLTAGE RATIO RATED POWER RATED CURRENT PRINCIPAL TAPPING TAPPING STEP TAPPING RANGE NO-LOAD LOSS NO-LOAD CURRENT LOAD LOSS TOTAL LOSSES TEMPERATURE RISE MONTHLY AVERAGE TEMPERATURE YEARLY AVERAGE TEMPERATURE SOUND PRESSURE LEVEL KINDS AND RATINGS KINDS RATING REQUIREMENTS REQUIRED STRUCTURE Type /24

3 5.1.2 Off circuit tapping Cooling Core Windings HV bushing LV bushings Cable boxes Glands Earthing terminal Fittings Over pressure relief valve Tank Tank finish Gaskets REQUIRED CHARACTERISTICS Short circuit impedance Temperature rise Duty under faults Insulation Load and no load losses No-load current Voltage drop Efficiency Bushing Sound level Insulation oil TESTS TYPE TESTS ROUTINE TESTS SPECIAL TESTS RATING PLATES MARKING PACKING AND DELIVERY SPARE PARTS DOCUMENT AND CERTIFICATE /24

4 11.1 INFORMATION TO BE PROVIDED WITH THE BID DOCUMENTS TO BE APPROVED BY GECOL DOCUMENTATION WARRANTY /24

5 GES (Technical Specification of GECOL) 11/0.4kV Oil Immersed Ground Mounted Three Phase Sealed Type Distribution Transformers 1 Scope and service conditions 1.1 Scope This specification covers the 11/0.4kV oil-immersed ground mounted three (3) phase sealed type distribution transformers for the distribution station of underground GECOL distribution network. 1.2 Service conditions Normal service conditions The transformers shall be installed at indoors or outdoors in Libya with salt laden dusty atmosphere. The transformers shall be suitable for continuous operation at the below site conditions. (a) Maximum altitude: 1,000m (ASL) (b) Maximum ambient air temperature: +50 C (c) Minimum ambient air temperature: -10 C (d) Monthly average temperature of the hottest month: 40 C (e) Yearly average temperature: 30 C Unusual service conditions Conditions other than those listed in for transformers are considered to be unusual. The manufacturer should discuss with GECOL for the unusual service conditions. 2 Normative references The distribution transformers shall confirm to the latest edition of following international standards: (a) IEC 60076: Power transformers (b) IEC 60137: Insulated bushings for alternating voltages above 1,000V (c) IEC 60228: Conductors of insulated cables (d) IEC 60296: Specification for unused mineral insulating oil for transformers and switchgear 5/24

6 (e) IEC 60354: Loading guide for oil-immersed power transformers (f) IEC 60507: Artificial pollution tests on high-voltage insulators to be used on a.c. systems (g) BS 171: Power transformers (h) BS 6436: Specification for ground mounted distribution transformers for cable box or unit substation connection (i) IEEE Std. C : General requirements for liquid immersed distribution, power, and regulating transformers (j) GES : Unused mineral insulating oil for transformers 3 Definitions 3.1 Oil-immersed type transformer A transformer of which the magnetic circuit and windings are immersed in oil 3.2 High-voltage winding The winding having the highest rated voltage 3.3 Low-voltage winding The winding having the lowest rated voltage 3.4 Rated voltage ratio The ratio of the rated voltage of a winding to the rated voltage of another winding associated with a lower or equal rated voltage. 3.5 Rated power A conventional value of apparent power assigned to a winding which, together with the rated voltage of the winding, determines its rated current 3.6 Rated current The current flowing through a line terminal of a winding which is derived from rated power and rated voltage for the winding 3.7 Principal tapping The tapping to which the rated quantities are related 3.8 Tapping step The difference between the tapping factors, expressed as a percentage, of two adjacent tappings 6/24

