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1 SF IAS Electrical Design Seminar April , 2011 Medium Voltage Switchgear MV MetalClad Switchgear Still The Best MV Solution Gary H. Fox, PE GE Energy Senior Specification Engineer T 925 969 3608 C 510 219 6868 E [email protected] www.geindustrial.com/design 2120 Diamond Blvd., Suite 100 Concord, CA 94520 General Electric Company San Francisco IEEE / IAS Electrical Design and Applications Seminar April 29,2011

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1SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

MV MetalClad Switchgear

Still The BestMV Solution

Gary H. Fox, PEGE EnergySenior Specification Engineer

T 925 969 3608C 510 219 6868E [email protected]/design

2120 Diamond Blvd., Suite 100Concord, CA 94520General Electric Company

San Francisco IEEE / IAS Electrical Design and Applications Seminar

April 29,2011

2SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

SAFETY FEATURESDEAD FRONT CONSTRUCTION CLOSED DOOR RACKINGREMOTE BREAKER RACKING & CONTROL AVAILABLEPT & CPT ROLLOUT TRAYSBREAKERS CANNOT RACK IN/OUT IF CLOSEDCANNOT CLOSE BREAKERS IF NOT FULLY RACKED INSPRINGS DISCHARGE WHEN BREAKER IS MOVEDMECHANICALLY INTERLOCKED SHUTTERSGROUND & TEST DEVICES AVAILABLESAFE AUXILIARY SECONDARY FUSES ACCESSIBILITYEXTERNAL BREAKER POSITION INDICATORFULLY ISOLATED 2-HIGH CABLE COMPARTMENTS

3SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

MetalClad Switchgear & Breakers:ANSI C37.04 - AC Power Circuit Breaker rating Structure

ANSI C37.06 - 1987 & 2000* - Preferred Ratings of Power Circuit Breakers

ANSI C37.09 - Test Procedures for Power Circuit breakers

ANSI C37.54 – Conformance Test Procedures

ANSI C37.010 – Application Guide for Power Circuit Breakers

ANSI C37.11 – Power Circuit Breaker Control Requirements

ANSI C37.20.2 – Standards for Switchgear Assemblies

NEMA SG-4 & 5 - Power Circuit Breakers & Switchgear Assemblies

Optional: UL & CSA Listing

*Why is there two years??

Codes & Standards

4SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

ANSI C37.06-1987

5SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

ANSI C37.06-2000

6SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

Voltage - 1.0 kV thru 15 kV Maximum

Nominal Voltage Classes

4160V, 7200V, 13800V

Short Circuit Current Ratings:

Nominal MVA Classes

4160-250MVA - 29KA (sym)

4160-350MVA - 41KA

4160-450MVA - 63KA*

7200-500MVA - 33KA

7200-785MVA - 63KA *

13800-500MVA - 18KA

13800-750MVA - 28KA

13800-1000MVA - 37KA

13800-1500MVA - 63KA*

Equipment & Breaker Ratings

Maximum KA Ratings (ANSI 2000)

4760-31.5KA (sym)

4760-40KA

4760-50KA

4760-63KA*

8250-40KA

8250-50KA*

8250-63KA*

15000-20KA

15000-25KA

15000-31.5KA

15000-40KA

15000-50KA

15000-63KA

* Exceed ANSI Preferred Ratings

7SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

•Vacuum interrupters first conceived in the 1920’s, manufacturing of Vacuum Breakers began in 1961•Vacuum breakers allowed 2-high drawout designs beginning in 1976

•5 Cycle (std) & 3 Cycle (optional)

Interrupting Speed Capability

•Reduced & Easier Maintenance Than Other Interrupting Designs, Such as SF6 & Air Magnetic

Vacuum Interrupter

8SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

VACUUM BREAKER CONSTRUCTION

CONTINUOUS CURRENT - 1200A thru 4000A (forced air)Modular Phase Interrupters - Simple ReplacementCopper Ground BarManual Trip/Close ButtonOperations CounterSpring Charge IndicatorRating Interference PlateWheels On Frame For MobilityContact Wear Indicator

Mechanism

Interrupter Assemblies

PrimaryDisconnects

FrontCover

SecondaryDisconnect

9SF IAS Electrical Design Seminar

April , 2011

Medium Voltage SwitchgearAll MetalClad meets Metal Enclosed, but Metal Enclosed gear does not meet MetalClad Requirements!

Metal Enclosed Switchgear (C37.20.3)Completely enclosedPrimary power circuit switching or interrupting devicesBusesConnectionsControl and auxiliary devices. Access provided by doors or removable covers, or both.

Metalclad Switchgear (C37.20.2)Main switching and interrupting device must be drawout. Circuit breaker (usual) or a load-break interrupter switch (unusual). Extensive barrieringShuttersAll live parts enclosed within grounded metal barriersInsulation-covered busAll compartments separated by metal barriers with no intentional openings.

10SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

And there’s more to C37.20.2!

