Transformer Specifications.pdf

SECTION 26 22 00.00 10

480-VOLT STATION SERVICE TRANSFORMERS

10/07

PART 1 GENERAL

1.1 PAYMENT PROCEDURES

The 480-Volt Station Service Transformers will be paid by the lump sum job basis for costs associated with furnishing the 480-Volt Station Service Transformers and other completed work, as specified.

1.2 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI)

ANSI C39.1 (1981; R 1992) Requirements for Electrical Analog Indicating Instruments

AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME)

ASME B1.1 (2003; R 2018) Unified Inch Screw Threads (UN and UNR Thread Form)

ASME B1.20.1 (2013; R 2018) Pipe Threads, General Purpose (Inch)

ASME B1.20.2M (2006; R 2011) Pipe Threads, 60 Deg.

General Purpose (Metric)

ASTM INTERNATIONAL (ASTM)

ASTM B187/B187M (2020) Standard Specification for Copper, Bus Bar, Rod and Shapes and General Purpose Rod, Bar and Shapes

ASTM B188 (2015; E 2016) Standard Specification for Seamless Copper Bus Pipe and Tube

ASTM B236 (2007) Standard Specification for Aluminum Bars for Electrical Purposes (Bus Bars)

ASTM B236M (2007) Standard Specification for Aluminum Bars for Electrical Purposes (Bus Bars) (Metric)

ASTM B317/B317M (2007; R 2015; E 2016) Standard Specification for Aluminum-Alloy Extruded Bar, Rod, Tube, Pipe, Structural Profiles, and Profiles for Electrical Purposes (Bus

Conductor)

INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE)

IEEE C37.13 (2015) Standard for Low-Voltage AC Power Circuit Breakers Used in Enclosures

IEEE C37.16 (2009) Standard for Preferred Ratings, Related Requirements, and Application Recommendations for Low-Voltage AC (635 V and below) and DC 3200 V and below) Power Circuit Breakers

IEEE C37.17 (2012) Standard for Trip Devices for AC and General-Purpose DC Low-Voltage Power Circuit Breakers

IEEE C37.20.1A (2020) Metal-Enclosed Low-Voltage (1000 Vac and below, 3200 Vdc and below) Power Circuit-Breaker Switchgear Amendment 1:

Control and Secondary Circuits and Devices, and All Wiring

IEEE C37.20.2A (2020) Metal-Clad Switchgear Amendment 1:

Control and Secondary Circuits and Devices, and All Wiring

IEEE C37.20.3 (2013) Standard for Metal-Enclosed Interrupter Switchgear

IEEE C37.90 (2005; R 2011) Standard for Relays and Relay Systems Associated With Electric Power Apparatus

IEEE C57.12.01 (2020) General Requirements for Dry-Type Distribution and Power Transformers Including Those with Solid-Cast and/or Resin-Encapsulated Windings

IEEE C57.12.50 (1981; R 1998) Ventilated Dry-Type Distribution Transformers, 1 to 500 kVA, Single-Phase, and 15 to 500 kVA, Three-Phase, with High-Volt 601 to 34,500 Volts

IEEE C57.12.51 (2019) IEEE Guide for Mechanical Interchangeability of Ventilated Dry-Type Transformers

IEEE C57.12.91 (2011) Standard Test Code for Dry-Type Distribution and Power Transformers

IEEE C57.13 (2016) Standard Requirements for Instrument Transformers

NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)

ANSI C80.1 (2020) American National Standard for Electrical Rigid Steel Conduit (ERSC)

ANSI C80.3 (2020) American National Standard for Electrical Metallic Tubing (EMT)

NEMA AB 3 (2013) Molded Case Circuit Breakers and Their Application

NEMA C37.50 (2018) Switchgear--Low-Voltage AC Power Circuit Breakers Used in Enclosures - Test Procedures

NEMA C37.51 (2018) Switchgear--Metal Enclosed Low-Voltage AC Power, Circuit-Breaker Switchgear Assemblies-Conformance Test Procedures

