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 load break and vacuum interrupter switch ways. The switch manufacturer shall be ISO 9001:2000 and ISO 14001 certified.

A. SWITCH CONFIGURATION
Each switch shall have:

_____ (Qty.) 3-phase load switch ways with integral ground position.

_____ (Qty.) 3-phase vacuum interrupter tapped way(s) with internal ground switch in series permitting positive visible break of all three phases.

Switches shall be designed for: (check)

_____ Front access to cables and operators.

_____ Front/back access to cables and operators (four ways max.).

B. SWITCH CONSTRUCTION
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.

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.

Vacuum Interrupters - 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.

C. DESIGN RATINGS AND STANDARDS
Load break Puffer Switches:
Switches shall be designed, tested and built per ANSI C37.72-1987 and IEC 265 standards. Certified test reports shall be provided. The switch shall be rated: (select column)

Vacuum Interrupters:
The vacuum interrupter shall be a non-reclosing, manual reset device incorporating vacuum bottles. It shall be designed, tested and built per application sections of ANSI C37.60-1981 and C37.72-1987. The vacuum interrupter assembly shall be rated: (select column)

*16kA and 20kA ratings available.

Total Number of Fault Interruptions: 116

E. CABLE ENTRANCES
Load break Puffer Switches:
Cable entrances shall be tested to ANSI/IEEE 386 and be one or more of the following: (check)

____ 600 amp Quik-Change disconnectable apparatus bushing

____ 600 amp Apparatus bushing

Vacuum Interrupters:
Cable entrances shall be tested to ANSI/IEEE 386 and be one or more of the following: (check)

____ 600 amp Quik-Change disconnectable apparatus bushing

____ 600 amp Apparatus bushing

____ 200 amp Deepwell bushing

F. 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.

G. 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.

H. 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 and end stops.

- Type 1 vacuum interrupter trip module. 

I. OPTIONAL COMPONENTS (check)
The following options shall be supplied:

___ Stainless steel tank.

___ Low pressure warning device.

___ SF6 density switch for SCADA or remote indication of dielectric.

___ 4/0 brass ground lug(s).

___ Parking stands.

___ Keylock provisions.

___ Current transformers (600:5) (500:1) (1000:1) on load break ways for current monitoring on automation schemes.

___ Automatic transfer control package for a maximum 5 seconds per mechanical switching operation.

___ 24VDC motor actuators.

___ Switch controllers.

___ Remote Terminal Units.

___ Auxiliary switches.

___ Analog voltage sensors.

___ Digital voltage sensors.

___ Type 2 trip modules including ground fault trip and time delay selector switches (three phase only).

___ Type 3 vacuum interrupter trip modules including programmable vacuum fluorescent display (VFD) and RS232/485 port.