Metal barrier in front of or part of switching device to ensure that no live parts are exposed when the outer cover is opened while in the connected position.Mechanical interlocks provided for proper operating sequence

> Prevent movement while closed> Prevent closing unless disconnects are fully engaged or at safe distance> Prevent disconnection and access to primary fuses on CPT unless secondary open> Stored energy mechanisms cannot be discharged unless fully charged> Complete withdrawal not permitted until closing mechanism is blocked> Automatic discharge of stored energy mechanism before or in process of removal

from housing> Provisions for locking to prevent moving into Connected position

11SF IAS Electrical Design Seminar

April , 2011

Medium Voltage SwitchgearSTANDARD Construction & Dimensions

• Typical Indoor

Dimensions:

95” H

36” W

94” D

•36” Width

Sections for Indoor

and Outdoor

CTs GSCT

Cable

Trough

Surge

Suppressors

Main Bus

Breakers

Front

Of

Gear

Standard 2-High Sideview

12SF IAS Electrical Design Seminar

April , 2011

Medium Voltage SwitchgearSWITCHGEAR CONSTRUCTION BASICS Separate Breaker, Bus, & Cable

Compartments, isolated with 11 gauge steel barriers.

Bolted Steel Frame Construction, with gusseted corners – very rigid, stable

NEMA 1 & 3R Construction Outdoor with or without aisle Closed Door Breaker Drawout 11 Gauge Steel Doors, (2) 14 Gauge

Panels Between Sections All steel is either Zinc plated, or

painted. No bare metal.

Main Bus CompartmentCable Compartments

Breaker Compartments

13SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

SWITCHGEAR BUS BASICS

1200, 2000, 3000, 3500 & 4000* AMPS. (* 4000A breaker section is fan cooled)

80KA Asym. Bracing, 130KA Peak, Std.6” Copper Bus Bars Full Tin Plate Standard, Silver Available.

Note Silver is used on all sliding contact surfaces.

All Phase Bus Fluidized Bed Epoxy Coated1/4” X 2” Ground Bus StandardPolyester-Glass Supports Standard,

Porcelain OptionalVinyl Boots With Nylon Hardware On JointsFully Isolated with 11-Gauge Steel

Riser Bus Main Horizontal Bus

Bus Boot

14SF IAS Electrical Design Seminar

April , 2011

Medium Voltage SwitchgearBREAKER/AUXILIARY COMPARTMENTSPolyester-Glass Primary Supports (std)Polyester-Glass or Steel Shutters,

Mechanically Interlocked With Racking Mechanism in Breaker CompartmentsMax of 4 CTs Per Phase, Per Breaker On

Primary SupportsPT/CPT, 4 Trays Per Section PT/CPT Primary Fuses are Inaccessible unless

Tray Is DisconnectedOpen / Close / Test Position IndicatorSecondary Disconnect Block

15SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

CABLE COMPARTMENT CONSTRUCTION

Provision For Cable, Bus Duct, Potheads or REBsNEMA Drilling For 2-750 MCM Per Phase With Space For Stress ConesSteel Isolation Trough For 2-High Breaker CablesFront to Rear Control Wire TroughMounting For Ground Sensor CT (GSCT) Arrestors, CPTS/CTS Surge Suppressors For Switching Transient Suppression on Feeders

16SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

Enclosures

IndoorIndoor Drip-proofOutdoor, No AisleOutdoor Protected AisleOutdoor Common AisleIndoor provided in Equipment Power CenterSite Specific Seismic Withstand Levels: Ss, Sds

17SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

Covers

Bolted rear covers with lifting handlesHinged rear coversProvisions for locks, rear and/or frontIR Scanning Ports on rear covers

18SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

Did YOU Notice that ALL MV breakers are electrically operated ???????Ac (120 V, 240 V) vs dc (48 V, 125 V)Trip and close circuits can be differentPG&E requirementsMicroprocessor based relays require control power

(ac not a good choice)Supplied from ??? CPTs – Line or bus connectedThrowover contactors on multiple mainsIntegral branch panels not necessary

19SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

Control Wire/ Terminations Options

Uninsulated spade, CT wiring with ring typeInsulated terminalsRing type for allOrigin/destination sleevesShort circuit type terminal blocks on CT

secondary

20SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

Circuit Breaker

5 cycle std3 cycleCapacitor Switching dutyAuxiliary Contacts (MOC)Position Switch (TOC)Control voltage

21SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

Copper Main Bus

Polyester bus supportsPorcelain supportsTin plated jointsSilver plated joints

22SF IAS Electrical Design Seminar

April , 2011

Medium Voltage Switchgear

Auxiliary Devices

Surge Arresters, Class, Rating or indicate system grounding method

Current Transformers, ratios and accuracyPotential TransformersProtective RelaysIndicating Lights: Incandescent, LEDInstrumentation & Power MeteringNetwork Gateways, SwitchesRemote Racking OperatorBreaker Test Cabinet (located external to switchgear)Ground and Test Device