This standard covers oil-immersed 15/20/25/28 MVA 3-Phase, 116 kv Y/12.6 kv two winding, LTC power transformers for Springfield Utility Board.

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1 1 SCOPE This standard covers oil-immersed 3-Phase, 116 kv Y/12.6 kv two winding, LTC power transformers for Springfield Utility Board. 2 NATIONAL STANDARD The power transformers shall be manufactured, tested, and furnished according to the latest edition, revision or amendments to the applicable standards of ANSI, NEMA, ASME and IEEE except as specifically noted in this standard. 3 MODIFICATIONS TO REFERENCE STANDARDS 3.1 Windings The power transformer shall be outdoor, three phase, two winding 60 Hz, 55/65 C average winding temperature rise, rated and 116 kv Y/12.6 kv. The transformer shall be rated on ONAN/ONAF/ONAF basis. The windings shall be connected Delta on the 116 kv high side and Wye on the 21.8 kv low side for use on a grounded Wye system. The high voltage windings will lead the low voltage windings by 30. This angular displacement between the high voltage and low voltage windings is shown below: Load Tap Changer The three phase automatic-manual load tap changer shall be designed to vary the 21.8 kv winding from 10% above rated voltage to 10% below rated voltage in thirty-two 5/8% steps. (Taps shall be per ANSI C ). All taps below 21.8 kv shall be for use at a current equal to the transformer current at full rated KVA and 21.8 kv. All taps above 21.8 kv shall be full KVA rated. SHEET 1 OF 18

2 3.1.2 No Load Taps No load taps shall be provided on the 116 kv winding and they shall be at 121.8, 118.9, 116.0, 113.1, and kv (2.5% per tap from base). All the no load taps will be for use at the full forced cooled rating of the transformer Basic Impulse Level The 116 kv high voltage winding shall have a BIL withstand rating of 450 kv. The 21.8 kv low voltage winding shall have a BIL withstand rating of 150 kv. 3.2 Noise Level The transformer noise level shall meet NEMA standards. 3.3 Bushings General Requirements a. The bushings shall have 1-1/8 to 1-1/2 studs unc-12 threads per inch. b. Provision shall be made for installing two (2) bushing-type current transformers in each 116 kv and 21.8 kv bushing wells. c. Provide a replaceable, tinned, NEMA standard, four (4) hole copper terminal pad to stud connector for each bushing. d. All bushings shall be ceramic, ANSI 70 light gray in color. e. Each bushing shall have potential taps suitable for power-factor test. f. Manufacturer shall be ABB, PCORE, Trench, or SUB approved equal High Voltage Bushings a. The high voltage bushings shall be Paper Oil Condenser (POC) construction. b. High voltage bushings shall be located on the transformer cover in ANSI Segment 3. c. The 116 kv bushing shall be ANSI, NEMA rated, 800 ampere draw lead construction with 550 kv BIL capability. d. Oil level of the bushing shall be visible from the ground. SHEET 2 OF 18

3 3.3.3 Low Voltage Bushings a. The 21.8 kv bushings shall be ANSI, NEMA rated 1200 amp with 150 kv BIL capability. b. Low voltage bushings shall be mounted on the transformer cover in ANSI Segment 1. c. The Neutral bushing shall be the same as the line bushing. Provide a neutral bushing that is interchangeable with the 21.8 kv phase bushings. 3.4 Lightning Arresters General Requirements a. All arresters shall be mounted on the transformer in such a manner as to vent away from bushings and transformer. b. Lightning arresters must maintain equivalent or greater spacing of energized parts than bushings on high and low sides. c. Top of the lightning arresters shall be at the same height as the top of the bushing it is protecting. d. Lightning arresters shall be double-grounded with each end of the copper bus bar terminating at a separate grounding pad. Ground pads shall be 2 x 3 1/2 copper faced or stainless steel with NEMA bolt spacing. e. Line lugs to have NEMA four (4) hole pad standard spacing. f. All lightning arresters shall be ceramic, ANSI 70 light gray in color. g. Manufacturer shall be ABB, Cooper, Hubbell, or Siemens High Voltage Provide three station type metal-oxide lightning arresters for protection of the 450 kv BIL winding. High voltage arresters shall be rated 96 kv Duty Cycle Low Voltage Provide three station type metal-oxide lightning arresters for protection of the 150 kv BIL winding. Low voltage arresters shall be rated 18 kv Duty Cycle. SHEET 3 OF 18

