Exhibit A - 33 73 13 - Power Transformer Spec - Skov 05302024.pdf

NWCPUD24001 MAY 2024

33 73 13 (EQUIPMENT PURCHASE) 1 SUBSTATION POWER TRANSFORMER

SECTION 33 73 13

SUBSTATION POWER TRANSFORMER

1 PART 1 GENERAL

1.1 REQUIRED INFORMATION TO BE SUBMITTED WITH PROPOSAL

A. In addition to other forms and documents to be submitted with the Quotation

Proposal, the following information must be included and titled Bidder's

Equipment Information Statement (EIS) for the transformer. The EIS shall be submitted in a list format with item numbers which correspond to the items listed below:

1. Names of subcontractors who will perform field services and specific transformer installation and start-up tasks identified to be performed.

2. Location of plant where transformer will be manufactured, and location of plant where coil and core are manufactured, if different than assembly plant. Acceptable transformers and components shall be manufactured and assembled in the contiguous United States.

3. Drawings and literature showing transformer dimensions (including base for pad design), center of gravity of transformer filled with oil, weight, description, and location of bushings, surge arresters, pumps, fans, and accessories.

4. Description of core and coil construction and materials.

5. Capacity tables showing percent life loss at various ambient temperatures, oil temperatures, and peak load periods in standard format.

6. Description of alarm, protection, pressure relief, and safety devices.

7. Complete description of controls proposed including manufacturer(s), types, and options available.

8. Description of manual no-load (de-energized) tap changer (DETC) and on-load tap changer (OLTC).

9. Manufacturer, type, current rating, and stud dimensions of all high-voltage bushings.

10. A full description of the surge arresters, including all sparkover voltages and IR discharge voltages.

11. Guaranteed no-load (core) losses at rated primary voltage

12. Guaranteed load (copper) losses, including auxiliary losses, at rated MVA and rated primary voltage.

13. Efficiency at 1/4 load, 1/2 load, 3/4 load, and full load.

14. Percent resistance, reactance, and impedance H to X windings at rated

MVA (55 degrees C rise).

15. Short-circuit test data on similar unit.

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16. Excitation current at 100 percent, 105 percent, and 110 percent rated voltage.

17. Maximum no-load in-rush current.

18. The following guaranteed withstand voltage values at:

a. Basic insulation level.

b. Chopped wave, 3 microsecond.

c. Low frequency.

19. Number of groups of forced cooling equipment, and hp rating of each group.

20. Guaranteed maximum noise level at each rating in dB.

21. Proposed manner of shipment:

a. Upright own cover.

b. Upright with shipping cover.

c. Upright with bushing pockets removed.

d. Other (describe).

22. Maximum top oil temperature rise of cooling medium.

23. Specific tests recommended by the manufacturer to be made in the field at time of energization.

24. Schedule of stipulated cancellation charges in 30-day intervals starting at the award date.

25. Describe special tools and spare parts recommended by manufacturer.

26. Schedule for submittals; schedule must conform to Submittal requirements in Section 33 73 13, Part 1, Article 1.4.

1.2 OPTIONS

A. The OWNER may choose to purchase optional components and services as described in this section.

B. The OWNER may choose to store the transformer at the manufacturer's facility beyond the delivery date deadline, as described under this section.

C. The OWNER may choose an acceptable biodegradable seed or vegetable oil-based substitute as an alternate to pure mineral oil insulation, as described under this section.

1.3 REFERENCES

A. Electrical equipment and materials shall conform to the latest editions of all applicable standards.

B. The following is a list of specific standards which may be referenced in this section:

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1. American National Standards Institute (ANSI):

a. B16.5, Slip-On Welding Flanges.

b. C57.12.00, Standard General Requirements for Liquid-Immersed

Distribution, Power, and Regulating Transformers.

c. C57.12.90, Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers and Guide for Short-Circuit

Testing of Distribution and Power Transformers.

d. C57.12.10, Transformers.

e. C57.12.11, Guide for Installation of Oil-Immersed Transformers.

f. C57.92, Guide for Loading Mineral-Oil-Immersed Power

Transformers.

g. C57.131, Standard Requirements for Tap Changers

h. C80.1, Standard Specifications for Rigid Steel Conduit.

i. 24, Standard Performance Characteristics and Dimensions for

Outdoor Apparatus Bushings (IEEE C 76.2).

j. 359-A, Standard Colors for Color Identification and Coding.

2. National Electrical Manufacturers' Association (NEMA):

a. TR-1, Transformers, Regulators, and Reactors.

b. ICS 1, General Standards for Industrial Control and Systems.

c. 250, Enclosures for Electrical Equipment (1,000 Volts Maximum).

3. Institute of Electrical and Electronics Engineers (IEEE): 32, IEEE

Standard Requirements, Terminology, and Test Procedures for Neutral

Grounding Devices.

1.4 SUBMITTAL REQUIREMENTS

A. Administrative Submittals: Shipping notification letters detailing complete routing. Include Purchase Order identification, description of items shipped, number of cartons, and shipping date.

B. Shop Drawings:

1. Descriptive information and drawings for equipment, material, devices furnished, and nameplate. Use device and equipment tag numbers that appear on Drawings.

2. Certified outline drawings showing general arrangement size, dimensions, capacity, and special features required, physical dimensions, and center of gravity (shipping and installed), both horizontal and vertical. Also show location of accessories and indicate phase-to-phase and phase-to-ground dimensions.

3. Elementary (schematic) diagrams.

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4. Interconnection and connection diagrams of terminal boards, panels, and control circuits.

5. Calculated values of impedance (reactance and resistance).

6. Schematic (elementary) control diagrams, using NEMA device designations and symbols for electric circuit diagrams. Make content of schematic (elementary) connection or interconnection diagrams in accordance with latest edition of NEMA ICS 1.

a. Manufacturer's standardized elementary diagrams are not acceptable unless applicable portions of the diagram have been clearly identified and nonapplicable portions deleted or crossed out.

