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Type 298 DB1 MV Switchgear Technical Design Specification

Rev B ­ January 2007

Revision B

Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

Table of Contents 1 Introduction ............................................3 1.1 1.2 1.3 1.4 General Description .............................3 Unlimited Internal Arcing Faults ...........3 Ratings ................................................3 Main Relevant Specifications ...............3 4.1 Enclosures .......................................... 8 4.2 Front Doors ......................................... 8 4.3 Vacuum Contactors (VCU's)................ 8 4.3.1 Contactor Truck ............................ 8 4.3.2 A Vacuum Contactor ..................... 8 4.3.3 Fuses............................................ 9 4.3.4 Contactor Control Supplies ........... 9 4.3.5 Primary Disconnects ..................... 9 4.3.6 Secondary Disconnects ................ 9 4.3.7 Contactor Status Indication ........... 9 4.4 VCU Operation .................................... 9 4.5 Circuit Earth Switch ........................... 10 4.6 Interlocks........................................... 10 4.7 CT Accommodation........................... 10 4.8 Shutters............................................. 10 5 Cable Terminations ............................. 11 5.1 5.2 5.3 Power Cable Termination .................. 11 Auxiliary/Control Cable Terminations. 11 Cable Termination Kits ...................... 11

2 Bus Bar System......................................3 2.1 2.2 2.3 2.4 General Description .............................3 Bus-Bars..............................................3 Bus-Bar Insulation................................4 Bus-Bar Plating/Finish..........................4

3 Circuit Breaker Cubicles........................4 3.1 Enclosures ...........................................4 3.2 Front Doors..........................................4 3.3 Circuit Breakers ...................................4 3.3.1 Carriage ........................................4 3.3.2 Circuit Breakers.............................4 3.3.3 Operating Mechanism ...................5 3.3.4 Operations Counter .......................5 3.3.5 Primary Disconnect Contacts.........5 3.3.6 Compartment Shutters...................5 3.3.7 Secondary Disconnect...................5 3.4 Bus Section Transition Cubicles...........5 3.5 Bus "A" Earth Truck/VT Cubicle ...........5 3.6 Circuit Earth Switches ..........................6 3.6.1 Description ....................................6 3.6.2 Operation ......................................6 3.6.3 Indication.......................................6 3.6.4 Earth Switch Locking .....................6 3.6.5 Earth Switch Rating .......................6 3.7 Bus Bar Earth Switches .......................6 3.7.1 Description ....................................6 3.7.2 Operation of the Bus Bar Earth Truck ...............................................6 3.7.3 Indication.......................................7 3.8 Interlocks/Protection against Mal-operation . ........................................7 3.9 Current Transformers (CT's) ................8 3.10 Voltage Transformers (VT's) ................8 3.10.1 Description ....................................8 3.10.2 Primary Disconnect Contacts.........8 3.10.3 Primary Fuses ...............................8 3.10.4 VT Compartment Shutter...............8 3.10.5 Circuit VT's ....................................8 3.10.6 Bus Bar VT's .................................8 4 Vacuum Contactor Cubicles..................8

6 General ................................................. 11 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 Ingress Protection ............................. 11 LV Compartment ............................... 11 Surge Arrestors ................................. 12 Voltage Indication.............................. 12 Cubicle Heaters................................. 12 Paint Finish ....................................... 12 Labels ............................................... 12 Protective Circuits and Earth conductor Bonding ............................................. 12

7 Accessories ......................................... 12 7.1 7.2 7.3 7.4 7.5 7.6 Circuit Breaker Service Trolley .......... 12 VT Installation Ramp ......................... 13 Racking Handle ................................. 13 Door Fastening Tool .......................... 13 Extended Umbilical Test Leads ......... 13 Test Bushing ..................................... 13

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Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

1 Introduction

1.3 Ratings The continuous current and fault ratings available for each panel width are: 400mm wide: 400A, <50kA 650mm wide: 630A/1250A, <31.5kA 800mm wide: 1250A/1600A, <50kA 1000mm wide: 2000A/2500A/3150A/4000A, <50kA The maximum rated voltage and dielectric levels available for each panel width are: 400mm wide: 650mm wide: 800mm wide: 1000mm wide: 7.2kV, 60kV 13.8kV, 95kV 13.8kV, 95kV 13.8kV: 95kV