4 3.5 Instrument Transformers General Requirements a. Provide necessary current transformers as required for standard accessories. Current transformers may not be used for more than one purpose unless approved by SUB. b. Transformer monitor current transformers shall be meter accuracy. c. All taps for each current transformer secondary shall be connected to suitable short circuiting type terminal blocks located in the control cabinet for customer s use. d. All current transformer wiring shall be no smaller than 10 AWG. e. All current circuit wiring shall have ring terminal lugs Bushing Well CT s a. Provide six (6) multi-ratio relay accuracy (C 800) bushing current transformers with a maximum ratio of 600/5. Install two in each high voltage bushing well. b. Provide six (6) multi-ratio relay accuracy (C 800) bushing current transformers with a maximum ratio of 1200/5. Install two in each low voltage bushing well. c. Provide a multi-ratio relay accuracy (C 800) bushing current transformer with a maximum ratio of 1200/5 in the neutral bushing well. 3.6 De-Energized Tap Changers Manually operated de-energized tap changer control handle shall be located on the side of the tank within easy reach from the ground and provided with means for padlocking any position. 3.7 On-Load Tap Changer General Requirements a. The load tap changer shall be Reinhausen RMV-II b. The tap changer shall be constructed such that maintenance intervals are 500,000 operations or greater than 6 years. c. If a series transformer is required to reduce the current level to the LTC, it shall be of the same design and constructions as the main core-and-coil assembly, including short circuit withstand capability. SHEET 4 OF 18

5 d. A hand-crank mechanism shall be included, to manually operate tap changer, interlocked with the electrical system so that when the manual handle is used, the motor is disconnected from its source. The interlock must show a visible break in the motor circuit. e. The load tap changing drive motor and all necessary control relays shall be capable of operating from a 120/240 volt, single phase, 60 Hz, three wire source On-Load Tap Changer Compartment a. The tap changer shall be in a separate compartment. b. The compartment shall be oil-filled. c. The tap changer compartment shall be able to withstand a full vacuum, but shall not require vacuum filling after the oil is drained for maintenance inspections. d. The Tap Changer compartment shall have a maintenance free, self de-hydrogenating breather (Messko, type DB100). e. The load tap changing drive motor and all necessary control relays shall be capable, of operating from a 120/240 volt, single phase, 60 Hz, three wire source On-Load Tap Changer Control Panel a. The load tap changer shall be provided with a Reinhausen TAPCON 250 load tap changer control. b. The load tap changer shall be provided with a BECKWITH first house protector (M-5329) c. The load tap changer control shall include the following features: d. A line drop compensator (LDC) with polarity switch. e. Automatic to Manual control transfer switch and manual Raise - Lower switch. f. A Normal (Internal) to External voltage source transfer switch. Standard Banana jacks shall provide easy access for external voltage checks and supplying an external voltage source. The external voltage source transfer switch with disconnecting device for de-energizing the LTC windings. The disconnecting devices shall open the control circuit from the potential sources and short and isolate the internal current transformers from the control circuit. g. Overload protection and disconnecting devices for tap changer drive motor circuits and line drop compensator circuits. h. The necessary internal current power supply (LDC CT) for the tap changer operation shall be located on X1 to Ground. The potential power supply (provided by the Owner) for voltage control shall be 100 to 1 ratio. SHEET 5 OF 18