NEMA FB 1 (2014) Standard for Fittings, Cast Metal Boxes, and Conduit Bodies for Conduit, Electrical Metallic Tubing, and Cable

NEMA TR 1 (2013) Transformers, Regulators, and Reactors

NEMA WC 70 (2021) Power Cable Rated 2000 V or Less for the Distribution of Electrical Energy

NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)

NFPA 70 (2020; ERTA 20-1 2020; ERTA 20-2 2020; TIA

20-1; TIA 20-2; TIA 20-3; TIA 20-4)

National Electrical Code

UNDERWRITERS LABORATORIES (UL)

UL 489 (2016; Rev 2019) UL Standard for Safety Molded-Case Circuit Breakers, Molded-Case Switches and Circuit-Breaker Enclosures

1.3 SUMMARY

a. As shown in the proposal schedule (bid form) in the Statement of Work accompanying these specifications, two (2) transformers shall be offered as base bid items, one (1) transformer rated at 750 kVA, one transformer rated at 1000 kVA.

b. The location and general arrangement of the low-voltage metal-enclosed station service transformers are shown. Modifications of the equipment arrangement or the equipment device requirements shown shall be subject to approval. The transformer assemblies shall be completely assembled and wired at the factory.

c. Each transformer shall be provided with removable lifting channels with eye bolts for attachment of crane slings to facilitate lifting and handling. The equipment shall be shipped as completely assembled and wired as feasible so as to require a minimum of installation work. Any indicating instrument or other device which cannot withstand the hazards of shipment when mounted in place on the transformer shall be carefully packed and shipped separately. These pieces shall be marked with the number of the panel on which they are to be mounted and fully identified so they can be readily mounted and connected.

d. All finished painted surfaces and metal work shall be wrapped suitably or otherwise protected from damage during shipment. All parts shall be prepared for shipment so that slings for handling may be attached readily while the parts are in a railway car or transport truck.

1.4 SUBMITTALS

Government approval is required for submittals with a "G" or "S" classification. Submittals not having a "G" or "S" classification are for information only. When used, a code following the "G" classification identifies the office that will review the submittal for the Government.

"PO" refers to the Project Office (Field Office).Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:

SD-02 Shop Drawings

Shop Drawings; G, PO Installation; G, PO Terminal Blocks; G, PO

SD-03 Product Data

Installation, Operation, and Maintenance Manuals

SD-04 Samples

Nameplate Illustrations; G, PO

SD-06 Test Reports

Factory Inspection and Tests

PART 2 PRODUCTS

2.1 NAMEPLATES

The Contractor will be permitted to supply and attach to the transformer assembly a nameplate or trademark. Include a drawing or illustration showing the proposed nameplate, its size and location. Nameplates shall be made of laminated sheet plastic or of anodized aluminum approximately 3 mm thick, engraved to provide white letters on a black background. The nameplates shall be fastened to the panels in proper positions with black finished roundhead screws. Nameplate markings shall be subject to approval.

2.2 COPPER AND ALUMINUM BARS AND RODS

Copper bars and shapes for main bus and ground bus conductors shall conform to the requirements of ASTM B187/B187M, ASTM B188, ASTM B236M ASTM B236, and ASTM B317/B317M.

2.3 CONDUIT AND ELECTRICAL METALLIC TUBING

Rigid conduit shall conform to ANSI C80.1 and shall be zinc-coated (galvanized) both inside and outside by the hot-dip method. Electrical metallic tubing shall conform to ANSI C80.3. Fittings for rigid metal conduit and electrical metallic tubing shall conform to NEMA FB 1.

