gm38 switchgear - energy switchgear is designed for use in industrial plants, commercial buildings,...
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Power Transmission & Distribution
Selection and Application GuideE50001-U229-A320-X-US00
GM38 Switchgear38kV
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Table of Contents
Introduction . . . . . . . . . . . . . . . . .01–02
Overview . . . . . . . . . . . . . . . . . . . .03–05
Construction . . . . . . . . . . . . . . . . .06–11
Accessories . . . . . . . . . . . . . . . . . . . . .12
Protective Relays . . . . . . . . . . . . . . . . .13
Vacuum Circuit Breakers . . . . . . .14–20
Technical Data . . . . . . . . . . . . . . . .21–24
Dimensions . . . . . . . . . . . . . . . . . .25–28
Side Views . . . . . . . . . . . . . . . . . . . . . .29
Notes . . . . . . . . . . . . . . . . . . . . . . . . . .30
Siemens experience gained in over 80 years of supplying metal-cladswitchgear in the U.S. has been captured in the GM38 design. The objectivehas been to incorporate features designed to provide safety, while simplifyingoperation and maintenance, as well as minimizing installation cost.
GM38 switchgear is designed for use in industrial plants, commercialbuildings, electric utility systems, cogeneration installations, and otherelectrical systems.
GM38Medium Voltage Metal-Clad Switchgear
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Siemens GM38 38kV metal-clad power switchgearassemblies with horizontal drawout type 38-3AH3 vacuumcircuit breakers take advantage of the latest developmentsin vacuum interrupter technology.
Voltage transformers with their associated drawoutprimary fuses can be located in the cell above a 1200A or2000A circuit breaker, allowing significant space savings.Siemens introduced this feature to the 38kV switchgearmarket with the launch of the GM38 design in 1993.
The equipment meets or exceeds the latest standards ofANSI, IEEE, and NEMA.
GM38 switchgear is designed for use in industrial plants,commercial buildings, electric utility systems,cogeneration installations, and other electrical systems. Itis commonly used for protection and switching oftransformers, capacitors, buses, distribution feeder lines,and, in general, for protection of any medium voltagepower circuit.
Siemens experience gained in over 80 years of supplyingmetal-clad switchgear in the U.S. has been captured in theGM38 design. The objective has been to incorporatefeatures designed to provide safety, while simplifyingoperation, maintenance, and minimizing installation cost.
The switchgear structure and the drawout vacuum circuitbreaker are an integrated design, with dielectric, thermal,and interruption integrity built directly into the basicdesign, not added as an afterthought.
Siemens 3AH3 Operating MechanismThe 38-3AH3 circuit breaker uses the proven Siemens3AH3 stored-energy operating mechanism. This operatoris an evolution of the 3A family of operators firstintroduced in 1976. Over 60,000 3AH3 operatingmechanisms have been produced since 1998.
Faster InterruptionStandard interrupting time is 5-cycles with an optionavailable for 3-cycles.
Siemens Vacuum InterruptersThe vacuum interrupters used in the 3AH3 circuitbreaker are manufactured by Siemens and have beenproven in thousands of installations since 1976. Thechrome-copper contact design used in these interruptersassures low chopping levels, eliminating the need forsurge protection on most circuits.
Front Mounted Operating MechanismThe simple 3AH3 operating mechanism makesmaintenance and inspection easy. The mechanism islocated on the front of the circuit breaker, rather thanunderneath.
Maintenance IntervalsIf applied under ANSl "usual service" conditions,maintenance of the circuit breaker mechanism is onlyneeded at five year intervals.
Maintenance of the switchgear cubicle is recommendedat five year intervals, and primarily consists of cleaninginsulation.
Overview
Front Side (Barrier Removed) Rear
Figure 1: 38-3AH3 Circuit Breaker
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Floor RolloutNo lift truck or dolly is needed to insert or remove circuitbreakers or drawout fuse trucks in the lower cell ofswitchgear located at floor level. For indoor switchgearlocated on a raised “housekeeping” pad or for outdoor non-walk-in switchgear, a lift truck is required to handle circuitbreakers or drawout fuse trucks.
"Universal" Spare Breaker The physical configuration and interlock logic allow theuse of a single circuit breaker to serve as a "universal"spare breaker at an installation site. The interlock logicchecks the principal rating characteristics (continuouscurrent, maximum voltage, and interrupting current),and allows a circuit breaker to be inserted in any circuitbreaker cell, provided that the ratings of circuit breakerequal or exceed the ratings required by the cell.
Single Source ResponsibilitySingle source responsibility is assured since the completeequipment is designed by Siemens and is manufacturedand tested in a single facility. The vacuum circuitbreakers are checked in the switchgear cells as part ofproduction testing. After tests and interchangeabilitychecks, the circuit breakers are separately packed forshipment.
Full ANSI Design BackgroundFull design integrity is assured. ANSl C37.09 andC37.20.2 require design tests on circuit breakers andstructures together. The 3AH3 operator is produced inour global center of competence for circuit breakers inBerlin, and final assembly of both the drawout 38-3AH3circuit breaker and the switchgear structures occurs in asingle facility. Siemens controls the entire process, fromdesign concept to production. Records are maintained toand production is certified to ISO 9001 requirementsdocument compliance with ANSl standards.
UL or C-UL Listing Available (40kA only)Where the arrangement of components allows, UL orC-UL Listing is available.
Quality SystemsFacilities involved with application, engineering, designand production are certified to ISO 9001 requirements.
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Figure 2: Circuit Breaker Cell (1200A or 2000A) with VTAuxiliary (3000A Similar Except Upper Cell Reserved forFan-Cooling Equipment)
Structural FlexibilitySiemens GM38 metal-clad switchgear provides enhancedflexibility in locating circuit breaker, auxiliary, andmetering cells within the structure layout. Circuit breakersare located in the lower cell positions. The upper cellposition can be used for voltage transformers with theassociated drawout primary fuses.
Each vertical section contains the main bus barcompartment plus a rear compartment for incoming andoutgoing connections. The front portion of the verticalsection contains an upper cell for auxiliary devices,voltage transformers, or drawout primary fuses for acontrol power transformer located in the lower cell.
The front portion of the vertical section contains a lower cellfor circuit breaker, auxiliary devices, voltage transformers,control power transformer (if primary fuses are located inupper cell), or drawout primary fuses for a control powertransformer located in the rear of the section.
Circuit breaker cells include primary and secondarydisconnects, current transformers, and secondary wiring, asnecessary. Instruments, relays, and power meters alongwith their secondary wiring and other components arelocated in the upper cell. The switchgear is normallydesigned so that additional vertical sections may be addedin the future.
Enclosure DesignThe GM38 design includes full ANSI/IEEE C37.20.2 Metal-Cladconstruction. This means complete enclosure of all live partsand separation of major portions of the circuit to retard thespread of faults to other compartments. Removable platespermit access to all compartments. The rear panels areremovable to allow access to outgoing cable connections.
The structure is constructed of bolted steel for betterdimensional control than with welded designs. Sheet steelinter-unit barriers extend the full height and depth of eachvertical section for isolating adjacent sections. The ground busextends the entire length of the complete switchgear lineup,and to each circuit breaker cell.
Circuit Breaker InterchangeabilityThe GM38 switchgear cubicle and the drawout 38-3AH3circuit breaker element are both built to master fixtures socircuit breakers of the same ratings are interchangeablewith each other even if the circuit breaker is required foruse with a cell with "provisions only" supplied yearsearlier. The 38-3AH3 circuit breaker is interchangeablewith the 38-3AF circuit breaker, provided that the ratingsare equal. The 38-3AF circuit breaker is notinterchangeable with the 40kA 38-3AH3.
