26 25 00.00 26 R0002.pdf

CJD Excitation Units 1 – 16 Replacement 21050 Bridgeport, WA W912DW24R0001

SECTION TABLE OF CONTENTS

DIVISION 26 - ELECTRICAL

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BUS STRUCTURES

PART 1 GENERAL

1.1 DESCRIPTION OF WORK

1.2 REFERENCES

1.3 SUBMITTALS

1.4 GENERAL REQUIREMENTS

1.4.1 General

1.4.2 Materials, Equipment, and Installation

1.4.3 Standard Products

1.4.4 Corrosion Prevention

1.4.5 Equipment Storage and Handling Instructions

1.5 DRAWINGS

PART 2 PRODUCTS

2.1 NON-SEGREGATED METAL ENCLOSED BUS

2.1.1 General

2.1.2 Bus Conductors

2.1.3 Bus Insulation

2.1.3.1 Bus Supports

2.1.3.2 Bonding

2.1.4 Threaded Connections

2.1.4.1 Bus Sections

2.1.4.2 Bus Connections

2.1.4.3 Housing

2.1.4.4 Fittings

2.2 PAINTING

2.3 ACCESSORIES

PART 3 EXECUTION

3.1 BUS DESIGN

3.1.1 General

3.1.2 Coordination

3.2 FACTORY INSPECTION AND TESTS

3.2.1 General

3.2.2 Metal-Enclosed Bus Design Tests

3.2.3 Metal-Enclosed Bus Production and Field Tests

3.3 OPERATION AND MAINTENANCE MANUALS

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R0002

SECTION 26 25 00.00 26

BUS STRUCTURES

PART 1 GENERAL

1.1 DESCRIPTION OF WORK

This section covers bus which will be installed external to the excitation system for supplying DC field current from the excitation system to the brush rigging similar to the existing arrangement.

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.

ASME INTERNATIONAL (ASME)

ASME B1.1 (2020) Unified Inch Screw Threads (UN and UNR Thread Form)

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

ASTM INTERNATIONAL (ASTM)

ASTM A 123/A 123M (2017) Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products

ASTM A 153/A 153M (2016) Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware

ASTM B187/B187M (2020) Seamless Copper Bus Bars, Rod, and Shapes

ASTM B188 (2015e1) Standard Specification for Seamless Copper Bus Pipe and Tube

INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE)

IEEE C2 (2017) National Electrical Safety Code

IEEE C37.23 (2015) IEEE Standard Guide for Metal-Enclosed Bus

NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)

NFPA 70 (2020) National Electrical Code

1.3 SUBMITTALS

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

submittals not having a "G" designation are for information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government. Submit the following

SECTION 26 25 00.00 26 Page 2 in accordance with Section 01 33 00 SUBMITTAL PROCEDURES, unless otherwise indicated below:

SD-02 Shop Drawings

Submit within 60 calendar days after Notice to Proceed (NTP).

Detailed Drawings; G

Outline Drawings; G

Outline drawings of all nonsegregated-phase bus to be furnished under this specification, together with weights, detail dimensions, disconnect locations and design, material requirements, and complete mounting details. Drawings are for design details and for installation and shall be furnished with any provisions for adjustments of connections to the new or existing equipment. Provide complete shop drawings showing complete detailed design of all bus sections, connections, terminations, structural supports, hardware and fittings. Provide details showing the existing bus sections to be removed or modified, the new bus joints, housing supports and anchoring. Provide detail drawings of each size and type of joint.

SD-03 Product Data

Submit within 60 calendar days after Notice to Proceed (NTP).

Non-Segregated Metal Enclosed Bus; G

SD-09 Manufacturer's Field Reports

Submit within 10 calendar days after completion of test.

Factory Inspection and Tests; G

1.4 GENERAL REQUIREMENTS

1.4.1 General

The Contractor is required to accomplish all coordination between the supplied bus and the excitation system components.

