G & W Electric
ISO 9001: 2000 and 14001 Certified
More Information
Specifications
Literature
Ratings
Contact Principle
Automation
Accessories / Options
Drawings
   
     
Typical Specifications
Rotary Puffer, Vault GRAM-RP Switchgear
Three Position

 

PART 1- GENERAL

 

1.1    DESCRIPTION

 

        A.     The switch shall consist of manually operated load interrupting, SF6 insulated, 600A rotary                 puffer, three position 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 as rated.

        B.     The manufacturer shall furnish certification of ratings of the load break switch 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, 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 switched ways and 3-phase load

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

 

        B.     Switches shall be designed for, as indicated on the one-line diagram:

  • ____ Close-Open-Ground switching (GRAM style),
  • ____ Close-Open-Test Ground switching (TRAM style),
  • ____ Close-Open-Close switching (RAD/RAJ style), or
  • ____ Close-Open-Tie switching (RAC/RAL style).

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 for 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.

 

2.3    DESIGN RATINGS

 

        A.     Load Break Switches

                The switch shall be rated: (choose appropriate column)

 SELECTION OF RATINGS

IEEE/IEC

  Maximum Design Voltage, kV

15.5

27

38

  Impulse Level (BIL) Voltage, kV

110

125

150

  Continuous Current, Amperes

630

630

630

  Load break Current, Amperes

630

630

630

  One Minute Withstand (dry), AC kV

35

60

70

  Production Test Rating

34

40

50

  15 Minute Withstand, DC kV

53

78

103

  Momentary Current, kA, ASYM

32

32

32

  Fault-Close Current, kA, ASYM

32

32

32

  One Second Current, kA, SYM

20

20

20

  Mechanical Endurance, Operations

2000

2000

2000

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    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.

 

2.6    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.

2.7    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.

2.8    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.

 

 

 

 
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