G & W Electric
ISO 9001: 2000 and 14001 Certified
Overview
Padmount Switchgear
Vault Switchgear
Overhead Switchgear
Reclosers
Automation Products
Current Limiting System Protection
Cable Accessories
Junction Bars
   
     

Typical Specifications
Trident® Solid Dielectric Switchgear

 

PART 1- GENERAL

 

1.1    DESCRIPTION

 

        A.     This specification covers the requirements for solid dielectric, load break switches and fault

                interrupters for distribution systems through 27kV.  They shall be manufactured by G&W

                Electric Co. and designated as Trident® Series.

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 C37.72, 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.     Switches shall be Padmount style with mild steel enclosure; Padmount style with

                stainless steel enclosure; Vault style, nonsubmersible control enclosures, if required; or

                Vault style, submersible control enclosures, if required, as indicated on the one-line

                diagram.

 

        B.     Two-Way (using one module) shall consist of single phase, load break; single phase, fault

                interrupter; three phase, load break; or three phase, fault interrupter, as indicated on the

                one-line diagram.

 

        C.     Multi-Way (using two through six modules) shall consist of three phase load break

                modules and three phase fault interrupter modules, as indicated on the one-line diagram.

 

2.2    SWITCH CONSTRUCTION

 

        A.     General

                Assembly shall be a deadfront design.  The operating mechanism housing shall be

                stainless steel with a viewing window for verification of contact position.  The housing shall

                be painted ANSI 70 light gray using corrosion-resistant epoxy paint.  Operating handles

                shall be padlockable and adaptable to keylock schemes.  The operating shaft shall be

                stainless steel providing maximum corrosion resistance.  A double “O” ring shaft seal shall

                be used for a leak resistant, long life seal.

 

        B.     Load Break Switches

                The load break switch shall consist of vacuum bottle(s) encapsulated within solid dielectric

                epoxy modules with spring-assisted operating mechanism.  For three phase switches the

                mechanism shall consist of three vacuum bottles mechanically linked to a single, spring-

                assisted operating mechanism.  The operating mechanism shall be actuated from outside

                the mechanism housing.

 

        C.     Fused Load Break Switches

                The fused load break switch shall consist of a load break switch (described above) with

                provisions for elbow mounted encapsulated fuses.  Parking stands shall be available as an

                accessory.  An optional interlock shall be available to prevent access to the fuses unless

                the switch is open.  Fuses shall be current limiting with epoxy insulation and an integral

                600A elbow (T body) connector for connection to the switch.  The load side of the fuse shall

                be either a 200A deepwell or 600A apparatus ANSI/IEEE 386 separable connector

                interface.

 

        D.     Fault Interrupter

                The fault interrupter shall consist of vacuum bottle(s) and internal current transformer(s)

                encapsulated within solid dielectric epoxy modules with spring-assisted operating

                mechanism.  For three phase interrupters, the mechanism shall consist of three vacuum

                bottles mechanically linked to a single spring-assisted operating mechanism.  Electrical

                opening shall be by a solenoid that is activated from an interrupter relay.  Closing (reset) of

                the interrupter shall be mechanical with the use of an operating mechanism actuated from

                outside the mechanism housing.  The mechanical linkage assembly shall provide for a “trip-

                free” operation which allows the fault interrupter to operate independent of the operating

                handle.

 

2.3    DESIGN RATINGS

 

        A.     Load Break Switches

                The switch shall be rated (choose appropriate column):    

  SELECTION OF RATINGS

IEEE/IEC

  Voltage Class, kV

15

25

  Maximum Design Voltage, kV

15.5

27

  Impulse Level (BIL) Voltage, kV

110

125

  Continuous Current, Amperes

630

630

  Load break Current, Amperes

630

630

  One Minute Withstand (dry), AC kV

35

60

  Production Test Rating

34

40

  15 Minute Withstand, DC kV

53

78

  Momentary Current, kA, ASYM

20

20

  Fault-Close Current, kA, ASYM

20

20

  One Second Current, kA, SYM

12.5

12.5

  Mechanical Endurance, Operations

2000

2000

        B.     Fault Interrupters

                The fault interrupter shall be rated (choose appropriate column):

  SELECTION OF RATINGS

IEEE/IEC

  Voltage Class, kV

15

25

  Maximum Design Voltage, kV

15.5

27

  Impulse Level (BIL) Voltage, kV

110

125

  Continuous Current, Amperes

630

630

  Load break Current, Amperes

630

630

  One Minute Withstand (dry), AC kV

35

60

  Production Test Rating

34

40

  Symmetrical Interrupting Rating, kA

12.5

12.5

  Asymmetrical Interrupting Rating, kA

20

20

  Fault-Close Current, kA, SYM

12.5

12.5

  Mechanical Operations

2000

2000

        C.     Fuses

                The fuses shall be rated:

