PART 1- GENERAL

1.1    DESCRIPTION         

        A.     The switch shall consist of manually operated load interrupting, SF6 insulated, 600A rotary

                puffer switches and manually operated vacuum interrupter fault interrupting tap switches,

                electronically controlled. The switches shall be designated G&W Triad Series 2 (Model

                VTNI) incorporating internal ground switching for both the loadbreak and vacuum interrupter

                switch ways.

1.2    QUALITY ASSURANCE

        A.     Manufacturer Qualifications:  The chosen manufacturer shall have at least 20 years

                experience in manufacturing SF6 insulated medium voltage switchgear.  The manufacturer

                of the switches shall be completely and solely responsible for the performance of the load

                break switch and fault interrupter as well as the complete integrated assembly as rated.

        B.     The manufacturer shall furnish certification of ratings of the load break switch, fault

                interrupter and the integrated switch assembly upon request.

        C.     The switch shall comply with requirements of the latest revisions of applicable industry

                standards, including: 

                        (a)  IEEE C37.71, IEEE C37.74, IEEE C37.60, ANSI/IEEE 386, IEC 60265-1

        D.     The switch manufacturer shall be ISO 9001:2000 and ISO 14001:2004 certified.

1.3    DELIVERY, STORAGE, AND HANDLING

        A.     Load break switches and fault interrupters shall be shipped preassembled at the factory. 

                No field assembly shall be required.

        B.     The contractor, if applicable, shall handle, transfer and move the switches in accordance

                with manufacturer’s recommendations.

PART 2- PRODUCTS

2.1    SWITCH CONFIGURATION

        A.     Each switch shall be equipped with 3-phase load switch ways with integral ground position

                and 3-phase vacuum interrupter tapped way(s) with internal ground switch in series

                permitting positive visible break of all three phases, as indicated on the one-line diagram.

        B.     Switches shall be designed for front access to cables and operators or front/back access

                to cables and operators (four ways max.).

2.2    SWITCH CONSTRUCTION

        A.     General

                Switch contacts and cable entrance terminations shall be contained in a single welded mild

                steel tank with entrances internally connected by copper conductors.  Construction shall

                be a deadfront design.  Switches shall be shipped factory filled with SF6 gas conforming to

                ASTM D-2472.  Switch tanks shall be painted ASA70 light gray using a corrosion-resistant

                epoxy paint.

        B.     Load Break Puffer Switch

                Each switching way is to be equipped with an internally mounted operating mechanism

                capable of providing quick-make, quick-break operation in either switching direction.  The

                mechanism must be capable of delivering sufficient torque and shall be provided with

                latches for each position to assure load interrupting, fault closing and momentary ratings.  

                All switch positions are to be clearly identified, padlockable and adaptable to keylock

                schemes.  The operating mechanism shall be actuated from outside the switch tank with

                an operating handle.  The operating shaft shall be made of stainless steel providing

                maximum corrosion resistance.  A double "O" ring type operating shaft seal shall be used

                for a leak resistant, long life seal.  Switch contacts shall be of a rotary puffer design made

                with copper alloy contacts with silver plating to assure permanent, low contact resistance.  

                Each rotating contact simultaneously disengages from two fixed contacts, thus providing

                two break points per phase giving improved interrupting capability compared to single break

                contact systems.  Contact travel shall be 60 degrees to assure efficient arc extinction and

                a wide open contact gap.  Arcing is confined away from the main contact surfaces.  The

                stationary contacts shall be supported independent of the cable entrance bushings,

                eliminating possible misalignment.  Auxiliary blades used for load interruption are not

                acceptable.

        C.     Vacuum Interrupter

                The vacuum interrupter shall consist of vacuum bottles and a spring-assisted operating

                mechanism.  The mechanism used shall be designated "Model NI" for three phase

                operation.  The mechanism shall consist of three vacuum bottles mechanically linked to a

                single spring-assisted operating mechanism.  The vacuum interrupter operating mechanism

                shall consist of the support assembly, linkage, spring latch mechanism, and solenoid

                utilized for electronic tripping.  Maximum interrupting time shall be three cycles (50 msec).

                The movable contact shaft shall be flagged to indicate the contact position, open or closed.

                This contact position indicator shall be fully visible through viewing windows supplied in the

                switch tank.  Each tap phase is to be equipped with an individual 600A vacuum interrupter

                fully enclosed in an SF6 insulated switch tank.  Electrical opening shall be by a solenoid

                that is activated from sources external to the switch tank.  Reset or closing of the vacuum

                interrupter shall be mechanical with the use of an external operating handle.  The

                mechanical linkage assembly shall provide for a "trip-free" operation which allows the

                vacuum interrupter to interrupt independent of the operating handle.

2.3    DESIGN RATINGS

        A.     Load Break Switches

                The switch shall be rated: (choose appropriate column)

        B.     Vacuum Interrupters

                The vacuum interrupter assembly shall be rated: (choose appropriate column)

              ANSI C37.60 Fault Interrupting Duty

2.4    CABLE ENTRANCES

        A.     Load Break Puffer Switches

        Cable entrances shall be tested to IEEE 386 and be, as indicated on the switch drawing:

• ____ 600 amp G&W Quik-Change disconnectable apparatus bushing,
• ____ 600 amp Apparatus bushing,
• ____ 600 amp Universal bushing, or
• ____ 200 amp Deepwell bushing.