Individual cut-sheets shall bear the manufacturer’s name, trade name, or logo for identification purposes and items furnished shall be indicated or highlighted, or unused items crossed out.

b. Modify manufacturer's standard drawings and schematic diagrams to include appropriate device, equipment, and circuit tag numbers.

7. Current transformer ratio correction factor secondary excitation curves, polarity, nameplate, and connection diagrams.

8. Bill of Material, keyed to plan and section drawings.

9. Installation Instruction Manual and Operation and Maintenance Manual.

10. Complete components parts list, including original manufacturer's catalog numbers and prices.

C. Quality Control Submittals:

1. Manufacturer's test reports.

2. Complete set of factory tests shipped with each piece of equipment.

3. Product data for impact recording system.

4. Operation and maintenance manuals.

5. Written certification that transformer has been installed and tested in accordance with Manufacturer's requirements and is ready for energization.

D. Contract Closeout Submittals:

1. Special guarantee

2. Approved Shop Drawings

3. Complete copy of final record drawings in AutoCAD format, plus electronic file(s) of each Submittal drawing.

4. Five copies of final Installation and Operation and Maintenance

Instruction Manuals.

5. Maintenance Information:

a. Location of nearest transformer repair shop and spare parts.

b. Location and availability of nearest service engineer.

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c. Location and availability of nearest application engineer.

d. Approximate maximum time to supply repair parts.

1.5 SUBMITTAL SCHEDULE AND PROCEDURE

A. The CONTRACTOR shall prepare for the ENGINEER’s review and approval of a Submittal Schedule demonstrating a plan for fulfilling all Contract

Submittal Requirements. The schedule shall be submitted to the ENGINEER for approval within 25 working days of the Contract award.

B. Information in this schedule shall be comprehensive and shall represent all activities including submittals necessary to complete this Contract. Typical minimum detail shown on the schedule that is to be submitted to the

ENGINEER shall include but not be limited to the following:

1. Delivery date of general submittal information and shop drawings.

2. Date for start of transformer manufacturing.

3. Date for completion of transformer assembly.

4. Date for transformer factory testing.

5. Delivery date of transformer test reports.

6. Delivery date of final submittal information and shop drawings.

7. Date for shipment by Manufacturer.

8. Date for arrival at project site.

C. Submittal data shall be fully sufficient in detail for determination of compliance with the Contract Documents.

D. The review of documents by the ENGINEER will be limited to general design requirement only and shall in no way relieve the CONTRACTOR from responsibility for errors and omissions contained therein.

E. The CONTRACTOR shall submit to the ENGINEER for review four copies of all preliminary submittal information and five copies of all final submittal information.

F. Additional submittal and notification requirements appear in the Paragraph

SOURCE QUALITY CONTROL and other sections of this document. These requirements shall be included in the Submittal Schedule prepared by the

CONTRACTOR.

G. Submittal data shall be furnished in sufficient time to allow not less than 10 regular working days for examining and review of the information. Submittals will be acted upon by the ENGINEER as promptly as possible and returned to the CONTRACTOR no later than the time allowed for review. Delays caused by the need for re-submittals shall not constitute a reason for an extension of contract time.

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1.6 DELIVERY, STORAGE, AND HANDLING

A. Packing and Shipping: Ship as follows:

1. Ship f.o.b. site with oil in transformer if weight limitations allow.

2. Ship so transformer and accessories will arrive at the destination simultaneously.

3. Install impact recorder(s) on transformer at the factory to record impacts in directions that occur during shipping and placing on the foundation.

B. Storage and Protection:

1. Packing methods and material shall be such that it will provide weatherproof protection in outdoor storage areas.

2. Method of shipment preparation shall be such as to adequately protect the transformer, relays, bushings, and other auxiliary devices and accessories against corrosion, dampness, and breakage.

C. Substation Access

1. Coordinate with the OWNER about the site access for delivery.

1.7 EXTRA MATERIALS

A. Furnish, tag, and box for shipment and storage the following spare parts, special tools, and materials to be shipped at the same time as the power transformer:

1. One high-voltage bushing, complete with gaskets.

2. One low-voltage bushing, complete with gaskets

3. One complete relay and contactor each type furnished.

4. One complete motor and fan assembly cooling fan.

5. One complete set of contacts and coils for each type of contactor or relay furnished.

6. Miscellaneous spare parts, tools and materials:

a. One complete set of spare parts, list catalog numbers and prices.

b. Two, 1-quart cans of equipment paint.

c. One complete set of gaskets for cover, manhole, handholes, and radiators.

d. One complete set of special tools required to maintain, assemble, dismantle, or move transformer, list catalog numbers and prices.

1.8 SPECIAL GUARANTEE

A. Provide manufacturer's extended guarantee or warranty, with OWNER named as beneficiary, in writing, as special guarantee. Special guarantee shall provide for correction, or at the option of OWNER, removal and replacement of Work

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specified in this Specification section found defective during a period of 5 years after the date of energization.

2 PART 2 PRODUCTS

2.1 SERVICE CONDITIONS

A. Suitable for outdoor service with the following conditions:

1. Maximum Elevation of Installed Site Above Sea Level: 800 feet.

2. Maximum Ambient Air Temperature: 118 degrees F.

3. Minimum Ambient Air Temperature: -14 degrees F.

4. Seismic: Uniform Building Code Seismic Zone 2B, 0.20g.

5. Annual Average Precipitation: 14 inches.

6. Maximum Wind: 100 mph.

2.2 TRANSFORMER

A. Bid Item A-1 Transformer:

Characteristics: Two-winding step-down; 115 kV (high side) to 12.47/7.2 kV

(low side), delta-grounded wye, 24/32/40 MVA ONAN/ONAF/ONAF with 55 degrees C temp rise, three-phase, oil-immersed power transformer with de-energized tap changer (DETC) and on-load tap changer (OLTC).

