Specifications include, but are not limited to: Quantity: • 15kVA – Three (3) transformers • 25kVA - Seven (7) transformers • 50kVA – Three (3) transformers Frequency: • 60 Hz Primary Voltage: • 7.2/12.47kV Ground Wye Secondary Voltage: • 120/240V System Voltage: • 12.47kV phase-to-phase nominal Standards: • C57.12.00 IEEE General Requirements for Liquid Immersed Distribution, Power and Regulating Transformers • C57.12.25 IEEE Standard Requirements for Pad-Mounted, Compartmental-Type, Self-Cooled, Single-Phase, Distribution Transformers with Separable Insulated High Voltage Connectors • C57.12.28 Pad-Mounted Equipment Enclosure Integrity • C57.12.90 IEEE Standard Test Code for Liquid-Immersed Distribution, Power and Regulating Transformers • ASTM D3487 Standard Specification for Mineral Insulating Oil Use in Electrical Apparatus • US DOE – 2016, or newer, US Department of Energy efficiency standards for liquid-immersed medium-voltage distribution transformers Construction: • All transformer units shall be newly constructed and manufactured in North America. Repaired, rebuilt, or remanufactured units will not be accepted Ratings: • Primary and secondary ratings shall be as indicated in Request for Bids (RFB) • Primary basic lightning impulse insulation level (BIL) ratings shall be 95kV • Secondary BIL ratings shall be 30kV for all secondary voltages • Transformers shall be designed with an average winding rise (AWR) of 65°C above ambient when tested at the transformer rating Tank Construction: • Transformers shall be of welded construction • Transformers shall conform to RUS dead-front requirements • Transformers shall be constructed in accordance with cabinet configurations of ANSI C57.12.25 including a minimum cabinet depth of 16-inches • The transformers tank bottom shall be raised above grade level, and provide a tank skirt • Transformer tank, fins (if present), skirts, cabinets, casings, doors, hinges, pins, pentabolt enclosures, locking eyes, and all steel hardware and welds that will be exposed to outside weather, shall be constructed of 304 stainless steel • Hinges shall allow for removal of cabinet doors • A recessed, captive, penta-head bolt that meets the dimensions of C57.12.28 shall secure all access doors; provide one (1) spare penta-head bolt per each supplied transformer • Cabinet doors shall include a locking eye provision for padlock or similar means of securing access • Lifting lugs shall be included with each transformer and shall be welded to the tank • Grounding provisions shall include a minimum of two (2) ground pads with NEMA 2-hole configurations • Transformers shall have a green painted finish in accordance with the requirements of ANSI C57.12.28 and be suitable for installation in a marine environments Transformer Nameplate and Marking: • Nameplate shall be made of corrosion resistant metal, and permanently marked with nameplate information required to meet C57.12.00 and shall include: manufacturer; serial number; date of manufacture; voltage and kVA ratings; electrical diagram; oil capacity; PCB parts per million; wet and dry weights. • Nameplate shall be permanently attached to the inside of the transformer cabinet • Each transformer shall be stenciled or decaled on the outside of the transformer tank with the kVA rating and secondary voltage. Stencil/decal lettering shall be reflective and a minimum of 2” high • Primary and secondary terminals and ground lugs shall be clearly marked on the lead in the accordance with ANSI standards • Transformer cabinet door(s) shall be decaled on the outside with an ANSI Z535-compliant reflective “Warning” sign
