Revised 48 19 23.pdf

Replace Transformers A & B, Fox Pnt. Hurricane Barrier, Prov., RI Amendment February 16, 2021

SECTION TABLE OF CONTENTS

DIVISION 48 - ELECTRICAL POWER GENERATION

SECTION 48 19 23

CLASS I POWER TRANSFORMERS

PART 1 GENERAL

1.1 DESCRIPTION OF WORK

1.2 GENERAL ARRANGEMENT

1.3 REFERENCES

1.4 SUBMITTALS

1.5 WARRANTY REQUIREMENTS

PART 2 PRODUCTS

2.1 TYPE AND RATING

2.1.1 General

2.1.2 Descriptive Data

2.1.3 Transformer Limiting Dimensions and Equipment Arrangement

2.1.4 Requirements

2.1.5 Standard Products

2.1.6 Ratings and Electrical Characteristics

2.2 STRUCTURAL DESIGN CRITERIA AND SEISMIC CALCULATIONS

2.2.1 Structural Design Criteria

2.2.2 Seismic Calculations

2.2.3 Anchorage to Concrete for Seismic Restraint

2.3 THERMAL DESIGN

2.4 CORE

2.5 WINDINGS

2.5.1 General

2.5.2 Insulation Levels

2.5.3 Short Circuit Capability

2.5.4 Embedded Fiber Optic Probes

2.6 DE-ENERGIZED TAP CHANGER

2.7 TANK

2.7.1 Construction

2.7.2 Lifting and Moving Facilities

2.7.2.1 Lifting Facilities

2.7.2.2 Moving Facilities

2.7.3 Connections

2.7.3.1 General

2.7.3.2 Stainless Steel

2.7.4 Steel Pipe and Fittings

2.7.5 Grounding

2.7.6 Steel Supporting Base

2.7.7 Jack Ports

2.7.8 Center of Gravity

2.7.9 Oil Level Markings

2.8 GASKETING

2.9 VALVES

2.10 COOLING EQUIPMENT

2.10.1 Radiators

2.11 BUSHINGS

SECTION 48 19 23 Page 1

2.11.1 General Bushing Requirements

2.11.2 High-Voltage Bushings

2.11.3 Low-Voltage and Neutral Bushings

2.11.4 High-Voltage Terminals

2.11.5 Low-Voltage and Neutral Bushing Terminal Connections

2.11.6 Core Ground Bushings

2.11.6.1 Main Transformer

2.11.7 SFRA Test Shipping Bushings

2.12 LOW-VOLTAGE BUSHING THROAT

2.13 HIGH-VOLTAGE BUSHING THROAT

2.14 TRANSFORMER MOUNTED ACCESSORIES

2.14.1 General

2.14.2 Contacts and Devices

2.14.3 Liquid Level Indicator

2.14.4 Analog Temperature Indicating Equipment

2.14.4.1 Liquid Temperature Indicator

2.14.4.2 Winding Temperature Equipment

2.14.5 Transformer Tank Pressure Relief Device

2.14.5.1 General

2.15 OIL

2.15.1 Quantity and Transformer Oil Certification

2.15.2 Type of Oil

2.15.3 Chemical, Physical and Electrical Characteristics

2.15.4 Sampling

2.15.5 Testing

2.16 OIL PRESERVATION SYSTEM

2.16.1 General

2.16.2 Inert-Gas for Transformer Processing

2.16.3 Inert-Gas Pressure System

2.16.3.1 General

2.16.3.2 Pressure Regulating Equipment

2.16.3.3 Alarm functions

2.16.3.4 Enclosure

2.17 TRANSFORMER CONDUIT ENTRY TERMINAL BOX

2.17.1 General

2.17.2 Terminal Blocks

2.17.2.1 Control Signal Type

2.17.2.2 Short-Circuiting Type

2.17.2.3 Power Distribution Blocks

2.17.2.4 Terminal Blocks - Conduit Entry Terminal Box

2.18 INSULATED WIRE AND CABLE

2.19 CONDUIT SYSTEMS

2.19.1 General

2.19.2 Conduit and Fittings

2.19.3 Outlet and Junction Boxes

2.20 SPARE PARTS

2.21 NAMEPLATES

2.21.1 Transformer Nameplate

2.21.2 Lifting Nameplate

2.21.3 Device Nameplates

2.21.4 Additional Transformer Identification

PART 3 EXECUTION

3.1 TRANSFORMER DESIGN REVIEW MEETING

3.1.1 General

3.1.2 Design Data Review Meeting Requirements

3.2 TRANSFORMER FACTORY ASSEMBLY

3.2.1 General

SECTION 48 19 23 Page 2

3.2.2 Outline and Assembly Drawings

3.2.3 Detail Drawings

3.2.4 Welding

3.2.4.1 General

3.2.4.2 Welder Qualifications

3.2.4.3 Welding Materials

3.2.4.4 Welding Procedures

3.2.4.5 Preheat and Interpass Temperature

3.2.4.6 Inspections, Tests and Weld Inspector Qualifications

3.2.5 Manufacturing Inspection by Government Personnel

3.3 TRANSFORMER FACTORY ACCEPTANCE TESTS

3.3.1 General

3.3.2 Factory Acceptance Test Report

3.3.3 Zero-Phase Sequence Impedance

3.3.4 Analog Temperature Gauges

3.3.5 Temperature Rise Test

3.3.6 Audible Sound Level Test

3.3.7 Impulse Tests

3.3.8 Induced Voltage Test With Partial Discharge Measurements

3.3.8.1 General

3.3.8.2 7,200 Cycle Enhancement Level

3.3.8.3 Data Reporting

3.3.9 Dissolved Gas-In-Oil Analysis

3.3.10 Leak Test

3.3.11 Leakage Reactance Measurement Test

3.3.12 Sweep Frequency Response Analysis Tests

3.3.12.1 Required Tests

3.3.12.2 Test Equipment and Test Parameters

3.3.12.3 Test Cable Integrity

3.3.12.4 Test Connections

3.3.12.5 Data Reporting

3.3.12.6 Data Interpretation

3.3.13 Single Phase Excitation Tests

3.3.14 Load Tap Changer

3.3.14.1 Load Tap Changer Design Tests

3.3.15 Insulated Wire and Cable

3.4 BUSHING TESTS

3.4.1 General

3.4.2 Bushing Design Tests

3.4.3 Bushing Withstand Test Voltages

3.4.4 Bushing Routine Tests

3.5 FACTORY CLEANING AND PAINTING

3.5.1 General

3.5.2 Interior Surfaces

3.5.3 Exterior Surfaces

3.5.4 Machined Surfaces

3.6 TRANSFORMER SHIPMENT, HAULING AND SITE ASSEMBLY

-- End of Section Table of Contents --

SECTION 48 19 23 Page 3

SECTION 48 19 23

CLASS I POWER TRANSFORMERS

PART 1 GENERAL

1.1 DESCRIPTION OF WORK