7 3.9 Tapping range The variation range of the tapping factor, expressed as a percentage, compared with the value '100' 3.10 No-load loss The active power absorbed when rated voltage (tapping voltage) at rated frequency is applied to the terminals of one of the windings, the other winding or windings being opencircuited 3.11 No-load current The r.m.s. value of the current flowing through a line terminal of a winding when rated voltage (tapping voltage) is applied at rated frequency, the other winding or windings being open circuited 3.12 Load loss The absorbed active power at rated frequency and reference temperature associated with a pair of windings when rated current (tapping current) is flowing through the line terminals of one of the windings, and the terminals of the other winding are short circuited Total losses The sum of the no-load loss and the load loss 3.14 Temperature rise The difference between the temperature of the part under consideration and the temperature of the external cooling medium 3.15 Monthly average temperature Half the sum of the average of the daily maxima and the average of the daily minima during a particular month over many years 3.16 Yearly average temperature One-twelfth of the sum of the monthly average temperatures 3.17 Sound pressure level Ten times the logarithm to the base 10 of the ratio of the square of the sound pressure to the square of the reference sound pressure. It is measured in decibels. 7/24

8 4 Kinds and ratings 4.1 Kinds Rated power of transformer shall be determined according to the Table 1 of this specification. 4.2 Rating Specification No. Table 1 Kinds of transformers Rated Power (kva) (a) The normal rated power specified in Table 1 shall be the continuous rating under the worst temperature conditions encountered in Libya. (b) The nominal primary voltage shall be 11kV, 50Hz and the highest voltage for equipment shall be 12kV. (c) The nominal secondary voltage shall be 400/230V, 50Hz. The neutral point shall be earthed. (d) The primary winding connection shall be connection (3-phase 3-wire) and the secondary winding connection shall be Y (3-phase 4-wire) connection. Vector group shall be Dyn11. (e) The normal voltage ratio of the transformers at principal tapping shall be 11000/400 Volts. 5 Requirements 5.1 Required structure Type The transformers shall be sealed type. Off circuit tapping The HV winding of the transformers shall have 5 tapping positions they are principal 8/24

9 tapping and ± 2.5% 2 tapping positions operated by an off-circuit tapping switch clearly marked position indicator. Tapping position shall be visible at the safe distance. Tap changer shall have locking device. Switching position of No. 1 shall correspond to maximum plus tapping. The contacts of the tap changer shall be of robust and shall have sufficient surface area. Insulating sleeves for the transformer tappings shall be in crepe paper or better Cooling Cooling system of the transformers shall be natural circulation of oil and air (ONAN). Core The core shall be constructed of the best quality low loss, cold-rolled grain oriented steel laminations confirming with the latest edition of IEC The core shall be assembled in a manner which reduces vibration and minimize inherent noise. Both sides of individual stampings shall be coated with an insulating material which shall be resistant against oil and temperature. The complete core shall be effectively earthed. The flux density in any part of the core shall not exceed 1.72 Tesla at nominal voltage and frequency. Thickness of a lamination shall not exceed 0.3mm (M5). The core plates shall be insulated from one another to minimize the core loss and the core shall be held together by bolts and clamping plates all of which shall be adequately insulated. The completed core and winding assembly shall be provided with lifting eyes to facilitate its removal from the transformer tank and shall be adequately braced and supported to prevent movement during transit or service. Windings The windings shall be made of best soft drawn copper having high conductivity and complying with the requirements of the latest edition of IEC The windings shall be designed to meet the three fundamental requirements: mechanical, thermal and electrical. The windings shall be capable of sustaining short circuit forces on the transformer as required in clause 0of this specification. All windings shall be fully insulated according to IEC for standard insulation level and for a system highest voltage of 12kV. And windings shall be wound with adequate bracing and securing tapes in order to achieve a strong, self supporting structure. Adequate cooling ducts shall be provided to ensure that temperature rise is within the permissible limits at normal operating conditions. The HV and LV windings shall be separated without difficulty for replacing each winding. 9/24