6 i. A tap position indicator with remote resettable drag hands from the control panel. The position indicator shall be easily read from the ground. j. An operation counter to record the number of operations of the tap changer. k. The current and potential circuit for the load tap changer control shall be electrically isolated from the 120/240 volt, single phase auxiliary power source. l. Neutral indicating light on control panel. m. Complete integrity controls for vacuum bottle interrupters only. n. TAPCON 250 shall be capable of DNP3 communication over fiber optic. 3.8 Transformer Control Cabinet General Requirements a. The transformer control cabinets shall be located on the low voltage side of the transformer, in ANSI Segment 1. b. The control panel shall be enclosed in weatherproof housing with shockproof mountings attached to transformer tank. c. Customer will provide 120/240 volt single phase, three wire, 60 Hz source for operation of all transformer auxiliaries. d. Control housing completely assembled and wired Contents a. Provide a cabinet heater, 240-volt AC single phase with thermostat. b. A 120 V ac, 20 A, GFCI convenience outlet shall be available on the exterior of the control cabinet. The outlet shall be mounted in a weatherproof junction box with weatherproof cover. The junction box shall be protected by a metal shroud welded and painted on the exterior of the breaker. Outlet wiring shall be terminated on suitable terminal blocks in the control cabinet c. Provide terminals for fan control with customer connection of 120/240-volt single phase three wire source. d. Terminations for all control and monitoring outputs requested. e. A light shall be provided inside the control cabinet. f. Tap Changer Control panel g. Alarm Annunciator h. Transformer monitor SHEET 6 OF 18

7 3.9 Cooling Equipment General Requirements a. Cooling equipment shall be radiator type construction with fans. b. Cooling equipment shall meet OSHA regulations c. Fans used for cooling equipment shall be suitable for operation with 240 volt, single phase, 60 Hz. d. Provide automatic switching in both hot legs of fan circuits for both stages. e. An auxiliary relay shall be furnished to provide alarm indication to annunciator for loss of power to cooling equipment, with 30-second time delay Control Provide all necessary control devices and circuit protection for both stages of cooling. The cooling equipment shall be controlled from winding hot spot temperature gauge, not via the LTC control or transformer monitor. The winding temperature relay shall have four adjustable contacts. a. The first stage of forced cooling starts at 85 C, b. The second stage of forced cooling starts at 95 C. c. The third stage contact shall initiate an alarm output at 115 C, d. The fourth set to initiate the temperature trip alarm at 125 C Radiators a. All radiators shall be removable, b. Radiators shall be furnished with suitable valves on the transformer side of the mounting flanges and top and bottom pipe taps with plugs, to permit draining and removal without draining oil from the transformer tank. c. All shutoff valves shall be easily accessible with all radiators in place. d. Radiators shall be equipped with lifting eyes and designed so they can be handled without the addition of special bracing. e. Radiators shall be manufactured by either Menk or Trantech. SHEET 7 OF 18

8 3.9.4 Fans a. Fans shall be located on the sides or bottom of the radiators to provide accessibility with adequate clearance from transformer live parts. b. Fans to be Krenz-Vent 24 part # F24-A7836 or 26 part # F26-A8682 with a male plug & cord connected Tank Construction a. Transformer shall be positive pressure nitrogen system with welded cover. b. During welding of the transformer cover, a fiberglass rope or similar inorganic gasket will be permanently located between the cover and the tank flange to prevent weld spatter from entering the tank. c. There shall be a manhole in the transformer cover. Covers on all manholes and inspection openings shall be bolted on. d. All bushings shall be bolted on. e. Purging fitting to be tapped into opposite side of transformer tank from inert gas inlet. f. Lifting eyes on cover, lifting lugs on tank and provisions for jacking Field filling a. The transformer shall be designed for field filling with non-inhibited mineral transformer oil and the space above the oil filled with inert gas. Provide necessary gas handling equipment to maintain positive pressure. b. Tank, radiators and accessories shall be designed for field vacuum filling at -15 psig. c. Provide necessary oil fill and drain valves. d. Necessary valves for filling and purging gas space shall be provided Oil SUB Specification The transformer oil furnished with the equipment shall meet or exceed SUB s specification MSD3005 which includes the dielectric strength of the oil. SHEET 8 OF 18