 SELECTION OF RATINGS

IEEE/IEC

Nominal Voltage, kV, Gnd-Y

Impulse Level (BIL) Voltage, kV

8.7/15

95

15/25

125

Continuous Current, Amperes

Load break Current, Amperes

One Minute AC Withstand, kV

Fifteen Minute DC Withstand, kV

Interrupting, Amperes, RMS, SYM

10-140

630

34

53

50k

10-25

630

40

78

50k

 

              ANSI C37.60 Fault Interrupting Duty

 

Percent of Maximum:

Interrupting Rating

Approx. Interrupting:

Current Amps

No. of Fault:

Interruptions

15-20%

2000

44

45-55%

6000

56

90-100%

12000

16

Total Number of Fault Interruptions: 116

 

2.4    BUSHINGS

 

        A.     Two-Way (using one module) 

                Bushings shall be integral to the switch module and designed and tested to IEEE 386.

                Bushings closest to the operating mechanism shall be 600 or 200 amp and bushings away

                from the operating mechanism shall be either 600 or 200 amp, as indicated on the switch

                drawing.

 

        B.     Multi-Way (two through six modules)

                Bushings shall be designed and tested to IEEE 386. Bushings shall be 600 amp or 200

                amp, as indicated on the switch drawing.

 

2.5    FAULT INTERRUPTER RELAY

        For fault interrupters, a relay shall monitor the current on each phase using the integral

        encapsulated current transformer(s).  The relay shall compare currents on each phase of the

        load circuits with pre-selected time current curves and cause the fault interrupters to interrupt the

        current at the appropriate time.  The relay shall be powered from the current transformers molded

        into the epoxy encapsulation.  No external power source shall be required for protection. 

 

2.6    PADMOUNT ENCLOSURE (if applicable)

        Enclosures shall be made of 12 gauge mild or stainless steel and manufactured to ANSI C37.72

        and C57.12.28 standards.  The enclosure shall be mounted independently to allow for easy

        removal for cable installation or future replacement.  Enclosures shall be tamper-resistant

        incorporating hinged access door(s) with pentahead locking bolt(s) and provisions for

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

        7.0GY3.29/1.5 green finish.

 

2.7    FACTORY PRODUCTION TESTS

        Each assembly shall undergo a mechanical operations check, a one minute phase-to-phase,

        phase-to-ground and across the open contact AC hi-pot test.  Circuit resistance shall be

        checked on all ways.  Each module shall undergo an X-ray inspection and a partial discharge

        test to ensure void-free construction.

 

2.8    STANDARD COMPONENTS

        The following shall be included as standard:

  • Welded stainless steel mechanism housing painted light gray with stainless steel and brass fasteners.
  • Lifting provisions.
  • Corrosion-resistant nameplates and line diagram.
  • Switch operating mechanism(s) with padlock provision and single keylock provision.
  • Mounting provisions.
  • Ground provisions (1/2-13 threaded boss).
  • For padmount switches:  Padmount enclosure (see section 8). 

2.9    OPTIONS (included in catalog number)

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

  • ____ Auxiliary contacts installed on spring operating mechanism.
  • ____ Stationary mounted motor actuator with auxiliary contacts installed on spring operating mechanism.                                                                              
  • ____ Single way, stationary motor control.
  • ____ Multi-way, stationary motor control (not available on two way switches).
  • ____ Type 1 interrupter relay.
  • ____ Type 2 interrupter relay.
  • ____ Type 3 interrupter relay.
  • ____ Type 4 interrupter relay.
  • ____ Provision for Type 5 interrupter relay.
  • ____ Type 6 interrupter relay.
  • ____ Type 7 interrupter relay.

2.10 ACCESSORIES (additional items)

        The following accessories shall be supplied: (check all that apply)

  • ____ 4/0 brass ground lug(s).
  • ____ Portable motor control.
  • ____ Remote terminal units.
  • ____ Junction box for connection of remote power/remote trip or auxiliary contacts.
  • ____ Digital voltage sensors.
  • ____ Galvanized frame (24” high bushing height)
  • ____ Laptop programming kit for Types 3, 4 and 7 relays.
  • ____ Parking stands for each phase.
  • ____ Type 5 oil fuse cutout interrupter relay.
  • ____ Removable operating handle.

2.11  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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