1. Surge Arresters: On 115 kV high side and 12.47/7.2 kV low side.

2. Ratings:

a. Number of Phases: Three-phase.

b. Frequency: 60-Hz.

c. Insulating Fluid: Mineral Oil. Alternate option --- Biodegradable vegetable oil (Sec. 2.5 D)

3. MVA Rating 55C:

a. ONAN: 24 MVA.

b. ONAF: 32 MVA.

c. ONAF: 40 MVA.

4. Temperature Rise Rating:

a. ANSI C57.12.00.

b. Average winding temperature rise above ambient temperature shall not exceed 55 degrees C when measured by resistance.

c. Hottest spot winding temperature rise above ambient temperature shall not exceed 80 degrees C when measured by resistance.

5. High-Voltage Windings:

a. Rated Voltage: 115 kV

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b. Basic Insulation Level: 450 kV, Impulse BIL 550 kV

c. Delta connected.

d. Full Capacity Rated Taps with a Manual Tap Changer for De-

Energized Operation:

1) Two taps, one at 2.5% and one at 5.0 %, above rated voltage.

2) Two taps, one at 2.5% and one at 5.0 %, below rated voltage.

6. Low-Voltage Windings:

a. Rated Voltage: 12.47/7.2 kV.

b. Basic Insulation Level: 110 kV.

c. Grounded wye connected.

d. ON-Load Tap Changer (OLTC)

1) OLTC shall provide an automatic +/- 10 % voltage adjustment in +/- 16 steps for a total of 32 steps at approximately 5/8 % volts for each increment as per

C57.12.10.

7. Impedance: 8.5 percent, at 55 degrees C, rated voltage, and self-cooled

MVA.

8. Noise Level: Audible noise level when energized at maximum ratings

(including future ONAF) shall be 72 decibels or less.

9. Angular Displacement: The angular displacement between high voltage and low voltage phase voltages shall be 30° with the low voltage lagging the high voltage.

2.3 BUSHINGS

A. Design:

1. High-Voltage Terminals: 115 kV Class, 450 kV BIL.

2. Low-Voltage Terminals: 15 kV Class, 110 kV BIL.

3. Low-Voltage Neutral Terminals: 15 kV Class, 110 kV BIL.

B. General:

1. Bring winding leads out through bushings.

2. Bushings of like voltage: Interchangeable.

3. Design bushings so there will be no undue stress on any parts due to temperature changes.

4. Adequate means to accommodate conductor expansion.

5. Standard threaded stud-type terminals on bushings.

6. Meet requirements of ANSI C57.12.00, Section 9.1.

7. Supply liquid-filled bushings with liquid level indication and provision for power factor test.

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8. Color: ANSI 359-A, No. 70, light gray.

C. Locations:

1. High-Voltage Line Bushings: On transformer cover, Segment 3, in accordance with ANSI C57.12.10.

2. Low-Voltage Line Bushings: On transformer cover, Segment 1, in accordance with ANSI C57.12.10.

3. Low-Voltage Transformer Neutral Bushing: On transformer cover in accordance with ANSI C57.12.10.

D. Current Ratings:

1. Base on continuous line current at maximum specified MVA rating.

2. Sufficient excess capacity to permit transformer loading with "moderate sacrifice of life expectancy" as tabulated in ANSI C57.92.

2.4 COOLING

A. Oil-immersed, self-cooled/future forced-air-cooled (ONAN /ONAF/ONAF)

B. Loading: Design to permit transformer loading with "moderate sacrifice of life expectancy" as tabulated in ANSI C57.92.

C. Fans, Radiators, and Controls:

1. Transformer Forced Cooling: Automatically controlled forced-air cooling actuated by transformer winding temperature.

2. Energize cooling system from an independent electrical circuit.

3. Fans: Rated 240 Vac, 60-Hz, single-phase.

4. Removable Radiators: Provide with the following:

a. Lifting eye on each radiator.

b. Isolating shutoff valves at top and bottom of each radiator to permit removal of radiator without interfering with operation of transformer.

c. Oiltight blank flanges properly gasketed, for shipment of tank without radiators attached and to make flanges available when a radiator needs to be removed in service.

d. Drain plug and vent plug in each radiator header.

e. No gasketed joints are allowed between valves and tank, so when valves are closed all gasketed joints are accessible for maintenance without requiring transformer tank be drained.

5. Fan Motors, Leads, Associated Protective Equipment, and Control:

a. Weatherproof and suitable for outdoor operation at substation site.

b. Equip individual fan motors with weatherproof plugs and receptacles for ease in removal.

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c. Enclose controls, fuses, and breakers for cooling equipment in one cabinet.

d. Selector Switch: Three-position switch with ON/OFF/AUTO positions for manual and automatic control of each stage of cooling.

e. Furnish fan motors with overload protection.

6. Fans shall have OSHA approved safety guards.

7. Magnetic Contactor

a. Furnish for each group of fans.

b. Bring contactor coil leads to terminal blocks in control cabinet.

c. Each contactor shall have two auxiliary contacts that are independently reversible.

8. Fan Manufacturer:

Krenz & Company, or Engineer approved equal.

2.5 TRANSFORMER OIL

A. Pure mineral oil prepared and refined by fractional distillation of petroleum, especially for use in transformers, free from moisture, acid, alkali, polychlorinated biphenyls (PCBs), and injurious sulfur compounds, and in compliance with current EPA regulations.

B. Oil shall not form a deposit under normal operating temperatures.

C. Minimum Dielectric Strength: 30,000 volts between 1-inch discs spaced 1/10 inch apart.

D. If available by the manufacturer, provide an alternative adder price to design and supply the transformer with an accepted biodegradable seed or vegetable oil-based substitute that meets all ASTM, IEEE, and ANSI performance requirements (KNAN/KNAF/KNAF).

