11kv switchgear

190 of 221 75/10455/41747 Multi Purpose Hall at Qatar University Electrical Specifications Rev. A

21. 11 KV PANELS and VACUUM TYPE CIRCUIT BREAKERS FOR USE ON THE 11KV DISTRIBUTION SYSTEM

21.1 SCOPE: The design, manufacture, testing, supply, delivery and performance requirements of 11kV vacuum circuit breakers for use on the Electricity Networks Distribution system. The switchgear shall be of any of the following generic types, subject to the conditions stated in this Specification and shall fully conform to Kahramaa latest Specification/requirement.

The switchgear will be installed in purpose made buildings, which will not usually be air-conditioned. The switchgear will be of the 'Indoor' type,

i) Arc interrupting media - vacuum

ii) Circuit breaker isolation and - withdrawal:

a) truck mounted vertical isolation, horizontal withdrawal.*

OR

b) truck mounted horizontal isolation, horizontal withdrawal.*

* Meaning that the integral truck operates at floor level, and that no ancillary devices are needed to move the circuit breaker.

iii) Feeder earthing facilities:

a) Integral, using the circuit breaker without special attachments.

OR

b) Integral using a fully rated spring assisted manual independent switch located within each fixed portion.

iv) Busbar Earthing:

a) Integral, using the circuit breaker

OR

b) Integral, using a fully rated, spring assisted manual independent switch located within each fixed portion.

OR

c) Using suitable interlocks, the feeder earthing switch(es) may be used for busbar earthing also.

OR

d) Using loose light weight portable earthing truck.

Particular details of these options are specified within the body of this specification.

The specification is based upon, or has reference to, the following international Standards:


IEC 60298 1994 A.C Metal Enclosed Switchgear and Control Gear.

IEC 60529 1999 Classification of Degree of Protection provided by enclosures.

IEC 60694 1996 Common specification for High Voltage Switchgear and Control Gear,

IEC 60044 1996/97 Instrument Transformers part 1 & 2,

IEC 60056 1987 High Voltage A.C. Circuit Breakers,

All Standards shall include all additions or amendments to date.

In all cases of variance between this Specification and the relevant Standards, the requirements of this Specification shall prevail. In cases of variance between the International Standards, the most onerous condition shall prevail.

The equipment shall have been manufactured to a standard equivalent to ISO 9001.

21.2 SYSTEM & ENVIRONMENTAL CONDITIONS

21.2.1 A) Environmental Conditions:

The following conditions prevail generally throughout the State of Qatar:-

1. Altitude - Low lying, generally close to sea level, no point exceeding 100 metres above sea level.

2. Maximum air temperature 50°C (46°C typical).

3. Minimum air temperature 0°C (10°C typical).

4. Mean maximum Summer air temperature, 45°C typical.

5. Mean maximum exposed sunlight temperature, 75°.

6. Solar Radiation - Peak, 1030 Watts/Sq.m.

7. Humidity -100% Humidity is common throughout the year and may occur at air temperatures of 30°C or more,

8. Rainfall Very low on average. The Winter Season may bring infrequent very heavy rainfall.

9. General Atmospheric Conditions: A hot atmosphere containing very fine, highly penetrating dust particles. In parts the atmosphere contains a highly corrosive salt laden sea mist. Prevailing winds generally from the northwest mostly light but occasionally gusting in excess of 30 knots.

10. Ground temperature at one meter depth in summer is typically 35° C,

11. General Ground Conditions: -

a) Very dry limestone type, including rock. Typical Thermal Conductivity 2.0 to 4.0 deg.C CM/W.

b) Very wet, high salt and sulphate content, very corrosive.

B) System Conditions:

The 11 kV system has three phase and earth


Nominal Voltage : 11kV

Maximum Voltage : 12kV

Maximum Symmetrical fault level : 25kA

Limited earth fault current through earthing transformer : 4.5 kA

Frequency : 50 Hz

Impulse : 75 kV

21.3 TYPE OF SWITCHGEAR

21.3.1 Overall Design

The Switchgear required is of a type using vacuum arc interrupter, The interrupters shall be from one of Kahramaa’s approved vendors

It shall be strictly in accordance with the current edition of IEC Standard 60529 except where otherwise required in this Specification.

The Switchgear shall consist of a single busbar, metal clad, indoor type integrated unit incorporating enclosures for Circuit Breaker Units, busbar, current and voltage transformers and auxiliary wiring. The Switchgear shall be configured as required by the Schedule of this Specification and the manufacturer shall supply all necessary busbar couplings, end plates, foundation bolts and cubicles bolts to enable the switchgear to be assembled.

The Switchgear panels shall be equipped with the necessary Protection, Control Devices, Instruments, Fuses, Labels, Operating Tools and all other loose items required to install and operate the Switchgear.

The Switchgear, shall be of robust construction and shall be designed generally for maximum reliability of service.

Cable sealing boxes, glands and terminal lugs shall be supplied with the Switchgear in accordance with the Schedule to this Specification.

The design of the Circuit Breakers and Secondary wiring must be such that any Circuit Breaker can be interchanged with any other Circuit Breaker of the same rating supplied under this tender, without affecting the tripping, inter-tripping and normal protection and indication functions.

21.3.2 The Enclosure and Compartment

The enclosure shall be of the enclosed metal-clad type. The minimum degree of protection shall be fully in accordance with :

IP 3 x of IEC 60529 for enclosures,

IP 3 x of IEC 60529 for all compartments.

The enclosure shall conform to the requirements of IEC Standard 60298.