This SECTION covers the design, manufacturing and factory testing of two three-phase, oil-filled, Class I power transformers rated 12,200 kVA nominal with a temporary overload rating of 18,300 kVA for a duty cycle of 6 hours, 11 kV high-voltage, 4.16 kV low-voltage, Class ONAN cooling, for delivery f.o.b. Destination. The transformers' shipment, hauling, site movement, installation, site re-assembly, connection to the Fox Point Hurricane Barrier Pumping Station and testing requirements are as required in SECTIONS 48 20 00, TRANSFORMER SHIPMENT, HAULING, SITE MOVEMENT, SITE REASSEMBLY AND FIELD TESTING and 26 05 00, BASIC ELECTRICAL MATERIALS AND METHODS. Throughout this SECTION, the transformer tank layout is identified by Segments 1 through 4, as defined by IEEE C57.12.10, Figure 1 and as indicated on drawing sheets E-201 and E-202.

Each transformer A and B shall be tapped at the primary to provide power to the primary side of the 300kVA station service transformer at the respective side of the distribution system. New conductors must be provided for these power feeds.

1.2 GENERAL ARRANGEMENT

The transformers specified in this SECTION will replace two existing three-phase transformers, designated and referred to in Government pump station documentation as Fox Point Hurricane Barrier. The transformers shall be sized per the requirements of paragraph RATINGS AND ELECTRICAL CHARACTERISTICS. Reference drawings show the layout and the existing location of the transformers. The new transformers shall be designed and manufactured as required herein for separable steel foundation.

1.3 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.

NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)

AMERICAN SOCIETY FOR NONDESTRUCTIVE TESTING (ASNT)

ASNT SNT-TC-1A (2016) Recommended Practice for Personal Qualification and Certification in Nondestructive Testing

ASME INTERNATIONAL (ASME)

ASME B1.1 (2003; R 2008) Unified Inch Screw Threads (UN and UNR Thread Form)

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

SECTION 48 19 23 Page 4

ASME B16.1 (2015) Gray Iron Pipe Flanges and Flanged Fittings Classes 25, 125, and 250

ASME B16.24 (2016) Cast Copper Alloy Pipe Flanges, Flanged Fittings, and Valves (Classes 150, 300, 600, 900, 1500, and 2500)

ASME B18.2.6M (2012) Metric Fasteners for Use in Structural Applications

ASME BPVC SECTION IX (2015) Qualification Standard for Welding and Brazing Procedures, Welders, Brazers, and Welding and Brazing Operators

ASTM INTERNATIONAL (ASTM)

ASTM A343/A343M (2014) Standard Test Method for Alternating-Current Magnetic Properties of Materials at Power Frequencies Using Wattmeter-Ammeter-Voltmeter Method and 25-cm Epstein Test Frame

ASTM A53/A53M (2012) Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless

ASTM A664 (2015) Standard Practice for Identification of Standard Electrical Steel Grades in ASTM Specifications

ASTM A717/A717M (2012) Standard Test Method for Surface Insulation Resistivity of Single-Strip Specimens

ASTM A876 (2017) Standard Specification for Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed Types

ASTM D923 (2015) Standard Practice for Sampling Electrical Insulating Liquids

ASTM D1533 (2012) Standard Test Method for Water in Insulating Liquids by Coulometric Karl Fischer Titration

ASTM D1535 (2014) Specifying Color by the Munsell System

ASTM D3487 (2016; E 2017) Standard Specification for Mineral Insulating Oil Used in Electrical Apparatus

ASTM D4059 (2000; R 2010) Analysis of Polychlorinated Biphenyls in Insulating Liquids by Gas Chromatography

SECTION 48 19 23 Page 5

AMERICAN WELDING SOCIETY (AWS)

AWS A2.4 (2012) Standard Symbols for Welding, Brazing and Nondestructive Examination

AWS D1.1/D1.1M (2015; Errata 1 2015; Errata 2 2016) Structural Welding Code - Steel

AWS D1.6/D1.6M (2017) Structural Welding Code - Stainless Steel

INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE)

IEEE C57.12.00 (2015) General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers

IEEE C57.12.10 (2013) Liquid-Immersed Power Transformers Corrigendum 2: Correction of A.3.2.13 Autotransformer LTC Application Considerations

IEEE C57.12.70 (2011) Standard Terminal Markings and Connections for Distribution and Power Transformers

IEEE C57.12.80 (2010) Standard Terminology for Power and Distribution Transformers

IEEE C57.12.90 (2015; Corr 2017) Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers

IEEE C57.19.00 (1991) Standard General Requirements and Test Procedure for Outdoor Power Apparatus Bushings

IEEE C57.19.01 (1991) Standard Performance Characteristics and Dimensions for Outdoor Apparatus Bushings

IEEE C57.104 (2008) IEEE Guide for the Interpretation of Gases Generated in Oil-Immersed Transformers

IEEE C57.113 (2010) Recommended Practice for Partial Discharge Measurement in Liquid-Filled Power Transformers and Shunt Reactors