A circuit breaker of higher rating can be used in a cell ofequal or lower rating, i.e., a 2000A 40kA 38-3AH3 circuitbreaker can be used in a 1200A 31.5kA 38-3AH3 or 38-3AF circuit breaker cell.
Tested to ANSl/IEEE StandardsSiemens GM38 switchgear is tested to meet therequirements of ANSl/IEEE standards. A complete design testprogram, including short circuit interruption, load currentswitching, continuous current, mechanical endurance, closeand latch current, short time and momentary withstand,impulse withstand, and the other tests required by thestandards, has been successfully completed.
These tests encompass the complete equipment design,including both the switchgear structure and the circuitbreaker removable element. Production tests in accordancewith ANSl/IEEE standards are performed on every group ofswitchgear and on each circuit breaker. Certified copies oftest data can be furnished to customers upon request.
The switchgear is not classified as arc-resistantswitchgear, and has not been tested for resistance tointernal arcing per IEEE C37.20.7. Qualification to seismicrequirements of various codes (e.g., IBC-2006, UBC, IEEE693, etc.) is available. Consult Siemens with detailedrequirements.
UL or C-UL Listing AvailableWhen specified, if the component configuration allows, theswitchgear rated 40kA can be provided with the UL or C-UL(for use in Canada) listed label, indicating conformance tothe requirements of ANSl C37.54 and ANSI C37.55.
Overview
A. Drawout primary CL fuses forVT’s
B. Voltage transformers (stationary)
C. Upper door for relays,instruments, etc.
D. 38-3AH3 vacuum circuit breaker
E. Lower door (blank)F. Copper main bus 1200A,
2000A, or 3000A self-cooledG. Power cable termination areaH. Current transformers
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D
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Construction
Switchgear CompartmentsVacuum Circuit Breaker CellThe circuit breaker cell is a bolted, reinforced sheet steelenclosure, with provisions for a type 38-3AH3 vacuumcircuit breaker. It includes a hinged front door, inter-compartment and inter-unit barriers, primary andsecondary disconnects, racking mechanism, interlocks,and current transformers, as required by the application.
Vacuum Circuit Breaker ElementThe 38-3AH3 vacuum circuit breaker includes a storedenergy operating mechanism, primary and secondarydisconnects, auxiliary switch, ground contact, controlwiring, and interlocks.
Auxiliary CellAn auxiliary cell is similar to a circuit breaker cell, exceptwithout provisions for a circuit breaker. Space may be usedfor VTs, a CPT, drawout primary fuses, or other auxiliarydevices. Opening of the front door does not automaticallydisconnect a drawout primary fuse truck located inside thecell. Instruments and relays can be located on the frontdoor of an auxiliary cell.
Bus Compartment The bus compartment is a separately enclosed space forthree-phase insulated main power bus bars, supports,and connections to circuit breaker cells.
Primary Termination CompartmentThe rear area of the unit includes space for connectingincoming or outgoing power cables, bus duct connections,transformer connections, or surge protection devices.
Figure 3: Two Views of Same Circuit Breaker Cell Interior
A. Shutter operatinglinkage
B. ShuttersC. Racking
mechanismpadlockprovisions
D. Primarydisconnects(behind shutters)
E. MOC mechanism-operated cellswitch (optional)
F. Currenttransformers(behind barrier)
G. Secondarydisconnect
H. Trip-free padlockprovisions
I. Currenttransformerbarrier
J. Rackingmechanism
K. Ground barL. Rating interlocks
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B
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Circuit Breaker Cell Features Vacuum Circuit Breaker CellA circuit breaker cell consists of a bolted, reinforced sheetsteel enclosure, with provisions for a 38-3AH3 vacuumcircuit breaker. The cell includes a blank hinged front door,inter-compartment and inter-unit barriers, stationaryprimary and secondary disconnects, automatic shutters,drawout guide rails, circuit breaker racking mechanism, andnecessary interlocks. Control wiring, terminal blocks, andcurrent transformers are provided as needed for theapplication. Instruments and relays are mounted as neededon the front panel of the upper cell. Secondary controlcircuit cutouts are located inside the upper cell.
Floor RolloutCircuit breakers in the lower cell can be rolled out directly onthe floor in front of the unit, without a handling device, lifttruck, or hoist for indoor (if not on raised “housekeeping”pad) and Shelter-Clad installations. A lift truck accessory isoptionally available for handling drawout primary fusetrucks in upper cells, or circuit breakers in non-walk-inoutdoor enclosures.
Closed Door Circuit Breaker RackingThe circuit breaker can be racked in or out with the celldoor open or closed. The mechanism includes anindicator to show the racking mechanism position withthe door closed. For racking, a manual drive crank or anoptional electric motor drive may be used.
Electrical Racking Accessory (Optional)An electrical racking motor accessory is available. Thisconsists of a motor drive assembly, which installs(without tools) on mounting brackets on the switchgearfront panel of a circuit breaker compartment. The unitincludes a power cord, which can be plugged into aduplex receptacle in the vicinity of the switchgear, plus acontrol cable, which allows the operator to control theracking operation from a distance. An alternativearrangement is available, which includes a control boxthat can be mounted at a distance from the switchgearand permanently connected to control power. In turn,the racking motor can be connected to the control boxwith a long cord.
InterlocksInterlocks prevent moving a closed circuit breaker in thecell by preventing engagement of the racking crank (orelectric racking accessory) if the circuit breaker is closed.A second interlock lever holds the circuit breakermechanically and electrically trip-free betweenpositions. The racking mechanism can be padlocked torestrict unauthorized racking of the circuit breaker.Separate padlock provisions may be used to hold thecircuit breaker in the trip-free condition.
Automatic ShuttersAutomatically operated grounded steel shutters allow orblock access to the stationary primary disconnects in circuitbreaker cells. The shutters are opened by the circuit breaker
Construction
Figure 4: Circuit Breaker Being Racked Out with DoorClosed (Person Shown for Illustrative Purposes Only -Comply with NFPA 70E Electrical Safety Requirements)
Figure 5: Electrical Racking Accessory Mounted on theSwitchgear
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Construction
as it moves toward the connected position. The shuttersclose as the circuit breaker is racked away from theconnected position to the test position. The shutters remainclosed until they are forced open by insertion of the circuitbreaker. This design enhances protection for personnel, ascompared to shutters which link to the racking mechanism.
Current Transformers Front-access current transformers may be mountedaround both the upper and lower stationary primarydisconnect bushings. Up to a total of four currenttransformers per phase may be located in each circuitbreaker cell, two on the bus side and two on the loadside, around the primary disconnect bushings. Thecurrent transformers may be standard accuracy (typeMD38) or optional special accuracy (type MDD38).
WiringSecondary wiring is neatly bundled and secured on thesides of the cell. Wiring is not routed on the floor of theswitchgear.
Primary DisconnectsThe cubicle stationary primary disconnect contacts arerecessed inside the insulator assemblies, and are locatedbehind grounded steel shutters to prevent accidentalcontact when the circuit breaker is withdrawn. Theprimary disconnect finger clusters are mounted on thecircuit breaker, for ease of inspection.
Secondary DisconnectsThe cubicle mounted stationary disconnect contacts matewith spring loaded secondary contacts on top of the circuitbreaker. The secondary disconnects automatically engagein both the test and connected positions, and they remainengaged between these positions.
