261400_RMU_TechSpecs_JULY_2012.pdf

26 14 00: TECHNICAL SPECIFICATIONS: 12KV RING MAIN UNIT (RMU)

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JULY 2012 (100% FINAL)

Ring Main Unit

Technical Specs

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1. GENERAL

1.1. DESCRIPTION:

1.1.1. Work includes providing all materials, equipment, accessories, services tests, and ancillary works necessary to complete and make ready for operation 3 Ring Main Units (RMU) in accordance with attached drawings and the specifications to follow.

1.2. SUBMITTALS

The following data shall at least be provided by the equipment vendor:

1.2.1. Construction and installation details for the ring main unit equipment.

1.2.2. Floor plan and top views showing outline dimensions and arrangement of cubicles.

1.2.3. Details of connection of high voltage cables to the cubicles.

1.2.4. Handling, installation and assembly drawings.

1.2.5. Complete technical data on the ring main unit and other equipment including data on operating characteristics, compliance with standards, dimensions, weights, detailed description, operating mechanism etc.

1.2.6. Complete technical data on instruments, protective and auxiliary relays, measuring instruments including manufacturer's catalogues, operating characteristics, operating curves, and detailed technical information for fuses.

1.2.7. Successful bidder shall submit for approval (before proceeding to manufacture) all technical and dimensional drawings as well as full ratings and characteristics schedules.

1.2.8. Successful bidder shall submit complete workshop drawings and civil/constructional drawings necessary for the preparation of site for the proper installation and operation of the RMU.

2. PRODUCTS

2.1. General Provisions:

2.1.1. Full compliance with the requirements and specifications of the respective Egyptian Electrical

Distribution Company is mandatory. RMUs to be installed in Maadi (Qty. 2) and Zamalek (Qty. 1), Cairo, Egypt.

2.1.2. The RMU will be of the factory assembled type, with a type tested design by one of the renowned switchgear manufacturers of European or American origin. All components and switching devices should be of European or American origin. Switchgear shall be of the metal-clad, factory assembled, with busbar construction for power distribution.

2.1.3. Manufacturer shall be one of the firms regularly engaged in the manufacture of medium voltage switchgear and ring main units of the types and capacities required and whose products have been in satisfactory use in similar service and location for not less than 5 years.

2.1.4. Switchgear, switching devices, and all other power or control devices will comply with the latest issue of the following IEC standards:

2.1.4.1. IEC 60694: Common specifications for high voltage switchgear and controlgear

2.1.4.2. IEC 62271-200 (replacing IEC 60298): A.C. metal enclosed switchgear and controlgear for rated voltage above 1kV and up to 52kV

2.1.4.3. IEC 60265-1: High voltage switches for rated voltage above 1kV and up to 52kV

2.1.4.4. IEC 62271-100 (replacing IEC 60056): High voltage alternating current circuit breakers

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2.1.4.5. IEC 62271-105 (replacing IEC 60420): Alternating current switch-fuse combination

2.1.4.6. IEC 62271-102 (replacing IEC 60129): Alternating current disconnectors and earthing switches

2.1.4.7. IEC 60255: Electrical relays

2.1.4.8. IEC 60071: Insulation Coordination

2.1.4.9. IEC 62271-102: A.C. Disconnectors (isolators) and Earthing Switches

2.1.4.10. IEC 60265: HV Switches

2.1.4.11. IEC 60099: Surge Arrestors

2.1.4.12. IEC 60044-1: Metering and Protective Current Transformers (CTs)

2.1.4.13. IEC 60186: Metering and Protective voltage Transformers (VTs)

2.1.4.14. IEC 60051: Reading Instruments

2.1.4.15. IEC 60521: Watt-Hour Meters

2.1.4.16. IEC 60076, 60726: Power Transformers

2.1.4.17. IEC 60376: Sulfur Hexa-Fluoride

2.1.4.18. IEC 60282-1: Fuses

2.1.5. RMU will comply with all applicable local codes, standards, and the Egyptian National Electric Code (NEC). RMUs to be installed in Maadi/Zamalek, Cairo, Egypt.

2.1.6. In case of conflict between any of the referenced standards/codes, the more stringent standard will prevail

2.1.7. The entire switchgear and switches shall be rated for continuous operation under full/rated conditions at an ambient temperature of 40°C.

2.1.8. Precaution shall be taken at contacts between aluminum and other material to avoid electrolytic action.

2.1.9. Structure shall be designed to allow for the addition of future units.

2.1.10. The switchgear shall be constructed with a degree of protection IP3X according to IEC 60529.

2.1.11. Direct panel to panel busbar connection shall be made without the use of interconnecting links.

2.1.12. The arrangement shall permit cables to enter from the bottom of the enclosure and connect at their respective terminals without interference.