10 HV bushing HV bushings shall be plug-in type which are connected with elbow connector or tee connector. They shall be mounted on the tank and sealed by cable box. The minimum phase to phase clearance and phase to earth clearance shall not be less than those stated in Table 5 of IEC HV bushings shall be connected with three core XLPE insulated 240mm 2 copper cable. The plug-in type HV bushings shall be installed in a manner to prevent ingress of moisture and to facilitate easy connection with heat shrinkable or pre-molded connectors. Current rating of plug-in type HV bushings shall be 200A and number of bushings shall be 3 Nos. Dimensions of HV bushings shall comply with Figure 1 of this specification. LV bushings LV bushings including neutral bushing shall be outdoor porcelain type conforming to IEC They shall be mounted on tank and sealed cable box. Bushing palms shall be made of brass be suitable for the bolting of conductor compression lugs of termination for indoor use. The minimum phase to phase clearance shall not be less than those stated in Table 5 of IEC The porcelain shall not engage directly with the hard metal and gaskets shall be interposed between them and the surface in contact with the gasket shall be unglazed. They shall be installed in a manner to prevent ingress of moisture and to facilitate easy removal. Cable boxes The transformer shall have HV and LV cable boxes. The HV and LV cable boxes shall be mounted on opposite sides of the tank and arranged for cables entering vertically from bottom. All cable boxes shall be completely sealed and provided with sealing glands to suit cables. HV cable box shall be suitable for terminating a three (3) core XLPE 240mm 2 cable via 1 gland. LV cable box shall have following number of glands and shall be suitable for terminating following number of cables by rated power. Rated Power Table 2 Number of Glands and Cables to be connected to LV Terminals No. of Glands No. of Cables by Phase No. of Cables for Neutral 300 kva kva kva kva Cross Sectional Area of a Cable Single Core XLPE 400mm 2 10/24

11 Rated Power No. of Glands No. of Cables by Phase No. of Cables for Neutral 1000 kva kva kva Cross Sectional Area of a Cable Single Core XLPE 400mm 2 The cable boxes on the transformer shall be suitable for the above arrangement and shall be complete with all necessary fittings, suitable cable lugs, glands, armour clamp, etc. The cable boxes shall be suitable for approved type of heat shrinkable and pre-molded terminations Glands The glands shall be electrically separated from cable box, and the dielectric characteristics of the insulation between gland and cable box shall meet the requirements listed below. (a) Power frequency withstand voltage: 2 kv at least (b) Impulse withstand voltage: 6 kv at least Earthing terminal Earthing terminal shall be parallel groove clamp type or I bolt type. The terminal shall be able to connect the earthing wire of which cross sectional area between 25mm 2 and 70mm 2. It shall be located at the bottom on the HV side Fittings The transformer shall be completely assembled with all its fittings and supplied with first fill of oil. All bolts, nuts and all metal portions exposed to atmosphere continuously shall be treated suitably to withstand the weather conditions in Libya. Followings shall be considered as the minimum requirements. (a) Off load tap changer (b) Oil level gauge (c) Oil temperature indicator (d) Over pressure relief valve (e) Tank earthing terminal (f) Lifting lugs for lifting of whole transformer (g) Oil filling hole and cap (h) Valve at the bottom of the tank for oil filtering and drain (i) Oil sampling cock (k) Bi-directional rollers 11/24