2.4 CONNECTIONS

All bolts, studs, machine screws, nuts, and tapped holes shall be in accordance with ASME B1.1. Threads for sizes 6 to 25 mm or 1/4 to 1 inch, inclusive, shall be NC or UNC series. The sizes and threads of all valves, pipe and fittings, conduit and fittings, tubing and fittings, and connecting equipment shall be in accordance with ASME B1.20.2M or ASME B1.20.1. Manufacturer's standard thread and construction may be used on small items which, in the opinion of the Contracting Officer, are integrally replaceable, except that threads for external connections to these items shall meet the above requirements.

2.5 STATION SERVICE TRANSFORMER

2.5.1 Type and Rating

The station service transformers shall be indoor ventilated VPI dry-type, self-cooled, NEMA Class AA, with 220 degrees C limiting temperature insulation and shall conform to the applicable requirements of IEEE C57.12.01 and NEMA TR 1. The transformers shall be 3-phase, 60-Hz, 13,800-480 volts and the windings shall be connected delta-wye. The transformer impedance shall be +/-7.5% tolerance. One (1) transformer, designated as Transformer #1, shall be rated at 750 kVA. One (1) transformer, designated as Transformer #2, shall be rated at 1000 kVA.

The transformer shall be designed to carry rated load continuously without exceeding 80 degrees C temperature rise above 40 degrees C ambient temperature when installed in its ventilated sheet metal enclosure and cooled by natural air circulation. BIL ratings for the transformers shall be higher than standard due to greater exposure to overvoltages from lightning strikes: 110 kV for the high voltage insulation and 20 kV for the low voltage insulation.

2.5.2 Core and Coils

The core, coils and metal enclosure of the transformer shall be rigidly attached to a structural steel base suitable for moving the complete transformer by the use of rollers. Jacking facilities and removable lifting eyes shall be provided on the core and coil assembly. The core laminations shall be free from burrs which may puncture the insulation between laminations and shall be securely fastened to prevent excessive vibration in normal service or displacement under short-circuit conditions. Four 2-1/2 percent full-capacity taps, 2 above rated voltage and 2 below rated voltage, shall be provided in the high-voltage windings, and suitable means shall be provided for changing the taps while the transformer is de-energized. The terminal board shall be accessible through a door or removable panel in the enclosure. All transformer leads and taps shall be securely braced to prevent displacement or injury during transit or installation and under short-circuit condition. Wiring for transformer accessories shall be adequately supported to prevent breaking of the conductors due to vibration of the transformer and shall be connected to accessible terminal blocks.

2.5.3 Instrumentation

Each transformer shall be equipped with an three-phase digital temperature monitor. The monitor shall receive temperature data from a K-type thermocouple in each of the 3 coil assemblies. The monitor shall have a local display to indicate the temperature of each coil assembly and the maximum temperature stored. The monitor shall have a temperature alarm LED and internal buzzer to indicate a high temperature condition. The alarm setpoints shall be adjustable. Communications for remote monitoring shall include Form C alarm contacts and Modbus RTU. A fused control power transformer shall provide the necessary power for the unit.

2.5.4 Enclosure

The transformer shall be provided with a ventilated sheet steel NEMA 1 enclosure, except that a formed enclosure of not less than No.13 MSG may be used. Doors or removable panels shall be provided in the enclosure to permit access to the transformer, and suitable removable lifting eyes or other approved means shall be provided to permit lifting the enclosure alone and also the complete transformer by the use of a crane. The enclosure shall be adequately braced and stiffened on the inside, and shall be coated with sound-deadening material if necessary, so that the audible sound level of the enclosed transformer when operating at rated load will not exceed the value permitted in Table 0-3 of NEMA TR 1. The dimensions of the enclosure bases shall allow the transformers to be placed over the existing floor penetrations shown in the drawings contained in Appendix A to these specifications, thereby enabling connection of the existing primary and secondary conductors to the new transformer terminals.

Infrared inspection windows shall be provided in the primary and secondary terminal compartments and in the transformer section to permit infrared inspection of the terminal connections and windings. Each IR-transmissive lens shall be 100 mm in diameter and shall be secured in a housing with a protective cover.