The construction shall be such that it shall not be possible for vermin to enter any part of the enclosure with access doors closed. In addition all parts of the circuit breaker shall be insulated or shrouds shall be fitted to circuit breaker bushings to prevent vermin gaining access to the busbar spouts when the circuit breaker is in the normal service position. "Vermin" in this context shall include lizards and snakes in addition to small mammals.

21.3.3 Ventilation

Ventilation of compartments may be utilized where the manufacturer considers this necessary to meet the requirements of this Specification provided that the requirements of Clause 3.2 are complied with in full.

21.3.4 Internal Arc:

All switchgear shall be designed and tested for internal arc protection, in general accordance with Appendix AA of IEC 60298.

The level of protection shall be such as to protect an operator in the event of an internal arc, within the switchgear. Accessibility type A shall apply.

It is not sufficient for tests to prove only that the pressure relief flaps open correctly. The manufacturer shall certify the performance in terms of the Criteria stated in Appendix AA.

The applicable fault level shall be a minimum of 25 kA.

The time duration of the arc shall be not less than 1.0 second.

The manufacturer shall provide, at time of tender full certification details, such certification having been issued by an independent test station,

21.4 CHARACTERISTICS OF CIRCUIT BREAKER The following characteristics and ratings are required:

4.1 Number of Poles - 3

4.2 Class - Indoor

4.3 Rated Voltage - 12 kV

4.4 Rated Insulation Level - 75 kV

4.5 Rated Frequency - 50 Hz

4.6a Rated Normal Current (Busbar - 800A

4.6b Rated Normal Current (Transformer) - 400A

4.6c Rated Normal Current (Feeder) - 400A

4.7 Rated Transient Recovery Voltage - 20.6kV

4.8 Rated Short Circuit Breaking Current

(A.C. R.M.S. Component) - 25 kA

4.9 Rated Duration of Short Circuit - 3 seconds minimum


4.10 Rated Short Circuit Making Current - 62.5 kA

4.11 Rated Operated Sequence

0 - 30 min - CO - 3 min - CO

Where 0 is an Opening Operation CO is a Closing

operation followed immediately (that is, without any intentional time delay) by an Opening Operation.

4.12 Rated Supply Voltage of opening devices- 30V d.c.

21.5 CIRCUIT BREAKER TRIPPING AND CLOSING MECHANISM The Circuit Breakers are to be fitted with independent manual spring charged closing mechanisms.

The operating mechanism fitted shall be of the trip-free type such that the circuit breaker shall be free to open immediately during a closing operation in the event of the tripping device operating. The circuit breaker shall be capable of closing and latching against the rated making current.

The actions of "Spring Charge" and "Circuit Breaker Close" shall be separate and independent. The initiation of a "Close" or an "Open" operation shall be by the operation of separate push-buttons provided for the purpose.

The connections between the actuating device of the mechanism and the contact bars shall be such that under all conditions the drive is positive in both directions and that the mechanism and moving contacts move in unison.

Mechanical indication of the operating positions of the circuit breakers shall be provided. The indicators shall be positively driven in both directions from the operating mechanism and shall show whether the circuit breaker is 'ON' or 'OFF', when in the service, isolated and earth positions. The indicators shall be inscribed, 'ON' in white letters on a red background and 'OFF' in white letters on a green background. This Specification does not permit the use of mimic diagrams, rotating bars or other symbolic indications as the primary means of indicating the 'ON' and 'OFF' positions.

In addition to above, each circuit breaker should be provided with 240V AC, 50Hz thermally protected motor to charge the operating spring. It shall be possible to charge the operating spring with the circuit breaker in either open or closed position. In normal operation, recharging of the operating spring shall commence immediately and automatic upon completion of the closing operation. Closure while a spring charging operation is in progress shall be prevented and release of the spring shall not be possible until they are fully charged. The charging spring motor shall be interlocked so that it can not be operated when manual charge is selected.

The circuit breaker shall be equipped with 30V DC electrical tripping/closing switch with pad lock facility and mechanical tripping devices. The mechanical devices shall be operated by a push button which shall be capable of being locked to prevent operation. Selector switches shall be provided for remote and local operation with pad locking facility.

Locking facilities shall be provided so that in any location:

i) the circuit breaker can be prevented from being closed when it is open.

ii) the circuit breaker can be prevented from being manually tripped when it is closed.


Each requirement shall be met by the fitting of a separate single padlock and shall not entail the fitting of any loose components prior to insertion of the padlock. It shall not be possible readily to gain access to any part of the mechanism which would permit defeat of the locking of the manual tripping device. It shall not be possible to lock mechanically the trip mechanism so as to render inoperative the electrical tripping circuit.

The Padlocks to be used shall be of the following types:

Body

Height 44.5 mm

Width 38 mm

Thickness 19mm

Shackle:

Major Axis 32 mm

Minor Axis 19mm

Dia 6.5 mm

The hole to accommodate the lock shall not exceed 8mm diameter.

All forms of operating mechanism for the same type and rating of equipment of a given manufacturer shall be mechanically interchangeable as units. It shall not be possible to interchange units of different ratings.

Whenever any manual operations are necessary each mechanism shall be so designed that it can be operated without undue effort by an operator of average physique. In particular the maximum force required to carry out any normal operation shall not exceed 400N (approx. 40 kgf).