1.1 General Description Independently type tested in accordance with IEC 60298, the S&I "Type 298 DB1" range of MV Switchgear and Motor Control Centres is suitable for indoor installations and comprises a modular range of floor-mounted, air-insulated, extensible, metal-clad cubicles. Available in widths from 400mm up to 1000mm, the 3-chamber cubicle design permits a fullysegregated functional unit, bus-bar chamber and rear access cable termination chamber. Dependent upon the application, the cubicle functional unit can be equipped with either a Circuit Breaker or a Contactor, in addition to a separately segregated withdrawable Circuit or Bus-Bar VT, where required. All cubicles permit integral circuit earthing to be fitted. Bus-bar earthing is achieved through the use of a dedicated withdrawable Bus-Bar Earthing Truck. All functional devices have a horizontal isolation and withdrawal design and are fully operable behind a closed door. The minimum degree of protection is IP4X (BSEN 60529:1991) which can be enhanced, where required, up to IP42. 1.2 Unlimited Internal Arcing Faults All DB1 cubicles and each of their 3 segregated internal chambers have been constructed to withstand the effects of unlimited internal arc faults. The cubicle design has been independently tested and meets the requirements of IEC 298, Appendix AA, Type A accessibility across test criteria 1-6 inclusive. All cubicles are available rated to withstand these effects at fault levels < 50kA for 1 second.

1.4 Main Relevant Specifications IEC 60298 IEC 60056 IEC 60129 IEC 60470 IEC 60632 IEC 60694 Metal Enclosed Switchgear Circuit Breakers Earth Switch HighVoltage AC Contactors High Voltage Motor Starters Common Specifications for High Voltage Switchgear and Controlgear Standards

2.0 Bus Bar System 2.1 General Description A single bus, 3-wire system runs through an air insulated bus-bar chamber, in a direct line and common position within all cubicle widths and along the entire length of the installed equipment, utilising the same cross-sectional area throughout. The main horizontal bus-bars have a maximum short-time fault rating of 50kA/3sec. Continuous current ratings are available up to and including 4000A. 2.2 Bus-Bars The main horizontal bus-bars and dropper connections to the top primary disconnect contacts are horizontal or vertical laminations of HDHC radius edged copper. All bus-bars are supported by an array of stand-off post insulators.All bar-tobar joints have fully bolted and torqued connections.

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Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

2.3 Bus-Bar Insulation The standard bare copper, air-insulated bus-bar system allows a minimum rated voltage of 11kV with a minimum bus-bar dielectric level of 75kV BIL. Where required by customer specification, and for rated voltages of 13.8kV/95kV BIL, the horizontal and vertical bus-bars will be insulated with an epoxy moulding. All associated bus-bar joints are fully insulated with removable EDPM joint covers. 2.4 Bus-Bar Plating/Finish All main circuit conductors are silver-plated at the joint faces of a bolted connection. 3 Circuit Breaker Cubicles 3.1 Enclosures Enclosures are available in widths of 650mm, 800mm and 1000mm and are selected to suit the continuous current rating and the breaking capacity of the Circuit Breaker to be fitted within the front housing of the enclosure. At ratings above 3150A, the enclosures are cooled by forced air. Circuit Breaker cubicles will be configured for operation as either an Incomer, a Feeder or a Bus Section. To accommodate an increased power cable gland plate area, the enclosures can be increased in depth to 2000mm. 3.2 Cubicle Doors Both the associated relay compartment and Circuit Breaker front doors are hinged. The Circuit Breaker front door has a window to view the

position of the Circuit Breaker and the status of its closing spring. Doors can only be opened with a tool and are padlockable in the "Closed" position. Rear hinged doors are also provided for easier access to the cable termination chamber. 3.3 Circuit Breakers 3.3.1 Truck The Circuit Breaker is on a withdrawable truck, which has two locations inside its cubicle: "Service" and "Test/Disconnected". The Circuit Breaker truck can only be racked with the Circuit Breaker door closed and the door can only be opened when the Circuit Breaker is in the "Test/Disconnected" position. The truck is racked into either the "Service" or "Test/Disconnected" position by means of a loose racking handle. 3.3.2 Circuit Breakers Circuit Breakers from the following ranges can be fitted within the front housing of the enclosure:

