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Material Specification Distribution Transformers – Padmount City of Burley Electric Department Exhibit DISTRIBUTION TRANSFORMERS SPECIFICATION Sections 6,7,8, and 9 cover the requirements for three phase transformers ---PAGE BREAK--- Material Specification Distribution Transformers – Padmount City of Burley Electric Department 6. PAD-MOUNTED TRANSFORMERS – THREE PHASE 6.1. Ratings 6.1.1. All ratings shall be for 60 Hertz alternating current, oil immersed, self-cooled transformers capable of continuous operation at rated KVA without exceeding either a 65° C average temperature rise or an 80° C hot spot temperature rise. 6.1.2. The electrical characteristics of the completely assembled high and low voltage terminals shall be in accordance with IEEE C57.12.26, Table 3 and Table 4. 6.1.3. The basic impulse level (BIL) shall be 95 kV. 6.1.4. Voltage: 12,470 / 7,200 Volt Grounded Wye 6.2. Transformer Type 6.2.1. Transformers shall be radial feed construction, in accordance with IEEE C57.12.26. 6.3. Core Construction 6.3.1. The core shall be either triplex or five-legged construction. The configuration shall be WYE – WYE. 6.4. Pressure Relief Device 6.4.1. All transformers shall be designed such that all excessive pressure build-ups are released without damage to the tank in accordance with IEEE C57.12.26. 6.4.2. All transformers shall be equipped with a pressure relief device (either Tomco Series 1776K or Qualitrol Model 202-032-1). 6.5. Transformer Taps 6.5.1. The transformer is to be equipped with 2 taps above the rated voltage and two taps below the rated voltage. A total of five tap positions shall be available. Tap positions shall be at 2-1/2% intervals. 6.6. High Voltage Bushings 6.6.1. Transformers shall come equipped with high voltage bushing wells and corresponding load break inserts for dead front application. The bushing wells shall be externally clamped, 200-amp rated, separable, and rated for primary switching per IEEE 386. 6.6.2. The load-break bushing inserts shall be Cooper Power Systems (Catalog No. LBI 215) or Elastimold (Catalog No. 1601A4). 6.6.3. Inserts shall be shipped with physically wired down & secured dust caps or use a dust cap equipped with a pressure relief hole to prevent pressure build up in the dust cap that would cause loss of the dust cap. 6.7. Low Voltage Bushings 6.7.1. Transformers shall be equipped with fully insulated, low voltage bushings, in accordance with Gig, 8(a) of IEEE C57.12.26. 6.7.2. Transformers shall be furnished with the following NEMA standard stud or spade terminals as per IEEE C57.12.26 Fig. 9. ---PAGE BREAK--- Material Specification Distribution Transformers – Padmount City of Burley Electric Department Table 6: Three Phase Padmount Transformers – Terminal Sizes KVA Secondary Voltage Terminal Size 75-300 480Y/277 Stud, 5/8” – 11 UNC – 2A (Fig. 9d) 75-150 240, 208Y/120 225-300 240, 208Y/120 Stud, 1” – 14 UNC – 2A With 6 hole Spade (Fig. 9d) 500 480Y/277 500 240 Spade, 6 hole – (Fig. 9b) 500 208Y/120 750 [PHONE REDACTED] 480Y/277 Spade, 10 hole – (Fig. 9c) 750-1500 208Y/120 1000 240 2000-2500 480Y/277 6.7.3. Ten-hole spade pads shall be furnished with additional support, as designed by the manufacturer. The supports shall be attached to the pads at the farthest point from the tank wall and attached in a manner so as to not interfere with the use of any of the pad’s holes. 6.8. Grounding Lugs 6.8.1. Transformers shall be furnished with a total of 3 ground lugs: one ground lug installed in the transformer low-voltage ground provision and two ground lugs installed in the transformer high-voltage ground provision. 6.8.2. The ground lugs shall be Fargo (Catalog No. GC-207) or equivalent. 6.9. Compartmental Locking 6.9.1. All hinged or removable cabinet access lids or doors shall have a three point latch and be provided with a 9/16” stainless steel or silicon bronze Pentahead captive bolt locking device and provisions for padlocking. The Pentahead bolt shall be coordinated so that it must be engaged before a padlock can be inserted into or removed from the hasp. All transformers shall meet the requirements for tamper- resistance of NEMA TR-1 and Western Underground Guide No. 2.13. 