21.6 CIRCUIT BREAKER ISOLATION The circuit breakers shall provide positive isolation between the fixed and moving contacts. Isolation, that is the disconnection of the circuit breaker from live contacts, may be horizontal or vertical. The circuit breaker shall be withdrawable and the actions of isolation and withdrawal shall be separate and independent. In the withdrawn position, or in the isolated position if this is attained by movement of the circuit breaker, all high voltage contacts which could be alive shall be fully concealed behind independently lockable shutters. At no time during the routine operation of the circuit breaker shall contacts which could be alive be accessible to an operative other than by the opening of the shutters. The shutters and their operation shall be as defined in Section 9 of this Specification.

21.7 CIRCUIT BREAKER WITHDRAWAL In addition to routine maintenance, operational routines require that clear access to the fixed contacts is available for live phasing operations. To provide these facilities it shall be possible to withdraw the circuit breaker without the need for additional items of equipment, although the use of tools is not precluded for this purpose. Withdrawal shall only be possible when the circuit breaker has been isolated and interlocks shall be provided to prevent any incorrect operation. Circuit breakers shall be one of the following types:

i) Truck mounted, vertical isolation, horizontal withdrawal.


ii) Truck mounted, horizontal isolation, horizontal withdrawal,

In all cases, the action of withdrawal shall be deemed to be complete when access becomes available to the circuit breaker housing including the Busbar and Feeder Shutters.

Circuit Breakers, which need a special truck to achieve withdrawal, are not acceptable.

Where the circuit breakers is truck mounted, rollers and their guide rails shall be designed to facilitate alignment and leveling of the truck relative to the enclosure during movement of the truck into and out of the enclosure. It is deemed to be important that the truck shall have free and unimpeded travel.

Full and automatic isolation of the secondary wiring shall be achieved simultaneously with the withdrawal of the circuit breaker.

21.8 CIRCUIT BREAKER RATING PLATE Each circuit breaker shall be fitted with a rating plate fixed such that the details may be read with the circuit breaker in the normal service position. The following details shall be given.

Manufacturer Name

Circuit Breaker Type, Serial Number and Year of Manufacture

Rated Voltage and Frequency

Rated Lighting Impulse Withstand Voltage

Rated Normal Current

Rated Short Circuit Breaking Current and Duration.

Rated Supply Voltage of Opening Device

Rated Supply Voltage of Auxiliary Circuits

Number of Relevant Standard(s)

21.9 INTERLOCKS Interlock mechanisms shall be mechanical and when manually operated shall be provided with labels which are readily visible and which contain clear and concise instructions in the English language for operation. The requirement for mechanical interlocks does not preclude the provision of electrical interlocks in addition but does imply that any electrical interlock shall be secondary to the main mechanical interlock for any function.

Interlocks shall be provided to prevent the following operations:

i) The movable portion from being withdrawn from or inserted into the fixed portion when the circuit breaker is in the closed position. An attempt to withdraw a closed circuit breaker shall not cause the circuit breaker to trip,

ii) The closing of the circuit breaker unless the movable portion is correctly plugged into the selected location or is fully isolated or withdrawn from the fixed portion.

iii) The movable portion being withdrawn or replaced unless the contacts are isolated and the circuit breaker is in the appropriate position for withdrawal or replacement.


iv) The operation of any selectors or interlocks when the circuit breaker has been closed in the normal service location,

v) The circuit being closed in the service location without completing the appropriate auxiliary circuit between the fixed and moving portions,

vi) The feeder or busbar integral earthing devices being operated when the circuit breaker is in the normal service position.

The interlock to meet conditions (i) and (ii) above shall incorporate a handle for manual operation which shall have two positions clearly labelled ISOLATION MECHANISM LOCKED' and 'ISOLATION MECHANISM FREE' respectively. The handle shall be readily accessible and shall be operable by hand without the use of tools. The movement of the operating handle shall preferably be from side to side.

21.10 SAFETY SHUTTER DEVICES A set of metallic shutters shall be provided to cover each three phase group of fixed isolation contacts. Each set shall be capable of being individually operated and individually padlocked closed.

The shutters must accept a padlock with an 8mm hasp.

The shutters shall be opened automatically by a positive drive actuated as the circuit breaker is inserted. The closing operation shall also be automatic, either by means of a positive drive or by two independent means each of which shall be capable of closing one shutter. When padlocked the shutters shall prevent access to the fixed isolating contacts. To facilitate testing an integral device shall be provided for opening the shutters individually and retaining (but not padlocking) the shutters in the open position. The device shall be readily released manually to allow the shutters to close. The insertion of the moving portion shall over-ride the manual shutter operating device such that the automatic shutter operation is restored.

Busbar shutters shall be coloured, "Signal Red' Colour 537 and shall be clearly labeled 'BUSBARS' in large white letters. Feeder circuit shutters shall be coloured 'Lemon' Colour 355 and shall not be labelled.

On Bus-Section equipment both sets of shutters shall be coloured, "Signal Red' Colour 537 and shall be clearly labelled 'BUSBARS' in large white letters. In addition each shutter shall carry a white arrow pointing to the section of busbar with which the shutter is associated.

21.11 BUSBARS The Switchgear shall be of the single busbar type with the busbar normal rating as given in the Schedule of this Specification.

The Switchgear shall be designed and constructed such that no conductors operating at medium voltage are accessible under normal service conditions. Busbar section access panels shall be bolted in place and shall not be removable without the use of tools. Particular care shall be taken to ensure that all demountable panels are secured in a manner which provides a continuous earth bond between the enclosure and the panels.

The busbar shall be contained in a separate chamber which does not contain any equipment other than the busbars, busbar support insulators and busbar connections.