        B.     Vacuum Interrupters

        Cable entrances shall be tested to IEEE 386 and be, as indicated on the switch drawing:

• ____ 600 amp G&W Quik-Change disconnectable apparatus bushing,
• ____ 600 amp Apparatus bushing,
• ____ 600 amp Universal bushing, or
• ____ 200 amp Deepwell bushing.

2.5    VACUUM INTERRUPTER TRIP MODULE

        Trip modules shall be provided to sense load and fault current on each phase of the load tap

        circuits.) The trip modules shall be powered from the current transformers mounted inside the

        SF6 insulated switch tank.  No external power source shall be required for overcurrent protection.

        The trip modules shall monitor the current on the individual phases of the load tap circuits using

        input from the internal current transformers.  Electronic trip capability shall be selectable for each

        phase.  Temperature range shall be -40 degrees C to +65 degrees C.  Trip characteristics (TCC

        curves) shall be user selectable.  Maximum time for power up and ready-to-trip when closing on

        a circuit shall be ten percent of the trip time or 1/2 cycle, whichever is greater.  Trip selection

        may be made with the load taps energized.  Trip modules shall not require a computer or other

        external device for programming trip settings or other operational parameters.

        The vacuum interrupter control shall be designated as G&W Type 1.

2.6    FACTORY PRODUCTION TESTS

        The bulk SF6 gas supply and each individual switch shall be tested for moisture content.  Each

        individual switch shall undergo a mechanical operation check and a leak test.  The switch shall

        be factory filled with SF6 and AC hi-pot tested one minute phase-to-phase, phase-to-ground and

        across the open contacts.  Circuit resistance shall be checked on all ways.  Switches will be

        shipped factory filled with SF6 gas.  Tank shall be designed to withstand 15 psig internal

        pressure and an external pressure of 14 psig without affecting the performance of the switch.

2.7    STANDARD COMPONENTS

        The following shall be included as standard:

• Welded steel tank painted light gray with stainless steel and brass fasteners.
• Lifting provisions.
• Gas pressure gauge and fill valve.
• Grounding provisions for switch tank and all cable entrances.
• Stainless steel three line diagram and corrosion-resistant nameplates.
• Switch operating handle(s) with padlock provision. 
• Type 1 vacuum interrupter trip module. 

2.8    OPTIONS

        The following options shall be supplied: (check as appropriate)

• ____ 304 stainless steel tank.
• ____ 304 stainless steel enclosure.
• ____ Front/back access to cables and operators.
• ____ Temperature compensated gas density gauge.
• ____ Low pressure warning device.
• ____ SF6 density switch for SCADA or remote indication of SF6.
• ____ 4/0 brass ground lug(s).
• ____ Keylock provisions.
• ____ Keylocks to lock in open position.
• ____ 600 amp Apparatus Bushings.
• ____ 600 amp Universal Bushings.
• ____ Current transformers for load break ways.
• ____ Potential transformers for voltage monitoring and/or control power.
• ____ Automatic transfer control type ATC451-4.
• ____ Automatic transfer control type ATC101.
• ____ Motor actuators for remote switch operation.
• ____ Stationary switch control(s) for remote switch operation and SCADA integration.
• ____ DC portable switch controls for remote switch operation and SCADA integration.
• ____ Remote terminal units and communication packages for SCADA integration.
• ____ Operations counters.
• ____ Auxiliary switches for remote switch position indication.
• ____ Analog voltage sensors.
• ____ Digital voltage sensors.
• ____ Voltage indication panel(s).
• ____ Type 2 vacuum interrupter control including ground fault trip and time delay selector switches (three phase only).
• ____ Type 3 vacuum interrupter control including ground fault trip, inrush restraint, programmable vacuum fluorescent display (VFD) and RS232/485 port.
• ____ Type 4 vacuum interrupter control (same as Type 3 with laptop programming only).
• ____ External power / trip for vacuum interrupter control.
• ____ 20kA symmetrical interrupting rating.
• ____ Refill kit consisting of regulator, hose and SF6 bottle.

2.9    LABELING

        A.     Hazard Alerting Signs

                The exterior of the padmounted enclosure (if furnished) shall be provided with “Warning--

                Keep Out--Hazardous Voltage Inside--Can Shock, Burn, or Cause Death” signs.  Each unit

                of switchgear shall be provided with a “Danger--Hazardous Voltage--Failure to Follow These

                Instructions Will Likely Cause Shock, Burns, or Death” sign. The text shall further indicate

                that operating personnel must know and obey the employer’s work rules, know the hazards

                involved, and use proper protective equipment and tools to work on this equipment.  Each

                unit of switchgear shall be provided with a “Danger--Keep Away--Hazardous Voltage--Will

                Shock, Burn, or Cause Death” sign.

        B.     Nameplates, Ratings Labels, and Connection Diagrams

                Each unit of switchgear shall be provided with a nameplate indicating the manufacturer’s

                name, catalog number, model number, date of manufacture, and serial number.  Each unit

                of switchgear shall be provided with a ratings label indicating the following:  voltage rating;

                main bus continuous rating; short-circuit rating; fault interrupter ratings including

                interrupting and duty-cycle fault-closing; and load break switch ratings including duty-cycle

                fault-closing and short-time.