1.4.2 Materials, Equipment, and Installation

New equipment shall be furnished and any defective material or equipment damaged in the course of installation shall be replaced or repaired.

Testing shall be performed to check the installation of and the proper operational functions of the electrical equipment. The installations shall be in accordance with the National Electrical Code, NFPA 70 , the National Electrical Safety Code, IEEE C2 , except where otherwise specifically shown or specified, in which case the drawings and specifications shall govern. Omission of details on the drawings or in the specifications may not be construed as permitting deviations from Code requirements.

1.4.3 Standard Products

Material and equipment shall be the standard products of manufacturers regularly engaged in the manufacture of these products and shall

SECTION 26 25 00.00 26 Page 3 essentially duplicate items that have been in satisfactory use for at least 5 years prior to bid opening. Bus manufacturers are required to make a site visit to verify connections of new buswork to existing equipment, and routing layout dimensions prior to submitting the Arrangement Drawings as specified in 48 19 26 DIGITAL EXCITERS.

1.4.4 Corrosion Prevention

Equipment shall be protected to prevent deterioration from corrosion. The general requirements are specified below; however, other corrosion-resisting treatments that are the equivalent of those specified may be used.

a. Fastenings and Fittings. Screws, bolts, nuts, pins, studs, springs, washers and other miscellaneous fastening and fittings shall be of corrosion-resistant material or shall be treated in an approved manner to render them resistant to corrosion.

b. Corrosion-Resisting Materials. Corrosion-resisting steel, copper, brass, bronze, copper-nickel-copper alloys are acceptable corrosion-resisting materials. Contact between dissimilar metals shall be avoided, except where one of the dissimilar metals is steel, or in the case of wiring and connections.

c. Corrosion-Resisting Treatments. Treatments shall be in accordance with ASTM A 123/A 123M or ASTM A 153/A 153M .

d. Finish. Final painting in accordance with Paragraph 2.4, PAINTING.

1.4.5 Equipment Storage and Handling Instructions

Materials and equipment shall be suitably protected from dust, dirt, and physical damage, and stored in accordance with the manufacturer's instructions, until acceptance by the Government.

1.5 DRAWINGS

Submit detailed drawings and outline drawings showing the overall bus system for each type of bus and details of connections with a schedule of materials.

PART 2 PRODUCTS

2.1 NON-SEGREGATED METAL ENCLOSED BUS

2.1.1 General

The bus conductors shall be hard drawn copper. The furnished bus structures and housing shall conform to, except as otherwise specified, the requirements of IEEE C37.23 . Copper bars and shapes for dc bus shall conform to the requirements of ASTM B187/B187M andor ASTM B188.

2.1.2 Bus Conductors

The bus shall be of copper and of shapes as approved. The Contractor is responsible for field verifying existing materials and shapes in order to match the new equipment to the existing equipment. The electrical ratings of the new bus from the excitation systems to the generator field shall be

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1200 amperes or as otherwise stated in the Contract Drawings.

2.1.3 Bus Insulation

The bus shall have each conductor completely insulated and mounted with insulated supports. The bus insulation shall be Class 105 and shall be of the shrink fit, molded, or epoxy-resin type, of flame retardant, track-resistant, non-hydroscopic material, and shall meet the dielectric requirements of IEEE C37.23 . The use of any polyvinyl chloride (PVC) is not acceptable. Insulation of equivalent mechanical and electrical strength as that enclosing the bus shall be provided at bus joints, and insulation in contact or overlapping with the existing bus insulation shall be compatible for long service life.