Mechanism Operated Cell (MOC) Switch When required, up to 24 stages of the MOC auxiliaryswitch can be mounted in the circuit breaker cell. All spareMOC contacts are wired to accessible terminal blocks foruser connections. As standard, these MOC switches areoperated only when the circuit breaker is in the connectedposition. Optionally, they may be arranged to operate inboth the connected and test positions.
Truck Operated Cell (TOC) SwitchWhen required, up to 12 stages of TOC switch can bemounted in the circuit breaker cell. All spare TOC contactsare wired to accessible terminal blocks for user connections.
Unobstructed Terminal Block SpaceTerminal block areas are located on each side of circuitbreaker or auxiliary cells. Since racking systemcomponents are not mounted on the cubicle sides, theside-mounted terminal blocks are not obstructed as in
other designs. Installation of field wiring is simplified, aswiring can be easily laid directly against the side sheets.It is not necessary to "fish" the wiring under, around, andthrough obstructions.
Auxiliary CellsAuxiliary cells are constructed in a similar manner as thecircuit breaker cells, except without provisions for a circuitbreaker element. Auxiliary cells may be located in theupper cell or lower cell of a vertical section.
The front door panels may be used to mount meters,relays, or other instrumentation. The interior portion ofthe cell may be used for mounting devices, such as voltagetransformers, control power transformer (lower cell only),automatic transfer switches, or other auxiliary devices.
For ease in operation, primary current limiting fuses forcontrol power transformers and voltage transformers arearranged in a drawout configuration, while the heavytransformers are stationary. This greatly reduces the effortrequired to isolate transformers for inspection ormaintenance. The racking mechanism for the drawoutfuse truck is manually operated with the compartmentdoor open, but it is otherwise similar to the circuit breakerracking mechanism.
Auxiliary Cell Relay & Instrument SpaceThe front panel of auxiliary cells is suitable for mounting ofdevices. Even if the auxiliary cell contains rollout traydevices (rollout fuses for VTs or CPT), the space availableallows for mounting any of the devices commonlyspecified for use on metal-clad switchgear.
Figure 6: Auxiliary Cells
A. For VT’s or rollout fuses for CPTlocated in lower cell, or for fan if3000A circuit breaker in lower cell
B. For circuit breaker, VT’s, rolloutfuses for CPT located in rear orremote, or CPT when rollout fuseslocated in upper cell
A
B
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Voltage TransformersUp to three voltage transformers with their drawoutmounted current limiting fuses may be mounted in anauxiliary cell. VTs can be accommodated in the upper cellabove a circuit breaker, or in either the upper or lower cellsof a section which does not have a circuit breaker cell.
When the drawout fuses are moved to the disconnectposition, they are automatically disconnected, and thetransformer windings are grounded to remove any staticcharge. A insulating shutter is provided, arranged tooperate before primary fuses become accessible forinspection or removal.
Control Power TransformersControl power transformers can be accommodated in eitherof two manners. For single phase and small three-phasetransformers, the primary drawout fuses can be located inthe upper auxiliary cell of a vertical section, and the fixedmounted control power transformer can be located in thelower front cell of the same vertical section.
Alternatively, the primary drawout fuses can be located inthe lower auxiliary cell of a vertical section, and the fixedmounted control power transformer can be located in therear of the section.
The secondary molded case breaker is interlocked with thedrawout primary fuses so that the secondary breaker mustbe open before the control power transformer primary canbe disconnected or connected.
This prevents accidental load current interruption on themain primary contacts. With the secondary molded casebreaker open and the latch released, the primary fuse truckcan be moved easily to the disconnect position. Theoperation of the drawout fuse truck and insulating shutter issimilar to that for the VTs.
Current TransformersSiemens torroidal current transformers comply withANSI/IEEE standards, and are mounted at the rear of thecircuit breaker cell. Up to four standard accuracy typeMD38 or special accuracy type MDD38 currenttransformers may be mounted on each phase: two on thebus side and two on the load side around the primarydisconnect bushings. Current transformers may be addedor changed with the cell de-energized without removingbus bar or cable connections. Multi-ratio currenttransformers are available.
Construction
Figure 9: Fuse Truck on Extension Rails
Figure 7: Primary CL Fuses Accessible When Fuse Truck inDisconnect Position and Access Door Open
Figure 8: VT Cell with Fuse Truck Withdrawn (ShutterClosed, VT Primaries Grounded)
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Construction
Primary Termination Compartment The primary termination compartment at the rear of theswitchgear section is separated from all othercompartments by barriers. This space can be used forconnecting power cables, bus duct, or for connection toan adjacent power transformer. Surge arresters may alsobe provided in this compartment. Bolted rear plates areprovided as standard to provide access to the cable areafor each unit. Hinged rear doors are available as anoption.
Infrared (IR) viewing windows are optionally availablefor use in checking temperature of conductors in theprimary termination compartment.
Bus Bar SystemFull-round-edge copper bus bar with silver plated jointsis standard. Tin-plated copper bus is available as anoption. High strength Grade 5 steel hardware with splitlock washers assures constant pressure, low resistanceconnections. A 0.25 in (6 mm) x 2.0 in (51 mm) copperground bus bar is standard in all vertical sections and isaccessible at each end of the lineup and in the primarytermination of each section. The main bus is available in1200A, 2000A, or 3000A self-cooled ratings. The mainbus bar system is enclosed by grounded metal barriers.
Bus Bar InsulationBus bars are insulated using heat shrink insulation.Bolted bus joints are insulated by pre-formed moldedboots which are held in place by nylon hardware. For busconfigurations where no boot design is available, tapedjoints are used. The main bus is supported withcycloaliphatic epoxy inserts where the bus passes fromone section to another. Other bus is supported usingporcelain standoff insulators. Circuit breaker supportinsulators and cubicle primary disconnect supports aremolded epoxy. Interphase and other barriers are track-resistant, flame retardant glass polyester.
Bus Joint Insulation For normal joint configurations, bolted bus joints areinsulated by pre-formed molded polyvinyl boots (double),which are held in place by nylon hardware. Preformedinsulating materials eliminate the need for molding andtaping joints when connecting shipping groups in the field,reducing installation time and costs. The same preformed,high dielectric strength joint boots used in factoryassembly are also used in field assembly of shipping-splitbus connections. For uncommon joint configurations,taped joint insulation is used. Boots for insulating user’spower connections are available as an option.
Bus Support Insulation Bus bars are supported on porcelain standoff insulatorsusing a glass-polyester saddle-clamp system. Inter-unitbus is supported on cycloaliphatic epoxy insertsmounted in a glass-polyester sheet.
Figure 10: Main Bus Construction
WiringThe secondary and control wiring is connected toterminal blocks which have numbered points foridentification. One side of the terminal blocks forconnections leaving the switchgear is reserved forexternal connections. Secondary and control wire isminimum No. 14 AWG, extra-flexible, stranded type SISwire, insulated for 600 volts, except when devices (e.g.,transducers, communicating devices, etc.) requiredifferent wire. Insulated barrel, crimp-type locking forkterminals are used for most applications, except wherethe devices require a different type of terminal. Wherethey pass through primary compartments, secondarycontrol wires are armored or enclosed in grounded metalwire covers or sheaths.
Figure 11: Cell Wiring
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Instrumentation and RelaysInstruments, meters, and relays can be traditionalswitchboard type, or modern electronic type,depending on the requirements of the specification. Iftraditional electromechanical devices are used, theyhave semi-flush cases with dull black covers. Indicatingand recording instruments, meters, and relays are ofthe rectangular type, semi-flush mounted. All scaleshave a suitable range and are designed with blackletters on a white background.
Control and Instrument Switches Switches furnished are rotary, switchboard type andhave black handles. Circuit breaker control switcheshave pistol-grip handles, while instrument transferswitches have round notched handles, and auxiliary ortransfer switches have oval handles.
