SPECIFICATION FOR SF6 GENERATOR SWITCHGEAR SYSTEM

FOR INDOOR INSTALLATION

Scope

This specification covers the design, production, testing and delivery of SF6 generator circuit-breakers and related equipment for installation in the run of an isolated phase busbar. The specification consists of the following parts:

1 General

2 Service Conditions

3 Generator Circuit-Breaker

4 Disconnector

5 Earthing Switch

6 Instrument Transformers

7 Surge Protection Equipment

8 Start-up Disconnector

9 Short-Circuiting Connection with Disconnector

10 Rules for Transport, Storage, Erection and Maintenance

11 Information to be Given with Tender

Appendix 1: Technical Data of Generator Switchgear System

Intent of Specification and Drawings

The intent of the specification and the drawings is to prescribe a complete work which the manufacturer undertakes to do. If there is any apparent contradiction or ambiguity between the specification and the drawings, the manufacturer shall bring this fact to the attention of the purchaser and shall obtain his decision as to the true meaning or intention before proceeding with the portion of the work affected. All work that may be called for in the specification and not shown on the drawings, or shown on the drawings and not called for in the specification, shall be performed by the manufacturer as if described in both and should any work be required which is not denoted in the specification or drawings, but which is nevertheless necessary for the proper carrying out of the intent thereof, the manufacturer shall perform all such work as fully as if it were particularly described.

General

General Requirements

The generator switchgear system shall be designed for installation in the run of an isolated phase busbar. Each phase of the switchgear shall be mounted in a separate aluminium enclosure. Beside the generator circuit-breaker the generator switchgear shall also include:

[ ] a series disconnector[ ] an earthing switch on the transformer side[ ] one/two single pole insulated voltage transformer(s) on the transformer side with up to two

secondary windings[ ] one current transformer on the transformer side with up to three cores[ ] a surge arrester on the transformer side[ ] a start-up disconnector on the generator side[ ] an earthing switch on the generator side[ ] one/two single pole insulated voltage transformer(s) on the generator side with up to two

secondary windings[ ] one current transformer on the generator side with up to three cores[ ] a switched short circuiting connection between circuit-breaker and disconnector (with/without a

manually fitted link for earthing the short circuiting connection)

Also provided shall be capacitors both on the generator and the transformer side of the generator circuit-breaker in order to limit the rate-of-rise of the transient recovery voltage appearing across the contact of the circuit-breaker after a short-circuit current interruption. These capacitors at the same time serve as surge capacitors. A single line diagram of the power plant is enclosed with this specification.

The generator circuit-breaker shall perform the following functions:- carry the full load current of the generator- synchronize the generator with the system- separate the generator from the system (switching off the unloaded or slightly loaded generator)- interrupt load currents (up to the full load current of the generator)- make and break generator-source short-circuit currents- make and break system-source short-circuit currents- make and break currents under out-of-phase conditions

Codes and Standards

All equipment and materials furnished under this specification shall conform to the latest revisions of the applicable IEC- and ANSI/IEEE-Standards. In particular the following standards shall apply:

General:- IEC 694: Common Clauses for High-Voltage Switchgear and Controlgear Standards

- IEC 298: A.C. Metal-Enclosed Switchgear and Controlgear for Rated Voltages Above 1 kV and Up to and Including 52 kV

Generator Circuit-Breaker:- IEEE Std. C37.013: IEEE Standard for AC High-Voltage Generator Circuit Breakers Rated on a

Symmetrical Current- IEC 56: High-Voltage Alternating-Current Circuit-Breakers

Note: Generator circuit-breaker rating structures and tests shall conform to the latest revision of IEEE Std. C37.013

Disconnector:- IEC 129: Alternating Current Disconnectors (Isolators) and Earthing Switches

Earthing Switch:- IEC 129: Alternating Current Disconnectors (Isolators) and Earthing Switches

Instrument Transformers:- IEC 185: Current Transformers - IEC 186: Voltage Transformers

Surge Protection Equipment:- IEC 99-4: Metal-Oxide Surge Arresters without Gaps for A.C. Systems- IEC 358: Coupling Capacitors and Capacitor Dividers

Service Conditions

The generator switchgear system will be mounted indoors.

- Altitude ..... m

- Ambient air temperature: - Maximum 40 °C

- Minimum -5 °C

The air inside the isolated phase bus and the generator switchgear will be dry and free of dust, oil etc.