2.1.13. Cable termination boxes shall be provided for incoming and outgoing feeders having 3-core, or single core XLPE insulated, Aluminum cables of cross-sectional area as indicated on the drawings.

2.1.14. Switchgear shall be extensible on either side, finished with the manufacturer standard color.

2.1.15. The switchgear shall be vermin-proof and suitable for the climatic conditions at site.

2.1.16. Each switchgear unit shall be provided with rating plate showing all relevant ratings in accordance with IEC recommendations.

2.1.17. Type Test Certificates: Submit to verify compliance of main equipment with the relevant IEC

Standards, including the following:

2.1.17.1. Impulse withstand-voltage tests

2.1.17.2. Power frequency withstand-voltage tests.

2.1.17.3. Temperature-rise tests.

2.1.17.4. Short time current tests.

2.1.17.5. Verification of making and breaking capacity.

2.1.17.6. Mechanical endurance / operation tests.

2.1.17.7. Verification of degrees of protection for persons against contact with live and moving

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parts.

2.1.17.8. Internal arc tests.

2.1.17.9. Degree of Protection test to IEC 60529.

2.1.18. Routine Tests: Each complete switchgear unit is to undergo routine tests at the manufacturer's works in accordance with the relevant standards. Submit routine test reports, prior to shipping equipment, indicating ambient test conditions and guaranteed rating of equipment under site conditions. All routine tests according to IEC will be attended by client representatives and it’s consultant in factory before delivery of the panels.

2.2. Technical Specifications and Requirements:

2.2.1. The Ring Main Unit shall comprise four, three-pole load break switches rated 630 Amps, 12/11kV (Rated/Service). Two load break switches for the incoming ring main feeder cables, one additional network load break switch, and one load break switch with fuse links for the outgoing cables connected to transformers as indicated on the drawings. The Ring Main Unit will comprise one Metering Cubicle fully equipped with appropriate CT (Current Transformers) and PT (Potential Transformers) and metering devices for Tariff Metering in full compliance with the requirements of the respective Egyptian Electrical Distribution Company. RMUs to be installed in Maadi and Zamalek, Cairo, Egypt.

2.2.2. The ring main unit shall be of the SF6 insulated type to provide compact design and dimensions.

2.2.3. The gas filled compartment shall be a sealed pressure system to IEC 60298.

2.2.4. The ring main unit shall be provided with a floor mounting support frame of adequate strength.

2.2.5. Bus-bar: Electrolytic Copper of 99 % purity and of not less than minimum size required by the

Standards, SF6 or air insulated, designed to withstand highest earth- fault current of power system without showing any signs of thermal or mechanical damage or degradation. Earth bus is to extend full length of switchgear.

2.2.6. An SF6 monitor is to be provided to monitor the leakage of SF6 gas for warning.

2.2.7. Power Cable Terminations: Whether plug-in or bolted type, are to be complete with cable terminating fittings for connection of all incoming and outgoing cables, unless otherwise specified.

Cable compartments are to be designed to permit cables to enter enclosure and connect at respective terminals from below, or as shown on the Drawings. Terminations are to include appropriate sealing ends, fittings, earthing straps and accessories for type of cables used, including stress cones or other stress relieving accessories, cold shrinkable sleeves, end boxes or end bushings and fittings of any kind necessary to support and protect specified cable. Necessary accessories to connect Aluminum cable to copper Terminals.

2.2.8. Cable Boxes:

2.2.8.1. Cable boxes shall be of approved design and shall be suitable for accepting 24kV, 3-core, 240 sq.mm or 185sq.mm or "As per Utility Specification" stranded Aluminum conductor, XLPE insulated.

2.2.8.2. The bottom plate of the cable box shall be removable and shall be fitted with a suitable gland for the above type of cables. The minimum clearance between floor level and gland shall be 100 mm.

2.2.8.3. Lead length from the gland to the center phase terminal of cable box shall be minimum 450

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mm and for the other 2 phases shall be maximum 500 mm.

2.2.8.4. The body of each cable box shall be earthed by a flexible copper not less than 95 sq.mm to the earth bond of the equipment.

2.2.8.5. No wood or any other combustible material shall be used within the cable chamber or for any kind of support or barrier.

2.2.9. Cable Clamps: Suitable cable clamps shall be provided on all switchgear to support the rising run of cables from the cable trench (tray) to the cable box.

2.2.10. Load Break Switches shall be SF6 gas insulated to form a compact ring main unit capable of interrupting safely, their nominal full load current.