12 Over pressure relief valve A replaceable and resealable over pressure relief valve shall be located on the tank above the 140 C top oil level and so located as not to interfere with use of other devices or fittings. The outlet port shall be sufficient to discharge the pressure. Exposed parts shall be weather and corrosion resistant materials. Gasket and O-ring shall withstand oil vapor at 105 C continuously without seizing or deteriorating for the life of the transformer. The valve shall have a pull ring for manually reducing pressure to atmosphere level using a standard hookstick. Venting pressure shall be 0.7±0.14 kg/cm 2, sealing pressure shall be minimum 0.42 kg/cm 2 and venting quantity shall be minimum 3.0m 3 /min at 1kg/cm 2 pressure. The valve shall be easily checked its operation status on ground. Tank The transformer shall not leak of oil. Tank shall be fabricated of excellent quality mild steel. The tank shall be designed so that the completed transformer can be lifted and transported without deformation or oil leakage. The tank shall withstand pressures developed during normal and abnormal operation of the transformer without permanent deformation. The tank shall be electrically welded and tested for leaks. The tank body and cooling radiators shall be of corrugated type. The top cover of tank and radiator shall be designed in such a way that water does not accumulate. There shall be an oil level mark inside the thank that indicates proper oil level at 30 C of ambient temperature. The transformer undercarriage shall be provided with bi-directional rollers to allow longitudinal and transverse movement on flat surfaces. Tank finish The painting process of steel parts shall ensure that no corrosion takes place under. The painting process of steel parts shall ensure that no corrosion takes place under severe climatic conditions prevailing in Libya. Prior to the painting of the tank, the cover and oil conservator shall be sand-blasted or shot-blasted for removal of mill and welding scale. The painting shall be made with a single coat of one-pack epoxy paint. The finishing paint shall be made with two or three coats. The primer coat shall contain rust inhibitor, both oil and heat resistant. Secondary coats shall contain resistant components of salt spray, chemicals and humidity. Minimum thickness of coats shall not less than average 60µm and shall not less than 80% at any point. The out side color of the tank shall be painted in grey. Gaskets All the gaskets used for sealing the tanks and connected external parts shall be made of NBR (Nitrile (Acrylonitrile) Butadiene Rubber) or better that totally prevents the leakage 12/24

13 of oil and ingress of humidity and air to the oil and windings under all operating conditions. The minimum thickness shall be 6mm. The gaskets shall not have any joint and shall withstand insulation oil. It shall not have variation of characteristics caused by temperature variation. 5.2 Required characteristics Short circuit impedance The minimum short circuit impedance shall comply with Table 3 of this specification. Table 3 Minimum short circuit impedance Rated Power Minimum short circuit impedance 300 kva 4 % 500 kva 4 % 630 kva 4 % 750 kva 5 % 1000 kva 5 % 1500 kva 6 % 2000 kva 6 % The guaranteed short circuit impedance shall be stated by the supplier. The tolerance shall be ±10.0% of the declared value at principal tapping and ±15.0% of the declared value at other tappings Temperature rise The transformers shall be capable of carrying their full normal rated current continuously under the worst temperature conditions encountered in Libya. Temperature rise of top oil shall not exceed 50 C as measured by thermometer and temperature rise of winding shall not exceed 55 C as measured by resistance. Duty under faults The transformers shall be capable of sustaining short circuit current without damage or distress at least 2 seconds. Insulation The insulation of the bushings, terminations and windings shall be suitable as to meet the requirements of the appropriate insulation class as specified in IEC The insulation of HV side shall be designed to withstand 28kV rms for power frequency test voltage and 75kV peak for impulse test voltage. And LV side shall be designed to 13/24

14 withstand 3kV rms for power frequency test voltage Load and no load losses Load loss and no load loss shall be stated by the supplier and shall not exceed the values of Table 4 of this specification. Tolerance shall not exceed +15% of no load loss, +15% of load loss and +10% of total loss. Table 4 - No-load loss and load loss limit Rated Power No Load Loss (W) Load Loss (W) No-load current 300 kva 720 4, kva 1,070 7, kva 1,265 8, kva 1,460 9, kva 1,815 12, kva 2,460 16, kva 2,965 19,700 No-load current shall not exceed the value of Table 5 of this specification. Tolerance shall not exceed +30% of the declared value Voltage drop Rated Power Table 5-No load current Maximum No Load Current 300 kva 2.0 % 500 kva 2.0 % 630 kva 1.5 % 750 kva 1.5 % 1000 kva 1.5 % 1500 kva 1.0 % 2000 kva 1.0 % The maximum voltage drop shall not exceed the values in Table 6 of this specification. All values shall be measured at 1.0 power factor, 100% load and adjusted to 75 C. 14/24