Generator Circuit-Breaker

General

The generator circuit-breaker shall use SF6 as insulating and interrupting medium. For current interruption the SF6-self extinguishing principle shall be applied.The arc voltage of the generator circuit-breaker shall be high enough to ensure current zeros in the case of generator-source short-circuit currents with missing current zeros.The generator circuit-breaker shall have two separate contact systems, one for load current carrying and one for arc interruption.The circuit breaker with contacts open and insulating gas at atmospheric pressure must be capable of withstanding 3 times the phase voltage.. This requirement is to assure that the circuit breaker in the open position is capable of withstanding voltages to which he can be subjected under such conditions when the two systems are out-of phase.All parts of the insulation structure, including those between phases to ground and across the open contacts, shall be of an inherently stable nature with a minimum susceptibility to dielectric tracking.The completely assembled circuit breaker, including linkages and all other parts, shall have ample mechanical strength to withstand without damage all stresses incident to operation within the rated short-circuit current or the related required capabilities of the circuit breaker, as well as stresses resulting from mounting, moving or maintaining the circuit breaker in a proper manner.The time between the first and last poles to open or close shall not exceed 120 electrical degrees.The circuit breaker shall be trip free and anti-pumping.

Operating mechanism

A hydraulically charged spring drive mechanism shall be furnished for the circuit breaker, complete with all control equipment and the only external requirement for operation shall be the electrical supplies.The capacity of energy facilities shall be of sufficient size to permit at least 2 complete closing-opening operations.The design of the operating mechanism shall be coordinated with the circuit breaker design to insure positive opening of the circuit breaker and circuit interruption, whether the tripping impulse is received in the fully closed or any partially closed positions.For purposes of inspection and adjustment, means shall be provided to permit local operation of the circuit breaker. In addition an emergency operating lever shall be supplied to allow manual opening and closing of the circuit breaker.

SF6 Supervision

A SF6 gas density monitor shall be supplied for each three phase circuit breaker. An electrical contact (micro-switch) shall be provided to indicate that the gas density has reached a level where refilling is necessary.Two additional contacts shall be provided, each connected to one trip circuit, to prevent tripping of the breaker when gas density falls below a level which will be too low to successfully complete an operation of the breaker at its ratings.

Circuit breaker control

Two trip coils shall be provided. One circuit (primary) will be wired in the normal circuit-breaker control scheme and the secondary circuit wired to terminal blocks for customer use. This secondary trip circuit will include all the interlocking associated with the primary circuit.Upon loss of drive energy, control power supply or SF6, the breaker shall remain in the fully closed or open position.

Interphase Cabling and Pipework

Interphase cabling and pipework shall be supplied with the circuit breaker.

Accessories

Each circuit breaker shall be equipped with an operation counter.A reliable, mechanical position indicator shall be furnished to indicate the open and closed position of the circuit breaker.A manual operation device for maintenance purposes shall be provided.A minimum of auxiliary contacts shall be provided for each circuit breaker mechanism for the buyer's use in addition to those contacts required by the seller. Contact multiplying is allowed.

Control cabinet, control circuit

All control devices shall be designed to withstand, without damage, the mechanical shocks incident to handling and operation at rated short-circuit current and at related required capabilities of the equipment.Wire sizes for control wiring shall be coordinated with the inherent current requirements and voltage drop limitations.All spare auxiliary contacts on the proposed equipment shall be wired to terminal blocks for future use as detemined by the buyer. All terminal blocks associated with these spares shall be located at a convenient location.All terminals of control wires shall be identified in a substantial manner. Physical arrangements of all wiring terminals shall be identical on all similar circuit breakers.

Nameplate

A non-corrosive nameplate shall be attached to the circuit breaker assembly. The nameplate shall be placed in such position that it is clearly readable when standing in front of the circuit-breaker.Each circuit-breaker assembly shall have a unique serial number with pole designations.

Painting

All surfaces of the circuit-breaker, operating mechanism, and other parts exposed to possible corrosion shall be weatherproofed and designed to prevent accumulation of moisture. Those surfaces which require paint shall be shotblasted, sandblasted or chemically cleaned.

Conductors

Conductors shall be of high conductively copper or aluminium. All bus joints shall have silver-to-silver contacts surfaces. Insulating supports shall meet the dielectric strength requirements

specified, and shall be capable of withstanding the mechanical forces imposed by closing and opening operations and by the currents specified.Conductor terminations shall be designed for direct connection to the bus conductors.Connections will be made with bolted, flexible connectors to be supplied by the isolated phase bus manufacturer. The manufacturer shall furnish to the isolated phase bus manufacturer all pertinent details including forces transmitted to the bus during circuit breaker operation and the terminal configuration required for the design of the connections.