2.6 OIL PRESERVATION SYSTEM

A. Equip transformer with an inert gas-pressure oil preservation system.

B. Other types of oil preservation may be provided upon acceptance by OWNER.

C. If inert gas-pressure is supplied, furnish complete with reducing valves, gauges, and cylinders of gas necessary to purge gas space and place transformer in service. Locate gas cylinder and controls so as to be operable at ground level and housed in a suitable weatherproof enclosure mounted on transformer tank.

D. The pressure regulator shall be of a make and type which has been in successful operation with transformers for a period of not less than five years. All fittings and tubing for nitrogen connections between the pressure regulating equipment and transformer tank shall be furnished with the transformer, and shall be either copper tubing with bronze fittings, or stainless-steel tubing and fittings. The

33 73 13 (EQUIPMENT PURCHASE) 11 SUBSTATION POWER TRANSFORMER

tubing shall be adequately anchored to the transformer tank along its length a minimum of every 36-inches. The pressure regulating equipment shall maintain the transformer nitrogen pressure as follows:

1. Low pressure regulator: 0.5 psi

2. High pressure regulator: 5.0 psi

3. Pressure relief valve: 6.5 psi

E. Alarm contacts suitable for use on a 125 Vdc ungrounded circuit shall be provided to indicate the following. Alarm contacts shall be wired to terminal blocks within the cabinet, and to the transformer control cabinet.

1. Empty cylinder alarm: 200 psi

2. Low pressure alarm: 0.25 psi

3. High pressure alarm: 8.5 psi

F. A NEMA 3R rated steel enclosure, meeting the requirements of NEMA 250, containing the gas cylinder and pressure regulating equipment shall be mounted as low as possible on each transformer tank. The enclosure shall be painted to match the transformer, and shall have the following features:

1. A gasketed window permitting viewing of the gauges without opening the door.

2. A removable stainless-steel floor with a 'lipless' threshold.

3. A means for locking of the door.

4. A door activated light.

5. A thermostatically controlled heater.

6. A GFCI outlet.

7. The enclosure shall be grounded to the transformer tank by means of a bonding jumper.

2.7 WIRING AND TERMINAL CABINETS FOR ACCESSORIES

A. Run wiring for relays, current transformers, temperature detectors, and other control and indication devices in rigid conduit to terminal blocks in a centrally located terminal cabinet mounted on transformer. Insofar as possible, all wiring shall be factory installed, terminated, and tested prior to shipment.

B. Cabinet:

1. NEMA 250, Type 3R (raintight), located on Segment 1 sidewall of transformer at a convenient height, with three-point latch.

2. Include provision for locking and an ample-sized bottom plate for conduit entrance, which will be field drilled.

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3. Label wires, terminal blocks, and devices, identify in accordance with schematic and wiring diagrams.

C. Terminal Blocks:

1. Screw type, and except for electrical conducting parts, fabricated from a thermometer phenolic material that is unaffected by contact with transformer insulating oil.

2. Types of blocks that depend upon spring return of deformed metal to secure terminal leads are not acceptable.

3. Provide with bases and barriers molded integrally with brass inserts.

4. Rated for not less than 600 volts and accommodate up to No. 8 AWG wire.

5. Furnish marking strips for terminal designations.

6. Each block shall have one spare blank marking strip.

7. Furnish 20 percent spare terminals.

8. Equip terminals for current transformers with devices for short circuiting secondary leads.

D. Wiring:

1. Control, Signal, and Auxiliary Circuits: Insulated wire, oil- and water-resistant, with an insulation temperature rating of 90 degrees C with stranded copper conductor.

2. Current Transformer Secondary Circuit: Minimum No. 10 AWG stranded copper.

3. Other Circuits: Minimum No. 12 AWG stranded copper.

4. Where construction requires bending of wires while in service, provide multistrand hinge wire.

5. Wiring terminations shall be made with preinsulated crimped ring-tongue terminals on all wires terminated on screw or stud terminals.

6. All interpanel wiring shall be routed in a suitable wiring duct system and shall provide easy access for inspection and replacement. All wiring shall be installed in wiring channels and ducts as far as possible and shall be protected where it leaves a channel or duct.

7. Wiring not installed in channels or ducts shall be formed into compact wire bundles suitably bound together and properly supported. Wire and wire bundles shall be supported with permanently installed studs or other tie means. Adhesive (sticky back) cable tie supports shall not be permitted.

8. There shall be no splices in any of the wiring and all connections shall be made at terminal studs or terminal blocks.

9. Wires shall be marked at each end with plastic, tubular shrink-on marker.

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2.8 NO-LOAD TAP DE-ENERGIZED CHANGING MECHANISM

A. Furnish an operating handle for hand operation accessible near the foundation level, capable of being padlocked in any position and to include an outside position indicator.

2.9 ON-LOAD TAP CHANGER

A. The on-load tap changer (OLTC) equipment shall be mounted on the Segment 1 transformer tank sidewall, as indicated.

B. Tank color: Color: ANSI 359-A, No. 70, light gray.

C. The OLTC shall operate on the preventive autotransformer (reactor) switching principle with vacuum interrupters to accomplish the tap change, and shall be of a three-phase design with full insulation between phases and to ground.

D. The oil-filled switch compartment shall be designed to withstand full vacuum, sealed to prevent the interchange of insulating oil between the main transformer tank, and contain the tap and change-over selectors, vacuum interrupters and bypass switches.

E. The OLTC motor drive mechanism, cam switches, position indicator, and operation counter in accordance with IEEE C57.131. Controls shall be housed in a separate enclosure.

F. The OLTC shall be as manufactured by Reinhausen, Model VACUTAP RMV-

II, or engineer approved equal.