IEEE C57.131 (2012) Standard Requirements for Load Tap Changers

IEEE C57.149 (2012) Guide for the Application and Interpretation of Frequency Response Analysis for Oil-Immersed Transformers

SECTION 48 19 23 Page 6

MANUFACTURERS STANDARDIZATION SOCIETY OF THE VALVE AND FITTINGS

INDUSTRY (MSS)

MSS SP-110 (2010) Ball Valves Threaded, Socket-Welding, Solder Joint, Grooved and Flared Ends

MSS SP-72A (2010) Ball Valves with Flanged or Butt-Welding Ends for General Service

NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)

NEMA 250 (2014) Enclosures for Electrical Equipment (1000 Volts Maximum)

NEMA C80.1 (2015) Electrical Rigid Steel Conduit

(ERSC)

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

NEMA MW 1000 (2016) Magnet Wire

UNDERWRITERS LABORATORIES (UL)

UL 50 (2007; Reprint Apr 2012) Enclosures for Electrical Equipment, Non-environmental Considerations

UL 360 (2013; Reprint May 2018) UL Standard for Safety Liquid-Tight Flexible Metal Conduit

UL 514A (2013; Reprint Aug 2017) UL Standard for Safety Metallic Outlet Boxes

UL 514B (2012; Reprint Nov 2014) Conduit, Tubing and Cable Fittings

1.4 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals having an "I" designation are for information only. A designation following the "G" or "I" designation identifies the office that shall review the submittal for the Government. The following shall be submitted in accordance with SECTION 01 33 00, SUBMITTAL PROCEDURES, unless otherwise indicated below:

SD-02 Shop Drawings

Outline and Assembly Drawings; G, DO

Detail Drawings; G, DO

SD-05 Design Data

Descriptive Data; G, DO

Spare Parts List; G, DO

SECTION 48 19 23 Page 7

Preliminary Transformer Design; G, DO

SD-06 Test Reports

Transformer Factory Acceptance Test Report; G, DO

Bushing Design Tests; G, DO

Bushing Routine Tests; G, DO

Weld Inspection and Test Report; G, DO

SD-07 Certificates

Transformer Oil Certification; G, DO

Notification of the Date of the Transformer Design Review Meeting;

G, DO

Notification of the Date of Factory Tests; G, DO

Welder Qualifications; G, RO

Weld Inspector Qualifications; G, RO

Notification of the Date of In-process Inspections; G, DO

SD-08 Manufacturer's Instructions

Factory Test Procedures; G, DO

Welding Procedures; G, DO

Prequalified Weld Procedures; G, DO

1.5 WARRANTY REQUIREMENTS

In addition to the requirements outlined in FAR 52.246-17 and SECTION 01 78 00 CLOSEOUT SUBMITTALS, the manufacturer’s warranty for the power transformers shall continue for a period of 5 years from the date of final acceptance of the work. If the Government takes possession of any part of this work before final acceptance, this warranty shall continue for a period of 5 years from the date the Government takes possession. The following transformer issues will also be considered warranty repair items:

a. Transformer gassing rates beyond the Condition 1 level as defined in Table 2 and 3 of IEEE C57.104, or concentrations exceeding the Condition 1 limits as defined in Table 1 of IEEE C57.104

b. Transformer oil leaks.

PART 2 PRODUCTS

2.1 TYPE AND RATING

2.1.1 General

The transformers to be furnished under these specifications shall be

SECTION 48 19 23 Page 8 three-phase, two-winding, with one high-voltage and one low-voltage winding per phase, oil-immersed type suitable for outdoor operation. The transformers shall be self-cooled type, Class ONAN, and shall be of a design that has an established record of satisfactory operation with the type of oil preservation system specified. The transformers shall be designed and manufactured for shipment by rail and trucking by heavy hauler, and for shipment by sea if the transformers has a probability of being transported by this method.

Each transformer A and B shall be tapped at the primary to provide power to the primary side of the 300kVA station service transformer at the respective side of the distribution system. New conductors must be provided for these power feeds.

2.1.2 Descriptive Data

Descriptive data or catalog data of all accessory devices and ancillary equipment provided with the transformers shall be submitted for approval within 180 calendar days after notice to proceed, to demonstrate fully that all parts of the equipment shall conform to the requirements and intent of the specifications.

2.1.3 Transformer Limiting Dimensions and Equipment Arrangement

The transformers design, configuration, and dimensions shall be as indicated on the contract drawings. Refer to original contract drawing FP-1-1245 included in this contract set of drawings. The transformer shall not exceed the limiting dimensions as shown on drawings E-201. The transformer terminal box shall be aligned above the existing embedded conduit floor as shown in the contract drawings unless otherwise approved by the government. The disassembled transformers shall fit over the existing, downstream transformer platforms at the pump station.

Existing conditions and dimensions must be verified in the field prior to ordering all equipment.

2.1.4 Requirements

Except as otherwise specified herein, the transformers, accessories, and spare parts shall conform to the applicable requirements of IEEE C57.12.00, IEEE C57.12.10, IEEE C57.12.70, IEEE C57.12.80, IEEE C57.12.90 and

IEEE C57.131.

2.1.5 Standard Products

Material and equipment provided with the transformers shall be standard products of a manufacturer regularly engaged in their manufacture, and shall essentially duplicate items that have been in satisfactory use for at least three years prior to bid opening, unless otherwise specifically approved. All materials shall conform to the requirements of these specifications. Materials shall be of industrial quality, free from defects and imperfections, of recent manufacture, and of the classification and grades designated. All materials, supplies, and articles not manufactured by the Contractor and/or Sub-Contractor shall be the products of other recognized reputable manufacturers. If the Contractor desires for any reason to deviate from the standards designated in these specifications, a statement shall be submitted for approval describing the exact nature of the deviation, including complete specifications for the materials that are being proposed for use.