Circuit-Breaker enclosure

Enclosures shall be designed for welded connection to the isolated phase bus enclosures. Each enclosure shall be fabricated of aluminium and capable of conducting currents equal to the current ratings specified.Inspection windows shall be provided in each enclosure as required to allow visual checks of the isolating contact position, the grounding switch position and to allow inspection of the bus and interior of the enclosure.The construction of each enclosure shall be such as required to permit complete disassembly of the phase assembly without removing the enclosure from its anchors.The temperatures of the circuit-breaker current path and enclosure at the points where connections to the isolated phase bus are made shall be coordinated between manufacturer of circuit-breaker and IPB-system.

Ground Pads

Two copper or stainless steel ground pads shall be provided on each circuit breaker assembly, close to ground level and located opposite each other. The control cabinet shall be grounded with an internal/external ground connection.

Testing

The Manufacturer shall furnish test reports of design test for the equipment offered, shall perform production tests on the equipment furnished and shall provide technical services to review the procedure for and the results of the commissioning tests performed. The Manufacturer shall furnish certificates of short-circuit and switching performance from an independent laboratory for the offered equipment. All tests shall conform to IEEE Std.C37.013 and consider the requirements according to the system data.

Design Tests

Design tests to verify the adequacy of the design to meet the specifed ratings under the specified operating conditions shall be made only on representative breakers. Equipment ratings exceeding available testing facility capabilities using presently available testing procedures shall be substantiated with calculation methods. All equipment ratings shall be verified.

Production Tests

Production tests shall be conducted. The Bidder shall submit with his proposal a listing of his standard production tests.

Commissioning Tests

Commissioning tests shall be performed on the generator switchgear to confirm that the switchgear was not damaged during shipping and to check the operation of the equipment under actual installation conditions. The Manufacturer shall furnish technical services to review the procedures for and the results of the commissioning tests performed.

Instructions books

The instruction manuals shall provide complete information necessary for the installation, operation, and maintenance of the equipment throughout the life of the equipment

Technical data

Refer to Appendix 1

Disconnector

General

A series disconnector shall be provided on the transformer-side of the generator circuit-breaker. The disconnector shall be a tubular telescopic unit with the moving contact tube connected on the transformer-side and the fixed contact being on the circuit-breaker-side of the unit. The isolating gap of the disconnector shall be in air of atmospheric pressure and a window shall be provided in the enclosure to allow visual checking.

Operating mechanism

Motor mechanism shall be of heavy duty construction and operate on the voltage indicated in the technical data section. The motor operated mechanism shall be designed to enable it to complete its normal travel to either "open" or "close" position, once started, without holding the control switch continuously in that position. Means of stopping the travel between fully open and closed position is not acceptable. A crank handle shall be provided for emergency manual operation. Key interlocking in the positions "Closed" and "Open" shall be provided. An additional interlock shall prevent motor operation while the disconnector being manually operated. Mechanically driven semaphores shall be provided.

Technical data

Refer to appendix 1

Earthing Switch

General

The earthing switches shall be of the blade type, air insulated, gang-motor driven with optional manual drive and shall be integrated with the circuit-breaker and the disconnector into one single phase, tubular aluminium enclosure forming a straight section of an isolated phase bus. No making or breaking capabilities are required for the earthing switches. The earthing switches operation shall be interlocked with the circuit breaker and disconnector.The control of the earthing switch including the interlocking circuits shall be accomodated in the circuit breaker control cabinet. A local remote switch and push buttons for local control shall be provided.Where applicable the manual operating handle on the motor-operated device shall be so designed as to enable the switch to be operated in either direction by hand, starting from either the open or closed position. Means shall be provided so that manual operation of the switch will automatically disconnect the motor-operated mechanism.The motor operated mechanism shall be provided with an auxiliary switch.A reliable, mechanical position indicator shall be furnished to indicate the open and closed positions of the earthing switches.

Operating mechanism

Motor mechanism shall be of heavy duty construction and operate on the voltage indicated in the technical data section. The motor operated mechanism shall be designed to enable it to complete its normal travel to either "open" or "close" position, once started, without holding the control switch continuously in that position. Means of stopping the travel between fully open and closed position is not acceptable.