9 PCB Certification a. The oil shall be certified as a non-pcb (polychlorinated biphenyl) and shall have a tag, sticker or label firmly attached to the equipment stating such. b. A separate document shall be sent to SUB s representative showing the oil certification, amount of oil delivered, oil manufacturer, type of oil and with the transformer s serial number clearly stated on the certification c. If the transformer oil is to be delivered for the equipment via tank truck, the fluid must be certified to contain no PCB s. d. The manufacturer of the equipment will be responsible to provide the certification Delivery a. The oil delivery shall be coordinated with SUB. b. Oil shipped external from the transformer shall be tested once at delivery site to prove meeting all of SUB s specification MSD3005, prior to filling the LTC or transformer Nitrogen System a. Housing for the nitrogen tank and regulation system shall be in a NEMA type 3R enclosure mounted with the floor two inches above transformer base. b. Nitrogen cylinder shall be provided with cubic foot capacity. c. The regulation system shall be a Three-stage pressure reduction system. Stage 1 & 2 shall reduce the pressure from 3000 down to 10 pounds and the third stage shall be adjustable from 0-12 pounds. d. Identical, separate low pressure gauges that are weather proof and UV resistant shall be provided for the transformer tank, and on the third stage in the nitrogen system enclosure. e. An oil filled cylinder pressure gauge shall be used that shall display from 0 to 3,000 pounds. f. There shall be an oil filled pressure gauge monitoring the third pressure stage, 0-12 psi. g. The nitrogen tank assembly shall allow for maintaining pressure in the main transformer tank. Shutoff valve shall be installed on the line. h. A moisture -separating unit shall be used in the system i. High pressure, low pressure and empty cylinder alarm contacts shall be brought back to alarm annunciator. SHEET 9 OF 18

10 3.13 Core and Coil Assembly Construction a. All windings shall be copper. b. The use of jacking bolts to apply pressure to the coils shall not be allowed. c. The manufacturer shall use only the highest quality grain oriented core steel available. The core steel shall be sequentially cut and stacked in the same order it is cut. d. Core grounds shall be accessible on an external 600 volt bushing. The bushing shall have a shield or protective cover. The grounds shall be able to be separated for testing without removing an access cover into the tank Process a. The core and coil assembly shall be dried to provide less than a 0.5% power factor. b. The insulation shall be dried via the vapor phase process or other means that does not damage the insulation Paint General Requirements a. All surfaces of the transformer tanks, covers, panels, etc., shall be thoroughly cleaned by degreasing and abrasive blasting to remove grease, scale, rust and corrosion. b. All surfaces shall then be given at least one coat of zinc rich epoxy primer. c. The top surface of the main tank and LTC compartment shall have a non-skid coating Exterior The exterior surface of the transformer tank, covers, panels, etc. shall be given two coats of finish enamel or other SUB approved paint. Color - ANSI No Interior The interior of all control cabinets and the tanks shall be painted white Seismic Design The equipment shall be designed and constructed to meet or exceed a moderate seismic level event in accordance with Section IEEE 693. SHEET 10 OF 18

11 3.16 Short Circuit Requirements The transformer is to be designed to meet the short circuit requirements given in the short circuit test code as per ANSI C , C Accessories Transformer shall be furnished complete with the necessary fans, pumps, oil and all of the standard accessories (ANSI C ) usually furnished and necessary for its operation, including but not limited to the following: General Requirements a. Oil sampling valves shall be provided on all oil filled compartments. b. Filter press connections shall be provided on main tank and LTC compartment. c. Connection diagram nameplate d. NEMA standard 2-hole grounding pads. Grounding pads near the bottom of the transformer shall be within 6 inches of the transformer base. There shall be one located at each lower corner of the main tank, and one on the top of the tank adjacent to the X0 bushing. e. The copper ground bus shall be attached to the transformer a minimum of every 24. f. All accessories utilizing DC power or having contact outputs, shall be capable of operating between 100 V DC and 150 V DC Gauges a. All gauges and exposed accessories are to be outdoor weatherproof type. b. All liquid level and temperature gauges shall be mounted to permit reading and resetting of maximum pointers from ground level near the transformer c. Main tank and LTC oil level gauges shall have low level alarm contacts routed to annunciator (Messko, type MTO-ST160) d. Qualitrol under oil sudden pressure relay and seal-in relay with alarm and trip contacts routed to the annunciator Pressure Relief Valves a. Transformer main tank and LTC compartment shall be supplied with pressure relief valves designed for normal operation with a top oil temperature range of 100 degrees centigrade without operation of the pressure relief valves. Pressure relief valve shall operate at 10 psi (Messko, type MPreC LMPRD N07-01). SHEET 11 OF 18