SECTION 48 19 23 Page 9

2.1.6 Ratings and Electrical Characteristics

The ratings and electrical characteristics of the transformers shall be as follows:

a. Continuous ratings, at the 65 degree C temperature rated temperature rise, on all taps kVA:

ONAN Rating: 12,200 kVA

ONAN Overload Rating (Duty cycle defined as 6 hours on followed by 6 hours off for a period of 48 hours, once a year): 18,300 kVA

b. Frequency, Hz: 60

c. Number of phases: 3

d. Rated voltage, kV:

(1) High-voltage windings: 11

(2) Low-voltage windings: 4.16

e. Winding connections:

(1) High-voltage windings: Delta

(2) Low-voltage windings: Grounded-Wye

f. Impedance, at ONAN rated current, subject to IEEE tolerances, percent: 5.7

g. Angular displacement degrees: 30

h. Basic impulse insulation levels (BIL), kV:

(1) Line ends of the high-voltage windings, not less than: 110

(2) Low-voltage windings, not less than: 75

(3) Neutral ends of the low-voltage windings, not less than: 75

i. Taps in high-voltage windings: Taps in high-voltage windings for De-Energized Tap Changing equipment to provide automatic regulation of +/- 5 percent in steps of 2.5 percent, with 2 steps above and 2 steps below the rated voltage.

l. Maximum average sound level at rated voltage and frequency, dB: 68

m. Maximum transformer total weight, completely assembled and oil filled with all accessories installed, pounds: 53,300 (see paragraph

STRUCTURAL DESIGN CRITERIA AND SEISMIC CALCULATIONS)

2.2 STRUCTURAL DESIGN CRITERIA AND SEISMIC CALCULATIONS

Structural design criteria and seismic calculations shall be submitted for approval within 180 calendar days after date of award. Design criteria and calculations shall be performed by qualified structural engineers who

SECTION 48 19 23 Page 10 are presently registered professional engineers (PE). A cover sheet for the submittal shall be provided and stamped or sealed and signed by a PE.

Structural design criteria and seismic calculations shall be provided for the transformer design, to include, but not limited to, the main tank and all major components such as bushings, cooling equipment, on-load tap changers, and oil preservation equipment.

2.2.1 Structural Design Criteria

Structural design criteria shall include the following:

a. Indicate the industry design standards and allowable stresses or capacities to which steel plate, structural steel shapes, welds, bolts and studs shall conform.

b. Indicate the industry standards used in developing the seismic forces and analysis techniques used in design of the transformer and transformer components.

c. Seismic design for equipment restraint shall be in accordance with Chapter 13 "Seismic Design Requirements for Nonstructural Components", of ASCE 7-10 with the seismic design force computed as per Section

13.3 "Seismic Demands on Nonstructural Components". Electrical equipment restraint shall be designed in accordance with the provisions in IEEE 693 Annex D or Section 13.3 of ASCE 7-10 whichever produces the more adverse seismic effects.

2.2.2 Seismic Calculations

Seismic calculations shall include the following:

a. Derivation of seismic forces and load cases. Load cases used for developing seismic anchorage of the complete transformer shall account for the effect of the righting force of the weight of the transformer.

b. Calculations for use in the design of anchorage to resist overturning and base shear. The maximum uplift and shear force per anchor bracket bolt shall be provided in pounds or kips.

c. A schematic depicting the location of the center of gravity, the applied seismic forces relative to the base, and the location of seismic anchors.

d. Calculations for individual components and their attachment to the transformer.

2.2.3 Anchorage to Concrete for Seismic Restraint

For the purposes of performing seismic calculations and for transformer design for anchorage to the pump station concrete floor, the structural steel supporting base will be welded to steel plates on a foundation anchored to the pump station deck.

2.3 THERMAL DESIGN

The temperature rise above ambient temperature of the transformers or parts thereof, when tested in accordance with its ratings, shall not exceed the limits of observable temperature rise for oil immersed apparatus as stated in IEEE C57.12.00 (paragraph 5.11.1). The winding temperature rise by

SECTION 48 19 23 Page 11 resistance shall not exceed 65 degrees C, and the hottest spot winding temperature rise shall not exceed 80 degrees C on the tap connections that give the highest losses at the self-cooled rating.

2.4 CORE

The transformers core shall be constructed of high-quality, non-aging, cold-rolled, grain-oriented steel especially suitable for the purpose.

Provide core steel laminations that meet the requirements of ASTM A664 and ASTM A876, and has an ASTM Core-Loss Type 27H074, with a maximum thickness of 0.270 mm, and a design flux density of not greater than 1.70 Tesla. The use of paper insulation in the core is not acceptable. Electrical core steel core loss, rms exciting power, rms and peak exciting current, and ac permeability shall be tested in accordance with ASTM A343/A343M. Each roll of sheet steel used shall have the surface insulation resistivity tested in accordance with ASTM A717/A717M. The core shall be carefully assembled and rigidly clamped to ensure adequate mechanical strength to support the windings and to prevent shifting of the laminations during shipment, and also to reduce vibration to a minimum under operating conditions. Core joints shall be interleaved. The transformers core design and construction methods shall be in such a manner to assure that the average sound level due to operation of the transformers and accessories shall not exceed 68 dB at rated voltage and frequency as measured in accordance with IEEE C57.12.90.

2.5 WINDINGS

2.5.1 General

The transformers shall be manufactured with windings meeting the requirements of paragraph RATINGS AND ELECTRICAL CHARACTERISTICS, consisting of one high-voltage winding (H) per phase and one low-voltage winding (X) per phase. The winding conductors shall be of high-conductivity copper magnet wire meeting the applicable requirements of NEMA MW 1000, and if of a core-form design shall be of a circular coil construction. Conductor insulation shall consist of thermally upgraded Kraft paper. As an alternative for low and medium-voltage windings, continuously transposed conductors can use nylon or polyester netting insulation tape as long as the windings meet all dielectric requirements as specified in paragraph INSULATION LEVELS. Consideration shall be given to all factors of service, such as high dielectric and mechanical strength of insulation, coil characteristics, and minimum restrictions to free circulation of oil. Coils shall be made up, shaped, and braced to provide for expansion, contraction, and shrinkage due to temperature changes and aging in service in order to avoid abrasion of insulation and to provide resistance to movement and distortion caused by abnormal operating conditions. Adequate barriers shall be provided between windings and core and between high-voltage and low-voltage windings. End coils shall have additional protection, if required, against normal line disturbances. The delta and wye winding connections shall be made inside the transformer tanks.

