mv fixed metalclad switchgear spec

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					Specification for Tender                                                             5ddf99c1-cbae-49f3-9b68-d6e3df30a9f9.doc




                           General Specification for medium
                           voltage metalclad distribution fixed
                           switchgear
                           The requirements define: -
                                  - The scope of the switchboard
                                  - The technical specification of the switchboard
                                  - The switchboard construction
                                  - The manufacturers requirements
                                  - The installation and operational aspects




Last update : 2011-11-22                                                                                             -1-
Specification for Tender                                                                                                        5ddf99c1-cbae-49f3-9b68-d6e3df30a9f9.doc




Table of contents:
  1.      Introduction ............................................................................................................................................................. 3
  2.      Scope of Works ....................................................................................................................................................... 3
  3.      Standards ................................................................................................................................................................ 3
  4.      Factory Tests .......................................................................................................................................................... 3
  5.      Ratings .................................................................................................................................................................... 4
  6.      Construction ............................................................................................................................................................ 4
       6.1 General ................................................................................................................................................................. 4
       6.2 Main HV Cable Box .............................................................................................................................................. 5
       6.3 Busbar End Cable Box ......................................................................................................................................... 5
       6.4 Pilot Cable Box ..................................................................................................................................................... 5
       6.5 Circuit Breaker ...................................................................................................................................................... 5
       6.6 Demounting of the circuit breaker ........................................................................................................................ 5
       6.7 Series Isolator ....................................................................................................................................................... 5
       6.8 Current transformers ............................................................................................................................................ 6
       6.9 Circuit voltage transformers ................................................................................................................................. 6
       6.10 Voltage presence indication (VPIS) .................................................................................................................... 6
       6.11 Secondary Wiring ............................................................................................................................................... 6
       6.12 Mechanism ......................................................................................................................................................... 6
       6.13 Internal Arc ...................................................................................................... Error! Bookmark not defined.7
  7.      Indication and Labels .............................................................................................................................................. 7
       7.1 Rating Label ......................................................................................................................................................... 7
       7.2 Circuit labels ......................................................................................................................................................... 7
       7.3 Phase Indication ................................................................................................................................................... 7
       7.4 Language .............................................................................................................................................................. 7
  8.      Installation and Operational Requirements............................................................................................................. 7




Last update : 2011-11-22                                                                                                                                                      -2-
Specification for Tender                                                              5ddf99c1-cbae-49f3-9b68-d6e3df30a9f9.doc




1. Introduction
   This specification covers the technical requirements for fixed, indoor, extensible type metalclad switchgear,
   comprising 200, 630 & 1250A circuit breakers, 630A and 1250A bus section circuit breakers and associated
   components.


2. Scope of Works
   The work shall comprise the design, manufacture, type and routine testing, supply and delivery of the completed
   equipment.

   Each manufacturer shall submit a data sheet with the tender containing single line diagram of the panel showing
   protection, metering and indication, outline dimensions and detailed technical description of protection, control,
   CT’s and VT’s, indication and instrumentation. The manufacturer shall also provide schematic diagrams of the
   equipment offered and shall be able to produce type test certificates for all tendered products if so requested.
   Failure to do so shall result in the tender being disqualified.

   All equipment offered shall be manufactured at a factory which complies to the following standards:-

   ISO 9001                 -       Quality management system requirements
   ISO 14001                -       Environmental Management System

   When requested certification confirming the factory of manufactures compliance with the above shall be submitted,
   failure to do so shall result in the tender being disqualified.


3. Standards
   All equipment shall be designed and manufactured to the latest revision of the following International and British
   Standards except where specifically defined otherwise:-

   IEC 60694               - Common specifications for switchgear & control gear
   IEC 62271-100           - High Voltage AC Breakers
   IEC 60265               - High Voltage AC Switches
   IEC 62271-200           - Metal Enclosed Switchgear & Control Gear
   IEC 62271-102           - HV AC Disconnectors & Earthing Switches
   ENA TS 41-36            - UK Energy Network Association Technical Specification for Distribution Switchgear*

   *All suppliers shall be able to provide copies of the certificate issued by the Energy Network Association (ENA)
   assessment panel to confirm compliance with this standard if so requested.


4. Factory Tests
   All equipment offered shall be comprehensively routine tested prior to dispatch, a test certificate verifying these
   have been carried performed shall be supplied with each item of equipment. It is essential that a partial discharge
   test is carried out routinely on each piece of equipment. Failure to do so shall result in the tender being
   disqualified.

   When requested it shall be possible to witness the routine tests in the UK.