12 b. Pressure relief valves shall have an oil-directed cover designed to direct spraying oil away from the transformer, other equipment, and personnel. c. Pressure relief alarm contacts shall be wired to the annunciator LTC Oil Temperature Dial type thermometer with alarm contacts and resettable maximum indicators for measuring top oil temperature in the main core and coil compartments. A 0-1mA analog temperature output shall be connected to the transformer monitor. (Messko, type MT-ST160) Top Oil Temperature Dial type thermometer with alarm contacts and resettable maximum indicators for measuring top oil temperature in the main core and coil compartments. A 0-1mA analog temperature output shall be connected to the transformer monitor. (Messko, type MT-ST160) Winding Temperature A dial type thermometer with resettable maximum indicators and alarm and fan contacts to show winding temperature shall be provided. A 0-1mA analog temperature output shall be connected to the transformer monitor. (Messko, type MT-ST160W) Ambient Air Temperature a. Ambient thermometer shall have a 0-1mA analog temperature output connected to the transformer monitor. b. The ambient thermometer shall be in an assembly such that the temperature sensor is protected from participation and solar radiation Alarm Annunciation a. The Annunciator shall be Schweitzer Engineering Laboratories, Inc. SEL-2523 (part number XAXXX, key 8176) b. All available alarms shall be wired to annunciator panel identifying the source of the alarm with a lamp that is visible in direct sunlight. c. The annunciator and alarms shall use 125 VDC power supply and control voltage. d. The annunciator shall communicate DNP3 over an EIA-232 serial port. e. The annunciator shall have local and remote reset capability. f. All alarm lights shall be able to be tested by individual or ganged test switch without causing an alarm contact closure to the SCADA system. SHEET 12 OF 18

13 The following alarms shall be wired to the annunciator: Loss of voltage to fans, Stage 1 Loss of Voltage to fans, Stage 2 Transformer rapid pressure rise relay (63) Phase A, B, C backup relay alarm Backup LTC relay blocking alarm Backup LTC hardware failure alarm LTC hardware failure alarm Transformer monitor failure alarm Nitrogen high pressure alarm Nitrogen low pressure alarm Nitrogen empty cylinder alarm Winding temperature alarm (115 C) Winding temperature trip (125 C) Transformer liquid level alarm Transformer top oil temperature alarm (105 C) Transformer top oil temperature alarm (115 C) LTC Motor thermal overload alarm LTC liquid level alarm LTC dehydrating breather malfunction LTC lockout alarm Transformer Monitor The transformer shall be equipped with a SEL-2414 Transformer Monitor (part number A5X9X74CA1030, Key: 0971). a. The following analog inputs shall connect to the transformer monitor: 2 each, fan currents via 0-20 ma current sensors on each fan stage of fans; 4 each temperatures, 0-1 ma ambient air, LTC oil, main tank top oil, main tank winding hot spot. b. The following digital inputs shall connect to the transformer monitor: Stage 1 cooling status Stage 2 cooling status. c. A, B, C phase voltages (provided by SUB) and currents (from transformer) shall input to the transformer monitor. d. Transformer monitor shall model the transformer thermal monitor based on IEEE C e. Transformer monitor shall be capable of serial DNP3 communications, over fiber. SHEET 13 OF 18

14 4 TESTS 4.1 Certified Test Reports The tests with complete certified reports shall include: a. Impulse tests; reduced wave, chopped wave and full wave as per ANSI C b. Routine tests as per ANSI C c. Three phase inducted potential test performed at 174 kv RMS, phase to phase for a period of one (1) hour, with transformer connected as in service, accompanied by continual monitoring of corona. RIV (Radio Interference Voltage) measured at the test voltage level during the one-hour test shall not exceed 100 micro-volts (including background). Tests shall adhere to C & hourly values shall not exceed those listed. 4.2 Witnessing of Test. SUB reserves the right to witness the specified test and requires at least 15-day notification prior to the proposed date of testing. 4.3 Acceptance Tests a. Manufacturer shall complete acceptance testing once the transformer has been delivered and assembled at the final transformer destination. b. Acceptance testing shall be performed by qualified personnel approved by SUB and the Manufacturer. c. Acceptance testing shall include onsite field tests verifying transformers adherence to this standard and correct operation of all equipment and accessories on the transformer. 5 COST ASSESSMENT 5.1 Quotation Analysis Transformer quotation analysis will be based on compliance with the standards, purchase order requirements, cost of transformer losses, and the base price. SHEET 14 OF 18