Circuit breaker control switches have a mechanical flagindicator showing a red or green marker to indicatethe last manual operation of the switch.
Outdoor HousingsTwo types of outdoor housing - Non-Walk-In andShelter-Clad - are available to meet almost anyapplication. For both types, the underside of the baseis coated with a coal tar emulsion. The switchgear isshipped in convenient groups for erection in the field.
Non-Walk-In DesignThe non-walk-in switchgear consists of indoor typecircuit breaker and auxiliary cubicles located in a steelhousing of weatherproof construction. Each verticalsection has a full height exterior front door withprovision for padlocking. Each cell is also equippedwith an inner hinged front door for mounting relays,instrumentation, and control switches. Two removable
rear panels are included for cable access to theprimary termination area. Each cubicle includesnecessary space heaters,a switched lamp receptaclefor proper illumination of the cubicle duringmaintenance and inspection, and a duplex receptaclefor use with electric tools. A molded-case circuitbreaker for space heaters is located in one cubicle.
Shelter-Clad Design - Single AisleThe Shelter-Clad switchgear consists of indoor typecircuit breaker and auxiliary cubicles located in aweatherproof steel housing having an operating aislespace of sufficient size to permit withdrawal of thecircuit breakers for inspection, test, or maintenance.An access door is located at each end of the aisle,arranged so that the door can be opened from theinside regardless of whether or not it has beenpadlocked on the outside. The aisle space is providedwith incandescent lighting, which is controlled bymeans of a three-way switch at each access door. Eachcubicle includes necessary space heaters. Each lineupincludes two utility duplex receptacles, one at eachaisle access door, for use with electric tools, extensioncords, etc. The weatherproof enclosure for the aisle-way is shipped disassembled for erection in the field.Optionally, for single-aisle configurations, the aisleportion of the enclosure can be shipped assembled.
Shelter-Clad Design - Common AisleThe Shelter-Clad common aisle switchgear consists oftwo lineups of indoor type circuit breaker andauxiliary units located in a weatherproof steel housinghaving a common operating aisle space of sufficientsize to permit withdrawal of the circuit breakers forinspection, test, or maintenance. Otherwise, theconstruction is as described for single aisle design,except that the aisle portion is always shippeddisassembled for erection in the field.
Construction
Figure 12: Shelter-Clad GM38 Lineup Figure 13: Shelter-Clad Single Aisle Braced for Shipment
Note: Each user must develop definitive operatingprocedures for incorporating safe operating practices.Only qualified personnel should be allowed to useground and test devices.
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Accessories
Standard Accessories Include:• manual racking crank• manual spring charging crank• drawout extension rails (facilitate handling of circuit
breakers in outdoor non-walk-in switchgear or drawoutfuse trucks when located above floor level)
• lifting sling (for circuit breakers or drawout fuse truckslocated above floor level)
• split plug jumper (standard unless test cabinet isfurnished)
• contact lubricant• touch up paint
Optional Accessories Include:• lift device (facilitate handling of circuit breakers in
outdoor non-walk-in switchgear or drawout fuse truckswhen located above floor level)
• test cabinet (in place of split plug jumper)• test plugs (if required by devices)• electric racking motor assembly (to enable racking
while operator is at a distance from the switchgear)• manual or electrical ground and test device
Test provisions, either a split plug jumper or a testcabinet, are available for testing the circuit breakeroutside its cubicle.
The split plug jumper is used to bridge the secondarydisconnects with a flexible cable, so the circuit breakermay be electrically closed and tripped with the controlswitch on the instrument panel while the circuit breakeris outside of its compartment. The test cabinet, includinga control switch, is used for closing and tripping thecircuit breaker at a location remote from the switchgear.
Manual Ground and Test DeviceThis is a drawout element that can be inserted into acircuit breaker cell. It opens the shutters, connects to thecell primary disconnecting contacts, and so provides ameans to make the primary disconnect stabs availablefor testing. It is suitable for high potential testing ofoutgoing circuits of the switchgear main bus, or forphase sequence checking. It also provides a means toconnect temporary grounds to de-energized circuits formaintenance purposes. Either 3-stud or 6-stud devicesare available.
Electrical Ground and Test DeviceAn electrical ground and test device includes a poweroperated switch (derived from a 38-3AH3 circuit breaker)arranged to allow grounding one set of disconnect stabs.Two devices, one each for the upper and lower stabs, arerequired if grounding is desired to either side of the unit.The device includes test ports to allow for testing forpresence of voltage on both the line side and the load sideof the cell. The device also provides a means of access tothe primary circuits for high potential tests or for phasesequence checking. These devices are able to close andlatch against short circuit currents corresponding to theratings of the equipment. Due to the unique requirementsfrequently involved in such devices, all applications ofelectrically operated ground and test devices should bereferred to Siemens for review.
Figure 14 Manually Operated G&TD with Doors Open and Closed Figure 15 Electrically Operated G&TD
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SIPROTECSIPROTEC has established itself across the market as thestandard for numerical protective relaying. Besides thecommon system platform and the unique DIGSI 4service interface that may be used for all protectivedevices, it also supports the new IEC 61850communication standard.
IEC 61850 What it is and what it can achieve?Users and manufacturers jointly developed the newinternational standard IEC 61850, which was approvedin early 2004. The agreed aim of this standard is toarrive at a complete communication solution forsubstations, thus providing users with interoperabilityamong different makes on the basis of Ethernettechnology. This opens up a whole new dimension inefficient substation management. Not only short-termsavings in operation and maintenance, but alsosimplified engineering, less complexity, and long-termexpandability can make you one of the winners intomorrow's power market.
With SIPROTEC relays and bay control units fromSiemens, we offer all the advantages of an expert andinnovative partner in the field of protective relaying andsubstation automation. We bring you attractively pricedintelligent solutions by paying particular attention tolowering your life cycle and system management costs.These solutions are the first ones available on themarket with the international IEC 61850 standard.
To enable you to profit from these advantages as quicklyas possible, Siemens collaborated in the preparation ofthis international standard and made every effort toensure no time was lost in bringing it out. The result iscertainly worth a look, because SIPROTEC and otherPower Automation products and Siemens systems areavailable on the basis of the IEC 61850 standard andcan even be retrofitted in systems supplied since 1998.
System Advantages One Bay, One UnitThe SIPROTEC 4 relay family offers fully integratedprotection, control, monitoring, and automation functionsincorporated in a single device. For many applications, thisproduct contains all the functions you need to meet allyour protection and control requirements with just oneunit per bay, saving on investment and installation costsand enhancing availability.
DIGSI 4 DIGSI 4 one tool for all tasks and products DIGSI 4 is acomputer program designed for all SIPROTEC relays.DIGSI 4 offers users a universal tool for all support tasksfrom setting and commissioning of devices to simpleanalysis and documentation of system faults. Ourpowerful analysis tool speeds up troubleshooting andsupplies important service information.
SIPROTEC protective relays and bay controllers - the first devices available with IEC 61850.
Protective Relays
Figure 17: GM38 Low Voltage Relay and InstrumentCompartment
Figure 16: SIPROTEC Numerical Multifunction ProtectiveRelays
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Vacuum Circuit Breakers
Type 38-3AH3 Vacuum Circuit BreakersSiemens Type 38-3AH3 circuit breakers are available in31.5kA through 40kA interrupting classes, or 1500MVA onthe older “constant MVA” rating basis. Continuous currentratings include 1200A and 2000A (self-cooled) and 3000Aforced-air cooled.