2.5.2 Insulation Levels

The transformers shall be manufactured with a BIL rating of the windings as specified in paragraph RATINGS AND ELECTRICAL CHARACTERISTICS, and shall be capable of withstanding IEEE Standard dielectric tests, in accordance with paragraph "Power Transformer Tests", corresponding to the specified winding insulation levels.

SECTION 48 19 23 Page 12

2.5.3 Short Circuit Capability

The transformers shall be capable of withstanding without injury the mechanical and thermal stresses caused by short circuits on the external terminals of any winding or windings, with rated voltages maintained across the terminals of all other windings intended for connection to sources of energy, under the conditions listed in IEEE C57.12.00 (paragraph 7.1.1).

2.5.4 Embedded Fiber Optic Probes

Fiber optic probes used for direct winding temperature measurement shall be embedded in the high and low voltage windings. Quantities and distribution shall be as indicated in paragraph TRANSFORMER FIBER OPTIC TEMPERATURE MONITOR. Probes shall be embedded in the calculated hottest spot for each winding.

2.6 DE-ENERGIZED TAP CHANGER

The transformers shall be equipped with an external, manually operated tap changer for changing connections to the taps in the high-voltage windings.

Taps will be changed only when the transformer is de-energized. The tap changer control shall be mounted on the transformer tank at approximately 48 inches above the base of the transformer and shall include an operating hand wheel, indicating pointer and dial, and means for locking the tap changer in any desired tap position. The operating hand wheel, if removable, shall be mechanically interlocked with the tap mechanism to prevent its removal when the mechanism is not in a completed tap position.

Transmission of motion from operating hand wheel shaft to taps shall be by interaction of rigid members. The tap changer contacts shall be silvered, and capable of withstanding the full short circuit current of the transformer without injury. The tap changing mechanism shall render it impossible to leave a winding open or short circuited when the operating wheel is placed in a locked position.

2.7 TANK

2.7.1 Construction

Provide the transformers with an oil-tight steel tank, with oil-tight covers per the requirements of IEEE C57.12.10 (paragraph 5.8). Provide a tank with one or more unobstructed manholes in the cover with minimum dimensions of 10 inches by 16 inches rectangular, or 15 inches diameter round as a minimum, to afford easy access to the lower ends of bushings, terminals, and the upper portions of the coils. Provide suitable positioning guides inside the tank to assure the core and windings are in the correct position during assembly. The main transformer tank and any attached compartment that is subjected to operating pressures shall be manufactured to withstand, without leakage or permanent deformation, an internal pressure not less than 10 psi. The tank shall be manufactured for vacuum filling (essentially full vacuum) in the field. All valves, fittings and piping affected by vacuum filling shall be rated for such filling. Auxiliary compartments such as reservoir tanks, when not designed for vacuum filling, shall be so designated, and suitable isolating valves shall be provided. The joints between the tank and cover, and between tank sections shall be welded, and the joint shall prevent weld splatter from entering the inside of the tank.

SECTION 48 19 23 Page 13

2.7.2 Lifting and Moving Facilities

2.7.2.1 Lifting Facilities

Provide lifting eyes, lugs or hooks designed for design loads two times the actual load to allow for possible unequal lifting forces, with a safety factor (using design loads) in accordance with IEEE C57.12.10 (paragraph 5.3.1). Lifting eyes, lugs, or hooks shall positively keep the lifting cable in place even when the cable is slack. The transformers shall be provided with the following lifting facilities:

a. Lifting attachments on the tank cover.

b. Adequate means for lifting the core and coil assembly from the tank.

c. Lifting eyes on the tank shall be adequate for lifting the complete transformer filled with oil, and located at the top of the tank sidewalls for a transformer of core-form design. The placement of the lifting eyes shall allow for lashing of the transformer during shipment.

2.7.2.2 Moving Facilities

Moving features shall be furnished as required for moving each transformer to its final location as indicated in the contract drawings, and shall be in accordance with IEEE C57.12.10 (paragraph 5.3.3).

2.7.3 Connections

2.7.3.1 General

All bolts, studs, machine screws, nuts, and tapped holes designed for customer connection shall be in accordance with ASME B1.1 (inch fasteners), or ASME B18.2.6M (metric fasteners). Bolting hardware shall be Grade 5 minimum, or equivalent, and all hardware not internal to the tank shall be galvanized, stainless steel bolting hardware is not allowed. Threads for sizes 1/4-inch to 1-inch, inclusive, shall be NC or UN 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 B1.20.1. Manufacturers' standard threads and construction may be used on small items which are integrally replaceable, except that threads for external connections to these items shall meet the above requirements.

2.7.3.2 Stainless Steel

All stainless steel connecting hardware supplied with commercially off the shelf components shall be installed using an anti-galling compound such as molybdenum disulfide on the threads prior to connection.

2.7.4 Steel Pipe and Fittings

Steel pipe shall conform to ASTM A53/A53M, Weight A, Class 2. Dimensions of terminating flanges shall conform to ASME B16.1 and ASME B16.24.

2.7.5 Grounding

Provide two ground pads on the transformers for grounding the tank and base. The grounding provisions shall be in accordance with IEEE C57.12.10 (paragraph 5.5). A 3/0 insulated copper conductor shall be installed on the transformers to connect the terminal of the neutral bushing for the

SECTION 48 19 23 Page 14 low-voltage windings to one of the ground pads at the base of the tank. The conductor shall be supported against the transformer tank a minimum of every 36-inches.

