TECHNICAL SPECIFICATIONS FOR

ISOLATED PHASE BUS DUCT

AZZ Bus Systems120 Aztec Drive

Richland, Mississippi 39218

Tel: +1.601.939.9191Fax: +1.601.420.8334

Email: marksamol@azz.comWebsite: www.azz.com

1.0 General:

2AZZ Inc. IPB2016-Rev 2

1.1 This specification provides for furnishing an Isolated Phase Bus system complete with accessories as per the Schedule of Equipment for connection between the generator and main step-up transformer. Taps shall be furnished from the main bus to:1.1.1 ( ) Unit Station Service Transformer(s)1.1.2 ( ) Potential Transformer Cubicles1.1.3 ( ) Generator Excitation Cubicle1.1.4 ( ) Other

1.2 The manufacturer’s proposal shall contain complete descriptions of all equipment to be furnished, unit pricing of all equipment, commercial terms and conditions of sale, detailed data sheets listing the design criteria and to include calculated results of the predicted performance of the Isolated Phase Bus while operating under the specified environmental conditions. Technical notes explaining the data sheets shall be supplied. The commercial terms and conditions shall contain the bus manufacturer’s standard engineering, manufacturing and shipping schedule along with rates for field service engineers. The proposal shall identify any and all exceptions taken to the specifications with a clear explanation as to why the exception was taken.

2.0 Standards and Codes:

2.1 All Isolated Phase Bus and accessories shall be built to meet or exceed requirements as listed in the latest edition of ANSI C37.23 “Switchgear Assemblies including Metal Enclosed Bus”.

3.0 Isolated Phase Bus Design Requirements:

3.1 The Isolated Phase bus shall be of the Electrically Continuous, Self-Cooled design. Bus sections shall be constructed in sections as long as practical for installation to reduce installation time.

3.2 The conductor shall be fabricated from high conductivity extruded aluminum tubes of a sufficient diameter and thickness to carry the specified continuous current without exceeding the allowable temperature rise as listed on the specification data sheet. At all field welded conductor splice joints, the conductor tube shall be factory prepared by beveling the ends of the tube and providing a backing ring to fit inside the tube to prevent any blow-through while welding. All conductor sections will be painted with flat black paint to aid in dissipation of heat.

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3.3 The enclosure shall be fabricated from high conductivity aluminum sheets and shall be of the necessary thickness to carry the enclosure currents without exceeding the allowable temperature rise as listed on the specification data sheet. All enclosure field splices shall provide sufficient space to allow proper welding of the conductor and shall have pre-rolled split weld-in-place covers. The enclosure interior shall be painted with a flat black paint to aid in the dissipation of heat. The enclosure exterior shall be painted with ANSI 61 enamel paint.

3.4 The insulators shall be wet process porcelain designed for the voltage and BIL level as specified on the specification data sheet. The insulators shall be grouped in sets and spaced along the bus at intervals to supply ample bracing for the short circuit currents as listed on the specification data sheets. The bus shall be so designed where individual insulators may be removed for maintenance without disturbing the conductor or any other insulator.

3.5 In the event that bolted covers must be used, bonding straps of sufficient size to carry the full enclosure currents shall be furnished.

3.6 Expansion Joints shall be supplied where necessary to prevent undue stress on any components of the bus system due to expansion or contraction.

3.7 Terminations of the bus enclosure to the equipment shall be accomplished with flexible insulating bellows to reduce vibration, stress, loading of equipment enclosures, and to reduce induced currents in the equipment. Termination of the bus conductors shall be accomplished with silver plated extra flexible connectors.

3.8 Bonding bars or plates shall be supplied to bond between the enclosure phases at each equipment termination. The bonding bars shall be of sufficient cross sectional area to carry the enclosure current without exceeding the specified allowable enclosure temperature rise. The bus enclosure ends shall be insulated from the equipment flanges with insulating bellows to reduce induced currents in the equipment. Each enclosure bonding locations shall have provisions for attaching grounding.

3.9 Connections of the isolated phase bus to all transformers shall be performed with flexible connectors of sufficient length to provide a minimum of 12” clearance between the bus spades and the transformer spades when the connectors are removed to facilitate testing of the transformers.

3.10 The bus manufacturer shall coordinate the bus connections to the equipment connections from drawings to be supplied by the purchaser.

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3.11 Termination compartments constructed of aluminum and at locations as indicated on the drawings shall be furnished by the bus manufacturer. These compartments shall have removable bolted covers to provide ample access to the equipment terminations for installation and removable of the flexible connectors.

3.12 Wall seal assemblies shall be provided where the bus penetrates an indoor to outdoor wall. The seal assemblies shall be fabricated from aluminum and must be complete to include seal-off bushings in the enclosure-conductor annulus. The seal assembly shall be designed to prevent the seal assembly from supporting of any of the bus weight. This seal assembly shall be insulated from the bus enclosure to prevent grounding at this point. Seal-off bushings shall be supplied in each phase at each equipment termination.