The busbars shall be fully insulated and the supply of the switchgear shall include the supply of all components required to insulate busbar connections between panels, Loose taping of busbars is not permitted.

21.12 EARTHING DEVICES Facilities for earthing each section of busbar and each feeder shall be provided:

21.12.1 Feeder Earthing:

EITHER

1) By circuit breaker earthing for which the circuit breaker shall be provided with means of selecting between 'Feeder Earth', 'Normal Service' and 'Busbar Earth' positions.

It shall be possible to use the circuit breaker without recourse to the fitting of any additional devices or equipment.

Positive identification of the location and positive inter-locking shall be provided.

In busbar and feeder earth positions all automatic electrically operated tripping devices shall be rendered inoperative.

OR

2) By a separate, three pole, linked earthing switch. The switch shall be spring-assisted such that the closing action is not dependent upon the speed or continuity of movement of the operating handle.

The switch shall have the same rated short circuit making current as the circuit breaker with which it is associated.

Operation of the switch shall be by means of a separate operating handle which shall be inserted into the front of the switchgear through a fully interlocked and lockable access orifice. It shall not be possible to operate the switch by means of any device other than the operating handle.

21.12.2 Busbar Earthing

1) By circuit breaker earthing without the attachment of a special device, for which the circuit breaker shall be provided with means of selecting this identified location.

OR

2) By a separate, three pole, linked earthing switch. The switch shall be spring-assisted such that the closing action is not dependent upon the speed, strength or continuity of movement of the operating handle.

The switch shall have the same rated short circuit making current capacity as the circuit breaker with which it is associated.

Operation of the switch shall be by means of a separate operating handle which shall be inserted into the front of the switchgear through a fully interlocked and lockable access orifice. It shall not be possible to operate the switch by means of any device other than the operating handle. As a minimum, this device shall be fitted to all circuit breakers intended for transformer control.


OR

3) Means by which, using suitable interlocks, the feeder earthing switch(es) may be used for busbar earthing also.

OR

4) By a separate light weight Portable Earthing Truck incorporated with rated (25kA/3sec) three pole earthing switch for Busbar earthing only. The switch shall be spring assisted such that the closing action is not dependent upon the speed, strength or continuity of the movement of operating handle. The earthing switch shall be suitable to lock by Pad lock mentioned elsewhere. One such Truck should be supplied free of charge for every 40 Nos. of Panels.

21.13 VOLTAGE TRANSFORMERS Voltage Transformers shall be fitted to panels only if specifically indicated in the Schedule to this Specification. The Transformers shall be three-phase, star-star wound having the primary star point floating and fully insulated and the secondary star point earthed. The ratio and burden of the required transformers shall be as stated in the Schedule. Transformers shall conform to IEC Standard 60044. The Transformers shall be circuit connected and shall be fully withdrawable. In the withdrawn position the live connecting bushings shall be automatically covered by a lockable metal shutter.

The primary connections shall be made through replaceable 11kV fuses, one per phase, access to which shall available by means of a lockable, removable cover. Secondary wiring protection may be by means of suitably rated HRC fuses or by means of miniature circuit breakers. These may be mounted inside the secondary wiring compartment or on the front of the cubicle. The protection device will constitute the point of secondary isolation and shall be clearly labelled as such,

21.14 CURRENT TRANSFORMERS Current Transformers shall be provided on all panels in accordance with the requirements given in the Schedule. The rating and burden shall be as stated in the Schedule. Current Transformers shall comply fully with the requirements of IEC Standard 60044.

Current Transformers shall be fully encapsulated, bar primary type and shall be capable of withstanding, without damage and with no change to the operating characteristics, the rated short circuit currents, 25KA for 3 seconds. The Knee point voltage of the current transformers should match the above requirements.

21.15 RELAYS AND SECONDARY WIRING The requirement shall be delivered complete with all of the relays detailed in the Schedule to this Specification and with all of the necessary secondary wiring and connections,

21.15.1 Relays

All relays shall be of the flush mounted type and shall be withdrawable from the front of the cubicle. They shall conform to the relevant requirements of IEC Standard 60255. Relays shall be clearly labelled to indicate their function and shall have easily visible indicators to show that the relay has operated.


Indicators shall be manually reset from the front of the relay. For static relays, suitable periodic testing facility such as test block should be provided with prior approval of KAHRA MAA.

21.15.2 Secondary Wiring

It is a requirement of this Specification that the auxiliary wiring connections between the fixed and moving portions of the switchgear shall be automatically and simultaneously disconnected when the moving portion is withdrawn. In order to carry out tests on breaker operation and Specification protection systems it shall be possible to maintain auxiliary connections to the circuit breaker in the withdrawn position and the manufacturer is required to include any separate auxiliary contacts and connections with his supply.

All secondary wiring shall be securely clipped to the cubicle or shall be run in suitable designed trunking. Clips shall be screwed or riveted to the panel, the use of adhesives is not permitted. Where secondary wiring passes through compartment divisions the aperture shall be sealed to maintain the degree of protection required between compartments.

Where 240/415V wiring is present the terminals shall be fully shrouded and clearly marked to indicate the presence of low voltage. All other wiring shall be terminated on clearly identified terminal blocks such that any circuit can be disconnected for testing purposes without disturbance to other circuits.

CT terminals shall be provided with CT shorting facility with sliding links. CT earthing terminals shall be provided through proper earth links.

Suitably rated terminal blocks shall be provided within the switchgear for acceptance of auxiliary supply cables at the voltages stated in the schedule.

Standard identification ferrule numbers shall be fitted on all wires.