2.7.6 Steel Supporting Base

The transformers shall be provided with a structural steel supporting base with skid channels designed for pad mounting and anchoring, as indicated on the drawings, without wheels that is a minimum of 4 inches thick, if required by the manufacturer. The steel supporting base and anchoring shall be designed to withstand seismic forces as required in paragraph STRUCTURAL DESIGN CRITERIA AND SEISMIC CALCULATIONS. The transformers shall be designed to be suitable for moving on rollers or skids when completely assembled and filled with oil, and shall be designed to permit moving the transformer in a direction parallel to either centerline, with suitable pulling eyes provided.

2.7.7 Jack Ports

The transformers base shall be provided with jack ports, bosses, or lugs, to permit jacking the complete transformer filled with oil per the requirements of IEEE C57.12.10 (paragraph 5.3.4). The design loads for jacking bosses or lugs shall be at least two times the actual loads to allow for possible unequal jacking forces.

2.7.8 Center of Gravity

The transformer base shall be manufactured so that the center of gravity of the transformer, with or without oil as normally prepared for shipment, shall not fall outside the base support members for a tilt of the base of 15 degrees from the horizontal.

2.7.9 Oil Level Markings

The 25 degree C oil level shall be indicated on the outside of the Segment 2 tank sidewall by suitable permanent markings, and the change in oil level per 10 degree C change in oil temperature shall be indicated on the transformer nameplate.

2.8 GASKETING

Gaskets between metal surfaces shall be set in expansion-limiting grooves or held in position by retainers so arranged that all contact surfaces are metal-to-metal when tightened. The gaskets shall be made of Nitrile NBR (Buna N) with a Durometer rating between 50 and 60. Gaskets shall be rated for compression by at least 25 percent of their original thickness. O-ring gaskets shall not be used for gasket grooves of rectangular cross-section.

2.9 VALVES

The transformers shall be provided with valves conforming with IEEE C57.12.10(paragraph 5.1.8), unless otherwise specified, below. All valves, shall be of stainless steel construction conforming to MSS SP-72A, circular flanged, reinforced PTFE valve seats, and shall be ball-type unless otherwise specifically indicated. The valves shall be of full-port type, when available, rated for use with insulating oil, have a 120 degrees Celsius minimum temperature rating, and shall be include provisions for locking of the handle. Valve handles shall be of a circular, or oval, type. Weather resistant locks shall be provided for all valves, keyed the

SECTION 48 19 23 Page 15 same. All valves which have an outbound connection remaining open shall be provided with either a blind-flange, including a gasket and associated hardware, or a plug/cap on the NPT threaded connection. Valves shall be provided for the following:

a. Upper filter connection. A 2-inch valve shall be located on the Segment 2 tank sidewall such that it can be used to fill the transformer with oil while the transformer is under vacuum. The outbound connection shall be a 2-inch female NPT thread, provided with a threaded plug.

b. Vacuum pump connection. A 3-inch valve shall be located on the tank cover for use in connecting a vacuum pump during the vacuum filling process. The outbound valve connection shall be a circular 4-bolt flanged, provided with a gasketed blind flange cover with an integral 3-inch NPT female connection with threaded plug.

c. Main drain. A 2-inch valve shall be located at the extreme bottom of the tank on Segment 2 tank sidewall for use in gravity draining of the transformer. The outbound valve connection shall be circular 4-bolt flanged, provided with a gasketed blind flange cover with an integral 2-inch NPT female connection with threaded plug.

d. Oil sampling valve. A sampling valve shall be located at the extreme bottom of the Segment 2 tank sidewall with a 1/2-inch NPT threaded discharge end. This valve may be integral to the lower filter valve. A 1/2-inch threaded sampling device, complete with protective cover, shall be provided for the purposes of obtaining oil samples, and shall be a United Brass Works Model 86, or equal as manufactured by United Brass Works, 714 S. Main Street, Randleman, NC 27317. The oil sampling valve salient physical, functional, or performance characteristics an equal item must meet to be acceptable are as follows:

(1) Sampling valve designed for oil sampling

(2) Brass valve body and brass cap

(3) Cover attached to body with brass ball-chain type lanyard

(4) Rated operating Temperature -50 degrees C to +135 degrees C

(5) Buna o-rings and Buna gaskets

e. Lower filter connection. A 2-inch valve shall be located at the extreme bottom of the tank on the Segment 4 tank sidewall. The outbound connection shall be a 2-inch female NPT thread, provided with a threaded plug.

f. Nitrogen gas connection. Two 1/2-inch valves shall be provided for connection of the oil preservation system tubing. These isolation valves shall conform to MSS SP-110.

g. Isolation valves. The following isolation valves shall be provided:

(1) Radiators. At the inlet and outlet of each radiator to permit removal without draining the oil from the tank. Radiator isolation valves at the transformer tank may be of a butterfly type, and stainless steel construction.

SECTION 48 19 23 Page 16

2.10 COOLING EQUIPMENT

2.10.1 Radiators

Provide transformers with a sufficient number of radiators to cool the oil properly. The radiators shall be so located on the tank to insure uniform circulation of the oil through the windings. The radiators shall be constructed of steel tubes or elements welded into steel headers. All welding shall be on the outside of the radiators such that there will be no crevices in which water might collect. The welding and fittings shall be smooth, both inside and out, so as to present no obstruction to the flow of oil inside. The radiators shall be fully hot-dip galvanized on the outside and remain unpainted. The radiators shall be rated to withstand essentially full vacuum to permit filling the transformer under vacuum with radiators in place and radiator valves open. Valves shall be installed on each connection to the main tank so that radiators may be removed for repairs without taking the transformer out of service. Provisions shall be made for draining and venting the radiators, and lifting eyes shall be provided for handling the radiators.

2.11 BUSHINGS

2.11.1 General Bushing Requirements

Each transformer shall have three high-voltage, three low-voltage, and one neutral leads brought out from the tank through bushings as specified below. Bushings of the same voltage and current rating shall be interchangeable and, as applicable, meet the requirements of IEEE C57.19.00 and IEEE C57.19.01 and shall be tested in accordance with paragraph BUSHING TEST. Viton gaskets shall be used for the installation of all bushings.

