General Specification and Technical Requirement of 45 MVA 132/33kV Mobile Substation

Transcription

1 General Specification and Technical Requirement of 45 MVA 132/33kV Mobile Substation MINISTRY OF ELECTRICITY, REPUBLIC OF IRAQ - 1 -

2 Contents MOE/45 MVA,132/33 KV/Mobile Substation Part-1 General Specification Section-1.1 : General Conditions Supply Complete 132/33kV Mobile Substation Technical Documents Tests and Inspections Packing for shipment Trainings Part-2 Technical Specifications Section-2.1 : General Technical Specification Standards and Design Condition General Requirement for Mobile substation Design Section-2.2 :Technical Specification for Equipment and Materials General Equipment to be mounted on the trailers Trailers Materials Section-2.3 : Test General Factory tests Section-2.4 : Technical Particulars & Guarantees of Equipment Section-2.5 : Typical Layout Drawing and Single Line Diagrams Part-3 Maintenance materials and Trainings Section-3.1 : Spare parts, Test Equipment & General Tools Spare parts Test Equipment General Tools Section-3.2 : Training for Mobile Substation Training for Operation and maintenance Training for Installation Works - 2 -

3 Part-1 General Specification MOE/45 MVA,132/33 KV/Mobile Substation Section-1.1 : General Conditions Supply complete 132/33kV mobile substation in two trailer a, (H.V equipment) trailer b (M.V) equipment Technical Documents General The contractor shall prepare necessary technical documents for the equipment including drawings, design calculations and specifications showing full details of the equipment and materials to be used as well as all arrangement and foundation drawings related to the works. Prior to the commencement of manufacturing at factories or installation at the site, the contractor shall submit technical documents and drawings to MOE for approval. Any comments given by MOE shall be taken into account before manufacturing at factories and/or the site works, and if any modification or change is directed by MOE, the documents shall be revised and resubmitted for approval after making necessary revisions. Approval of the documents shall in no way relieve the contractor from any of his contractual obligation. All costs and expenses for preparation and submission of the documents shall be borne by the contractor including for revision and submission of the documents. 1) Language All technical documents to be submitted shall be made in English. Technical terms in English shall preferably be referred to IEC standards as much as applicable. 2) Symbols, marks and abbreviations All symbols, marks and abbreviations etc. using on any documents shall be clearly explained by a legend on the same document or on separate sheets. The abbreviation and marks used for an individual device shall be identical throughout the complete documentation so as to avoid confusion. 3) Sizes and identifications of documents The size of the drawings shall be as follows: A1 ( 594 mm x 841 mm ) A2 ( 420 mm x 594 mm ) A3 ( 297 mm x 420 mm ) A4 ( 210 mm x 297 mm ) Design calculations, specifications, lists, instruction manuals and other documents shall preferably be prepared and submitted in A4 size

4 - 4 - MOE/45 MVA,132/33 KV/Mobile Substation All documents shall have a uniform title block at the bottom right hand corner, irrespective of the origin of the documents. The title block shall show the drawing title, drawing number, revision number or letter, date prepared, name of the contractor and/or manufacturer and the signature of the contractor s representative. A sufficient blank space shall be provided above the title block of each document for MOE s comments Typical Technical documents required to be submitted The contractor shall submit the following technical documents as per Master List of drawings and Documents (i.e., document control list): 1) Master List of drawings and Documents (document control list) After contract agreement, the contractor shall create and submit a master list of drawings and documents to be provided under the contract for approval of MOE, for a purpose of monitoring and smooth processing of document approval, which shall contain the document title and number, its size, date to be submitted, re-submission date, approval date etc under each column of relevant document classification or category. 2) Specifications The contractor shall prepare specifications for all principal equipment and materials. The specification shall bear the type, ratings, design, construction, materials, dimensions corrosion protection and other performance of the equipment. 3) Drawings The following drawing shall be submitted for approval. Arrangement and Layout drawings of equipment on the trailers Foundation drawings for installation purpose of mobile substations Installation drawings for mobile substations, gantry and 132kV conductors 4) Diagrams The following diagrams shall be submitted for approval. a) Single Line diagrams b) Circuit Diagrams including three line of power circuit and schematic diagrams c) Block diagrams where necessary d) Terminal diagrams 5) Calculation sheets The contactor shall submit design calculation sheets for capacity of auxiliary power supply, burden of instrument transformers, battery capacity etc. for MOE. s approval. 6) Lists The following lists shall be submitted for approval. a) Cable Lists b) Relay setting List c) List of testing equipment and standard tools d) List of spare parts 7) Test Schedules 8) Test Procedures