Wires causing trips shall have a red ferrule in addition,

All secondary wiring shall be of insulated copper conductor and size shall not be less than 2.5mm2.

21.15.3 Auxiliary Switches

In addition to the auxiliary switches required to comply with the specified protective schemes, the following spare auxiliary switches shall be provided:

1 - Normally Open

1 - Normally Closed

21.15.4 Electrical Tripping of Circuit Breakers

A push button or a rotary switch with locking facility shall be provided inside the relay compartment for each type of panel. The switch shall be connected parallel to the relays tripping contacts. Pad locks will be used to lock off the switches to avoid any circuit breaker tripping. Specifications of Pad lock has already been mentioned in this specification elsewhere.


21.16 MEDIUM VOLTAGE CABLE TERMINATIONS 11kV Cable Terminating Boxes shall be supplied on all feeder and transformer panels. All panels shall be capable of terminating 3 core PILCSTA and 3 core XLPE stranded copper cables up to a maximum size of 300 sq.mm, Terminations will be by heat shrink techniques.

Boxes shall be supplied with gland plates, terminating lugs and lug fixing bolts. Terminating kits will be supplied by others. Glands shall be suitable for terminating cables either with or without a lead sheath, but wire armoured. All uninsulated brass glands shall be Y size with armour clamps.

The terminating lugs shall be of the compression type, The lugs shall be capable of accommodating:

a) For Transformer Panel : Round core, 70 sq. mm copper stranded conductor.

b) For Feeder Panels : Round core, 240 sq, mm copper stranded conductor.

21.17 LABELS Operating Position Labels, Relay Identification Labels and Rating Plates shall be suitably secured to the panels. Should adhesives be used for this purpose the adhesive shall be suitable for prolonged exposure to high ambient temperatures. Labels shall generally be white with black engraved lettering.

Each panel shall be supplied with blank circuit identification labels at the front and rear of the cubicle. The labels shall be secured by means of four screws and shall measure 150mm x 50mm with fixing holes located at 140mm and 40mm centers, The Labels shall be manufactured from 'Sandwich' Traffolyte suitable for engraving to provide black lettering on a white background.

Circuit Identification Labels shall not be attached to movable covers and must be located, on the front of the panel, close to the control point to which they refer.

Labels referring to earthing positions shall not be of the same colour as other labels. It is preferred that labels relating to Feeder Earth positions shall be black letters on a lemon background and that those relating to Busbar Earth positions shall be black letters on a red background.

21.18 PAINT FINISHES All paint finishes shall be hard-wearing, durable and maintenance free. Painting shall conform to the best available practices and shall consist of not less than three separate coats of high quality paint to obtain the final finish. Details of the finishes and painting process shall be supplied at the tender stages. The final external paint finish shall be Dark Admiralty Grey, Shade 632 .

21.19 TOOLS All special tools and ancillary items required for the complete installation, operation and maintenance of the switchgear shall be described by the manufacturer at the time of tender. It is required that one set of complete tools, including tool rack shall be supplied for each four units of switchgear as defined in the Schedule. The positions of tools on the rack shall be clearly defined and labelled.

Details of all tool requirements shall be provided at the tender stage.

The term "tools" shall be deemed to include, where applicable the portable earthing device for busbar earthing, and any equipment necessary to move the circuit breaker clear of its associated panel. It also include test bushings, to enable testing to be carried out via the busbar and feeder spouts.


21.20 CONSTRUCTION OF SWITCH BOARDS Tenderers should assume that the Switchboards will comprise an average of 4 panels each, and must include provision for all necessary busbar couplings and end caps in the quotation, Additional 11 KV panels busbar couplings and end caps must be quoted on a per unit basis.

All necessary foundation bolts must be provided for in the quotation, and supplied with the Switchgear.

21.21 TESTS a) Type Tests:

The manufacturer shall provide at the time of tender. Type Test certificates relating to the type of equipment specified, The tests shall have either been carried out by, or witnessed by a competent party independent of the manufacturer.

b) Routine Tests:

The following Routine Tests shall be carried out by the manufacturer on 10% of the manufactured items:

IEC 60056

i) Power frequency voltage dry test on the main circuit.

ii) Voltage tests on control and auxiliary circuits.

iii) Measurement of the resistance of the main circuit.

iv) Mechanical Operations Test.

IEC 60298/60694

i) Power frequency voltage tests on the main circuit.

ii) Dielectric tests on control and auxiliary circuits.

iii) Measurement of the resistance of the main circuit.

iv) Mechanical Operations Test,

v) Verification of correct wiring,

IEC 60044

i) Verification of Terminal markings.

ii) Power frequency tests on primary windings

iii) Power frequency tests on secondary windings

iv) Over voltage on inter-turns test.

21.22 STORAGE AND TRANSPORT The Switchgear shall be packed, prior to shipment, in strong wooden non-returnable cases suitable to provide adequate protection during transport from the country of origin to the Purchasers Stores within the State of Qatar. Due regard shall be paid to the extremes of environmental hazard which are likely to be encountered during transport and measures shall be taken within the switchgear to prevent damage due to excessive humidity and condensation, The responsibility for the safe delivery of the equipment


shall remain within the Supplier or his Agent until an acceptance document has been issued by the Purchaser.

21.23 DRAWINGS The manufacturer shall supply, at the tender stage, three full sets of drawings showing, in detail the physical assembly arrangement, schematic and wiring diagrams of the 11kV equipment and earthing equipment, CTs, VTs, all secondary and auxiliary wiring, relays and instruments.