3.13 Custom tee-taps and elbows are available as required.

3.14 All current carrying contact surfaces shall be silver-plated.

3.15 All bus bolting hardware shall be zinc dichromate plated steel. All conductor bolted joints shall be silver-plated and incorporate spring washers.

3.16 Design tests shall consist of Basic Impulse Level test, Temperature Rise test and Momentary Short Circuit test. Should the bus manufacturer have existing test reports on the bus of a design similar to the bus as covered by these specifications, and where interpolations may be used to justify the design submitted by the bus manufacturer, it shall be the purchaser’s option to waiver actual test on this specific design. Design test on the specific bus as covered by these specifications shall be quoted as an option.

3.17 Production test shall consist of a factory Power Frequency Withstand test and shall be performed on each and every section of bus manufactured under these specifications.

3.18 The bus manufacturer shall supply all bus supporting members, unless directed otherwise by purchaser. Indoor bus shall be supported from the ceiling beams with trapeze hangers. The trapeze shall be complete to include steel hanger beams and crossbeams, hanger brackets and bolting hardware. The trapeze shall be painted with enamel. Outdoor bus shall be supported with two or more steel column supports. The column type supports shall be fabricated from steel and hot dipped galvanized after fabrication. All bolting hardware to include anchor bolts and shall be furnished for the outdoor supports and shall be hot dipped galvanized.

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3.19 Potential Transformer and Surge Protection Cubicles shall be supplied by the bus manufacturer. The cubicles shall be constructed from 11-gauge steel or aluminum and shall be free standing, base mounted. Each phase cubicle shall contain a rear entry compartment, which will house the cubicle main bus surge arrestor and surge capacitor. This compartment shall have rear bolted covers for full access to the components. The cubicle main bus shall be copper and have a continuous current rating and short circuit current rating as shown on the specification data sheet. Each P.T. Compartment shall be equipped with disconnect/grounding switches, interlocked hinged doors, draw-out trays, primary and secondary fuses and current limiting resistors, if required. The cubicles shall be painted ANSI 61.

3.20 A Neutral Grounding Cubicle shall be supplied by the bus manufacturer. The cubicle shall be constructed for ( ) Indoor or ( ) Outdoor use. The cubicle shall contain a dry type distribution transformer, resistor bank and other items as required by the specification data sheet. The cubicle shall be painted ANSI 61.

4.0 Specification Data Sheet:

4.1 BUS SYSTEM:4.1.1 Bus System Type Electrically Continuous4.1.2 Bus System Rated Voltage _________kV4.1.3 Bus System Operating Voltage _________kV4.1.4 Bus System Frequency _________Hz4.1.5 Basic Impulse Level _________kV

4.2 AMPACITIES:4.2.1 Main Bus Ampacity _________Amps4.2.2 Delta Bus Ampacity _________Amps4.2.3 Auxiliary Transformer Bus Ampacity _________Amps4.2.4 Potential XFMR/Surge Bus Ampacity _________Amps4.2.5 Excitation Bus Ampacity _________Amps4.2.6 Neutral Grounding Bus Ampacity _________Amps

4.3 SHORT CIRCUIT CURRENT:4.3.1 Main Bus (rms Asymm) _________kA4.3.2 Delta Bus (rms Asymm) _________kA4.3.3 Auxiliary Transformer (rms Asymm) _________kA4.3.4 Potential XFMR/Surge Bus (rms Asymm) _________kA4.3.5 Excitation Bus (rms Asymm) _________kA4.3.6 Neutral Grounding bus (rms Asymm) _________kA

4.4 ENVIRONMENTAL PARAMETERS:4.4.1 Ambient Temperature _________°C4.4.2 Max. Conductor Temp. Rise _________°C

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4.4.3 Max. Enclosure Temp. Rise _________°C4.4.4 Solar Radiation

4.4.4.1 Already accounted for in Ambient, Rise or Ampacities listed above ( )4.4.4.2 Solar compensate per ANSI C37.24, for Site location ( )

4.4.5 Site Elevation above Sea level _________Ft

4.5 P.T./SURGE PROTECION CUBICLES:4.5.1 Potential Transformers

4.5.1.1 Primary Voltage _________kV4.5.1.2 Secondary Voltage _________Volts4.5.1.3 Frequency _________Hz4.5.1.4 Basic Impulse Level _________kV4.5.1.5 Power Rating _________VA4.5.1.6 Accuracy ____________________________

4.5.2 Surge Capacitor4.5.2.1 Voltage Rating _________kV4.5.2.2 Capacitance (microfarads) _________

4.5.3 Surge Arrestor _________kV

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