ABB Type VD4 Vacuum Circuit Breaker ABB Type VM1 Vacuum Circuit Breaker ABB Type H/HR SF6 Circuit Breaker Toshiba Type VK Vacuum Circuit Breaker

A range of ratings is available from these Circuit Breakers. Technical data for the maximum range is as follows: Max rated voltage Max rated impulse test voltage Max rated AC test voltage Max rated current Max rated short circuit breaking current 13.8kV 95kV 38kV 4000A 50kA

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Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

Max rated short circuit making current Rated short circuit duration

125kA 3 seconds

3.3.6 Compartment Shutters The spout mouldings for the primary disconnect fixed contacts are covered by earthed metal shutters. The shutters are independently positively driven "Open" and "Closed" as the Circuit Breaker is moved to and from the "Service" location. Shutter mechanisms are independently padlockable in the "Closed" position. An additional option can be provided for direct padlocking of the shutter blades. 3.3.7 Secondary Disconnect The secondary plug cannot be removed unless the Circuit Breaker is in the "Test/Disconnected" position. This interlock is provided by the door interlock, which prevents access to the inside of the cubicle unless the Circuit Breaker is in the "Test/Disconnected" position. The secondary disconnect umbilical connection accommodates 58-off 1.5mm2 wires. A parking location is provided for the plug and umbilical cable when not in use. 3.4 Bus Section Transition Cubicles A Bus Section transition cubicle will be provided on the right hand side (Bus "B"+) of a Bus Section circuit breaker cubicle in order to route the bottom primary disconnect bus-bars back up to the horizontal bus-bar position. Within the transition cubicle, provision can be made to mount a withdrawable bus-bar earth truck. 3.5 Bus "A" Earth Truck/VT Cubicle As required, a dedicated cubicle will be provided to locate either: Bus Bar "A" Earth Truck and/or Bus Bar "A" VT

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Rated operating sequence 0-0.3 sec-CO-3min-CO or 0-3min-CO-3min-CO SF6 Circuit Breakers are provided with gas pressure alarm and monitoring facilities 3.3.3 Operating Mechanism A motor charged spring closing mechanism is fitted as standard. A manual spring charging facility can be fitted as an option. Electrical shunt trip and spring release (remote close) coils are fitted. Mechanical indicators show the Circuit Breaker condition: "Spring Charged/Spring Discharged" and "Circuit Breaker Open/Circuit Breaker Closed". Circuit Breakers suitable for a first auto-reclose cycle have a 0.3 second dead time, followed by further auto-reclose cycles with a 3-minute dead time to accommodate the spring re-charging time for the particular Circuit Breaker concerned. Circuit Breakers not designed for auto-reclose have an initial 3-minute dead time. An optional mechanical trip mechanism can be supplied to permit manual mechanical tripping of the Circuit Breaker with the door closed. 3.3.4 Operations Counter An operations counter is fitted to the Circuit Breaker, and is driven mechanically by the operating mechanism. 3.3.5 Primary Disconnect Contacts Each primary disconnect contact comprises two opposed rows of spring-loaded, self-aligning contact fingers fitted to the Circuit Breaker. The fixed contact is silver-plated copper.

Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

3.6 Circuit Earth Switches 3.6.1 Description A fault rated circuit earth switch can be mounted in a fixed position within the cable termination chamber. 3.6.2 Operation The operating mechanism is manual. The circuit earth switch is operated by attaching a loose handle to the drive linkage on the right-hand side of the Circuit Breaker compartment and rotating the handle anti-clockwise to close and clockwise to open. 3.6.3 Indication Indication of the circuit earth switch position is by a mechanical indicator operated from the earth switch shaft via a mechanically linked push cable system. Indication of the earth switch position is at the front of the switchboard. 3.6.4 Earth Switch Locking As a standard, the circuit earth switch can be padlocked in either the "Open" or "Closed" position. Alternative options allow:

3.7 Bus Bar Earthing 3.7.1 Description Withdrawable bus-bar earthing facilities can be optionally provided as follows:

On a common bus system/Bus "A" of a multiple bus system - a dedicated cubicle can house the Bus-Bar Earth Truck. On a multiple bus system, the Bus Section Transition Cubicle can house the Bus-Bar Earth Truck for Bus B+. With the circuit breaker removed, an incoming circuit breaker cubicle can be used as an insertion point for the Bus-Bar Earth Truck. This would be key figure interlocked to all associated Incomers/Bus Sections that may be present within the equipment configuration.