Failure to supply the requisite drawings will disqualify a tender.

21.24 MANUAL AND INSTRUCTIONS The manufacturer shall supply, with each and every complete switchboard, full instructions for the storage, unpacking and lifting, assembly erection, mounting and connecting the switchboard. Instructions shall also be provided for the final installation inspection and pre-commissioning tests. Due regard shall be paid to the special requirements for packing and storage under the adverse ambient environmental conditions to be encountered during transport and whilst awaiting installation.

Manufacturers shall supply at the tender stage details of their recommended maintenance periods based upon time in service or number of trip operations in normal service and the number of trip operations under system fault conditions at full short-circuit rating.

Manufacturers shall supply 5 Nos. fully bound Maintenance Manuals in the English language for each switchgear type supplied. The Manuals shall include all of the installation, operation and maintenance procedures applicable to the switchgear type. The Manuals shall be specific to the items delivered. Manufacturers standard commercial literature may be included but shall not constitute the basis of the manual.

21.25 SPARES Manufacturers shall submit at the tender stage a detailed list of the Spare Parts required to be held by the Purchaser to provide full maintenance for a period of three years of normal operational service. The supply of these parts, including the protective packing to prevent deterioration in storage, shall form part of the Tender.

21.26 QUALITY STANDARDS The manufacturer of the equipment specified shall possess certification, issued by a body authorised to do so, which indicates that the manufacturing unit operates to a standard equivalent to ISO 9001.

21.27 INFORMATION TO BE SUPPLIED AT TIME OF TENDER 1) 3 sets of detailed, dimensioned drawings of each type of circuit breaker, The drawings shall

identify all major components, and manual controls..

2) 2 sets of installation, operation and maintenance instructions..

3) Previous type and routine test data relating to the requirements of IEC 600298, and IEC 60056.

4) A detailed list of recommended spares.


5) A detailed list of special tool requirements.

6) The following details relating to quality standards :-

6.1 The identity of the certification body, being a national body authorised to certify under the auspices of the International Standards Organisation,

6.2 The identity of the items of equipment to which the award of ISO 9001 applies.

6.3 The identity of the manufacturing unit to which the certification applies.

6.4 The date of award of certification and its time validity,

21.28 INFORMATION TO BE PROVIDED WITH THE ORDER The following will be delivered at the same time as the switchgear,

1) Duplicated Routine Test Data in accordance with the specified tests.

2) 5 sets of installation, operation and maintenance instructions.

21.29 TRIPPING UNIT Tripping Units are to be supplied complete with battery and battery charger. The unit shall be of adequate design and capacity for operating the trip coils and relays supplied under the tender. The unit will be required to operate from a 13A socket outlet supplied at 240V 50 Hz. The unit is to be supplied in one metal container suitable for wall mounting indoors in the climatic conditions specified in paragraph 2 above.

The output of the tripping unit is to be 30V d.c, with suitable fuse and links to control the tripping circuits. The fuse link must be rated to give discrimination with fuse links on individual circuit breakers.

All batteries shall be of rechargeable sealed nickel-cadmium type. Battery ampere-hour shall not be less than 11 Ah. Batteries shall be maintenance free for at least 5 years.

Tenderers must give details of recommended maintenance and maintenance periods and preference will be given to those offering a significant maintenance free period of 5 years or more.

21.30 INSPECTION & WITNESSING TESTING KAHRAMAA reserves the right to inspect the items before 1st shipment and to witness any or all the routine tests. This shall be carried out by a maximum of 3 KAHRAMAA engineers. All the expenses shall be borne by the supplier.

21.31 DEVIATION FROM THE TECHNICAL SPECIFICATION The tenderers are required to attach a separate deviation list if the offered equipments do not meet the requirements of any Clause of the Specification.

Offers without any deviation list shall mean that the offer meets the requirements of the Specifications on all the clauses.

Offers with deviations listed out shall mean that the offer meets the requirements of the Specification on all the other clauses not included in the deviation list.


21.32 SCHEDULE OF SWITCHGEAR RELATED TO PURPOSE OF USE This Schedule categories the Circuit Breakers in terms of their intended function, and details the specific requirements for CT Ratios, Relays, Instruments and Terminations.

21.32.1 TRANSFORMER CBs

1.1 Current Transformers:

3x 100/50/5A 15VA class 1 for instruments . 3 x 100/50/5A 15VA Class 5P10 or equivalent for protection.

1.2 Relays:

1 x 5A 3 Pole extremely inverse definite time(EIDMT) relay with 2 over current elements (50 - 200%) and one earth fault element (20-80%), the over current poles to have a high set instantaneous element rated 800- 3200% and the earth fault to have a high set instantaneous element rated 400 -1600%. As far as possible mechanical flag indication will be preferred.

1.3 11kV Cable Termination:

The Cable Box must accept XLPE/SWA/PVC Cables up to 3c 300 mm2 with circular compacted stranded copper conductor to IEC 60502 Standard. A suitable brass wiping gland with armour clamp is also to be provided for termination of cable. The Cable Box is to be complete with compression type lugs to accept a conductor of size 70 mm2.

1.4 Ammeter:

3x Moving iron flush pattern ammeter with reversible scale with ranges 0-1 OOA and 0-50A suitable rated for the CTs in 1.1.

1.5 Intertrip Facility:

Provision is to be made for inter-tripping to and from the associated 415/240V Switchgear. Terminations must be supplied to accept a 4 core 4mm2 PVC SWA PVC Cable to BS 6346.