All bushings shall meet the following requirements:

a. Bushings shall be of recent manufacture and shall be of a type and style currently manufactured by the bushing manufacturer.

b. Bushings shall be nameplate rated and tested for use at 60 Hz rated frequency.

c. Bushings shall be rated for outdoor service. All bushings which will be exposed to direct sunlight shall have UV resistant insulating sheds.

d. Bushings shall be manufactured so that there will be no stressing of any parts due to temperature changes, and adequate means shall be provided to accommodate conductor expansion.

e. Bushings shall seal gastight and oiltight on the transformer tank as applicable.

2.11.2 High-Voltage Bushings

Provide high-voltage bushings conforming to the requirements of IEEE C57.19.01 (1991), and be tested in accordance with paragraph "Bushing Tests". The high-voltage bushings shall be air-to-oil solid bulk bushings of a low-corona design and shall be designed for horizontal mounting. The bushing insulators shall be made of porcelain and be gray in color. The porcelain shall be manufactured by the wet process, shall be homogeneous, free from laminations, cavities or other flaws affecting its mechanical

SECTION 48 19 23 Page 17 strength or dielectric quality. The glazing of the porcelain parts shall be free from imperfections, such as blisters and burns, shall be well vitrified, tough and impervious to moisture. All high-voltage bushings shall be rated, as a minimum, to the following:

a. Insulation class, kV: 15

b. BIL rating, kV: 110

c. Minimum current rating, Amperes: 1,200

2.11.3 Low-Voltage and Neutral Bushings

Provide low-voltage and neutral bushings conforming to the requirements of IEEE C57.19.01 (1991), and be tested in accordance with paragraph "Bushing Tests". The low-voltage and neutral bushings shall be air-to-oil solid bulk bushings of a low-corona design and shall be designed for mounting. The bushing insulators shall be made of porcelain and be gray in color. The porcelain shall be manufactured by the wet process, shall be homogeneous, free from laminations, cavities or other flaws affecting its mechanical strength or dielectric quality. The glazing of the porcelain parts shall be free from imperfections, such as blisters and burns, shall be well vitrified, tough and impervious to moisture. All low-voltage and neutral bushings shall be rated, as a minimum, to the following:

a. Minimum insulation class, kV: 8.7

b. BIL rating, kV: 75

c. Minimum current rating, Amperes: 8,000

2.11.4 High-Voltage Terminals

Provide high-voltage bushings with threaded copper terminal stud with dimensions in compliance with IEEE C57.19.01. Each high-voltage bushing shall be provided with a bronze alloy bolted stud-to-flat terminal connector, having a NEMA four-hole spacing. All contact surfaces of external terminals and of terminal connectors shall be silver-plated using pure silver free from copper.

2.11.5 Low-Voltage and Neutral Bushing Terminal Connections

Provide low-voltage and neutral bushings with spade-type copper terminal connections. All contact surfaces of external terminals and of terminal connectors shall be silver-plated, using pure silver free from copper.

2.11.6 Core Ground Bushings

2.11.6.1 Main Transformer

Provide two external bushings for core grounding of the main transformer;

one for the core ground, and one for the core frame ground. The bushings shall be manufactured with an integral cast copper stud, with an insulating body manufactured of either epoxy or solid porcelain. The bottom terminal shall be a tin plated threaded stud. The top terminal shall be either a tin plated threaded stud, or shall have a tin plated spade terminal soldered to the stud. Provide grounding straps between the bushing terminal and the core and tank wall. The minimum ground wire size from each bushing terminal to the tank wall shall be #4 AWG equivalent. The bushings shall be mounted

SECTION 48 19 23 Page 18 adjacent to each other, located on the transformer tank cover, protected with a removable cover to prevent inadvertent contact, and labeled to avoid confusion with other bushings. The core ground bushings shall have the minimum nameplate ratings:

a. Insulation class, kV: 2.5

b. BIL rating, kV: 45

c. Minimum current rating, Amperes: 100

2.11.7 SFRA Test Shipping Bushings

For the purposes of performing SFRA testing with the transformer in the shipping configuration when bushings are removed for shipping, each shipping cover installed after the bushings have been removed for shipment shall include a bushing that is connected to the winding leads, so that the SFRA tests can be performed just prior to transformer shipment and immediately after transformer delivery to the Fox Point pump station. This assembly shall permit the SFRA testing on the transformer without having to gain entrance into, or modifying the transformer shipping assembly. The winding leads shall be appropriately braced inside the transformer tank to assure there is no movement during shipment which could damage the bushings, or potentially alter the SFRA test results. During shipment, the external terminals of these bushings shall be grounded to the tank.

Testing shall be performed per the requirements of paragraph SWEEP FREQUENCY RESPONSE ANALYSIS TESTS. Each temporary SFRA Test Shipping Bushings shall be of the same manufacture and rating as the core ground bushing.

2.12 LOW-VOLTAGE BUSHING THROAT

Provide the transformers with a flanged throat surrounding the base of the low-voltage winding bushings, manufactured to bolt to a new section of 5 kV non-segregated bus housing enclosure as part of this contract, and readily drain standing water. The bolted-flange connection shall be raised 3-inches from the transformer cover and provided complete with gaskets.

Nonmagnetic materials shall be used where necessary to help prevent overheating due to eddy currents, and to meet temperature rise limitations. The details of the flanges and bolted connections shall be provided, and included on the manufacturer's shop drawings.

2.13 HIGH-VOLTAGE BUSHING THROAT

Provide the transformerss with a flanged throat surrounding the base of the high-voltage winding bushings, manufactured to bolt to a new section of 15 kV non-segregated bus housing enclosure as part of this contract, and readily drain standing water. The bolted-flange connection shall be raised 3-inches from the transformer cover and provided complete with gaskets.

Nonmagnetic materials shall be used where necessary to help prevent overheating due to eddy currents, and to meet temperature rise limitations. The details of the flanges and bolted connections shall be provided, and included on the manufacturer's shop drawings.