Last update : 2011-11-22                                                                                              -3-
Specification for Tender                                                                5ddf99c1-cbae-49f3-9b68-d6e3df30a9f9.doc




5. Ratings
   Busbar current                                     - 630/1250 Amps for 3 seconds
   Short time withstand current (main & earth)        - 25kA for 3 seconds
   Making current (main & earth)                      - 67.5kA peak.
   Normal current rating CB                           - 200A / 630A / 1250A
   Normal current rating isolator                     - 200A / 630A / 1250A
   Rated voltage                                      - 13.8kV
   Service voltage                                    - 3.3, 6.6, 11, 13.8kV
   Rated BIL                                          - 95kV


6. Construction

   6.1 General

   The equipment shall be of the indoor, extensible, metalclad, vacuum insulated, fixed / demountable type, fabricated
   from a minimum of 2mm sheet steel. The maximum panel width shall be 500mm for an incomer / feeder and
   1000mm for a bus section. The panels shall have an ingress protection of no less than IP3X. All busbar, CT and
   VT chamber covers shall be removable for installation. The LV cabinet shall be mounted no greater than 1.6m
   from ground level and contain all instrumentation, metering and protection devices. A separate wall mounted relay
   panel may be supplied for an incoming panel.

   The equipment fascia shall have a comprehensive, unambiguous mimic system which clearly indicates the position
   of the series isolator and vacuum circuit breaker. The fascia will have a screen printed mimic comprising white line
   marking on a black / dark grey background and be marked ‘Circuit breaker’ or ‘Bus-section’ to identify the device
   type.

   The vacuum circuit breaker and series isolator labelling must indicate: circuit breaker main ‘On’, ‘Off’, and series
   isolator ‘Main select’, ‘isolated’, ‘earth select’ and be located within the mimic white lining indicating the selected
   circuit, to clearly indicate the status of the contact arrangement. The use of a single ‘O’ and ‘I’ to indicate the
   contacts status is not permitted on the panel mimic. The mimic shall indicate that the main or earth circuit has been
   selected.

   For circuit breaker units the main spring condition shall be indicated by means of a label with indication of ‘Springs
   charged’ and ‘Springs free’. Indication must take place through a single window for both cases and both labels
   must not be visible at the same time. A third position shall be available to indicate ‘Springs charged’ yet not ready
   to be released. This shall indicate when the close spring is charged but the circuit breaker is in the ‘On’, it shall
   revert to ‘Springs charged’ once the circuit breaker has been opened.

   Selection between MAIN and EARTH for the circuit breaker is to be achieved by means of a mechanically operated
   interlock. The position may be locked by means of an ENA TS 41-36 standard padlock in either the earth or main
   position. There must be labelling on the sliding lever to indicate the Main or Earth position.

   A mechanically driven operation counter shall be fitted on the front of the unit.

   The label colouring must be as follows;

   Springs charged                        - black lettering on yellow background
   Springs free                           - black lettering on white background
   On                                     - white lettering on red background
   Off                                    - white lettering on green background
   Earth on                               - black lettering on yellow background

   Selection between MAIN and EARTH for both the switches and circuit breaker is to be achieved by means of a
   mechanically operated sliding lever situated on the equipment fascia. It shall be possible to fix an ENA TS 41-36
   standard padlock to the fascia preventing the panel from being moved to the ‘On’ position. The fitting of this
   padlock shall not prevent operation of either the ‘Earth’ or ‘Off’ positions. It shall also be possible to fix a padlock to
   the fascia preventing the panel from being moved to the ‘Earth’ position. The fitting of this padlock shall not

Last update : 2011-11-22                                                                                                -4-
Specification for Tender                                                                5ddf99c1-cbae-49f3-9b68-d6e3df30a9f9.doc




   prevent operation of either the ‘Main’ or ‘Off’ positions. The padlock arrangement shall not work on the principle of
   transferring the same lock, it shall be possible to have both locks fitted at the same time preventing the unit from
   being moved from the ‘Off’ position.

   A mechanically driven operation counter shall be fitted on the front of the unit.

   6.2 Main HV Cable Box

   The HV cable box shall comply with ENA TS 41-36 shall be suitable for accepting 1 x 3 core / 3 x 1 core cable on
   the 630A units and 2 x 3 core / 6 x 1 core on the 1250 Amp units, as standard from bellow. Inverted cable boxes
   shall be available as an option for accepting main cable entry from above.

   The cable boxes shall be suitable for accepting and terminated HV cables up to 400mm² three core and 630mm²
   single core per phase.

   Cable terminations shall not necessitate the need for a cable basement, the switchgear shall be installed in front of
   a conventional cable trench. To reduce the chance of the HV cable glands protruding into the cable trench there
   shall be minimum clearance of 220mm from the top of the trench to the bottom of the gland plate.