Technical data

Refer to appendix 1

Instrument Transformers

Current transformers

General

Ring core torodial current transformer at the transformer-side and at generator-side end of each phase of the switchgear unit shall be supplied. The secondary windings shall be permanently wired to terminal blocks in the switchgear control cubicle.

Technical data

Refer to Appendix 1

Voltage transformers

General

Single-phase, cast resin voltage transformers at the transformer-side and the generator-side end of each phase of the switchgear unit shall be supplied the secondary windings shall be permanently wired to terminal blocks in the switchgear control cubicle.

Technical data

Refer to Appendix 1

Surge Protection Equipment

Metal-oxide surge arrester

General

Metal-oxide surge arresters shall be fittet on the transformer-side connections of the switchgear unit to provide protection of the equipment connected to the generator busbar from overvoltages.

Technical data

Refer to Appendix 1

Surge capacitor

General

Surge capacitors shall be fitted on the transformer-side connection of the switchgear unit to provide protection of the equipment connected to the generator busbar from overvoltages and to limit the rate-of-rise of the transient recovery voltage. Capacitors to limit the rate-of-rise of the transient recovery voltage shall be also fitted on the generator-side connection of the switchgear unit if required for circuit-breaker operation. The capacitors shall be mounted in metal housings and use synthesized aromatic oil as dielectrica. The capacitors shall be permanently mounted within the enclosure.

Technical data

Refer to Appendix 1

Start-up Disconnector

General

The starting circuit shall provide a connection from an external source via the starting disconnector to the generator-side connection of the switchgear unit.The starting disconnector shall be a motor-driven blade type unit. The incoming connection to the hinged contact side of the starting disconnector shall be made by cable, with accomodation being provided for up to four terminations per phase. Bushings shall be provided to take the connections through the enclosure to the switch hinge point.

Operating mechanism

Motor mechanism shall be of heavy duty construction and operate on the voltage indicated in the technical data section. The motor operated mechanism shall be designed to enable it to complete its normal travel to either "open" or "close" position, once started, without holding the control switch continuously in that position. Means of stopping the travel between fully open and closed position is not acceptable.

Technical data

Refer to Appendix 1

Short-Circuiting Connection with Disconnector

General

The short-circuiting disconnector and its connection shall help to expedite the testing and adjustment of the power plant protection. Closure of the disconnector shall establish a three phase

short-circuit on the generator connection without involving ground. The short-circuiting point shall be between the generator circuit-breaker and the series disconnector. The actual short-circuiting point shall be external to the switchgear enclosure, the connections being insulated from the switchgear unit housing. The disconnector shall be a blade type switch with its hinge point on the short-circuiting side of the connection.

Operating mechanism

Motor mechanism shall be of heavy duty construction and operate on the voltage indicated in the technical data section. The motor operated mechanism shall be designed to enable it to complete its normal travel to either "open" or "close" position, once started, without holding the control switch continuously in that position. Means of stopping the travel between fully open and closed position is not acceptable.

Technical data

Refer to Appendix 1

Rules for Transport, Storage, Erection and Maintenance

Storage requirements

Pre-installation and on-site storage requirements shall be stated.

Installation instructions

Complete and detailed installation instructions including photographs or illustrations giving lifting points, adjustments, alignment, torque values and initial calibration details shall be included in this section. Any special installations, alignment and setup tools which are supplied or required shall be listed.

Operation instructions

These instructions shall contain the following information pertaining to the operation of the supplied equipment: - a complete and detailed list of pre-startup or preenergization requirements- complete and detailed startup instructions for all equipment supplied is to be furnished- complete and detailed equipment shutdown instcuctions for all equipment furnished- functional description of the operation of mechanical systems, etc.

Maintenance instructions

Complete and detailed information required for preventive maintenance shall be furnished, including recommended maintenance intervals, required tests, calibrations and inspections. A step-by-step description of the disassembly and re-assembly of the equipment shall be included, listing any precaution or critical adjustments or settings that are to be performed. A list of tools, test equipment or other equipment required for the proper repair and maintenance of the supplied equipment shall be included.A complete parts list identifying all parts which are expected to need replacement on a periodic basis and the quantities of each part shall be supplied. The information (part number, page number, item number, etc.) required by the manufacturer to supply spare parts shall be listed.