G. OLTC and Switch Compartment shall include the following:

1. Tap winding lead connections. Two-bolt connections shall be used to connect the transformers OLTC tap-winding leads to the OLTC tap terminal board. Single-bolt connections will not be acceptable.

2. Liquid Level Indicator. A magnetic-type liquid level indicator shall be provided. The alarm contact for low oil level shall be wired back to the main control cabinet. Manufacturer shall be MESSKO or approved equal.

3. Pressure Relief Device with discharge piping. A pressure relief device shall be provided on the OLTC oil-filled diverter-switch and tap-selector compartment, meeting the requirements of ‘OLTC Tank Pressure Relief’ paragraph, including the associated discharge piping. The mounting location of the device shall be so as to ensure visibility of the indicator pin from the ground. Manufacturer shall be MESSKO or approved equal.

4. An Electronic Rapid Pressure Rise Monitor, with associated seal-in relay, shall be provided on the OLTC oil-filled diverter-switch and tap-selector compartment. Manufacturer shall be MESSKO or approved equal.

5. Dehydrating Breather. A maintenance-free dehydrating breather, utilized for removing atmospheric moisture from the air drawn into the OLTC oil-filled diverter-switch and tap-selector compartment, shall be located

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adjacent to the OLTC compartment. Manufacturer shall be MESSKO or approved equal.

6. Drain Valve. A 1-inch valve shall be located at the bottom of the OLTC compartment for use in gravity draining. The outbound connection shall be a 1-inch NPT thread, provided with a threaded plug. The drain valve shall have an integral sampling device.

7. Handcrank with interlocking switch.

8. Top-Oil Liquid Temperature Indicator. A top-oil dial-type indicating thermometer (liquid temperature indicator) with its sensing element shall be provided. The dial indicator shall cover a range of 0 to 120°C and shall be equipped with two adjustable circuit closing alarm contacts suitable for use with an ungrounded 125 Vdc circuit. Manufacturer shall be

MESSKO or approved equal.

H. Motor Drive Enclosure and Controls

The OLTC motor drive enclosure and controls shall be mounted beneath the

OLTC oil-filled switch, and shall be as manufactured by Reinhausen, Model

Tapmotion MD-III, or equal. OLTC drive and controls shall include:

1. Regulation Range. The transformer's range of regulation shall be plus and minus 10 percent in 0.625 percent steps, with 16 steps above and 16 steps below rated voltage, per the requirements of IEEE C57.12.10, paragraph

4.5.2. The OLTC mechanism shall be designed to ensure that once a tap change is initiated, it will be carried through to completion. The transformer shall be suitable for full capacity operation at the low-voltage terminal rated voltage and above, and reduced capacity (constant current) operation below the low-voltage terminal nominal rated voltage. Subject to the limitations of IEEE C57.12.00 in regard to operation above rated voltages, the function of the OLTC equipment shall be:

a. To maintain constant voltage at the low-voltage terminals for fluctuating voltage applied at the high-voltage terminals.

b. To regulate the voltage at the low-voltage terminals for fluctuating load level.

2. Position Indicator, 33 positions with 32 steps, visible through a sealed window in the enclosure door. Design of positions: Standard dial indication, 16L…N…16R.

3. OLTC drive motor rated for 240 Vac, 60 Hz. operation.

4. Vacuum Interrupter Monitoring System, to protect the OLTC in the event that an interrupter fails to interrupt and transfer the load current during a tap change operation. In the event of a switching failure, the OLTC shall be returned to the original position before the tap selector can open the circuit and prevent further operations.

I. ON-LOAD TAP CHANGER AUTOMATIC VOLTAGE CONTROLLER

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An OLTC Automatic Voltage Controller shall be provided, mounted within the motor drive enclosure, and shall be as manufactured by Reinhausen, Model

Tapcon 250 , or equal. The OLTC controller shall provide the following:

1. Provide automatic voltage regulation and line drop compensation to the transformer OLTC motor drive controls.

2. Operating panel with LCD display and status LEDs. The operating panel shall include pushbuttons for parameterization, operation and configuration of the controller, including local/remote operation and manual/automatic control. The visual feedback shall include the following:

a. Controller status

b. Measured voltage

c. Desired voltage

d. Tap position

e. Upper and lower limits (bandwidth)

3. Communication interface card with RS232, RS485, and fiberoptic ports.

Provide DNP 3.0 communications protocol capability for SCADA communication.

2.10 GROUND CONNECTIONS

A. Furnish two NEMA two-hole ground pads welded on base or on tank wall near base on opposite sides of transformer. Locate pads so as not to interfere with jacking facilities.

B. Weld NEMA two-hole ground pads to top of tank near each surge arrester and furnish with copper clamp-type terminal to fasten surge arrester ground leads.

C. Connect common ground bus on high voltage and low voltage side of transformer to copper clamps and extend to ground pads at base.

D. Size of Ground Bus for Surge Arresters: 1/0 copper.

E. Furnish two or more one-hole tongs or other provisions to attach two 4/0 copper ground leads up the side of transformer from ground grid to transformer neutral bushing.

2.11 TANK CONSTRUCTION

A. Design: Construct to withstand operating pressures and stresses and to withstand full vacuum.

B. Welded Main Cover:

1. Construct so welded cover can be removed and rewelded without damage to coils.

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2. Furnish minimum one manhole with sloped cover, 15-inch minimum diameter, for access to lower ends of bushings, terminals, and upper portion of core and coil assembly.

3. Bolt-on manhole covers, no welding.

C. Furnish gasketed surfaces with gasketed recess and gasket compression limit stops.

D. Furnish guides for guiding of core assembly and coils when untanking transformer for inspection.

E. Clearly show center-of-gravity marks and permanently mark on transformer for both shipping assembly and fully assembled transformer.

2.12 WINDING

A. Windings, leads and all current carrying parts shall be copper.

B. Windings shall be circular in shape.

C. Transformer shall be capable of withstanding, without injury for a time of 2 seconds, thermal and mechanical stresses caused by a short-circuit on the terminals of any winding or combination of windings with rated voltage maintained on unshorted windings.