5 9) Test Reports 10) Instruction Manuals 11) As-built Drawings MOE/45 MVA,132/33 KV/Mobile Substation 12) Type test report The contractor shall submit the type test report for major electrical equipment for an evaluation of conformity to the specification in the tender process Required numbers of Documents Numbers of the documents to be submitted to MOE shall be as follows: 1) During the course of manufacturing and installation work - Documents for approval 2 copies - Reference documents 2 copies 2) After completion of the work - Complete sets of bound prints of 3 copies for each substation as-built documents - CD ROM contained as-built documents 3 sets in PDF format Tests and Inspections Factory tests 1) General Before any item of the equipment is packed or delivered from the manufacturer s factory, all tests itemized in Clause of the Technical Specifications shall be carried out by the contractor as far as practicable to prove compliance with the requirement of the Specifications. All tests shall be carried out in accordance with the approved test procedures. All tests results shall be approved by MOE. The approval of the tests, acceptance of the test certificates or waiving of tests shall not relieve the contractor from his contractual obligations. All costs and expenses associated with such tests and inspections shall be borne by the contractor. The contractor shall grant access for MOE and/or his assigned Representative to attend and witness the tests of the equipment at manufacturer s factory. 2) Date for Testing Written notice of the exact date, time and place of test to be attended as well as all necessary information shall be given to MOE and/or his assigned Representative in writing not later than four weeks prior to the date of any such test. The contractor shall provide the witnessing participants all facilities for a proper and timely execution of the tests. 3) Test Report The contractor shall compile all test results, test certificates, type test records etc. into a test report for each item of the equipment. The test report shall appear sufficient information for the subject of the test, project name, contract number, document number and the test date. The test report shall be countersigned by the witnessed MOE engineer or his assigned Representative

6 One (1) copy of the test report or its draft shall be handed over to each person witnessed the test. The test report shall be submitted officially two (2) copies to MOE the soonest after execution of each test. After completion of all factory tests, the contractor shall bind all test reports properly into books of A4 format and submit two (2) sets of the bound test reports to MOE. 4) Rectification of Deficiencies All deficiencies revealed during the tests shall be rectified by the contractor to the approval of MOE at his own cost and expenses. Rectified components shall be subject to re-testing. All costs and expenses for the re-testing shall be borne by the contractor Packing for shipment Each equipment and materials shall be packed or bundled or protected for shipment so that no damage should be sustained during shipping and transportation from the place of manufacture to the site. All outdoor porcelain bushings of equipment mounted on the trailer shall be equipped with suitable reinforcement fitted with detachable bracings for protection against otherwise possible damage by vibration and impact during shipping and transportation. Any equipment and device which are vulnerable to vibration and /or impact and therefore be necessary to be taken by a special care for transportation shall be, if necessary, rested into the transport-position and securely fastened with fixing plates or attachments by bolts. All materials for protection during transportation shall be kept separately, after each installation, for future use by MOE and therefore shall be painted yellow or red for an easy identification distinguishable from the other materials for picking up when required. Any end terminal of wire or connector-end block or strap-end etc. shall not be left free and shall be securely fastened to the nearby fixed-plate or frame of equipment by temporary fixing straps, bands or tapes during shipping and transportation. Materials necessary for installation of trailers and trailer-on-board equipment such as jacks, steel plates for jack ground base, 132kV conductor and power cables, lightning rod support, fences etc. shall be stored in the storage boxes mounted on the trailer floor or spaces under the trailer floor as much as possible and practicable. All those complete procedures to be taken before and after mobilization shall be fully described in the instruction manual, including necessary fittings and materials. Each crate of package shall contain a packing list and a copy in triplicate shall be forwarded to MOE prior to delivery. All items of material shall clearly marked for easy identification against the packing list. Each trailer shall be regarded as one shipping package so that all equipment and materials mounted on each trailer should be contained in its packing list which clearly describes to distinguish the equipment mounted, the materials for installation purposes in boxes and/or spaces, parts in boxes and/or spaces etc. All cases, packages, etc., shall be clearly marked on the outside to indicate the total weight, to - 6 -