1.6 Tripping Supply:

The tripping supply will be either bus wired from an adjacent panel (either right hand or left hand) or shall be provided via a 4c 4 mm2 PVC SWA PVC Cable to BS 6346.

21.32.2 FEEDER CB WITH PILOT WIRE PROTECTION/ IDMTL PROTECTION


3 x 400/5A 15VA Class 1 for instrumentation.

3x 400/300/5A 15VA Class X for Pilot wire protection.

3x 400/300/5A 15VA Class 5P10 for IDMTL.

2.2 Relays:

PWP-Electro-mechanical/Static high speed longitudinal differential pilot wire feeder protection which is suitable to use with two pilot cores. Insulation rated at 5kV . IDMTL- 1 x 5A 3 Pole standard inverse time relay with 2 over current elements (50 - 200%) and one earth fault element (20-80%). The relay will trip the CB via the 30V D,C. supply. The indicator flag is to be hand reset.


2.3 11kV Cable Termination:

As 1.3 above except lugs to be suitable for conductors size 185/300 mm2,

2.4 Ammeter:

3 x Moving iron flush pattern ammeters scaled 0-400A and rated for the C.T. in 2.1.


As 1.6 above

2.6 Pilot Cable Termination:

Termination to be suitable for 4c 4 mm2 PVC SWA PVC Cable to BS 6346

21.32.3 BUSBAR COUPLER CBs:


3 x 400/5A 15VA Class 1 for instrumentation.

3x400/300/5A 15VACIass 5P10 for Protection.

3.2 Relays:

Multiple characteristics 4 inverse time and 3 definite time ranges by switches selection, Two pole phase fault plus one earth fault, flush mounting, 5 ampere rating, 50 Hz, 30 to 34 volts D.C. trip supply. This relay shall be suitable for tripping the relay directly and shall be wired fully. The relay shall have a suitable test block for periodic maintenance checks.

3.3 11kV Connections:

The busbar coupler CB shall be suitable for connection to the 11kV busbars of the adjacent CBs (on the left and right hand sides) as specified in paragraphs 1, 2, 4, 5, 6. All materials necessary for the making of these connections shall be provided.

3.4 Ammeter:

3 x Moving iron flush pattern ammeters scaled 0-400A and rated for the C.T, in 3,1,


As 1.6 above

21.32.4 TRANSFORMER CBs WITH METERING FACILITIES:


For Protection: 3 x 100/50/5A; burden 15VA, Class 5P10 or equivalent.

For instruments 3x100/50/5A, 15VA Class 1 for instruments.

For Metering: 3 x 100/5A; burden 15VA, Class 0,5 or commercial metering accuracy.

Interposing/summation CT - 3 x 5/5A suitable for up to 3 inputs burden to suit the specified summation metering Class 0.5 or commercial metering accuracy (Metering CTs to be matched to Meters).

The interposing C.T. shall be installed in the CB Panel.


4.2 Relay:

As 1.2 above.

4.3 11kV Cable Termination

As 1.3 above.

4.4 Ammeter:

As 1.4 above.

4.5 Intertrip Facility:

As 1.5 above.

4.6 Potential Transformer:

The P.T, shall be 3 phase, star-star, primary star point floating and fully insulated, and secondary star-point earthed. The 11kV winding shall be connected to the circuit side of the CB panel. The P.T. shall be withdrawable and the live connecting spouts shall be able to be locked-off using a 1' 1/2" pin tumbles pad lock. All rails, wheels etc. necessary for isolating the P.T. shall be provided, 1 set for each P.T. supplied.

A replaceable 11kV fuse shall be fitted in all 3 phase of the withdrawable portion of the P.T, Rewireable fuses and fuse holders shall be fitted in all 3 phases of the P.T. secondary wiring and a removable solid link in the neutral. The neutral link and the secondary fuse-holders shall be mounted on the front of the CB cabinet; they shall have holes to accept a wire seal to prevent unauthorised removal,

P T. ratio shall be 11,000 / 110 V

3 3

The required burden is 100 VA and Class 0.5 accuracy.

4.7 Meters and Meter Cabinets:

The Meter Cabinets shall be suitable for indoor or outdoor mounting under the environmental conditions described in paragraph 2 hereof.

The Meters shall be manufactured in accordance with IEC recommendation 60521. The Meters shall be matched and rated to operate to the necessary degree of accuracy in conjunction with the CTs and PTs specified in paragraphs 4.1 and 4.6 respectively. The Meters will be installed remote from the CBs at a distance of up to 5 metres.

The Meters shall comprise:

1 - KWH Meter with maximum demand pointer reading to 10x106 KWH and 2,500 KW.

1 - KVAH Meter with maximum demand pointer reading to 10 x 106 KVAH and 2,500 KVA.

1 - KVARH Meter with maximum demand pointer reading to 10 x 106 KVARH and 2,500 KVAR.

The Energy Meters shall have roller type numbers with numbers approximately 6mm high. They shall have facilities for accepting a wire seal on all removable covers. They shall have screw type terminals. They shall give a direct reading with no multiplying factor being necessary. Meter cases shall be all insulated. They shall be suitable for unbalanced loads.

Maximum demand meters shall have facilities for a wire seal on the reset pointer.


The Meter Cabinets shall have a facility for accepting a 1 1/2" pin tumbler padlock. The front of the cabinet shall be hinged for access and shall have a glass window for reading of the Meters.

21.32.5 FEEDER CB WITH DIRECTIONAL OVER CURRENT & EARTH FAULT IDMTL PROTECTION


3 x 400/5,15VA Class 5P10 for directional over current and earth fault IDMTL Protection.