2.1.3.1 Bus Supports

Furnish all hardware as necessary for supporting the bus structures furnished and for bolting the bus housings to the support structures furnished. Any necessary inserts and associated bolts for attaching bus supports to supports shall be furnished. Supporting structures shall be finished to match the bus and all associated ferrous fasteners shall have a rust-resistant finish. External supporting members which are not an integral part of the bus housing and all associated ferrous fasteners shall be galvanized. The bus supports shall be insulated from the concrete anchors/fasteners to prevent heating in bus support structure due to circulating currents, if concrete anchors/fasteners come in contact with rebar. Bus structure shall be supported in a manner which does not compromise existing insulation points for the generator. Recommended method of anchoring, with size and quantity of bolts, shall be shown on the Contractor's drawings. All bus supports shall be seismically anchored according to section 13 48 00.00 26 SEISMIC RESTRAINT FOR MECHANICAL AND

ELECTRICAL EQUIPMENT.

2.1.3.2 Bonding

All bus housing sections shall be connected to the existing powerhouse ground system. Bus housing sections shall be bonded together or connected to a common ground bus to facilitate connection to the powerhouse ground system. The proposed method of grounding shall be subject to approval.

Multigrip clamp-type terminals shall be provided for connecting to a No.

2/0 copper ground cable. Contact surfaces at points of attachment of terminals shall be silver-plated.

2.1.4 Threaded Connections

All bolts, studs, machine screws, nuts, and tapped holes used shall be in accordance with ASME B1.1 . Threads for sizes 1/4-inch to l-inch, inclusive, shall be NC or UNC series. The sizes and threads of all 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, in the opinion of the GQAR, are integrally replaceable, except threads for external connections to these items shall meet the requirements outlined above.

2.1.4.1 Bus Sections

The straight sections of metal-enclosed bus shall be as long as practicable to manufacture and install, while being sectionable as indicated in contract drawings, so as to minimize the number of field

SECTION 26 25 00.00 26 Page 5 joints and to fit within the existing structural and equipment clearances. The sections shall be designed for easy assembly and disassembly as indicated in contract drawings. The bus shall be fabricated with expansion joints as required to suit the spacing and arrangement. Contact surfaces shall be silver-plated at bolted connections. The horizontal and vertical elbow and tee sections with all the frames, flanges, gaskets, covers, and structural supports required for mounting the buses shall be provided.

2.1.4.2 Bus Connections

All connections shall be coordinated with the equipment assembly manufacturers. Expansion joints shall be used where bus runs across concrete expansion joints. The Contractor shall furnish all necessary materials for connections of the new non-segregated bus. The bus expansion joints shall be constructed with flexible braid. Expansion joints utilizing sliding contacts are not acceptable.

2.1.4.3 Housing

The insulated conductors shall be mounted with insulating supports and spacers inside a common steel sheet metal housing. The nonventilated, drip-proof, and dust-tight bus housings and covers may be not less than No. 11 Manufacturer's Standard Gauge and shall be constructed to minimize magnetic heating and to limit induced circulating current losses. The sheet metal bus housings shall conform to the applicable requirements of IEEE C37.23 for 65 degree C rise rated bus conductors over a 40 degree C ambient. The design of the housings shall be such as to facilitate the installation and alignment of all bus sections and the completion of field joints in the conductors before the housing is completely closed.

Provisions for adjustments up to 1/2-inch due to site and installation variances shall be incorporated into the overall design. Readily removable gasketed plates, hinged panels or doors shall be provided for top or bottom access to the buses without disassembling bus conductors.

Readily removable cover plates of not less than No. 11 Manufacturer's Standard Gauge, bolted panels or doors shall be provided for access to the disconnect links and insulators for regular operation and maintenance.

All bus cover plates shall be connected to the housing with machine screws, lock washers, and captive nuts. The bus housing shall have filtered breathers at necessary intervals. Gaskets shall be of closed-cell neoprene or other approved material and shall be concealed for protection.

2.1.4.4 Fittings

The bus joints and the conductor terminals shall be silver-plated and provided with ample contact area and sufficient bolts. Flexible jumpers shall be provided where expansion joints are indicated or required.

Belleville-style washers and nonmagnetic steel washer plates shall be provided for maintaining pressure at equipment terminal connections.