3.7.2 Operation of the Bus-Bar Earth Truck All racking and switching operations are to be achieved behind a closed door. Subject to interlock conditions being met, the BusBar Earthing Truck is racked into its "Service" position and then closed to apply the earth to the bus-bar. The Bus-Bar Earth Truck is interlocked as described below, to prevent racking in any direction when the switch is closed. The operating mechanism is manual. The Bus- Bar Earth Switch is operated by attaching a loose handle and extension rod, through the front door of the enclosure, and onto the drive linkage on the front of the Bus-Bar Earth Truck. Rotating the handle anti-clockwise will open, and clockwise will close, the Earth Switch. A locking facility is provided to lock access to the opening and closing of the Earth Switch. This can be used to lock the Earth Switch in the "Open" or "Closed" position.

The fitting of a key figure lock to permit manual mechanical interlocking of the circuit earth switch with remote switchgear/ equipment. The key can be configured to be trapped or released with the earth switch in either the "Open" or "Closed" position. The fitting of a blocking magnet to incomer/interconnector cubicle, which allows an electrical interlock via a volt-free contact from remote switchgear/equipment. The interlock can be either AC or DC operated.

3.6.5 Earth Switch Rating Circuit earth switches can be supplied with either 1 second or 3 second through fault ratings.

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Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

The Bus-Bar Earth Truck is transportable using a Circuit Breaker Service Trolley and can be used to earth different sections of bus-bar. 3.7.3 Indication

control voltage is not present (electromechanical interlock). The low voltage secondary disconnect plug can only be inserted or removed when the Circuit Breaker door is open. Circuit earth switches can only be closed when the Circuit Breaker is in the "Test/Disconnected" position or has been removed from the cubicle (mechanical interlock). The Circuit Breaker truck cannot be moved from the "Test/Disconnected" position into the "Service" position when the circuit earth switch is closed (mechanical interlock). The shutters can be secured independent of each other with padlocks when the withdrawable Circuit Breaker/Bus-Bar Earth Truck/VT has been removed. The Circuit Breaker Truck/Bus-Bar Earth Truck/VT can be padlocked in the Test/Disconnected position. Alternatively, a key figure interlock can be provided to interlock this operation with remote switchgear/equipment. Where the equipment configuration permits, the Bus-Bar Earth Truck will be interlocked with its respective Incomer and Bus Section current breakers, via an internal mechanical shuttle interlock. The Bus-Bar Earth Truck cannot be racked into the "Service" position until both the Incomer and Bus Section circuit breakers have been racked into the "Test/Disconnect" position. Neither the Incomer nor the Bus Section circuit breaker carriages can be racked back into the "Service" position, until the Bus-Bar Earth Truck is racked into the "Test/Disconnected" position.

Indication of the Bus-Bar Earth Switch position is achieved by a mechanical indicator operated from the Earth Switch shaft via a mechanical linkage. Indication of both the Bus-Bar Earth Truck position and Bus-Bar Earth Switch Open/Closed status is through the viewing window on the front of the enclosure. 3.8 Interlocks/Protection against Mal-operation A series of interlocks is provided to prevent fundamentally dangerous situations and any maloperation with possible serious consequences, thus protecting both personnel and the switchboard itself. The interlocks, which are supplied as standard, are as follows:

The Circuit Breaker can only be moved from the "Test/Disconnected" position into the "Service" position with the door closed. The door cannot be opened unless the Circuit Breaker is in the "Test/Disconnected" position. The withdrawable truck can only be moved from the "Test/Disconnected" position into the "Service" position (and vice versa) with the Circuit Breaker/Bus-Bar Earth Switch open (mechanical interlock). The Circuit Breaker/Bus-Bar Earth Switch can only be closed when the withdrawable truck is in the "Test/Disconnected" position or "Service" position (mechanical interlock). The Circuit Breaker can only be opened manually when a control voltage is not present. The Circuit Breaker cannot be closed when a

On systems which employ 3 or more feeds onto a single bus, a mechanical key figure interlock will be fitted to ensure all required circuits are locked in their Test/Disconnected position, prior to the Bus Bar Earth Truck being racked into the "Service" position.

