Typical Specifications
Padmount Linear Puffer SPRAM/PRAM Switchgear
Two Position

PART 1- GENERAL

1.1    DESCRIPTION

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

                linear puffer switches.

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 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 C37.72, IEEE C37.74, 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 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 and 3-phase load

                unswitched ways, as indicated on the one-line diagram.

        B.     Switches shall be configured as front access with diagonal bushings (SPRAM-F style),

                front access with in-line bushings (PRAM-F style), or front/back access with in-line

                bushings (PRAM-L style), as indicated.

2.2    SWITCH CONSTRUCTION

        A.     General

                All switch components and entrances shall be assembled in a totally welded mild steel

                tank.  Entrances shall be internally connected by copper conductors capable of handling

                momentary and continuous current duty.  The switch shall contain no electrically floating

                metallic parts or components.  Construction shall be a deadfront design.  Switch tanks

                shall be painted ASA70 light gray using a corrosion-resistant epoxy paint.

        B.     Load Break 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 a tulip-bayonet design and

                made of plated, high-conductivity copper alloy with arcing tips of copper/tungsten alloy to

                assure permanent low resistance and to avoid sticking during operation.  The contacts

                shall be designed such that arcing does not occur in the area of main current interchange

                and contact pressure will increase with increased current flow.  The stationary contacts

                shall be supported independent of the cable entrance bushings, eliminating possible

                misalignment.  The contact nozzle shall have a converging/diverging geometry which

                improves the flow of SF6 into the arc zone.  Contact travel shall be a minimum of 3 inches

                and have sufficient open contact separation to assure efficient arc extinction and to

                withstand field DC testing levels and maintain BIL levels.  Switch contacts shall be clearly

                visible in the open position through viewing windows.  Auxiliary blades used for load

                interruption are not acceptable.

2.3    DESIGN RATINGS

        A.     Load Break Switches

                The switch shall be rated: (choose appropriate column)    

2.4    CABLE ENTRANCES

        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    ENCLOSURE

        Enclosures shall be made of 12 gauge galvanized steel and manufactured to ANSI C37.72 and

        C57.12.28 standards.  The enclosure shall be mounted independent of the switch allowing

        removal for ease of cable installation or future replacement if required.  Enclosures shall be

        tamper-resistant incorporating hinged access doors with pentahead locking bolts and provisions

        for padlocking.  The enclosure shall be provided with lifting provisions and painted with a

        Munsell 7.0GY3.29/1.5 green finish.

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.
• Parking stands.
• Switch operating handle(s) with padlock provision and end stops.
• 12 gauge galvainized steel padmount enclosure painted Munsell green with stainless steel hinges and pentahead locking mechanisms.

2.8    OPTIONS

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

• ____ 304 stainless steel tank.
• ____ 304 stainless steel enclosure.
• ____ 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).
• ____ 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.