Maintenance FeaturesThe 38-3AH3 circuit breakers incorporate many featuresdesigned to reduce and simplify maintenance, including:• virtually maintenance-free vacuum interrupter,• five year maintenance interval,• floor rollout,• front mounted operator,• common operator family,• simple interphase and outerphase barriers,• "universal" spare circuit breaker concept,• non-sliding current transfer, and• rugged secondary disconnects
Five Year Maintenance Interval on 38-3AH3 CircuitBreakerWhen applied under mild conditions (ANSI “usual service”conditions), maintenance is only needed at five yearintervals on the circuit breaker. The maintenance intervalfor the switchgear cubicles is also five years.
Low Maintenance RequirementsThe interrupter is a sealed unit, so the only maintenancenecessary is to clean off any contaminants and to checkthe vacuum integrity. The vacuum interrupters can bedisconnected from the stored energy mechanism quickly,without tools, and vacuum integrity inspected by hand;alternatively, a simple hi-pot test can be used.
Floor RolloutThe circuit breakers are arranged to rollout directly on thefloor in front of the switchgear if the indoor switchgear isnot located on a “housekeeping” pad. No adapter, hoist, orlift truck is necessary for circuit breakers located at floorlevel.
Mechanism OperationThe mechanism is arranged to pre-store closing energy inthe closing springs. The closing springs are selected sothat they provide sufficient energy not only to close thecircuit breaker safely into maximum "close and latch"currents, but also to pre-store the tripping energynecessary to open the circuit breaker. The closing springscan be manually charged during maintenance or inemergency conditions, but are normally chargedelectrically automatically after each closing operation.
InterlocksThe racking system prevents racking of a closed circuitbreaker, and keeps the circuit breaker trip-free duringracking. The racking mechanism can be padlocked toprevent unauthorized operation. Padlocks can also beapplied to the racking mechanism to maintain the circuitbreaker in the trip-free condition.
Stored Energy OperatorThe 38-3AH3 circuit breaker utilizes the Siemens 3AH3stored energy operator for long life, high reliability, andease of maintenance. Parts used in the manufacture of thecircuit breaker are precision tooled or produced onnumerically controlled equipment. The circuit breakerdesign includes frequent use of inherent alignmenttechniques.
Figure 18: 38-3AH3 Circuit Breaker
Front Side (Barrier Removed) Rear
Manual Controls and IndicatorsAll circuit breaker manual controls and indicators areconveniently located on the front of the circuit breaker.Standard features include manual close button, manualtrip button, open-close indicator, stored energy closingspring charge / discharge indicator, manual springcharging access port, and close operation counter.
Common Operator FamilySince the entire 38-3AH3 range of ratings uses acommon stored energy operating mechanism design,less training of maintenance personnel is required, andstocking of spare parts is reduced. The operatingmechanism is essentially the same operator as used onthe Siemens type GMSG circuit breaker for 5-15kVswitchgear.
Front Accessible Operating MechanismThe 38-3AH3 stored energy operator is located at thefront of the circuit breaker. The front cover can be easilyremoved to expose the operator for inspection and main-tenance. This feature eliminates the need to tilt or turnover the circuit breaker for normal service.
Trip-Free DesignThe operating mechanism conforms to the trip-freerequirements of ANSI/IEEE standards. The mechanismdesign assures that the tripping function prevails overthe closing operation.
Simple BarriersOuterphase and interphase barriers are of very simple de-sign and located on the circuit breaker, allowing the cell tobe free of barriers, except the current transformer barrierlocated in front of the shutters. The barriers on the circuitbreaker remove quickly and easily for maintenance. Mostmaintenance can be performed with the barriers in place.
Vacuum InterruptersThe 38-3AH3 circuit breakers use the Siemens family ofvacuum interrupters, proven in over 600,000 circuitbreakers produced since 1976. Axial magnetic fieldcontacts are used to maintain the arc in diffuse mode andminimize contact erosion. The chrome-copper contactmaterial assures lower chopping currents than withdesigns employing copper-bismuth contacts.
15
Vacuum Circuit Breakers
Figure 19: Vacuum Interrupter
D
E
G
H
A
B
C
F
A. Stationary current connection terminalB. Ceramic insulatorC. Arc chamberD. Chrome-copper contactsE. Ceramic insulatorF. Stainless steel bellowsG. Moving contact stemH. Mechanical coupling for operating mechanism
16
Vacuum Circuit Breakers
N
O
LD G KJ
Figure 20: 38-3AH3 Circuit Breaker Key Components
B A C
E
R
S
I
F
H
A. GearboxB. Closing springC. Opening springD. Jack shaftE. Auxiliary switchF. MOC switch operator
G. Spring charging motor (behindlimit switches)
H. Push-to-closeI. Push-to-tripJ. Closed breaker interlockK. Trip-free interlockL. Ground disconnect
M. Charged / discharged indicatorN. Open / closed indicatorO. Operations counterP. Secondary disconnectR. Close coilS. Trip coilT. Capacitor trip (optional)
M
P
T
17
Vacuum Circuit Breakers
Non-Sliding Current TransferThe vacuum interrupter movable stem is connected tothe lower disconnect stab of the circuit breaker by areliable flexible connector, a method pioneered bySiemens in the 1970's. This provides a low resistancecurrent transfer path, not subject to the wear andcontamination problems associated with sliding orrolling joints used in some designs.
Primary DisconnectsThe primary connection between the circuit breaker andthe cubicle is made of multiple sets of silver-platedcopper finger contacts which engage with silver-platedcopper stationary contacts. The cubicle primarydisconnect studs have a tapered leading edge, whichcontributes to smooth racking of the circuit breaker.
The contacts, mounted on the ends of the circuitbreaker disconnect stabs, have multiple fingers and arecompression spring loaded (one spring per double pairof fingers). This arrangement offers a large number ofcontact points to ensure proper alignment. The circuitbreaker finger assemblies are withdrawn with the circuitbreaker, and are available for inspection without de-energizing the switchgear main bus.
"Universal" Spare Circuit Breaker The physical configuration and interlock logic allow theuse of a single circuit breaker to serve as a "universal"spare circuit breaker at an installation site. The ratinginterlock logic checks the principal rating characteristics(continuous current, maximum voltage and interruptingcurrent), and allows a circuit breaker to be inserted in abreaker cell provided that the ratings of the circuitbreaker equals or exceeds the ratings required by thecell.
Secondary DisconnectsCircuit breaker-to-cubicle secondary disconnects are ofthe silver-plated sliding finger design. The secondarydisconnects are automatically engaged as the circuitbreaker is racked into the test position. They remainengaged as the circuit breaker is racked to the connectedposition. Since the secondary disconnects automaticallyengage in both the test and connected positions, there isno need to operate a separate linkage for testing.
The secondary disconnects are located on the top of thecircuit breaker element, where they are shielded fromaccidental damage. They are of an extremely ruggeddesign, in contrast to other designs, which employ lightduty electronics-style disconnects, located in hidden orinaccessible locations. Alignment of the disconnects canbe visibly observed, if desired, allowing positiveverification of secondary integrity, a feature not possiblewith designs employing a disconnect underneath orbehind the circuit breaker.
Figure 21: Primary Disconnects
Figure 22: Secondary Disconnect (Cell Portion)
Figure 23: Secondary Disconnect (Circuit Breaker Portion)
18
Vacuum Circuit Breakers
Auxiliary Switch (Circuit Breaker Mounted)The auxiliary switch assembly is mounted on thevacuum circuit breaker with contacts for use in thecircuit breaker control circuit and as spare contacts forother use. Normally, four auxiliary switch contacts, twoNO (52a) and two NC (52b), can be wired out forpurchaser use.