Site

The equipment shall be delivered to .................................................- Access to site by Rail/Road- Crane for off-loading Yes (Capacity)/No- Erection on prepared foundations Yes/No

Information to be Given with Tender

The bidder shall submit the following information with his proposal:

1. Earliest delivery date from receipt of order

2. Outline dimensions of complete circuit-breaker and anciliary equipment3. Weight of complete circuit-breaker and anciliary equipment4. Weight of the largest component for shipping 5. VA-rating, starting current and running current for the operating mechanism and tripping and

closing devices6. Quantity of SF6 gas required per three-phase circuit-breaker7. Recommended settings of the low gas alarm and lockout of the closing and tripping of the

circuit breaker8. List of standard production tests9. List of recommended spare parts with prices10. Recommended maintenance schedule of circuit-breaker and anciliary equipment including

maintenance parts list with prices.11. List of any exceptions or deviations from this specification. If the proposal is completely in

accordance with the specification, a statement to this effect shall be included in the proposal.

Appendix 1: Technical Data of Generator Switchgear System

A1.1 Generator Circuit-Breaker

Rated voltage kVrms 24

Maximum service voltage kVrms .............

Rated insulation level:Rated lightning impulse withstand voltage: to earth kVpeak 125 across open switching device kVpeak 125Rated power-frequency withstand voltage (1 min): to earth kVrms 60 across open switching device kVrms 60

Rated frequency Hz 50

Rated peak withstand current kApeak 300

Rated short-time withstand current kArms 100

Rated duration of short-circuit s 1

Rated current and temperature rise: Rated current with natural cooling, at 40 °C ambient Arms 11’500 Tempearture rise of contacts K < 65 Temperature of busbar connection °C < 90 Temperature of enclosure °C < 70

Rated short-circuit making and breaking current(system-source short-circuit current): Short-circuit making current kApeak 300 Short-circuit breaking current kArms 100 DC-component % 75 First pole-to-clear factor 1.5Transient recovery voltage: rate-of-rise kV/s 5.5 time delay s < 1 peak value kVpeak 46.6

Generator-source short-circuit current: Short-circuit breaking current kArms 80 DC-component % 110 First pole-to-clear factor 1.5Transient recovery voltage: rate-of-rise kV/s 2.2 time delay s < 0.5

peak value kVpeak 46.6

Making and breaking current under out-of-phase conditions: Out-of-phase angle deg 180 Making current kApeak 210 Breaking current kArms 70 DC-component % 75 First pole-to-clear factor 1.5Transient recovery voltage: rate-of-rise kV/s 7.4 time delay s < 1 peak value kVpeak 93.2

Load current: Load breaking current Arms 11’500 First pole-to-clear factor 1.5Transient recovery voltage: rate-of-rise kV/s 1.6 time delay s < 1 peak value kVpeak 23.3

Rated operating sequence:Short-circuit currents CO-30 min-

COLoad currents CO- 3 min-

COMechanical operations CO- 3 min-

CO

Rated time quantities: Making time ms < 60 Breaking time ms < 80 Simultaneity of poles during closing or opening ms < 2

Rated supply voltage and frequency of closing devices .............. Rated supply voltage and frequency of opening devices .............. Rated supply voltage and frequency of auxiliary circuits ..............

Maintenance intervals: Based on time in service years 15 Based on number of mechanical operations CO 10’000 Based on number of rated current interruptions CO 500 Based on number of rated short-circuit current interruptions CO 3

A1.2 Disconnector

Rated voltage kVrms 24

Maximum service voltage kVrms ..............

Rated insulation level:Rated lightning impulse withstand voltage: to earth kVpeak 125 across isolating distance kVpeak 145Rated power-frequency withstand voltage (1 min): to earth kVrms 60 across isolating distance kVrms 70

Rated frequency Hz 50

Rated peak withstand current kApeak 300

Rated short-time withstand current kArms 100Rated duration of short-circuit s 1

Rated current and temperature rise: Rated current with natural cooling, at 40 °C ambient Arms 11’500 Tempearture rise of contacts K < 65 Temperature of busbar connection °C < 90 Temperature of enclosure °C < 70

Rated supply voltage and frequency of auxiliary circuits ..............

Maintenance intervals: Based on time in service years 15 Based on number of mechanical operations CO 10000

A1.3 Earthing Switch

Rated voltage kVrms 24

Maximum service voltage kVrms ..............

Rated insulation level: Rated lightning impulse withstand voltage: to earth kVpeak 125Rated power-frequency withstand voltage (1 min): to earth kVrms 60

Rated frequency Hz 50

Rated peak withstand current kApeak 300

Rated short-time withstand current kArms 100Rated duration of short-circuit s 1

Rated supply voltage and frequency of auxiliary circuits ...................