2.5.5 Terminal Compartments

Metal-enclosed compartments shall be provided for terminating the incoming high-voltage power cables with stress cones. Access to the interior of the compartment shall be through removable bolted panels or bolted hinged doors. Connections between the terminals of the incoming cables and the high-voltage winding of the transformers shall be by means of copper bus rated for the continuous current-carrying capacity of the transformers and 24 kA asymmetrical amperes momentary current rating. As described in paragraph 2.5.4, the locations and dimensions of the primary and secondary terminal compartments shall accommodate the existing floor penetrations shown in the drawings contained in Appendix A to these specifcations. In addition, the high-voltage (primary) terminals shall be located at the heights shown in the drawings to enable connection of the existing primary conductors.

2.6 ACCESSORIES

The accessories shall include the following:

a. A one-quart container of paint for outside finish.

2.7 HIGH RESISTANCE GROUNDING SYSTEMS

As shown in the proposal schedule (bid form) in the Statement of Work accompanying these specifications, two (2) High Resistance Grounding (HRG) cabinets shall be offered as optional bid items, one cabinet per transformer. The HRG cabinets shall meet the requirements listed below:

a. High resistance grounding system shall be designed, built, and tested in accordance with IEEE C57.32.

b. System voltage: 480 VAC line-to-line.

c. Current: 1-10 Amps continuous.

d. Frequency: 60 Hz.

e. Phase: 3.

f. System connection: wye.

g. 120 Volt AC control power.

h. 600 Volt rated wiring.

i. Line and neutral disconnect switch.

j. Line and neutral wires shall be fused inside the cabinet.

k. Ground bus.

l. 385 °C temperature rise resistor.

m. Corrosion-resistant resistor elements.

n. Digital display with alarm view, acknowledge, and clear functions.

o. Pulser system for ground fault locating.

p. Green indicating light for normal condition.

q. Red indicating light and horn/buzzer for fault condition.

r. Communications: alarm contacts and Modbus RTU.

s. Enclosure type: indoor, freestanding, containing all components including resistor.

t. Enclosure finish: painted ANSI-61 gray.

u. Cooling: natural.

v. Anti-condensation heater.

w. Factory test reports shall be furnished with the systems.

x. Complete installation and maintenance manual and shop drawings shall be furnished with the systems.

2.8 FACTORY INSPECTION AND TESTS

Submit an electronic copy of the reports of all tests, including complete test data.

2.8.1 General

Each item of equipment supplied under this contract shall be given the manufacturer's routine factory tests and also other tests, as specified below, to insure successful operation of all parts of the assemblies. ANo equipment shall be shipped until it has been approved for shipment.

Notify the Contracting Officer in advance of the test date. The factory test equipment and test methods used shall conform to the applicable requirements of ANSI, IEEE and NEMA standards, and shall be subject to approval.

2.8.2 Testing

Each transformer shall be subjected to the tests below:

2.8.2.1 Assembled Equipment

The assembled equipment shall be checked for mechanical adjustment, alignment of panels and devices mounted thereon, adequacy of fastenings and general good workmanship.

2.8.2.2 Wiring

Control, instrument and relay wiring shall be given a point-to-point check, and the correctness of the control wiring shall be verified by actual operation of the devices.

2.8.3 Station Service Transformer Test

The station service transformers shall be subjected to the routine tests listed in paragraph 8.3 of IEEE C57.12.01, except that the temperature tests, if made, shall be made with the transformers in their enclosures in order to simulate actual operating conditions.

PART 3 EXECUTION

3.1 PAINTING

Exterior metal surfaces of the station service transformers shall be given not less than 2 coats of quick air drying lacquer or synthetic enamel, ANSI Indoor Light Gray No. 61 in color, with semi-gloss finish. Accessories and interior surfaces shall be finished in accordance with manufacturer's standard practices.

3.2 INSTALLATION

Installation of all materials specified herein will be performed by the Government.

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Appendix A

Existing 750 kVA and 1000 kVA Dimensional Drawings