Mechanism Operated Cell (MOC) SwitchWhen required, 6, 12, 18, or 24 stages of mechanismoperated cell (MOC) auxiliary switch can be mounted inthe circuit breaker cell. This switch is operated by thecircuit breaker mechanism, so that the switch contactschange state whenever the circuit breaker is closed ortripped. Normally, the MOC switch is operated onlywhen the circuit breaker is in the connected position,but provisions for operation in both the connected andthe test positions can be furnished. All spare MOCcontacts are wired to accessible terminal blocks, asshown in figure 24, for user connections.
Truck Operated Cell (TOC) SwitchWhen required, 4, 8, or 12 stages of truck operated cell(TOC) switch can be mounted in the circuit breaker cell.The TOC switch contacts change state when the circuitbreaker moves into or out of the connected position. Allspare TOC contacts are wired to accessible terminalblocks, as shown in figure 24, for user connections.
Figure 24: MOCs (12 Stages Shown) and TOCs (8 StagesShown) (Cover Removed)
19
Siemens Vacuum HeritageThe 38-3AH3 Vacuum Circuit Breakers take full advan-tage of Siemens long history with vacuum interruptersfor power applications. While early work was carried outin the 1920's, a successful vacuum interrupter could notbe perfected until the high vacuum pump becameavailable in the 1960's. Focused development effortbegan in 1969, culminating in the introduction of thetype 3AF circuit breaker in 1976. The knowledge gainedover years of application of this technology in the 3AFand 3AH circuit breakers is now available in the 38-3AH3 design. The advantages inherent in vacuuminterruption are summarized as follows:
Ideal DielectricIn a vacuum, the dielectric strength across a contact gaprecovers very rapidly, allowing a small contactseparation and an efficient interrupter design. Thevacuum does not interact with the arc or its componentsas do other dielectrics.
Quiet OperationInterruption of current by a vacuum circuit breaker is veryquiet as compared to the loud report which accompaniesinterruptions in some other types of circuit breakers.
Low Current Chopping CharacteristicsThe chrome-copper contact material used in Siemensinterrupters limits chopping currents to a maximum of5A. This low value prevents the build-up of unduly highvoltages and results in lower stress on the insulation ofload equipment.
No Arc Products Vented to the AtmosphereThe sealed vacuum interrupter prevents venting of arcproducts to the atmosphere, and prevents any possiblecontamination of the contacts by the atmosphere. Themetal vapor of the arc quickly recondenses on the surfaceof the contacts, although a small amount may recondenseon the arc chamber wall or arc shield. The recondensingmetal vapor acts as a "getter" and recaptures moremolecules of certain gases that might be liberated duringvaporization. This action tends to improve the vacuum inthe interrupter during its operating life.
Non-Toxic lnterruption By-ProductsThe interruption process occurs entirely within thesealed vacuum interrupter. Even if an interrupter isphysically broken, the arc products inside the interrupterare not toxic. In contrast, gas-filled interrupters producetoxic arc by-products, requiring special precautions inthe event of a ruptured interrupter housing.
Fewer Components The vacuum interrupter pole construction is extremelysimple and consists of only seven moving parts withinthe high voltage area and only two moving parts withinthe interrupter chamber. This means greater reliabilityand less maintenance with vacuum interrupters ascompared to the greater number of parts in other typeinterrupters, such as gas or oil.
Long lnterrupter Life The interrupter has a long expected service life due to thecareful selection of components. The chrome-coppercontacts allow efficient interruption with very littlecontact erosion.
Immunity to Environment The capability of the vacuum interrupter to interruptcurrent or to withstand voltage is not directly affectedby conditions external to the vacuum interrupter. Highor low altitudes, hot or cold temperatures, moist or dryconditions, or heavy dust conditions do not affect theconditions internal to the interrupter. Conditionsexternal to the interrupter, however, could affect theoverall system operation and should be considered inthe specifications.
Virtually Maintenance Freelnterrupter maintenance requires merely wiping dust orother atmospheric elements from the exterior, visuallychecking the contact wear indicator, and periodicdielectric testing to confirm vacuum integrity.
Lower Force RequirementsThe vacuum interrupter has a very low moving masscompared to that found in other interrupters. Thisallows a smaller, more compact stored energyoperator leading to long life and low maintenance ofthe circuit breaker.
Vacuum Circuit Breakers
Figure 25: Side View of 38-3AH3 Circuit Breaker (OuterPhase Barrier Removed)
20
Vacuum Circuit Breakers
Vacuum Interrupter PrinciplesWith Siemens 38-3AH3 vacuum circuit breakers, thechopping currents are held to 5A or less. This is lowenough to prevent the build-up of unduly high voltageswhich may occur on switching of inductive circuits. Thechrome-copper contact material keeps overvoltages to aminimum, so special surge protection is not required inmost applications.
When the contacts open, the current to be interruptedinitiates a metal vapor arc discharge, and currentcontinues flowing through this plasma until the nextcurrent zero.
The arc is extinguished near the current zero, and theconductive metal vapor recondenses on the contactsurfaces and the arc chamber wall or arc shield within amatter of microseconds. As a result, the dielectricstrength of the break recovers very rapidly and contacterosion is almost negligible.
The arc drawn in the vacuum interrupter is not cooled.The metal vapor plasma is highly conductive and theresulting arc voltage is only 20 to 200 volts. This low arcvoltage, combined with very short arcing times,produces only a very small arc energy in the vacuuminterrupter, accounting for the long electrical lifeexpectancy of the Siemens vacuum interrupter.
Axial magnetic field design is employed. In this configu-ration, the current flow creates a magnetic field along thelongitudinal axis of the interrupter. This magnetic fieldprevents constriction of the arc, and this forces the arc toremain in diffuse mode. Since the arc remains in diffusemode, localized overheating is avoided and contacterosion is held to low levels.
Figure 26: Siemens Vacuum Interrupter Family
21
Technical Data
Table 1: Type GMSG Circuit Breaker Ratings (New “Constant kA” Ratings Basis)These ratings are in accordance with the following standards:• ANSI/IEEE C37.04-1999 Standard Rating Structure for AC High-Voltage Circuit Breakers • ANSI C37.06-2000 AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis - Preferred Ratings and Related
Required Capabilities• ANSI/IEEE C37.09-1999 Standard Test Procedure for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis• ANSI/IEEE C37.010-1999 Application Guide for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis
Rated Values UnitsCircuit Breaker Type1
38-3AH3-31-
xxxx-82
38-3AH3-40
xxxx-104
Maximum Design Voltage (V)2 kV rms 38.0 38.0
Voltage Range Factor (K)3 ---- 1.0 1.0
Withstand Voltage LevelsPower Frequency kV rms 80 80
Lightning Impulse (BIL) kV crest 150 150
Continuous4 A rms12002000
3000FC
12002000
3000FC
Short-Circuit (I)5,6 kA rms sym 31.5 40
Interrupting Time7 mscycles
835
835
Permissible Tripping Delay (Y) Sec 2 2
Max. Sym. Interrupting (I) kA rms sym 31.5 40
% dc Component % 47 47
Short-Time Current (I) (3 seconds) kA rms 31.5 40
Closing & Latching (Momentary) Asymmetrical (1.55 x I) kA rms 49 62
Closing & Latching (Momentary) Peak (2.6 x I) kA peak 82 104
Footnotes:1 “xxxx” in type designation refers to the continuous current rating 1200, 2000, or 3000A, as appropriate. The 3000A fan-cooled rating is achieved using fan
cooling as indicated in footnote 4.2 Maximum design voltage for which the circuit breaker is designed, and the upper limit for operation.3 K is listed for informational purposes only. For circuit breakers rated on a “constant kA basis”, the voltage range factor is 1.0.4 3000FC indicates that fan cooling is included in the switchgear structure for this rating. 3000A rating is not available in outdoor equipment.5 All values apply to polyphase and line-to-line faults.6 Standard duty cycle is O - 0.3s - CO - 3 min. - CO.7 Standard rated interrupting time is 5 cycles (83ms). Optional rated interrupting time of 3 cycles (50ms) is available.