6.10. Hand Holes 6.10.1. A bolted on tank hand hole shall be secured against tampering by some means accessible only from the inside of the compartment. (Hand Hole is only required on Transformers larger than 1000 kVA) 6.11. Fusing 6.11.1. Transformers shall be provided with Cooper Power Systems Bay-O-Net fuse holders. They shall be of the sidewall mount type with flapper, Cat. No. 40003616C99FV. 6.11.2. Transformers shall be provided with Cooper Power Systems Bay-O-Net, dual sensing, load break, externally removable fuses. They shall also be provided with internally mounted partial range current limiting fuses (CLF) manufactured by Cooper Power Systems. 6.11.3. The partial rage current limiting fuses (type ELSP) shall be placed in series with the Bay-O-Net fuse holder and be mounted internally under oil. Partial range current limiting fuses shall have a nominal voltage rating of 8.3kV. 6.11.4. Oil drip shields shall be provided with the Bay-O-Net fuse holder and be designed to catch and hold oil. Oil drip shields that redirect oil rather than catch and hold it will not be allowed. ---PAGE BREAK--- Material Specification Distribution Transformers – Padmount City of Burley Electric Department 6.11.5. The Bay-O-Net Fuse size and type shall be painted on the inside of the primary side cabinet door utilizing yellow characters one inch high. In addition, the bayonet and current limiting fuse part numbers will be displayed on the nameplate. 6.12. Transformer Tanks 6.12.1. Transformer tanks shall be constructed in accordance with IEEE C57.12.26. 6.13. Oil Drain Valve 6.13.1. Transformers shall come equipped with an oil drain valve installed at the bottom edge in the transformer secondary compartment, ¾” minimum diameter, gate or ball activated. 6.14. Labeling 6.14.1. A danger label, complying with ANSI Z535, shall be located on the inside of the transformer and readily visible whenever the first equipment door is open. 6.15. Accessories 6.15.1. In addition to standard accessories, each transformer 1500 KVA and larger shall be properly equipped with the following gauges mounted in the low voltage compartment. 6.15.1.1. Oil Level Gauge. 6.15.1.2. Dial thermometer with maximum top oil temperature indicator and magnetic reset. 6.15.1.3. Tank Pressure Vacuum Gauge. 6.16. Tank Dimensions 6.16.1. The maximum dimensions of the 3 phase Padmount transformers shall be as shown below. These dimensions do not include cooling fins. Table 8: Three Phase Transformers – Maximum Dimensions 75 KVA Mini-Pad 150 to 500 KVA 750 TO 2500 KVA Height 42” max 70” max 89” max Width 44.5” max 72” max 88” max Depth 42” max 62” max 66” max 6.16.2. Depth of Apparatus Compartment – The minimum depth of the apparatus compartment (except 75KVA mini-pad) shall be 24 inches, as shown in Dimension F of Figure & of IEEE Standard C57.12.26 – 1992. The 150kVA – 208/120V Three Phase Padmount shall have a minimum primary bushing height of 36”. 6.16.3. Cooling Fins – Cooling fins shall not extend further than 12 inches beyond the dimensions shown above. ---PAGE BREAK--- Material Specification Distribution Transformers – Padmount City of Burley Electric Department 7. TRANSFORMER OIL 7.1. Transformers shall be insulated with new (unused) mineral oil. 8. NOISE 8.1. Transformer sound levels shall not exceed the values specified in the latest revision of NEMA Publication TR 1-0.00. 9. PAINT FINISH 9.1. The transformer shall have a corrosion resistant finish that shall be capable of meeting the functional specifications or exceed paint requirements of ANSI C57.12.28, latest revision. The outside shall be properly prepared, primed and painted with highly weather resistant finish coat. All transformers shall have the manufacturer’s premium paint system. 9.2. Pad Mounted Transformers – the finish coat shall be semi-gloss olive-green gray similar to Munsel no. 7GY3.29/1.5. The interior cabinet surfaces shall be primed and finished, with no less than 2.0 mils dry thickness. 9.3. Nameplates 9.3.1. Nameplates shall be made of stainless steel or anodized aluminum and permanently marked with essential operating data meeting ANSI standard C57.12.00 for nameplate b. 9.3.2. The transformer nameplate shall specifically state that the transformer is filled with “Mineral Oil” and the number of gallons of oil it contains. 9.3.3. The nameplate shall indicate that the PCB content of said transformer is less than 1 ppm or that at the time of manufacture gas chromatographic analysis certified non-detectable PCB. 9.3.4. Each nameplate shall contain a transformer bar code. The bar code label shall meet all the requirements of IEEE standard C57.12.35 – 1996. 9.3.5. The bayonet and current limiting fuse part numbers will be displayed on the nameplate for al Padmount units. 9.3.6. Nameplates shall be mechanically fastened with rivets, bolts, screws or corner tack welds.