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Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

3.9 Current Transformers (CT's) Located within the cable termination chamber, ring type 600V insulated CT's are mounted on earthscreened bushings which are fitted to the circuit side of the Circuit Breaker. The CT bushings are cast-filled epoxy resin and are rated to meet the maximum continuous current and short time fault rating of the respective enclosure. The CT ratios, their accuracy class and burden should be specified with the order. 3.10 Voltage Transformers (VT's) 3.10.1 Description All VT's are mounted in the front of the cubicle, at floor level, on a horizontal isolation/ horizontally withdrawable VT Truck. The VT truck employs a racking operating mechanism similar to that of the Circuit Breaker and Bus-Bar Earth Trucks. 3.10.2 Primary Disconnect Contacts Each primary disconnect contact comprises a row of spring-loaded, self-aligning contact fingers fitted to the VT. The fixed contact is silver-plated copper. 3.10.3 Primary Fuses Primary fuses are located within the primary contact arms of the VT. 3.10.4 VT Compartment Shutter The spout mouldings for the primary disconnect fixed contacts are covered by an earthed metal shutter. The shutter is positively driven "Open" and "Closed" as the VT is moved to and from the "Service" location. The shutter mechanism is padlockable in the "Closed" position. An additional option can be provided for direct padlocking of the shutter blade. 3.10.5 Circuit VT's Circuit VT's are located in the front of the cubicle, at floor level, within their respective circuit breaker cubicle as described above.

3.10.6 Bus Bar VT's For a common Bus/Bus "A" configuration, the Bus Bar VT truck is mounted within a dedicated Bus Bar Earth Truck/Bus Bar VT Truck cubicle. For a Bus "B"+ configuration, the Bus Bar VT will be located within the associated Bus Section cubicle. 4 Vacuum Contactor Cubicles 4.1 Enclosures All enclosures are 400mm wide and are configured for operation as either a Feeder or Motor Starter. Housed within the enclosure is an interchangeable, floor-mounted, withdrawable truck containing the vacuum contactor and certain accessories ­ called the "Contactor Truck". Interlocks are provided to ensure the safety of the operator and maintenance personnel and to ensure correct operational sequence of the equipment. 4.2 Front Doors Both the associated relay compartment and the Vacuum Contactor Cubicle front doors are hinged. The Vacuum Contactor cubicle front door has a window to view the status of the Vacuum Contactor and its closing spring. Doors can only be opened with a tool and are padlockable in the "Closed" position. 4.3 Vacuum Contactors (VCU's) 4.3.1 Contactor Truck The withdrawable Contactor Truck consists of a metal supporting frame, onto which the following equipment and devices are mounted: 4.3.2 A Vacuum Contactor Each contactor unit consists of a contactor/fuse combination which is fully tested for Type "C" Coordination to IEC 60632. The vacuum contactors are designed to be used on circuits rated up to 400A and voltages up to 7.2kV (see Table A for further details)

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Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

Vacuum contactors as standard are electrically held. Mechanically latched vacuum contactors can be supplied as an option. 4.3.3 Fuses Three MV HRC current limiting fuses are connected in series with the contactor, for protection against short circuits, complete with supports and a mechanical "Fuse Blow" device which trips the contactor when a fuse operates. 4.3.3.1 Fuse Ratings The maximum fuse rating which can be accommodated is 2 x 315A fuses in parallel at 7.2kV. 4.3.3.2 Fuses for Motor Protection Motor protection fuses protect against short circuits and provide back up protection against overcurrents due to overloads, single phasing, locked rotor and excessive starting up. They are coordinated with the contactor to protect the contactor from breaking fault currents higher than its breaking capacity.