2.13 ACCESSORIES

A. Nameplate: Stainless Steel, mounted on transformer, including:

1. Diagram of connections, including polarities.

2. Voltage of taps and corresponding ampere rating.

3. Impedances and corresponding MVA capacity ratings.

4. Weights: Core and coils, tank and fittings, oil, and total weight.

5. Quantity of oil (U.S. gallons).

6. Permissible vacuum.

7. CT connections, ratings, and polarity.

8. MVA ratings at 55 degrees C average winding rise.

9. Serial number.

10. Other information as prescribed in ANSI C57.92 and C57.12.00

Nameplate C schedule.

11. Manufacturer year and date.

B. General: The transformer shall be equipped with all accessories required by

ANSI Standards with the following additional requirements:

1. Furnish standard accessories located in accordance with ANSI C57.92 and C57.12.10 Table 11.

33 73 13 (EQUIPMENT PURCHASE) 17 SUBSTATION POWER TRANSFORMER

2. Group dial-type gauges, valves, and tap-charger handle together on low voltage side of transformer for easy accessibility and maintenance so that untanking is not required for removal of gauges. None of these items shall protrude beyond the floor space determined by the radiating surfaces.

3. Tilt gauge faces above 96 inches from foundation down at an angle of 30 degrees from the vertical.

4. Each gauge, dial, etc., shall have a legible, weatherproof nameplate.

5. Locate wells for thermometer bulbs and liquid-level gauge floats outside main tank so removal is not required for untanking.

6. Service Life of Accessories: Comparable with transformer.

7. Shock mount, or construct sufficiently rugged, gauges, meters, relays, recorders, thermal breakers, other instruments, and cabinets constituting or associated with control of fans, inert gas equipment, and all other temperature and pressure alarm systems to protect them from damage or wear which could be caused by normal transformer shock and vibration.

8. Contacts for ac Operation: Rated 250 Vac. AC control voltages shall be

120 Vac and 240 Vac.

9. Contacts for dc Operation: Rated 125 Vdc. DC control voltage shall be

125 Vdc.

10. Wire for Alarm and Auxiliary Circuits: Stranded, minimum No. 12 AWG copper, oil- and water-resistant, and suitable for operation at an ambient temperature of 90 deg C insulation.

11. Valves shall hold hot oil without leaking and shall withstand, when submerged, an air test of 125 psi.

C. Surge Arresters:

1. Surge arresters shall meet all requirements of ANSI C62-1.

2. Tank-mounted polymer housed station class metal-oxide type, one per phase on high voltage side of transformer and one per phase on low voltage side of transformer.

3. The high voltage side arresters shall be rated for 115 kV delta operation.

4. The low voltage side arresters shall be rated for 12.47 grounded wye 7.2 kV operation.

5. Height of arresters shall match the height of associated winding bushings.

6. Equip arresters with NEMA four-hole pads for conductor or bus attachment.

7. Color: ANSI 359-A, No. 70 light gray.

8. Manufacturers and Products:

a. High-Voltage Arresters, 115 kV: Ohio Brass; Type DynaVar station class, rated 70 kV MCOV, duty cycle rated 90 kV, or ENGINEER approved equal.

33 73 13 (EQUIPMENT PURCHASE) 18 SUBSTATION POWER TRANSFORMER

b. Low-Voltage Arresters, 12.47 kV: Ohio Brass; Type DynaVar station class, rated 8.4 kV MCOV, duty cycle rated 10 kV, or

ENGINEER approved equal.

D. Magnetic Liquid-Level Gauge:

1. As specified in 5.1.2 of ANSI C57.12.10, except with two stages of contacts.

2. Use first stage to initiate low oil alarm and use second stage for low oil level tripping.

3. Set second stage at least l-l/2 inches below alarm stage but at a level as not to cause damage to transformer.

4. Trip circuitry shall include an adjustable time-delay relay set to delay tripping from 18 to 180 seconds after second stage contacts close.

5. Alarm and Trip Circuitry Operation: Dry contacts rated 125 Vdc.

E. Indicating Thermometer:

1. Liquid temperature, dial type, with alarm contacts, mounted at approximately eye level to be easily read and reset from the ground.

2. Thermometer shall permit true temperature indication after alarm point is passed.

3. Furnish thermal well to allow thermometer bulb to be removed without lowering oil in tank.

4. Furnish an indicating hand and a maximum indicating hand.

5. High Temperature Alarm Contacts:

a. Dry contacts rated 125 Vdc for high temperature alarm and future tripping.

b. Adjustable type with factory temperature settings as follows:

Contact Function

1 Activate alarm relay at 90 degrees C

2 Activate tripping relay at 110 degrees C

F. Pressure-Vacuum Gauge:

1. Furnish to indicate gas pressure and vacuum in transformer tank, with an accuracy within 5 percent at full scale.

2. Furnish alarm contacts to signal overpressure or underpressure conditions within the tank.

33 73 13 (EQUIPMENT PURCHASE) 19 SUBSTATION POWER TRANSFORMER

G. Transformer Temperature Monitor

1. Provide an electronic monitoring and control system to monitor oil temperature and simulated winding hotspot temperature for one winding and to provide automatic control of the transformer cooling system.

2. A resistive temperature device (RTD) shall be provided in the transformer to monitor the transformer top-oil temperature and shall be pre-wired to control the unit.

3. The control unit shall accept current transformer input from one phase to provide current loading information to allow for simulation of winding hotspot temperature. Current transformer secondary from center winding shall be pre-wired to the control unit.