2.14 TRANSFORMER MOUNTED ACCESSORIES

2.14.1 General

Dials, indicators, and gages installed on the transformer shall be mounted

SECTION 48 19 23 Page 19 on the appropriate side of the transformer as shown on the contract drawings at a height of approximately 54 inches above the base of the transformer, unless otherwise indicated, and angled for convenient reading standing at the level of the deck. All indicators and gauges shall have glass faces. The following accessory devices shall be furnished, and shall be included in the price for the transformer. Accessories shall be provided per the requirements of paragraph 5 of IEEE C57.12.10, unless otherwise indicated.

2.14.2 Contacts and Devices

The contacts of all relays, gages, and thermometers shall be insulated from ground and shall be of a positive snap-action type. Separate alarm relay devices may be furnished if desired. Alarm contacts shall be suitable for operation on 125 V dc ungrounded circuits and rated 0.5 amperes (resistive) at 125 V dc.

2.14.3 Liquid Level Indicator

The transformer shall be provided with a magnetic-type liquid level indicator located for reading for reading when facing Segment 2 tank sidewall, equipped with a circuit-closing low-level alarm contact suitable for use with an ungrounded 125 V dc circuit. The indicator shall have a 6-inch dial face with a field-replaceable case, shall incorporate a method for switch testing, and the dial shall be marked to show the 25 degrees C oil level and the maximum and minimum oil levels. The liquid level detector shall include a 4-20mA analog output for future use.

2.14.4 Analog Temperature Indicating Equipment

Thermowells for the sensing elements of all analog indicating equipment and indicators shall be located on the Segment 2 tank sidewall.

2.14.4.1 Liquid Temperature Indicator

The transformer shall be provided with a dial-type indicating thermometer (liquid temperature indicator) with its sensing element located in the path of the hottest oil. The dial indicator shall cover a range of 0 to 120 degrees C and shall be equipped with four adjustable circuit closing alarm contacts suitable for use with an ungrounded 125 V dc circuit. The liquid temperature indicator shall include a 4-20mA analog output for future use.

2.14.4.2 Winding Temperature Equipment

a. General. The transformer shall be provided with one winding temperature indicator (WTI), with associated equipment, for use in indicating the temperature of one phase winding, and for use as an over-temperature trip. The WTI equipment shall be responsive to the current in the phase winding and to the top oil temperature, shall reflect the approximate hot-spot temperature of the winding, and shall be provided with a means for calibration. The WTI equipment shall include the following:

(1) A current transformer installed at the middle-phase of the low-voltage windings, supplying current proportional to the load.

(2) A closed thermowell located inside the transformer case located in the hottest oil near the top of the tank.

SECTION 48 19 23 Page 20

(3) A heating coil in the thermowell energized by the current transformer.

(4) A sensing element located in the thermowell for operation of a dial indicator with three switches.

(5) All necessary wiring and capillary tubing.

b. Dial Indicator and Switches. The dial indicator for the WTI shall have four electrically-independent, self-resetting contacts suitable for use on 125 V ungrounded dc circuits. The switches shall be utilized for the following:

(1) Winding high-temperature alarm

(2) Winding over-temperature trip

c. Leads. The leads from the WTI equipment shall be brought out through the transformer tank in watertight and oiltight conduit fittings. All leads from each WTI equipment shall terminate in the transformer control cabinet.

2.14.5 Transformer Tank Pressure Relief Device

2.14.5.1 General

2.15 OIL

2.15.1 Quantity and Transformer Oil Certification

Provide all oil required to fill the transformers to the proper operating levels as well as the oil required for factory tests. Transformer oil certification shall be submitted for approval a minimum of 14 calendar days prior to the filling the transformer. The transformer oil certification shall state that the oil furnished for placing the transformer in service meets the following requirements.

2.15.2 Type of Oil

The grade of insulating oil furnished shall be produced from a predominately naphthenic base crude petroleum, shall be new, and shall be specifically prepared and refined for use in electrical equipment as an insulating and cooling medium. Except for the oxidation inhibitor, the insulating oil shall be free from additives of every kind, either natural or synthetic.

2.15.3 Chemical, Physical and Electrical Characteristics

The insulating oil provided shall be tested in accordance with, and shall meet the test requirements of of Table 1 of ASTM D3487, Type II, with an oxidation inhibitor content of 0.3 percent by mass, prior to shipment. In addition to the requirements listed in Table 1 of ASTM D3487, the insulating oil for the transformer shall contain no Polychlorinated Biphenyls (PCBs) as tested in accordance with ASTM D4059, and the water content during final filling and assembly shall not exceed 20 parts-per-million (ppm) as tested in accordance with ASTM D1533. The Government, at point of delivery, may draw samples in accordance with ASTM sampling standards, for testing to determine whether the oil meets the specifications. Oil so tested and failing to meet the requirements will be

SECTION 48 19 23 Page 21 removed and replaced by, and at the expense of, the Contractor.

2.15.4 Sampling

Samples for testing shall be obtained as specified in ASTM D923.

2.15.5 Testing

Chemical, physical, and electrical tests shall be conducted by the Contractor in accordance with the test methods listed in Table 1 of ASTM D3487. A certified copy of the test reports shall be submitted for approval prior to shipment of the transformer.

2.16 OIL PRESERVATION SYSTEM

2.16.1 General

Provide the transformers with an inert-gas pressure type of oil preservation system conforming to the requirements as indicated, below.

2.16.2 Inert-Gas for Transformer Processing

Cylinders of nitrogen gas necessary for installing, flushing and charging the transformer shall be furnished by the Contractor. The nitrogen and cylinders shall conform to paragraph 6.6.3 of IEEE C57.12.00. Freight on returnable cylinders shall be paid by the Contractor and shall be included in the price bid for the transformer.

2.16.3 Inert-Gas Pressure System

2.16.3.1 General

The inert gas pressure system of oil preservation shall be complete for the supplied transformers, shall be fully automatic in operation, and shall maintain an adequate supply of dry nitrogen gas under a positive internal pressure in the space between the top of the oil and the tank cover.