4.3.4 Contactor Control Supplies As standard, it is assumed that an external control supply will be used for contactor control. Alternatively, a single-phase voltage transformer, complete with protection fuses, can be provided, to supply measuring instruments, protection relays or the closing electro-magnet. The VT primary fuses are located on the withdrawable truck, mounted integrally within the main circuit fuse holder mounting. Coil voltages are as detailed within Table A of this specification. 4.3.5 Primary Disconnects Six male plug-in isolating contacts are used to isolate the truck from bus-bar and circuit conductors. 4.3.6 Secondary Disconnects

4.3.3.3 Fuses for Transformer Protection When vacuum contactors are used for switching power transformer primary circuits, they are provided with back-up fuse protection. The fuses selected should be of a current limiting type, co-ordinated with other protection devices. They should also be able to withstand repeatedly the magnetising current surge, which occurs when the transformer is energised. 4.3.3.4 Fuses for Capacitor Protection The use of the vacuum contactor for protection and control of capacitors occurs in combination with current limiting fuses. The assembly is designed so as to be capable of withstanding the high inrush current peak associated with capacitor switching.

A multiple contact plug for the auxiliary circuits of the contactor is provided, complete with parking postion when not in use. 4.3.7 Contactor Status Indication Mechanical flag indication of the Contactor open/closed status is available as standard on the front of the contactor. This is viewed through the window on the front of the contactor enclosure. 4.4 VCU Operation All VCU truck insertion and isolation operations are carried out from the front of the enclosure with the front door closed. The carriage is racked into either the "Service" or "Test/Disconnected" position by means of a loose racking handle.

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Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

4.6 Interlocks In the "Test/Disconnected" position, the truck is completely housed within the enclosure with the door closed. The carriage position is viewed through a window in the VCU compartment. The design ensures the earthing of the truck structure over its full isolating stroke. 4.5 Circuit Earth Switch An earth switch with peak making capacity up to 15.8kA is provided to earth the outgoing cable. Mounted inside the cable termination chamber, the mechanically operated earth switch is fully interlocked with the contactor truck. As a standard, the earth switch is manually closed by pressing a mechanical pushbutton on the front of the enclosure. Two optional arrangements are available whereby the earth switch can be automatically closed: Interlocks are provided as standard for the enclosure and contactor truck as follows: The contactor cannot be closed unless the truck is fully in the "Service" position or "Test/Disconnected" position. The truck cannot be moved from the "Service" or "Test/Disconnected" position unless the contactor is open. Mechanical interlock that automatically opens the earth switch when the contactor truck is racked in. The enclosure door cannot be opened when the truck is in the "Service" position. The truck cannot be inserted into the "Service" position until the enclosure door is closed.

4.7 CT Accommodation Located within the cable termination chamber, "Ring" type 600V insulated CT's are mounted on earth screened bushings which are fitted to the circuit side of the Vacuum Contactor. The CT bushings are cast-filled epoxy resin and are rated to meet the maximum continuous and letthrough fault current. The CT ratios, their accuracy class and burden should be specified with the order. 4.8 Shutters The spout mouldings for the primary disconnect fixed contacts are covered by earthed metal shutters. The shutters are independently positively driven "Open" and "Closed" as the contactor is moved to and from the "Service" position. An over-centre mechanism is provided to allow each shutter to be independently kept open for test and inspection purposes. Operation of the respective shutter mechanism is automatically restored the next time the contactor truck is racked from the "Service" to the "Test/Disconnected" position.

Automatically when racking out from "Service" towards the "Test/Disconnected" position, or Automatically when removing the contactor Truck from "Test/Disconnected" position out from the enclosure into the substation.

The earth switch can only be opened by racking the Contactor truck into the "Service" position. Contactor Truck padlocking facilities are available to allow: Padlocking of the contactor truck in the "Test/Isolated" position with the front door interlock closed. Padlocking of the earth switch in either the "Open" or "Closed" position.

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Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

Shutter mechanisms are independently padlockable in the "Closed" position. As an additional option, padlock facilities can be provided for directly locking each shutter blade. 5 Cable Terminations 5.1 Power Cable Termination Power cables can be either top or bottom entry and are terminated onto power bushings with the following fixings: 450mm cubicle 650/800/1000mm cubicles M10 fixing M12 fixing

segregated trunking to allow the routeing of cables into the LV compartment. 5.3 Cable Termination Kits On 13.8kV and/or 95kV BIL rated systems, S&I will supply as standard, proprietary power cable termination shrouds which must be fitted over the completed cable termination and its respective bushing. Proprietary cable termination kits, cable glands and cable lugs are not supplied as standard, but are available upon request as an additional option. 6 General 6.1 Ingress Protection The exterior of all cubicles is built to the standard ingress protection of IP4X to (IEC 60529 : 1991) IEC 60298, which can be optionally enhanced to IP42 upon request. The minimum interior degree of ingress protection between segregated chambers is IP4X as standard. The minimum degree of ingress protection with a cubicle door open is IP2X giving finger-proof protection. 6.2 LV Compartment