15 5.1.1 Evaluated Cost The Evaluated Cost (total owning cost) will be calculated by adding the quoted unit price for each item bid, plus the cost of core losses, plus the cost of copper losses for each item bid. The Utility will use each bidder s losses as submitted on the Bid Form to complete the loss evaluation calculations. Evaluated Cost = Base Price plus Cost of Losses, where Cost of Losses = $8630 x (kw of core loss) + $ 5000 x (kw of copper loses at 15 MVA and 116 kv) Bandwidth The Utility will consider the lowest evaluated bidder and any/all additional bidders with total evaluated costs that fall within a range of plus three percent (+3%) of the minimum evaluated bid for each item as qualified bidders for final evaluation Bid Award The evaluation Committee will complete a final evaluation to analyze first cost/bid prices submitted by each qualified bidder for each item bid. The Utility will award each bid item based upon first cost/bid price criteria and the overall best interest of the Utility. 5.2 Loss Difference The chosen supplier shall provide the purchaser with certified loss data for each transformer by serial number before payment for the order can be made. If the overall evaluation of tested losses differs from the overall evaluation of losses guaranteed in the manufacturer s proposal the following actions will occur Actual Losses are Lower No credit to the manufacturer if the losses are less than guaranteed Actual Losses are Higher Penalty for losses in excess of guaranteed amount equal to the sum of the difference in losses times the loss value given in Evaluated Cost. This will be applied to each line item. SHEET 15 OF 18

16 6 WARRANTY 6.1 Standard Warranty Term The vendor warrants that the equipment furnished is free from defects in material and workmanship and agrees to repair or replace, for a period of 12 months from date of initial operation or 18 months from date of acceptance, whichever is earlier, any unit that is unsuitable for operation or fails in operation during normal and proper use Repair under warranty In the event that equipment must be transported to make warranty repairs, SUB will supply labor to disconnect and reconnect the equipment from our system. Additional charges for contractor and transportation will be at the manufacturer s expense. 6.2 Extended Warranty Optional five year warranty as separate line item shall be provided on bid. 7 VENDOR INFORMATION 7.1 Exceptions Any exceptions to this standard shall be presented to SUB at the time of bid opening in letter form for consideration. 7.2 Drawings and Documentation General Requirements All prints, instruction books, etc., shall be sent to Buyer Springfield Utility Board 1001 Main Street Springfield, Oregon sandiw@subutil.com (541) Approval Drawings a. Drawing approval before construction is required. SHEET 16 OF 18

17 b. The manufacturer shall furnish two (2) hard copy sets of drawings and one electronic (compatible with AutoCAD) for approval. c. These drawings shall include a general outline drawing, nameplate, wiring schematics and connection diagrams and list of equipment and accessories by style number. d. Constants for transformer loading shall be included in approval drawings. e. Seismic design calculations meeting performance criteria, shall be supplied with approval drawaings. f. The approval drawings must be received at SUB no later than eight (8) weeks after receipt of order by manufacturer. g. SUB shall be allowed a minimum of 2 weeks to review and reach concurrence Instructions Manuals and Final Drawings a. The manufacturer shall supply at least thirty days before shipment of the transformer two (2) hard copy sets of drawings, two (2) hard copy sets of instruction books and electronic files for each. b. The manufacture shall supply high resolution digital copies of the un-tanked transformer core and core assembly. 8 DELIVERY 8.1 Protective packing All bushings and accessories susceptible to damage shall be adequately protected to insure against damage during transit. 8.2 Impact Recorder An impact recorder, registering shocks in three dimensions, shall be mounted on the transformer prior to shipment. Results of the recorder shall be provided to SUB after transformer delivery. 8.3 Site Delivery Transformer shall be delivered to site given in bid document. SHEET 17 OF 18

18 8.4 Transportation costs Seller is responsible for obtaining and paying for all elements associated with the transport of the transformer including permits, fees, taxes, insurance, import duties and tariffs. 9 ADDITIONAL INFORMATION SUB request for quotations and purchase order must show the following information to be complete. 9.1 Delivery date. 9.2 Completed Transformer Data Sheets supplied. 9.3 Reference to this standard by drawing number and revision date 9.4 Price and Payment Firm pricing Prices quoted shall be firm prices Payment Terms Standard payment terms shall be full payment within 30 days after invoice or 30 days after unit is operable, whichever is later. SHEET 18 OF 18