2.2.11. The load break switches shall be operated by hand-operated handles through levers. Protective barriers shall be provided to safeguard personnel from unintentional contact with the live parts during switching operations. Marking labels shall be fitted to indicate the ON/OFF positions of the switches and the hand-operated handles shall be provided with locks. Insulating barriers shall be inserted between the open contacts when working on cables.

2.2.12. Cable termination boxes shall be provided for the incoming and outgoing units.

2.3. RMU Technical Specifications:

2.3.1. 12 KV RMU, metal clad, indoor type, type tested, completely wired and tested at the factory, ready for installation when received on site.

2.3.2. Precaution shall be taken at contacts between aluminum and other material to avoid electrolytic action.

2.3.3. RMU shall be Internal Arc Classified (Acc. to IEC 62271-200): IAC: A-FLR, 16kA/1s, Upward Exhaust.

2.3.4. RMU shall be class PI-Insulating Partition (Acc. IEC 62271-200)

2.3.5. RMU shall be class LSC2A for Loss of Service Continuity (Acc. to IEC 62271-200)

2.3.6. The RMU shall have a degree of protection IP 32.

2.3.7. RMU Type: SF6 gas insulated, Compact Type

2.3.8. Rated voltage: 12 kV

2.3.9. Nominal voltage: 11 kV

2.3.10. Maximum operating voltage: 12 kV

2.3.11. Rated current of Ring Main Load Break Switches 630 A

2.3.12. Rated current of Transformer Load Break Switches 630 A

2.3.13. Rated withstand voltage, 1 min: 28 kV

2.3.14. BIL between phase and earth: 75 kV

2.3.15. Rated short time current 1s: 25 kA

2.3.16. Rated impulse current: 63 kA

2.3.17. Rated making current: 63 kA

2.3.18. Short circuit level: 500 MVA at 12kV

2.3.19. Short circuit short time withstand: 1s

2.3.20. Short circuit rating of Earthing Switches: 25kA/1s

2.3.21. Fuse rating 100A/12kV/100kA (min)

2.3.22. (for protection of 1000kVA Transformer 11kV/0.4, DYn11)

2.3.23. The Contractor shall submit for approval the 3 phase symmetrical short circuit current at the

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ring main unit bus-bar taking into consideration the power short circuit level at the upstream MV switchgear and the impedance of the MV cables. Should the short circuit capacity calculated value exceed the above figure (25 kA for 1 second), then the RMU shall have a short circuit capacity at least equal to that calculated.

2.3.24. Potential Indicators: Neon indicators are to be provided at front of each switchgear unit, 1 per phase, using capacitive potential divider to indicate voltage state on cable terminals.

2.3.25. Earth fault Indicators are required.

2.3.26. Earthing switches shall be provided on the feeders’ side of each switching device to enable earthing the cable feeders (while working on the cables).

2.3.27. Load Break Switches shall be capable of breaking full load current but capable of carrying full fault current stated in this specification for a minimum of 1 seconds.

2.3.28. Earthing switches shall be capable of breaking negligible current but capable of carrying full fault current stated in this specification for a minimum of 1 seconds. Earthing switches shall be capable of making full fault current stated in this specification.

2.3.29. Full interlocks shall be provided between Load Break Switches and Earthing Switches to prevent one from being closed when the other is engaged (closed).

2.3.30. Interlocks are to be provided on RMU switchgear so that:

2.3.30.1. Main switching device cannot be isolated and earthed when in closed position, and cannot be put into service position or closed when isolated and earthed

2.3.30.2. Access to cable compartment cannot be made unless earthing switch is closed

2.3.30.3. Earthing switch cannot be opened unless cable compartment is closed.

2.3.30.4. Keys and padlocks are to be provided for interlocking two or more operations as required. Mechanical interlocks are to be provided for safe and functional operation of the system.

2.3.31. Padlocking facility shall be provided in all operating positions of Load Break Switches and Earthing Switches.

2.3.32. A mechanism shall be provided to trip the Load Break Switch in case of the associated fuse being blown.

2.3.33. Cable termination boxes shall be provided for the incoming and outgoing cables with cross-sections and specifications as indicated on the attached drawings.

2.3.34. Each cubicle must be equipped with space heaters to prevent the accumulation of moisture & humidity. One heater shall be provided in the cable compartment and the other in the load break switch compartment. Adequate control (by hygrostat) and protections for the heaters will be provided.

3. EXECUTION

3.1. Inspection and Testing:

3.1.1. Vendor shall provide test results to confirm that the ring main units have been tested according to applicable standards.

3.1.2. All tests shall be carried out by the manufacturer at works and at his expense and under control and supervision of the end client and his consultant and attendance of the electricity distribution company personnel.