Maintenance intervals: Based on time in service years 15 Based on number of mechanical operations CO 5000

A1.4 Instrument Transformers

A1.4.1 Current Transformers

Rated voltage kVrms 24

Rated insulation level:Rated lightning impulse withstand voltage: to earth kVpeak 125Rated power-frequency withstand voltage (1 min): to earth kVrms 60

Rated frequency Hz 50

Rated peak withstand current kApeak 300

Rated short-time withstand current kArms 100

Rated duration of short-circuit s 1

Rated current on primary side Arms ..............

Rated current on secondary side Arms ..............

Current transformer on transformer-side of generator circuit-breaker:Core 1: Class .............. VA-rating VA .............. Core 2: Class .............. VA-rating VA .............. Core 3: Class .............. VA-rating VA ..............

Current transformer on generator-side of generator circuit-

breaker:Core 1: Class .............. VA-rating VA .............. Core 2: Class .............. VA-rating VA .............. Core 3: Class .............. VA-rating VA ..............

A1.4.2 Voltage Transformers

Rated voltage kVrms 24

Rated insulation level:Rated lightning impulse withstand voltage: to earth kVpeak 125Rated power-frequency withstand voltage (1 min): to earth kVrms 60

Rated frequency Hz 50

Rated voltage factor (8 h) 1.9

Rated primary voltage kVrms ..............

First voltage transformer on transformer-side of generator circuit-breaker:Secondary winding 1: Rated secondary voltage Vrms .............. Class .............. VA-rating VA ..............

. Secondary winding 2: Rated secondary voltage Vrms .............. Class .............. VA-rating VA ..............

Second voltage transformer on transformer-side of generator circuit-breaker:Secondary winding 1: Rated secondary voltage Vrms .............. Class .............. VA-rating VA .............. Secondary winding 2: Rated secondary voltage Vrms .............. Class ..............

VA-rating VA ..............

First voltage transformer on generator-side of generator circuit-breaker:Secondary winding 1: Rated secondary voltage Vrms .............. Class .............. VA-rating VA .............. Secondary winding 2: Rated secondary voltage Vrms .............. Class .............. VA-rating VA ..............

Second voltage transformer on generator-side of generator circuit-breaker:Secondary winding 1: Rated secondary voltage Vrms .............. Class .............. VA-rating VA .............. Secondary winding 2: Rated secondary voltage Vrms ............. Class .............. VA-rating VA ..............

A1.5 Surge Protection Equipment

A1.5.1 Metal-Oxide Surge Arresters

Rated voltage kVrms 24

Rated insulation level:Rated lightning impulse withstand voltage: to earth kVpeak 125Rated power-frequency withstand voltage (1 min): to earth kVrms 60

Rated frequency Hz 50

Maximum Continuous Operating Voltage kVrms ....

Rated Discharge Current kA 10

A1.5.2 Surge Capacitors

Rated voltage kVrms 24

Rated insulation level:Rated lightning impulse withstand voltage: to earth kVpeak 125Rated power-frequency withstand voltage (1 min): to earth kVrms 60

Rated frequency Hz 50

Capactitance value nF 250

A1.6 Start-up Disconnector

Rated voltage kVrms 12

Maximum service voltage kVrms ..............

Rated insulation level:Rated lightning impulse withstand voltage: to earth with switching device closed N/A to earth with switching device open kVpeak 125 across open switching device kVpeak 125Rated power-frequency withstand voltage (1 min): to earth with switching device closed kVrms 36 to earth with switching device open kVrms 60 across open switching device kVrms 60

Rated frequency Hz 50

Rated peak withstand current kApeak 180Rated short-time withstand current kArms 60Rated duration of short-circuit s 1

Current carrying capability for 20 min A 4000

Rated supply voltage and frequency of auxiliary circuits ..........

Maintenance intervals: Based on time in service years 15 Based on number of mechanical operations CO 10000

A1.7 Short-Circuiting Connection with Disconnector

Insulation with respect to enclosure kVrms 2

Rated frequency Hz 50

Rated peak withstand current kApeak 300

Rated short-time withstand current kArms 100

Rated duration of short-circuit s 1

Current carrying capability for 2 min kArms 20

Rated supply voltage and frequency of auxiliary circuits ..........

Maintenance intervals: Based on time in service years 15 Based on number of mechanical operations CO 5000