15 5.2.8 Efficiency Rated Power Table 6 Voltage drop limit Maximum Voltage Drop 300 kva 1.6% 500 kva 1.5% 630 kva 1.5% 750 kva 1.4% 1000 kva 1.4% 1500 kva 1.3% 2000 kva 1.3% The minimum efficiency shall be equal or exceed the values in Table 7 of this specification. All values shall be measured at 1.0 power factor, 100% load and adjusted to 75 C Bushing Rated Power Table 7 Minimum efficiency Minimum Efficiency 300 kva 98.2% 500 kva 98.4% 630 kva 98.5% 750 kva 98.5% 1000 kva 98.6% 1500 kva 98.8% 2000 kva 98.9% The electrical characteristics of bushings shall meet the requirements of IEC and IEC Sound level All transformers with their accessories shall be designed and manufactured to reduce noise and vibration to acceptable level. The average surface sound level of transformers shall not exceed the following values. The transformer shall be subjected to sound level measurement as per IEC /24

16 Rated Power Insulation oil Table 8 Sound level limit Maximum Sound Level 300 kva 55 db 500 kva 56 db 630 kva 57 db 750 kva 57 db 1000 kva 58 db 1500 kva 60 db 2000 kva 61 db The transformer shall be supplied with being filled with mineral insulation oil. The characteristics of insulation oil shall meet the Table 2 of IEC and GES The oil shall not be contaminated by Poly Chlorinated Biphenyls (PCB). 6 Tests Routine tests shall be repeated in the presence of GECOL representatives on 10% of the quantity offered for inspection, chosen at random, subject to a minimum of 2 Nos. of each type of transformer. 6.1 Type tests (a) Temperature-rise test (IEC ) (b) Dielectric type tests (IEC ) Lightning impulse test 6.2 Routine tests (a) Construction test (b) Measurement of winding resistance (IEC , 10.2) (c) Measurement of voltage ratio and check of phase displacement (IEC , 10.3) (d) Measurement of short-circuit impedance and load loss (IEC , 10.4) (e) Measurement of no-load loss and current (IEC , 10.5) (f) Dielectric routine tests (IEC ) Separate source voltage withstand test Induced overvoltage withstand test (g) Oil pressure test 6.3 Special tests (a) Dielectric special tests (IEC ) 16/24

17 Chopped wave test (b) Measurement of zero-sequence impedance(s) on three-phase transformers (IEC , 10.7) (c) Short-circuit withstand test (IEC ) (d) Measurement of sound levels (IEC ) (e) Measurement of the harmonics of the no-load current (IEC , 10.6) (f) Leakage test for transformer tank and radiator 7 Rating plates The transformer shall be provided with a rating plate of weatherproof material, fitted in a visible position and clearly readable at safety distance when cables are connected, showing the appropriate items indicated below but not limited. The characters shall be English roman letters and Arabic numeral characters. Symbols and text shall be indelibly molded, stamped or engraved in a plate material and they shall be at least 4.0mm high. If not contrasting in colour, they shall be grooved at least 0.5mm high. The transformer shall be provided with a rating plate of weatherproof material, fitted in a visible position and clearly readable at safety distance when cables are connected, showing the appropriate items indicated below but not limited. The characters shall be English roman letters and Arabic numeral characters. Symbols and text shall be indelibly molded, stamped or engraved in a plate material and they shall be at least 4.0mm high. If not contrasting in colour, they shall be grooved at least 0.5mm high. (a) Kind of transformer (b) Applicable international standard (c) Manufacturer's name (d) Manufacturer's serial number (e) Year of manufacture (f) Number of phases (g) Rated power in kva (h) Rated frequency in Hz (i) Rated voltages and tapping range of HV(kV) and LV(V) (j) Rated currents of each tapping of HV and LV in A (k) Drawing of vector group (l) Short-circuit impedance, measured value in percentage (m) Type of cooling (n) Total mass (o) Mass of insulating oil (p) Insulation level of HV and LV (q) Temperature rises of top oil and windings (r) Insulating liquid 17/24