22
Technical Data
Table 2: Type 38-3AH3 Circuit Breaker Ratings (Historic “Constant MVA” Ratings Basis)These ratings are in accordance with the following standards:• ANSI/IEEE C37.04-1979 Standard Rating Structure for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis• ANSI C37.06-1987 AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis - Preferred Ratings and Related Required
Capabilities• ANSI/IEEE C37.09-1979 Standard Test Procedure for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis• ANSI/IEEE C37.010-1979 Application Guide for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis
Measure Parameter UnitsCircuit Breaker Type1
38-3AH3-1500-
xxxx-95
GeneralNominal Voltage Class kV 34.5
Nominal 3-Phase MVA Class9 MVA 1500
Rated Values
Rated VoltageMaximum Design Voltage (V)2 kV rms 38.0
Voltage Range Factor (K)3 ---- 1.65
Insulation Levels Withstand Voltage LevelsPower Frequency kV rms 80
Lightning Impulse (BIL) kV crest 150
Rated Current
Continuous 4 A rms12002000
3000FC
Short- Circuit (at rated maximum design voltage) (I) 5, 6, 10 kA rms sym 21
Interrupting Time11 mscycles
835
Permissible Tripping Delay (Y) Sec 2
RelatedRequiredCapabilities
Current
Rated Maximum Design Voltage (V) divided by K (=V/K) kV rms 23
Max. Sym. Interrupting (K x I)7 kA rms sym 35
Short-Time Current (K x I) (3 Seconds) kA rms 35
Closing & Latching (Momentary)
Asymmetrical (1.6 x K x I)8 kA rms 56
Peak (2.7 x K x I)8 kA peak 95
Footnotes:
1 “xxxx” in type designation refers to the continuous current rating 1200, 2000, or 3000A, as appropriate. The 3000A fan-cooled rating is achieved using fan cooling as indicatedin footnote 4.
2 Maximum design voltage for which the circuit breaker is designed, and the upper limit for operation.3 K is the ratio of the rated maximum design voltage to the lower limit of the range of operating voltage in which the required symmetrical and asymmetrical interrupting
capabilities vary in inverse proportion to the operating voltage.4 3000FC indicates that fan cooling is included in the switchgear structure for this rating. 3000A rating is not available in outdoor equipment.5 To obtain the required symmetrical interrupting capability of a circuit breaker at an operating voltage between 1/K times rated maximum design voltage and rated maximum
design voltage, the following formula shall be used: Required Symmetrical Interrupting Capability =Rated Short-Circuit Current (I) x [(Rated Maximum Design Voltage)/(Operatingvoltage)]. For operating voltages below 1/K times maximum design voltage, the required symmetrical interrupting capability of the circuit breaker shall be equal to K times ratedshort-circuit current.
6 Within the limitations stated in ANSI/IEEE C37.04-1979, all values apply to polyphase and line-to-line faults. For single phase-to-ground faults, the specific conditions stated inclause 5.10.2.3 of ANSI/IEEE C37.04-1979.
7 Current values in this row are not to be exceeded even for operating voltage below 1/K times rated maximum design voltage. For operating voltages between rated maximum design voltage and 1/K times rated maximum design voltage, follow footnote 5 above.
8 Current values in this row are independent of operating voltage up to and including rated maximum voltage.9 “Nominal 3-Phase MVA Class” is included for reference only. This information is not listed in ANSI C37.06-1987.10 Standard duty cycle is CO - 15s - CO.11 Standard rated interrupting time is 5 cycles (83ms). Optional rated interrupting time of 3 cycles (50ms) is available.
Footnotes:1 Current at nominal voltage.2 Capacitor trip.3 Value preceding slash (/) is the current for the standard trip coil with standard rated interrupting time. Value following slash (/) is the current for optional trip coil
with 3-cycle interrupting time.4 ---- means this selection not available in this voltage.
23
Technical Data
Table 3: Circuit Breaker Control Data4
Control Voltages, ANSI C37.06Close Coil Trip Coil
Spring Charging Motor
NominalRange Amperes Charging
Close Trip Amperes1 Amperes1,3 Run (Avg.) Inrush (Peak) Seconds
48 VDC 38 - 56 28 - 56 2.9 11.4 / 30 8 25 10
125 VDC 100 - 140 70 - 140 1.0 4.8 / 7.4 4 18 10
250 VDC 200 - 280 140 - 280 0.5 2.1 / 4.2 2 10 10
120 VAC 104 - 127 ---- 0.9 ----2 6 ---- 10
240 VAC 208 - 254 ---- 0.4 ----2 3 ---- 10
TypeSwitch
ContinuousCurrent
Amperes
Control Circuit Voltage
120AC
240AC
48DC
125DC
250DC
Non-Inductive
CircuitBreaker
10 10 510 /301 9.6 4.8
TOC 15 15 10 0.5 0.5 0.2
MOC 20 15 10 10 10 5
Inductive
CircuitBreaker
10 6 3 10 6 3
TOC 15 15 10 0.5 0.5 0.2
MOC 20 15 10 10 10 5
VoltageClass
Ratio
Accuracy Class at 120V Sec.
VA ThermalRating
(55oC Amb)W, X, Y, Z ZZ
38kV 1 Bushing
20125 / 115 0.3 1.2 1000
38kV2 Bushings
24000 / 12027600 / 11534500 / 115
0.3 1.2 1000
Table 4: Interrupting Capacity Auxiliary Switch Contacts Table 5: Voltage Transformers
Footnotes:1 2 contacts in series.2 All switch contacts are non-convertible.
Figure 27: SGM 38 Assembled with Aisle (OptionalFluorescent Lamp Fixtures and Insulated Aisle Shown)
24
Technical Data
Table 6: Current Transformers1
Ratio60Hz Metering Accuracy at Burden
Relay ClassB0.1 B0.5 B1.0 B2.0
Type MD38 Torroidal Standard Accuracy
100:5 2.42 ---- ---- ---- C 10
150:5 0.6 2.4 ---- ---- C 20
200:5 0.6 1.2 ---- ---- C 25
250:5 0.6 1.2 2.4 ---- C 35
300:5 0.6 1.2 1.2 2.4 C 40
400:5 0.3 0.6 1.2 1.2 C 60
500:5 0.3 0.3 0.6 1.2 C 75
600:53 0.3 0.3 0.6 1.2 C100
800:5 0.3 0.3 0.6 0.6 C130
1000:5 0.3 0.3 0.3 0.3 C170
1200:53 0.3 0.3 0.3 0.3 C200
1500:5 0.3 0.3 0.3 0.3 C180
2000:53 0.3 0.3 0.3 0.3 C210
2500:5 0.3 0.3 0.3 0.3 C300
3000:53 0.3 0.3 0.3 0.3 C300
Type MDD38 Torroidal Special Accuracy
75:5 2.42 4.8 ---- ---- C 15
100:5 2.4 4.8 ---- ---- C 20
150:5 1.2 2.4 4.8 4.8 C 35
200:5 0.6 1.2 2.4 4.8 C 50
250:5 0.6 1.2 1.2 2.4 C 70
300:5 0.3 0.6 1.2 2.4 C 90
400:5 0.3 0.6 0.6 1.2 C120
500:5 0.3 0.3 0.3 0.6 C150
600:53 0.3 0.3 0.6 0.6 C200
800:5 0.3 0.3 0.3 0.3 C250
1000:5 0.3 0.3 0.3 0.3 C300
1200:53 0.3 0.3 0.3 0.3 C400
1500:5 0.3 0.3 0.3 0.3 C440
2000:53 0.3 0.3 0.3 0.3 C450
2500:5 0.3 0.3 0.3 0.3 C550
3000:53 0.3 0.3 0.3 0.3 C700
Footnotes:1 1-second through-current and momentary
current are equal to the ratings of the associated circuit breakers.