Power cable gland plates are mounted integrally within the overall footprint/envelope of the cable termination chamber. The 650/800/1000mm width cubicles can be optionally extended to 2000mm depth to increase the cable glanding area by 400mm. On circuits where single core cables are to be installed, brass gland plates are fitted as standard. On circuits where multi-core power cables are to be installed, mild steel gland plates are fitted as standard. As an option, alternative gland plate materials are available upon request. 5.2 Auxiliary/Control Cable Terminations Multi-core cables can be either top or bottom entry and are terminated within a segregated block of field cable terminations within the LV compartment. Standard glanding facilities are provided at: The top of cubicle directly on and into the respective LV compartment The bottom left-hand side of the cubicle, accessible behind a removable cover plate located within the functional chamber at the front of the housing. An optional, top rear externally-mounted bottom entry cable termination box with internally

An LV compartment is mounted on the top front of every cubicle. As required by the specification, protection relays, meters and switches are accommodated on a hinged front door. Bus wiring terminations, communications cable termination units, auxiliary relays, fuses, carriage switches, multi-core terminals etc. are mounted on an equipment mounting plate, which is internally fixed to the back wall of the LV compartment. Cubicles which do not have any equipment mounted on the door are fitted with a removable

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Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

hinged blank door, which can be equipped at a later date if required. All LV Compartment doors are padlockable and additionally require a special hand tool to open the door fastening. Control wiring is PVC-insulated, having a minimum cross-sectional area of 1.0mm2, except for bus wiring and CT secondary wiring which will have a minimum cross sectional area of 2.5mm2. The cable complies with BS6231 and is tri-rated for use up to 105oC. 6.3 Surge Arrestors As an additional option, Surge Arrestors, which are sized to operate at the specified rated system voltage, can be fitted within a cable termination chamber. 6.4 Voltage Indication As an additional option, Capacitive Neon Voltage Indicators can be provided to display the presence of a voltage on either a circuit or bus- bar conductor. 6.5 Cubicle Heaters A 100W heater is fitted within the functional unit of each housing. These are commonly controlled from a thermostat, or optionally a humidity controller, mounted within the LV compartment of either the incomer or bus section LV Compartment. 6.6 Paint Finish The main framework and internal faces of the switchboard are finished in Aluzinc. The standard paint colour for doors and cover plates is grey to RAL 7032. Alternative paint colours and finishes are available as an additional option.

6.7 Labels Circuit title labels are of the Gravoply plastic sandwich type with black letters on a white background. Standard instruction and identification labels are manufactured in Gravoply plastic sandwich with black letters on a white background. As an additional option, labels can also be manufactured in either aluminium, stainless steel or screen printed with black letters on a white background. Warning labels of the permanent self-adhesive type are attached to all removable covers, behind which are situated live, high-voltage, connections and where such connections are the main bus-bars, an additional label inscribed "BUSBARS" is fitted.

6.8 Protective Circuits and Earth Conductor Bonding The metal cases of instruments, relays, switches etc. are connected by continuous connection to the earth bar. Panel doors supporting ancillary equipment are separately earthed to the main cubicle. Main earth bars are 1 x 50mm x 10mm tin-plated HDHC copper and are rated to meet the maximum fault level of the switchboard. 7 Accessories 7.1 Circuit Breaker Service Trolley A Circuit Breaker Service Trolley will be provided for each installed width of circuit breaker cubicle to facilitate the insertion/removal of a circuit breaker from its cubicle. The Service Trolley is fitted with multi-directional castors to increase mobility around the substation.