3.1.3. The vendor shall be responsible for testing all medium voltage switchgear, all protection

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equipment, etc. as per EEA (Egyptian Electrical Authority) requirements on his own expense.

3.1.4. Manufacturer will examine conditions under which RMU is to be installed at site. Manufacturer will inform owner in writing of any conditions that may prohibit the proper installation and operation of the RMU.

3.1.5. Routine tests (as per IEC) shall be carried out at the manufacturer's premises in presence of the owner and/or his representative.

3.2. Installation, Commissioning and Testing at Site:

3.2.1. Manufacturer shall provide full written instructions and requirements of applicable standards, to be followed during the installation of the RMU. Recognized industry practices shall be observed to ensure that installation complies with requirements and delivers a fully functional unit.

3.2.2. Manufacturer shall provide fuses of the ratings indicated on the drawings, with one complete set of spare fuses.

3.2.3. All mechanical parts and mechanisms shall be adjusted at site post-installation of the RMU to ensure free mechanical operation of the RMU.

3.2.4. Contractor shall install the ring main unit in accordance with the manufacturer's written instructions, and in accordance with recognized industry practices to ensure that installation complies with requirements and serves intended function.

3.2.5. All electrical connectors and terminals, including screws and bolts, shall be re-tightened at site in accordance with equipment manufacturer's published torque tightening values for equipment connectors

3.2.6. Contractor shall coordinate the installation of the ring main unit at site with other works including but not limited to the laying of cable feeders.

3.2.7. Contractor shall install the ring main unit on steel base frame imbedded in a concrete pad (or whatever other option is recommended by the manufacturer), and to ensure sufficient measures are applied to achieve level installation of the unit.

3.2.8. Contractor shall bond together the switchgear structure, sections, and all terminations with a bare copper earth conductor (cable) and connect to the switchgear earth bus and to the earthing loop as required.

3.2.9. The contractor shall adjust all operating mechanisms to provide and ensure free mechanical movement and operation of all parts of the unit.

3.2.10. Contractor shall coordinate and obtain the approval of the Utility Company of the equipment.

3.3. Field Testing:

3.3.1. Equipment: Inspect equipment upon delivery to site and report any damage to the client

Engineer.

3.3.2. Switchgear: Inspect and check switchgear for completeness and as recommended by the manufacturer and check phasing of buses, contact alignment and clearances.

3.3.3. Components: Check component ratings, types, sizes and wiring connections, including current and voltage transformers, fuses, switches, instruments and relays.

3.3.4. Where applicable, before energization carry out at least the following tests:

3.3.4.1. Insulation resistance on busbars (with circuit breakers in disconnected position), circuit breakers, bushings and insulators, feeder terminals etc., using at least a 5 kV Megger for MV

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circuits and a 1000V Megger on all control and protection circuits, with relays, lamps and the like components disconnected, to ensure satisfactory insulation resistance as recommended by the Standards and approved practices.

3.3.4.2. High voltage tests on busbars, circuit breakers in disconnected position, switches, PTs and insulators, by applying HV AC test voltage between phases and phase to earth at 80% of the IEC voltage withstand test for 1 minute.

3.3.4.3. Resistance across closed contacts of circuit breakers using appropriate micro-ohm meter.

3.3.4.4. Polarity check and ratio tests for CTs.

3.3.4.5. Calibration checks and adjustment for ammeters and voltmeters.

3.3.4.6. Primary and/or secondary injection tests to check relay operation, using appropriate test sets, followed by tripping of circuit-breaker once only, through its protective relay circuit.

3.3.5. Cables: With circuit breaker in disconnected position, ensure that HV testing of feeder cable and respective termination is carried out as required by standard cable tests.

3.3.6. After energization carry out inspection and checking as follows:

3.3.6.1. Switches are to be closed, one at a time, with as little load on the feeder as possible; check meters as load is increased and any indication of overheating detected by appropriate instruments or sensors.

3.3.6.2. Open switches after a prolonged test run, inspect and check load switches’ condition, isolating contacts, contacts on all instruments and control switches, connections at terminal blocks etc., busbar connections and busbars for any indication of overheating; check for loose connections and bolts etc. and finally re-apply Megger tests to ensure same quality of insulation as before energization.

3.3.7. Manufacturer's instructions are to be followed under all circumstances. Carry out and record measurement and tests recommended by the manufacturer.

3.4. Training:

3.4.1. Training shall be provided for client personnel on the procedures for start up, testing and operation of medium voltage ring main units and the associated auxiliary equipment. Three operator's manuals shall be provided showing full installation and operating instructions for the medium voltage ring main unit.

End of Specification