18 (s) Normal operation conditions: Ambient temperature, altitude 8 Marking Following markings shall be easily visible when the transformer is in service and the entries shall be indelibly marked. The characters shall be English capital roman letters and Arabic numeral characters. (a) Rated power: Rated power and its unit shall be of salient character on middle position of tank wall on HV side. Size of character shall be enough large to read it from safety distance when the transformer is connected with cables. The salient part shall be painted with red color indelible paint. (b) Terminal symbol: HV terminal symbol shall be 1U, 1V and 1W from left side. LV terminal symbol shall be 2N, 2U, 2V and 2W from right side and indelibly marked in front of terminal bushings. (c) Earthing terminal marking shall be marked adjacent to earthing terminal. 9 Packing and Delivery The supplier shall provide packing of the transformers as is required to prevent their damage or deterioration during transit to their final destination and long period of storage. The packing shall be sufficient to withstand, without limitation, rough handling during transit and exposure to extreme temperatures, salt and precipitation during transit and open storage. (a) All transformers and its components shall be shipped from the factory to the specified site. (b) The transformer shall be wrapped up in proper thickness of vinyl sheet to prevent ingress of humidity. The enough amount of dehumidifying agent shall be inside. The transformer shall be on a wooden pallet and the base of transformer shall be tied to the pallet with galvanized steel bolts and nuts. Wooden box shall cover the whole transformer and shall be connected to the pallet without looseness or disconnection. The pallet and packing case shall be suitable for handling by forklift truck and they shall have enough strength and thickness for protection of transformer. If the wood material is imported from outside of Libya, the wood material should be disinfected to avoid import of insects or virus. (c) Packing case size and weights shall take into consideration, where appropriate, the remoteness of the transformer's final destination and the absence of heavy handling facilities at all points in transit. (d) The parts of a transformer shall be packaged by one set even though the numbers of transformers to be supplied are plural. 18/24

19 (e) Each shipment shall include a detailed packing list identifying all items by part number, including hardware. (f) All material shall be carefully loaded for protection during shipment. (g) Small parts and fasteners shall be carefully boxed, crated, bagged or otherwise containerized and protected for shipment. (h) All materials shall be arranged to allow safe unloading at the site. (i) There shall be handling instruction to minimize damage. The outer packing must be clearly marked on at least four (4) sides as follows; (a) Name of the procuring department (b) Name of the supplier (c) Contract description (d) Final destination (e) Gross weight (f) Any special lifting instructions (g) Any special handling instructions (h) Any relevant pollution or environment classifications 10 Spare parts Following spare parts shall be supplied with the transformers (a) 1 set of HV bushing with every 10 transformer (b) 1 set of LV bushing with every 10 transformer (c) Other spare parts that are recommended by manufacturer 11 Document and certificate The transformers and all associated materials quoted by the supplier shall be approved by GECOL. The quantity of documents and certificates submitted shall be not less than three copies. The transformer shall conform to the latest edition of IEC including Clause 2 of this specification or any other equivalent international standards. The design and construction of transformer shall be subjected to the approval of GECOL Information to be provided with the BID Technical descriptions, data sheets, catalogues and other information shall be submitted with the BID and those which are submitted shall be sufficient to enable GECOL to evaluate thoroughly the proposal as to its compliance with the requirements of this specification. The minimum requirement is as follows: (a) Detailed summary of difference with this specification 19/24