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Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

The Service Trolley is locked into the front housing of the circuit breaker cubicle prior to withdrawal of the circuit breaker onto the service trolley. Once withdrawn onto the Service Trolley, the Circuit Breaker is securely locked in position and interlocked against the insertion of a racking handle whilst on the Service Trolley. Each Service Trolley provides lockable storage space for the other loose accessories which are supplied as required. 7.2 VT Installation Ramp As standard, a ramp is supplied to facilitate insertion and removal of a VT from a cubicle. 7.3 Racking Handle A common racking handle will be supplied and used for racking Circuit Breakers, Vacuum Contactor Trucks, Bus Bar Earthing Trucks, Test Bushings and VT's. 7.4 Door Fastening Tool A common door fastening tool will be provided and used for closing all hinged doors ensuring an adequate door seal pressure between the door and the cubicle housing. 7.5 Extended Umbilical Test Leads Where the facility to undertake functional testing of a circuit breaker or a vacuum contactor is required to be performed with the unit withdrawn from the cubicle, an extended umbilical test lead can be provided as an option.

7.6 Test Bushing A Test Bushing can be optionally provided to facilitate both the 3-phase primary injection and power frequency testing of the system. The Test Bushing, which is mounted on a withdrawable truck, is configurable to allow testing of either the Bus-Bar or Circuit connections. Once inserted into the "Disconnected" position, it can be racked into the "Service" position within a Circuit Breaker cubicle. Extended cable terminations allow the connection of test equipment prior to racking the Test Bushing into the "Service" position.

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Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

Table A ­ Vacuum Contactor Specification

TYPE FORM Rated insulation voltage Rated operational voltage Rated operational current Interrupting current (Duty) Rated frequency Making current (100 times) Breaking current (25 times) Short-time current Over current strength (peak value) Between live parts and ground Impulse withstand voltage Between main conductors CV-6HA 7200V 3300/6600V 400A 6300A (0-2 min.-CO) 50/60Hz 4000A 3200A 2400A-30s 4000A-12s 8000A-2s 85kA ­ 10ms 60kV 60kV 22kV AC 1 min. 1200 times/hour (AC3) 300 times/hour (AC3) 2.5 million operations 0.25 million operations 0.25 million operations 0.25 million operations 100/110, 115/120, 100/110, 115/120, 200/220, 200/220, 230/240V 230/240V AC/DC AC/DC 100/110, 120/125, 200/220, 240/250V DC 85% to 110% of the rated control voltage 5.0A 5.5A 0.6A 5.0A 70-80ms 15-25 ms 85% or less of rated control voltage (hot state) 60% or less of rated control voltage (cold state) 3NO-3NC 2NO-2NC Max.480V, Min. 48V 10A 700VA (PF.0.35) 60W (L/R 150 ms) Floor mount vertical installation 1000m or lower o -5 to 40 C 45-85% Max. 20Hz 1G Max.30G 1500/3000kW 1500/3000kW 2000/4000kVA 2000/4000kVA 2000/2000kVA 1000/2000kVA 19.5kg 20kg CV-6HAL 7200V 3300/6600V 400A 6300A (0-2 min.-CO) 50/60Hz 4000A 3200A 2400A-30s 4000A-12s 8000A-2s 85kA ­ 10ms

Dielectric strength Switching frequency Mechanical life Endurance Electrical life Rated control voltage Closing Tripping

Allowed control voltage fluctuation Closing current at 100-110V Holding current at 100/110V Tripping current at 100-110V Closing time Opening time Minimum pick-up voltage Maximum trip voltage Contact arrangement Operational voltage Ratings of Auxiliary Thermal current Contact AC capacity DC capacity Installation Altitude Ambient air temperature Application Relative humidity Vibration Shock Motor Max. applicable Transformer load capacity Capacitor (with reactor) Weight (approx.)

Page 14 of 16

Type 298 DB1 MV Switchgear Technical Design Spec Rev B ­ Jan 07

1600 900 700

510

400

LV CHAMBER

EMKA 1000 -U345

ISOLATION DISTANCE 200MM

SAFETY SHUTTERS

700

SECONDARY CONTACTS

CIRCUIT BREAKER

205

OFF

OJWN 12/63

260

CIRCUIT BREAKER CRADLE

ON

ABB(2) 750

CIRCUIT VT

Page 15 of 16

Powell Electrical Group Switchgear & Instrumentation Ltd. Ripley Road, Bradford BD4 7EH, UK

Tel: +44 (0) 1274 734221 Fax: +44 (0) 1274 731390 www.powellind.com [email protected]

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