3 x 400/5,15VA Class 1 for Ammeter.

5.2 Two single pole directional over current IDMTL Relays, 45° Current leading, 5A, voltage polarising 110V AC 50 Hz range 50 - 200% in phases R & B.

One ditto DE/F, range 10-40% but 45° current lagging.

5.3 11 kV Cable Termination : As in 2.3

5.4 Ammeter : As in 2,4

5.5 Tripping Supply : As in 2.6

5.6 Potential Transformer:

One three phase VT ratio 11000 110 110

3 3 3

100 VA per phase, Class 3P. Insulation level 12/28KV open delta teritiary, rated voltage factor 1.5 for 30 seconds. Primary fitted with HT fuses. Secondary fitted with fuse suitable to grade, one setter isolating voltmeter circuits, the other for isolating the protection circuits separately.

5.7 Voltmeter:

Scale shall be 0 –14 kV voltage selector switch to indicate R-Y, Y-B, R-B volts.

21.32.6 FEEDER CB WITH IDMTL PROTECTION AND METERING FACILITIES:


For instrumentation 3 x 400/5,15VA Class 1

For Protection 3 x 400/300/5,15VA Class 5P10.

For Metering one set of two CTs 400/5 Class 0.5 for KWHr Metering.

6.2 Relay:

IDMTL-1 x 5A 3 Pole inverse time relay with 2 over current elements (50 - 200%) and one earth fault element (20-80%). The relay will trip the CB via the 30V D.C. supply. The indicator flag is to be hand reset.

6.3 11 kV Cable Termination:

As in 2.3 above.

6.4 Ammeter:


As in 2.4


As in 1.6

Potential Transformer:

As in 4.6

6.7 Voltmeter: As in 5.7

6.8 Meters and Meter Cabinets:

The Meter Cabinets shall be suitable for indoor or outdoor mounting under the environmental conditions described.

The Meters shall be manufactured in accordance with IEC recommendation 60521. The Meters shall be matched and rated to operate to the necessary degree of accuracy in conjunction with the CTs and PTs specified in paragraphs 6.1 and 4.6 respectively. The Meters will be installed remote from the CBs at a distance of up to 5 metres.

The Meters shall comprise:

1 - KWH Meter with maximum demand pointer reading to 10 x 106 KWH and 8,000 KW (30 minute).

1 - KVAH Meter with maximum demand pointer reading to 10 x 106 KVAH and 8,000 KVA (30 minute).

1 - KVARH Meter with maximum demand pointer reading to 10 x 106 KVARH and 8,000 KVAR (30 minute).

The Energy Meters shall have roller type numbers with numbers approximately 6mm high. They shall have facilities for accepting a wire seal on all removable covers. They shall have screw type terminals. They shall give a direct reading with no multiplying factor being necessary. Meter cases shall be all insulated. They shall be suitable for unbalanced loads. Maximum demand meters shall have facilities for a wire seal on the reset pointer,

The Meter Cabinets shall have a facility for accepting a 1 1/2" pin tumbler padlock. The front of the cabinet shall be hinged for access and shall have a glass window for reading of the Meters.

21.32.7 BUSBAR COUPLER CBs WITH METERING

7.1 Current Transformers : As in 6.1

7.2 Relay : As in 3.2

7.3 11kV Connections : As in 3.3

7.4 Ammeter : As in 2.4

7.5 Tripping Supply : As in 1.6

7.6 Potential Transformer : As in 4.6

7.7 Voltmeter : As in 5.7


7.8 Meters and Meter Cabinets : As in 6.8

21.32.8 DRAWINGS:

8.1 The tender must be supported by full drawings of the physical assembly arrangement, schematic and wiring diagrams of the CT's, secondary wiring, relays and instruments. Any tenders not so supported will be rejected.

8.2 Kahramaa approval should be obtained for 11 kV panel/ manufacturer’s shop drawings prior to commencement of manufacturing

21.33 ADDITIONAL KAHARAMAA REQUIREMENTS FOR 11 KV SWITCHGEAR PROTECTION

Allow for Pilot wire Protection with current guard and pilot wire supervision facility relays in 11 kV switchgears.

The CTs at both ends for the Pilot wire supervision should be identical.

Co-ordinate with Kahramaa, and suppliers of associated HV panels at other ends (pilot cabels and HV/MV cables) for protection co-ordination and for selection of protection equipment/relays to achieve compatibility and satisfactory and acceptable operation.

The over current and earth fault relays for the transformer feeders need to be extremely inverse EIDMTL/Earth fault relays (50/50 N & 51/51N).

Allow for dual wound VTs, one with class 0.5 accuracy for kWh metering, and the other with class 3 P accuracy for protection.

The accuracy class of VTs needs to be Class 0.5/3P with separate core for open Delta.

Pilot Wire protection /current guard relay(s) need(s) to be at the Receiving and Sending ends and as per Kahramaa requirement.

Pilot wire protection relay should be identical to the 11 kV primary substation relays.

DC trip supply should be 30 VDC output with sufficient capacity of battery and charger.

The switchgear rating of 11 kV indoor substation should be 25 kA for 3 seconds.

The knee point voltage of the pilot wire protection CT should be calculated for 25 kA fault current. Submit knee point voltage calculations to the Client Representative.

In 11 kV substations where incoming feeders are directly from the primary substation, over current and earth fault protection shall be directional together with Pilot Wire Protection with pilot supervision and current check relay.

11kv switchgear

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