2 Exceeds ANSI C37.20.2 Accuracy Limit.3 Multi-ratio current transformers available.
The accuracy ratings shown apply only tothe full secondary winding.
25
Dimensions
Footnotes:1 Weight does not include circuit breakers, add separately from table 8.
2 Weight estimates are for circuit breaker only. Add 125 lbs (57 kg) for packaging.
3 Weight and dimensions are approximate.
4 Add 6” (152 mm) to each end of lineup for aisle extension 12” (304 mm) total.
5 96” (2438 mm) aisle space recommended allows room for interchange of circuit breakers. Minimum aisle space required for handling circuit breaker is 80”(2030 mm).
6 Add for roof overhang.
Non-Walk-In Shelter-CladRear (cable side) 3.875” (98 mm) 3.875” (98 mm)Front (drawout side) 6.875” (175 mm) 1.5” (38 mm)
7 If indoor switchgear is installed on a raised “housekeeping” pad, the pad must not extend further than 3” (75 mm) from the front of the switchgear to avoidinterference with the use of the portable lift truck.
8 Approximate circuit breaker dimensions in inches (mm) (W X D X H):
Net 44” (1117 mm) X 46” (1168 mm) X 51” (1294 mm)
Packed for shipment separate from switchgear: 48” (1218 mm) X 48” (1218 mm) X 60” (1522 mm)
TypeDimensions in Inches (mm)
Weight in lbs. (kg)Height Width Depth Drawout Aisle
Indoor GM38 110.0 (2794) 48.0 (1219) 130.0 (3302) 96.0 (2438)recommended 5000 (2273)
Shelter-Clad Single-Aisle SGM38 132.5 (3366) 48.0 (1219)1 234.5 (5956) 96.0 (2438)included 6400 (2909)
Shelter-Clad Common Aisle SGM38 132.5 (3366) 48.0 (1219)1 363.75 (9239) 96.0 (2438)included 11700 (5318)
Aisle-Less Non-Walk-In OGM38 130.5 (3315) 48.0 (1219) 139.35 (3539) 96.0 (2438)recommended 5800 (2636)
ContinuousCurrent (A)
Circuit Breaker Type
38-3AH3-31 38-3AH3-40 38-3AH3-1500
1200 800 (364) 850 (387) 800 (364)
2000 900 (409) 950 (432) 900 (409)
3000 1000 (455) 1050 (478) 1000 (455)
Table 7: Cubicle Dimensions Per Vertical Section1,3
Table 8: 38-3AH3 Vacuum Circuit Breaker Weight in lbs. (kg)2,3
139.35 (3539)
26
Figure 28: Switchgear End Views
Dimensions
Type GM38 Indoor Switchgear
Type SGM38 Shelter-Clad Single Aisle Outdoor Switchgear
Type OGM38 Non-Walk-In Outdoor Switchgear
Type SGM38 Shelter-Clad Common Aisle Outdoor Switchgear
110.0(2794)
130.0(3302)
126.87(3223)
130.5(3315)
127.0(3226)
139.35(3539)
8.0(203)
6.78(172)
229.0(5817)
132.5(3366)
234.5 (5956)
Field Assembly Factory Assembled
Switchgear BaseAisle Floor
Aisle
96.0(2438)
FloorLine
Fron
t Pa
nel
3.87(98)
8.0(203)
126.87(3223)
1.55(39)
Aisle
96.0(2438)
Fron
t Pa
nel
Fron
t Pa
nel
8.0(203)
356.0(9042)
132.5(3366)
126.87(3223)
FloorLine
3.87(98)
3.87(98)
363.75 (9239)
Field Assembly Factory AssembledFactory Assembled
Figure 29: Indoor GM38 Switchgear Floor Plan
27
Dimensions
A B C D E F G H J K L M
130.0(3302)
48.0 (1219)
40.0(1016)
4.25(109)
22.0(559)
4.0(102)
7.5(191)
3.5(89)
4.25(109)
43.75(1111)
45.68(1160)
0.12(3)
N P Q R S T U V W X Y Z
42.12(1070)
2.82(72)
2.13(54)
1.16(29)
45.84(1164)
87.06(2211)
126.91(3224)
6.0(152)
47.5(1207)
96.0(2438)
99.0(2515)
7.38(187)
Table 9: GM38 Switchgear Floor Plan Detail Dimensions in Inches (mm)
Footnotes:1 Recommended location of conduits for power cables, top or bottom.
2 Recommended location of secondary leads, top or bottom.
3 Customer conduit not to extend more than 1 in. (25 mm) above floor line.
4 Allow 6 in. (152 mm) clearance for lift truck on each end.
5 Floor must be level 80 in. (2032 mm) in front of switchgear to allow proper operation of lift truck.
Figure 30: Outdoor OGM38 Non-Walk-In SwitchgearFloor Plan
BCD
1E
F
A U
KQ
T
LR
S
J4, 5
G
M M
2 2P P
N
KQ
BCD
1E
F
A
J4, 5
G
M M
2 2P P
N
Z
28
Dimensions
Figure 31: Outdoor SGM38 Shelter-Clad Walk-In SingleAisle Switchgear Floor Plan
Figure 32: Outdoor SGM38 Shelter-Clad Walk-InCommon Aisle Switchgear Floor Plan
BCD
1E
F
A
J
G
M M
2 2P P
N
BCD
1E
F
A
J
G
M M
2 2P P
N
Y
V
W
DCB
1E
F
A
J
G
M M
2 2
P PN
W
V
X
29
Side Views
Figure 33: Auxiliary / 1200A, 2000A or 3000A CircuitBreaker (No Drawout Auxiliaries in Upper Cell for 3000AFan-Cooled Circuit Breaker)
Figure 34: Circuit Breaker Cell (1200A or 2000A) with VTAuxiliary (Downfeed Cables)
Figure 35: VT Auxiliary / 1200A or 2000A Circuit Breaker(Upfeed Cables)
Figure 36: CPT Fuse Truck / Stationary CPT 1Φ or 3Φ)
D. Drawout Primary CurrentLimiting Fuses for CPT
E. Control Power Transformer(1Φ or 3Φ)
E
D
Figure 37: Auxiliary / Bus Tie Circuit Breaker
F. Main Bus to Left SideG. Main Bus to Right Side
H. Bus Tie Circuit Breaker
G
F
110(2794)
Figure 38: Auxiliary / Feeder Circuit Breaker (Adjacent toRight Side of Bus Tie Circuit Breaker Section)
J. Feeder Circuit BreakerK. Main Bus to Right SideL. Transition Bus
M. Main Bus to Left Side (Bus TieCircuit Breaker Section)
L
MK
J
130 (3302) 30 (762)
A. Surge Arrester
A
B. Drawout Primary CurrentLimiting Fuses for VT’s
C. Voltage Transformers (VTs)
B
C
H
30
Notes
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