4. Provide a minimum of six Form C output contacts configured to operate at independently adjustable temperature setpoints for fan control, alarm and trip functions. Provide outputs configured and calibrated as follows or as recommended by the transformer manufacturer:

Output Temperature Setpoint Function

1 65 deg C, Winding Start first stage of cooling

2 70 deg C, Winding Starts second stage of cooling

3 100 deg C, Top-oil Initiate latching alarm relay

4 120 deg C, Winding Initiate latching alarm relay

5 130 deg C, Winding Initiate latching TRIP relay

6 Spare

5. Provide two latching relays, one for alarm and one for trip, with local manual reset pushbutton. Latching relays shall operate at 125 Vdc unless otherwise specified by the Engineer.

6. Provide internal data logging of up to 16 parameters, with configurable logging rate.

7. Provide internal event recording of up to 24 events.

8. Provide front-panel RS-232 serial port for device configuration and setup.

9. Provide fiber optic ports and RS-485 serial port for interface to SCADA system. Provide DNP 3.0 communications protocol capability.

10. Transformer Temperature Monitor System shall be SCHWEITZER SEL-

2414, part number: 241421A3A9X74CA0130.

11. Provide complete with NEMA 4 enclosure, mounted on transformer.

Enclosure shall have viewing window to allow inspection of displayed oil and winding temperatures without opening cabinet door.

12. Provide 120V space heater with adjustable thermostat.

33 73 13 (EQUIPMENT PURCHASE) 20 SUBSTATION POWER TRANSFORMER

H. Bushing-Type Current Transformers:

1. Provide one bushing type current transformer located on 12.47 kV Phase

B bushing for winding temperature monitor input. CT ratio to be as recommended by manufacturer.

2. Furnish in addition to current transformers required for hot spot detection:

Qty Per

Phase

Total

Qty Location Ratio

Accuracy

Class

2 6 115 kV High Voltage Bushing 600:5 C400

2 6 12.47 kV Low Voltage Bushing 2000:5 C400

1 1 Neutral Bushing 2000:5 C400

3. All current transformers shall have fully distributed windings and a minimum Thermal Rating Factor of 2.0.

4. Terminate current transformer secondary leads at an indexed terminal block equipped with short circuiting bars.

5. Locate bushing current transformer nameplate of diagrammatic type adjacent to terminal block and include the following:

a. Diagram of connections.

b. Secondary tap identification and corresponding turns ratio and primary amperes

I. Pressure-Vacuum Bleeder Device: Furnish if sealed-tank construction is proposed.

J. Provide one (1) each Oil Drain, Lower Filter Press Connection, and Sampling

Valves, each located in an accessible area near the bottom of the tank.

K. Flange for Vacuum Equipment:

1. 4-inch pipe size, 150-pound rating, in accordance with American National

Standard Requirements for Steel Pipe Flanges, Flanged Valves and

Fittings, including ratings for Class 150 (ANSI B 16.5).

2. Suitable for connecting a 4-inch Airco Temescal Vacuum Valve, Series

2520.

3. Separate flange from oil-fill valve as far as practical.

4. Locate on cover for connection of vacuum processing equipment.

L. Upper Filter Press: Furnish valve and connection located on cover diametrically opposite 4-inch flange for connection of vacuum processing equipment.

M. Utility Valve: Furnish 1/2-inch bronze or brass globe valve, installed in a horizontal position at highest point of transformer for venting when filling and testing.

N. Lifting Lugs:

33 73 13 (EQUIPMENT PURCHASE) 21 SUBSTATION POWER TRANSFORMER

1. Adequate strength and size, so arranged on transformer tank to provide a suitable lift of transformer unit.

2. Also provide lifting eyes for lifting cover and for lifting core and coil assembly.

3. Indicate any anchoring requirements.

O. Moving and Handling Facilities:

1. Suitable jacking facilities on transformer tank.

2. Pulling eyes and smooth base for skidding and rolling transformer in any direction.

P. Control Cabinet Heaters:

1. Mount two or more 120-volt, single-phase heaters in each control housing and terminal cabinet to prevent collection of moisture.

2. Wire one heater for continuous operation.

3. Thermostat-control remaining heater(s).

4. Make connections to heaters from below heaters to minimize deterioration of insulation of supply wires.

5. Locate heaters in lower portion of control housing and arrange so they can be energized from a completely independent circuit.

6. Heaters shall not be placed close to other devices.

Q. Pressure Relief Devices:

1. Recloseable, self-setting, mechanical type to automatically relieve internal pressure greater than 7 psi or 110 percent of maximum operating pressure, whichever is greater.

2. A device with nominal rated relief pressure greater than that specified above may be used, in which case tank pressure test shall be run at the higher nominal rating.

3. Construct device to minimize oil discharge when it operates.

4. Mount directly on top of transformer tank.

5. Furnish alarm contacts for pressure relief devices, with ability to reset alarm while transformer is energized.

R. Sudden Pressure Relay and Reset Switch:

1. Furnish to protect transformer against damage due to internal faults.

2. Relay shall operate on rate of pressure change but be insensitive to pressure pulses caused by electrical disturbances such as magnetizing in-rush currents or mechanical shocks such as a change in transformer temperature, while protecting against small arcs which would not cause a pressure relief device to operate.

3. Operation: 125 Vdc.

33 73 13 (EQUIPMENT PURCHASE) 22 SUBSTATION POWER TRANSFORMER

4. Furnish with two independent dry contacts, one for alarm and one for tripping.

2.14 FACTORY FINISHING

A. Thoroughly clean tank and auxiliary exterior surfaces free from scale, rust, oil, and grease prior to painting.

B. Painting: At least three coats as follows:

1. Initial coating of rust-inhibiting primer, an intermediate coat, and a finish coat of alkyd enamel.

2. Finish Coat: ANSI 359-A, No. 70, light gray.

C. Inside of main tank and control equipment cabinet shall be painted white. An accelerated aging test must be performed on the paint to be used inside the tank and test results provided to the OWNER.