20 (b) Technical Data Sheet duly filled in and signed (Annex A) (c) Material safety data certificates of all chemical materials used for manufacturing such as insulating fluid, painting, gasket and gas, etc. (d) Detailed drawing of all components in A3 or A4 size (e) Detailed handling, installation and maintenance manual & schedule for good operation (f) Brochures and catalogues containing outline dimensions, main electrical and mechanical data, etc. (g) Applicable design specification and standards in English language (h) Test certificates approved by international institute (i) Quality control system and relevant certificate 11.2 Documents to be approved by GECOL The supplier shall furnish all relevant technical information, drawings etc. to GECOL for approval prior to the start of manufacture. Offers without Technical Data Sheet completely filled in will be rejected. (a) Vendor(s) details/ Reference list (b) Technical Data Sheet (c) Tests schedule and procedures (d) Transportation schedule and storage conditions (e) Drawings of materials (All drawings shall be in A3 or A4 size with title block approved by GECOL) 11.3 Documentation All documents supplied under this specification shall be documented to the extent that the end user can easily understand its theory of operation, performance, installation and maintenance for the product. All documents shall be submitted being filed in order to approve of GECOL and reorder later. Language in all documents and drawings shall be written in English and dimensions shall be used in metric SI-units. 12 Warranty The supplier shall provide a full three-year limited warranty on all equipment supplied. The warranty shall cover all parts and all costs, which are directly attributable to the supplier. Warranty coverage shall begin on the date that the equipment is received. 20/24

21 Dia 44.5±0.2 Dia 32.5±0.2 Dia 30.9±0.2 Dia ± 1 Dia 48.5±0.2 Figure 1-200A plug-in type bushing 21/24

22 Appendix A Technical Data Sheet No. Description Particulars Manufacturer s name Applicable international standards Conservator or sealed type Rated power (kva) Rated voltage (kv) System highest voltage (kv) Rated voltage ratio at principal tapping (kv/v) Method of cooling Vector Group Off circuit tapping range Core a) Maximum flux density at nominal voltage and frequency (Tesla) b) Thickness of lamination (mm) c) Iron loss per kg. weight of core (W) Winding a) Material of HV winding b) Material of LV winding Resistance of windings per phase at 75 C a) HV winding (Ω) b) LV winding (Ω) Cross sectional area of winding a) HV winding (mm 2 ) b) LV winding (mm 2 ) Cable box a) Number of gland(s) and adaptable cable size at HV terminal b) Number of gland(s) and adaptable cable size at LV terminal Short circuit impedance a) At principal tapping & rated frequency (%) b) At highest tapping & rated frequency (%) c) At lowest tapping & rated frequency (%) Signature : 22/24

23 Technical Data Sheet No. Description Particulars Maximum temp. rise at rated full loading: a) Oil ( C) b) Winding ( C) Short circuit duration (Sec.) Losses a) Load loss at rated voltage and tapping, on full load at 75 C (W) b) No load loss at rated voltage & frequency (W) No load current (%) Voltage variation a) At 0.8 P.F. lagging (%) b) At 1.0 P.F (%) Efficiency a) 100% load at 1.0 P.F. (%) b) 100% load at 0.8 P.F. (%) Sound level (db) Insulation level a) Power frequency test voltage (kv rms) b) Impulse test voltage (kv peak) Tank a) Material of tank b) Tank finish method Thickness of tank plate a) Sides (mm) b) Bottom (mm) c) Top (mm) d) Radiator (mm) e) Max. pressure tank can sustain (kg/cm 2 ) Signature : 23/24

24 Technical Data Sheet No. Description Particulars Tank finish a) Type of paint applied internally b) Type of paint applied externally c) Color of tank d) Thickness of coating (µm) Gasket a) Material b) Thickness (mm) Over pressure relief valve a) Venting pressure (kg/cm 2 ) b) Venting quantity (m 3 /min.) Insulation oil a) Total oil required (Liters) b) Mass of oil (kg) c) Oil grade and standard specification adopted Mass a) Core and winding (kg) b) Complete transformer excluding oil (kg) c) Transformer arranged for shipment (kg) Overall dimensions (Height (mm) Length (mm) Width (mm)) List of attached fittings List and numbers of spare parts Signature : Designation : Name of Tenderer : Date : 24/24