   All cable termination’s shall be of the dry type.

   6.3 Busbar End Cable Box

   It shall be possible to bolt a simple type BECB on the RHS or LHS of the switchboard for accepting up to 2 x 3 core
   / 6 x 1 core cable approaching from above or below. The box shall be suitable for dry type termination’s.

   6.4 Pilot Cable Box

   Each unit shall be equipped with a top entry pilot cable box mounted at the rear of the unit, complete with all
   associated terminals and wiring for remote operation of the equipment. There shall be a removable gland plate
   fitted to the top of the pilot wiring box with prefabricated knock outs to prevent the need to drill the plate on site. The
   customer interface terminals shall be of the screw type design. The manufacturer shall be able to supply a terminal
   wiring diagram at time of tender if so requested.

   6.5 Circuit Breaker

   The circuit breaker shall utilise vacuum interrupters for the insulating medium. The vacuum bottles and switchgear
   panel shall be manufactured by the same company. The vacuum bottles shall utilise the axial magnetic field
   technology and be of a single ceramic construction. The contact arrangement shall be of the ON or OFF type with
   the open contacts of the vacuum circuit breaker shall not provide an isolating distance, a separate in line off load
   isolator shall be utilised to provide a means of isolation. It shall not be possible to switch directly from main on to
   earth on under any circumstances.

   The circuit breaker shall have an endurance of 10,000 operations up to and including load current and 100
   operations at maximum fault current.

   6.6 Demounting of the circuit breaker

   In the unlikely event that it is necessary, it shall be possible to remove the circuit breaker, complete with
   mechanism and vacuum interrupters, without disturbing the adjacent panels. The manufacturer shall provide real
   time video evidence to prove that this can be achieved within 30 minutes, operation and maintenance manuals or
   method statements detailing the process shall not be acceptable. This operation should be possible without the
   need for special tools and no proprietary device shall be required.

   6.7 Series Isolator

   The series isolator shall consist of sealed for life controlled air device housed in a cast resin enclosure. The cast
   resin enclosure shall be provided with a full earth screen to eliminate electrical stresses. The busbar connection
   from the isolator shall be fully encapsulated with single point fixing and connected with EPDM rubber connections.

Last update : 2011-11-22                                                                                                -5-
Specification for Tender                                                             5ddf99c1-cbae-49f3-9b68-d6e3df30a9f9.doc




   Fully earthed screened busbars and cable termination’s shall be available as an option for use in harsh
   environments to reduce the possibility of a fault. This single component shall be maintenance free.

   The series isolator shall be suitable for 2,000 of load operations.

   6.8 Current transformers

   The CT’s shall be of the bar primary ring type. It shall be possible to change the CT’s on site if necessary. It is
   permissible to access the CT chamber via the MV cable box.

   CT’s shall comply with the following local and international standards BS 3938, IEC 60044-1.

   6.9 Circuit voltage transformers

   The VT’s shall be of the air insulated, fixed, cast resin 3 x single phase type with a secondary voltage of 110V. The
   VT’s shall have a burden of 50VA and be of class 0.5 / 3p. Each VT shall be suitable for fitting 1 x 3.15 Amp HV
   fuse.

   The fuses shall be housed in an individual cast resin encapsulated carrier and shall be easily removable for HV
   pressure testing via access from the front of the panel.

   Circuit VT’s shall be mounted within the panel housing with no additional panel width. Busbar VT’s shall be housed
   in a dedicated panel for busbar related metering and or protection. The addition of a busbar VT shall not increase
   the overall height or depth of the switchboard arrangement.

   VT’s shall comply with the following local and international standards BS 3941, IEC 60044-2.

   6.10 Voltage presence indication (VPIS)

   Permanent live line indication shall be offered as standard on all panels. They shall be of the Voltage Presence
   Indication System (VPIS) design to IEC 61958. In addition to the permanent indication a test socket shall be
   provided suitable for accepting 4mm banana style sockets which can be used for verifying the indicator and
   phasing out between panels. The Pfisterer test device shall operate with these test sockets without the need for an
   interface connector.

   A bus section panel shall have both right and left hand side busbar voltage presence indication.

   6.11 Secondary Wiring

   All secondary wiring and components shall comply with EA 50-18. Secondary wiring shall comprise stranded 1.5
        2        2
   mm or 2.5mm PVC wire coloured ‘black’. Wire end termination’s shall be BICC crimped connector type and
   terminal boards plus CT/VT test terminals shall be of Klippon manufacture. Secondary MCB’s shall be of the
   MERLIN GERIN type. 240V AC terminals shall be segregated and shrouded.