2.2 PAINTING

Interior and exterior steel surfaces of the equipment housing shall be thoroughly cleaned and then receive a rust-inhibitive phosphatizing or equivalent treatment prior to painting in accordance with IEEE C37.23 .

Exterior surfaces shall be free from holes, seams, dents, weld marks, loose scale, or other imperfections. Interior surfaces shall receive not less than one coat of corrosion-resisting paint in accordance with the

SECTION 26 25 00.00 26 Page 6 manufacturer's standard practice. Exterior surfaces shall be primed, filled where necessary, and given not less than two coats of quick air-drying lacquer or synthetic enamel with semi-gloss finish. Paint to match excitation system cabinet. Lead-based paints shall not be used.

2.3 ACCESSORIES

The accessories to be furnished, which shall be packed and marked include:

1 - Complete set of all special wrenches and tools required for the installation, maintenance, and repair of the nonsegregated-phase bus.

The Contractor is required to touch up any damaged paint and provide the Government with a color code, manufacturer, and specification for the paint that was used.

PART 3 EXECUTION

3.1 BUS DESIGN

3.1.1 General

Unless otherwise specified, execution of the electrical work shall be in accordance with the National Electric Code, NFPA 70 and the National Electrical Safety Code, IEEE C2 .

3.1.2 Coordination

The Contractor shall coordinate with the manufacturers of the bus and all interfacing equipment for the exchange of all the dimensions, necessary drawings, templates, gauges, and other information required to ensure the complete and proper design and manufacture of all connecting or related parts. The bus manufacturers shall also field verify all dimensions and details of the existing bus associated with the system electrical reconfiguration shown to develop the bus design.

3.2 FACTORY INSPECTION AND TESTS

3.2.1 General

All tests required herein will be witnessed by the GQAR, unless waived in writing, and no equipment shall be shipped until it has been released for shipment by the Government. The Government shall be notified at least 4 weeks prior to testing if testing is in the US and at least 8 weeks prior to testing if testing is outside of the US so that arrangements can be made for the GQAR to be present at the tests. The Contractor shall furnish five (5)certified copies of the reports and data for all factory inspection and tests for approval. All test reports shall be signed by the manufacturer, and the reports of all tests made to be furnished under the contract shall be signed by the GQAR. The factory test data equipment and the test methods used shall conform to the applied requirement of ANSI, IEEE Standards and NEMA Publications and shall be subject to approval.

3.2.2 Metal-Enclosed Bus Design Tests

The metal-enclosed buses shall be subjected to design tests in accordance

SECTION 26 25 00.00 26 Page 7 with IEEE C37.23 , paragraph 6.2. Representative sections of the buses shall be design tested if the tests specified below have not been made previously. These tests shall not be required if satisfactory tests have previously been made on metal enclosed buses of the same design, construction and rating as that specified, in which case the Contractor shall furnish certified copies of these tests to prove adequacy of design. Tests shall be in accordance with IEEE C37.23 as follows:

a. Dielectric Tests, paragraph 6.2.1.

b. Rated Continuous Current Test, paragraph 6.2.2.

c. Momentary Withstand Current Test, paragraph 6.2.3.

d. Short-Time Withstand Current Test, paragraph 6.2.4.

e. Flame Resistance Tests, paragraphs 6.2.6 and 6.2.7.

3.2.3 Metal-Enclosed Bus Production and Field Tests

The metal-enclosed buses shall be subjected to production tests in accordance with IEEE C37.23 , paragraph 6.3 and the bus manufacturer's recommendations.

3.3 OPERATION AND MAINTENANCE MANUALS

Operation and Maintenance Manuals shall be prepared and submitted in accordance with Section 01 78 23 OPERATIONS AND MAINTENANCE DATA and Section 01 78 00 CLOSEOUT SUBMITTALS.

Bus torque specifications shall be included as part of the Operation and Maintenance Manuals.

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