D. The top of the main tank shall be non-skid coated.

E. Electrostatic paint application is required on the radiators.

2.15 SOURCE QUALITY CONTROL

A. Factory Inspections: Inspect transformers for required construction, electrical connection, and intended function.

B. The OWNER reserves the right to inspect the completed core and coil assembly prior to tanking. The manufacturer shall notify the ENGINEER at least 2 weeks prior to the date of tanking to allow the ENGINEER and OWNER to observe tanking, if so desired.

C. Notify ENGINEER at least 4 weeks prior to any testing to allow the

ENGINEER and OWNER to observe testing, if so desired.

D. Completely assemble and adjust transformer at the factory and perform manufacturer's standard shop tests, all ANSI tests, and other tests as specified.

E. Perform standard commercial tests that include no-load and copper losses in accordance with ANSI C57.12.90.

F. Prior to shipment, pressure test liquid-filled assembled transformer for minimum 8 hours at maximum operating pressure to determine presence of leaks.

G. In addition to standard commercial tests, perform the following factory tests:

1. Excitation losses at 100, 105, and 110 percent of rated voltage on rated tap, for 115 kV primary connections.

2. Excitation current at 100, 105, and 110 percent of rated voltage on rated tap for 115 kV primary connections.

33 73 13 (EQUIPMENT PURCHASE) 23 SUBSTATION POWER TRANSFORMER

3. Radio Influence Voltage (RIV): Check presence and magnitude of RIV during induced voltage tests in the high-voltage windings. The voltage shall be raised to the 1-hour level and held to verify there are no partial discharge problems. The voltage shall then be raised to the enhancement level and held for 7,200 cycles. The voltage shall then be reduced to the

1-hour level and held for 1 hour. During the 1-hour period, partial discharge measurements shall be made at 5-minute intervals.

4. Bushing Current Transformer Tests:

a. Test per applicable sections of ANSI C57.13 and check for proper nameplate and polarity markings.

b. To ensure correct installation, perform polarity check and current ratio check after mounting in transformer.

H. Short-Circuit Strength: Demonstrate transformer has sufficient mechanical strength to withstand, without failure, through-fault currents by one of the following methods:

1. Certified Test Data:

a. Showing transformer with a core and coil identical in design and construction and identical or similar with respect to kVA capacity, kV ratings, BIL, impedance, and voltage taps have been tested without failure for short-circuit strength.

b. Provide description of test code under which transformer was tested for short-circuit strength.

2. History of successful experience with transformers of identical or similar ratings, design, and construction as follows:

a. List transformers in service with core and coils that are essentially identical in design, construction, and manufacture to transformer covered by this Specification and provide information on date of installation, location, and failures, if any.

b. Where such transformers have not been built or cumulative service record is less than 20 transformer years, list transformers in service which represent closest approximation to transformer covered by this Specification.

c. Information provided shall be representative of total experience of manufacturer with design of transformer it proposes to furnish and include dates of installation or shipping, ratings of transformers, and failures and causes of failure if any have been experienced.

I. Transformer Loss Evaluation:

1. Test system accuracy must be verified for conformance with the requirements of C57.12.00. The Proposal shall include documentation which verifies the accuracy of the loss measurement system in accordance with the method of testing. Documentation provided with the

Proposal quotation must confirm the same system was used to test the transformer(s).

33 73 13 (EQUIPMENT PURCHASE) 24 SUBSTATION POWER TRANSFORMER

2. Reported losses shall use ANSI reference temperatures of 20 degrees C for no-load losses and 75 degrees C for full-load losses.

3. Test shall be performed at the rated tap at the higher primary voltage connection.

J. The manufacturer shall notify the ENGINEER and OWNER of any unusual event or damage occurring during the fabrication of the transformer and of all tests which do not meet the specified or guaranteed values. The OWNER reserves the right to inspect such damage or test failures. Corrective measures to overcome such damage or failure shall be reviewed with the ENGINEER and

OWNER.

K. Five certified copies of the certified test reports shall be delivered to the

ENGINEER not later than 5 days after completion of all factory tests.

L. Factory testing shall not be performed until all submittals required up to the point of factory testing have been reviewed and approved by the ENGINEER.

M. The transformer shall not be shipped until acceptance of test results by the

ENGINEER. The ENGINEER shall provide written release for shipment following review and acceptance of certified factory test results.

3 PART 3 EXECUTION

3.1 INSTALLATION

A. Contractor shall provide, as a minimum, installation services as listed below and shall coordinate all on-site work, including delivery with the OWNER.

Contractor shall provide all necessary materials and labor to accomplish the specified installation duties. All work shall be provided as part of the Lump

Sum amount.

B. Deliver transformer to the job site.

C. Off-load transformer and place in its final location. Transformer foundation pad and embedded anchor bolts will be provided by the OWNER.

D. Securely anchor transformer in a plumb and level condition, using anchoring methods suitable for the UBC Seismic Zone listed under SERVICE

CONDITIONS above.

E. Install all transformer-mounted accessories that are not factory-installed, including, but not limited to: bushings, lightning arresters, radiators, fans, gauges, instrumentation, transducers, junction boxes and control panels.

F. Complete all control, instrumentation and auxiliary wiring on the transformer not completed at the factory. For all external wiring connections, provide wiring to terminal blocks for interconnection of field wiring by the OWNER.

G. If the transformer is shipped without oil, provide oil, oil filling and filtering equipment and fill transformer with the proper quantity of specified oil.

33 73 13 (EQUIPMENT PURCHASE) 25 SUBSTATION POWER TRANSFORMER

H. If necessary, place inert-gas oil preservation system into service, including all tanks, valves, tubing, gauges and valves. Provide all required gas cylinders for initial operation.

I. The OWNER will provide all external wiring and bus connections, including primary and secondary bus, grounding conductors, auxiliary power and control wiring.

3.2 COMMISSIONING AND TESTING…