   6.12 Mechanism

   The mechanism shall be self lubricating, requiring minimal maintenance and manufactured from plated / treated
   steel, phosphor bronze and other corrosion resistive materials. The operating handle shall be of an integral racket
   design with a multi stroke action to charge the mechanism. Directly driven flags from the mechanism shall provide
   visual indications of circuit breaker springs charged, CB main on/off closing and tripping of the circuit breaker
   mechanism shall be by means of mechanical push buttons on the front of the unit.

   CB                      - Stored energy operation by means of energy stored in a motor
                           - charged spring with manual and electrical release.
   Disconnector:           - Interlocked dependant manual




Last update : 2011-11-22                                                                                             -6-
Specification for Tender                                                               5ddf99c1-cbae-49f3-9b68-d6e3df30a9f9.doc




   6.13 Internal Arc

   The equipment shall be designed, tested and manufactured to prevent any faults occurring in service. However, in
   the extremely unlikely event of fault, the unit shall be internal arc tested to prevent injury to the operator personnel.
   The equipment shall be type tested in accordance with ENA TS 41-36, that defines which chambers of the
   metalclad enclosure shall be internal arc rated to IEC 62271-200. The internal arc performance of the equipment
   chambers shall be 100% of the rated breaking capacity of the circuit breaker.
   IAC AF minimum required


7. Indication and Labels

   7.1 Rating Label

   The equipment shall be fitted with a permanently fixed, non fading rating label which is located at the front of the
   equipment within easy view of the operator. The label will comply with ENA TS 41-36 with regard to the content of
   the information.

   7.2 Circuit labels

   The equipment will be fitted with removable circuit labels which may be engraved with suitable inscriptions by the
   customer. The circuit labels shall comply with ENA TS 41-36 providing black lettering on a white background. The
   labels shall be positioned within easy viewing of the operator and fitted to none removable covers on the
   equipment.

   7.3 Phase Indication

   Phase indication by indelible, coloured and numbered markers for cabling and test purposes are provided on non
   removable covers adjacent to the equipment terminals.

   7.4 Language

   The language used for all labelling shall be English, unless otherwise agreed within the contract.


8. Installation and Operational Requirements
   8.1 Cable Sizes

   CB:             3 phase cable          max. core size             300mm sq.

   Cable sizes larger than those detailed above may be agreed with the manufacturer.

   8.2 Cable Termination’s

   Type:      Air using cable termination kits - heat shrink or cold termination (optional)
   Approved manufacturers:     Raychem; Sigmaform; Pirelli

   8.3 Earthing

   Housing: One earthing point is to be provided at the rear of the unit, to allow connection to station earth. All panel
   earth’s are terminated to this point. Flexible shunts connect the cable glands to the equipment main earth.

   8.4 Operation - Circuit breaker

   The circuit breaker closing springs shall be charged by means of a multi stroke fixed handle.

   All operations shall be carried out from the front of the unit.
Last update : 2011-11-22                                                                                               -7-
Specification for Tender                                                              5ddf99c1-cbae-49f3-9b68-d6e3df30a9f9.doc




   Closing of the circuit breaker shall be by means of a mechanical close button on the front of the unit or electrical
   closing coil. Closing of the mechanism shall charge the circuit breaker opening springs allowing the closing springs
   to be re-charged for auto closing duty.

   Tripping of the circuit breaker shall be achieved by a mechanical trip push button on the front of the unit or
   electrical trip coil.

   The closing and opening springs are compressed to their working length before energy is transferred to the contact
   system.

   The mechanism shall be trip free and cannot be stopped once spring assistance has taken place and must be fully
   opened or closed before further operations are allowed.

   The circuit breaker mechanism can be closed electrically by means of an electrical motor (optional extra) which
   charge the closing springs as indicated within the circuit breaker operation above.

   8.5 Operation – Series Isolator

   The series isolator shall be operated from the front of the unit and shall consist purely of an off load device. The
   unit shall be interlocked without the use of external keys to ensure that the dependant manual mechanism can only
   be operated when the vacuum circuit breaker is in the main off position.

   8.6 Operation – Circuit Earthing

   Circuit earthing shall be achieved through to operation of the series isolator from the isolated position to circuit
   earth and then the vacuum circuit breaker closing thus earthing the circuit. The circuit earth shall be fully rated.

   8.7 Cable Earth / Test

   Cable earth/test terminal access is only allowed with the switch in the earth on position. This allows the earth
   connecting bar to be removed for test.

   8.8 Manual Trip / Close Pushbuttons

   The trip/close pushbuttons shall be padlockable. It shall be possible to either the trip or close or both manual push
   buttons with a single padlock.




Last update : 2011-11-22                                                                                              -8-

				
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