7 show where the weight is bearing and the correct position of the slings and shall bear an identification mark relating them to the appropriate shipping documents. Cases, or packages which cannot be marked as above shall have tags made of metal or other durable materials with the necessary marking on them. The shipping mark shall bear typically the following information in sequence and in a frame commensurate with size of package: The packing inspection shall be carried out by MOE-nominated Inspection Agency before shipping of any goods to verify the packing condition of equipment and materials as well as to check the contents with the packing list of the packages which are to be delivered to the site. The contractor shall be entirely responsible for ensuring that the packing is suitable for shipping and transportation. The contractor shall keep the inspection records of all equipment and materials prior to the shipment Trainings a) Consignee : Ministry of Electricity, Iraq b) Project Name : c) Contract No. : d) Port of destination : e) Case Number, if applicable : Case Number in sequence : f) Description of contents : g) Net and Gross Weight : h) Dimension : i) Name of site : The contractor shall invite engineers from MOE for the following shop trainings: a) Training for operation and maintenance of the mobile substation. b) Training for installation works of the mobile substation. All necessary expense such as round trip air charge between Iraq and countries where the training to be carried out, accommodation charges as well as domestic travel charges in the countries where the training to be carried out etc., shall be borne by the contractor. The contractor shall submit the proposed training program descriptive of time schedule and detailed curriculums to MOE for approval. The contractor shall inform to MOE at least one (1) month prior to the proposed commencement date of the training

8 Part-2 Technical Specifications Section-2.1 : General Technical Specification Specification, Standards and Design conditions Specification and Applicable standards Units MOE/45 MVA,132/33 KV/Mobile Substation All electrical equipment and materials for mobile substation shall be designed, manufactured and tested and/or inspected according to the Technical Specifications. All the data and the specification mentioned hereinafter are according to Iraq standard and its experience, and they are generally covered by the IEC standard and the EN (& BS) standard. Unless IEC and EN(& BS) standards cover, other relevant international and national standards may be applied upon written approval of MOE. If the Technical Specification conflict with any or all of the above standards, the Technical Specifications, upon confirmation of MOE, shall have precedence and shall govern. International system of units (SI) shall be applied to all the works, except use of conventional units is much relevant and conformed to established rules etc Language All documents, correspondence, drawings, reports, schedules and instructions shall be written in English. Also name plates, rating plates, caution plates, instruction plates and notices shall be written in English Service conditions The service and climatic condition under which all equipment is required to operate satisfactorily are as follows; No. Item Description Specification Ambient temperature Maximum outdoor peak (for about 6 hours per day) +70 ºC Maximum daily average +45 ºC 1 Ambient temperature +55 ºC Maximum yearly average +30 ºC Lowest minimum -10 ºC Maximum temperature of all metal part exposed in direct sunshine +80 ºC Humidity Maximum relative humidity 92 % 2 Minimum relative humidity 12 % Yearly average 38 % 3 Wind Wind velocity for design purpose maximum 145 km/hr 4 Altitude above sea level Maximum 1,000 m Minimum 0 m 5 Barometric pressure Yearly average MPa Rain fall Maximum 500 mm 6 (Total rainfall per year) Minimum 50 mm Maximum in one day 65 mm Yearly average mm 7 Sand storm Average number of dust storms (days/year) 21 Average number of thunder storms(days/year) 15

9 Specification of Main and Auxiliary Electrical System 1) 132kV transmission system No. Item 132 kv system 33 kv system 1 Highest system voltage 145 kv 36 kv 2 Nominal system voltage 132kV 33kV 3 Number of phases Frequency 50Hz 50Hz Impulse with stand voltage 5 for bushing 650 kv 170 kv for winding 550 kv 170 kv for neutral 325 kv 170 kv 6 Power frequency Withstand test voltage ( for 1min. ) for bushing 275 kv 70 kv for winding 230 kv 70 kv for neutral 140 kv 70 kv 7 Rated breaking capacity 40 ka 31.5 ka 8 Short time current 40 ka/3 sec 31.5 ka/3 sec 9 Rated voltage and nominal discharge current of lightning arresters on phases 120 kv / 10 ka 39 kv / 10kA on neutral 75 kv / 10 ka 21 kv / 10 ka 10 Minimum clearance in air 320 mm (*2) 1,270 mm between phase and earth. (air cable box) 11 Minimum clearance in air 1,473 mm (*1) 320 mm (*2) 12 between different phases Minimum creepage distance of insulator and bushing 13 Earthing system 4,495 mm Effectively earthed neutral MOE/45 MVA,132/33 KV/Mobile Substation (air cable box) 576 mm (air cable box) Earthed through earthing TF (300A) (*1) The following clearance may be applicable as for the minimum clearance between different phases in air for high voltage (132kV) side of the Main Transformer if the transformer is subject to the impulse type test; Minimum clearance in air for BIL 550 kv (for winding) : 1100mm (*2) These clearances may be lower if it has been proven by tests on actual or similar configuration that the standard impulse withstand voltages are met. The type test shall be carried out for the equipment concerned or the type test report shall be submitted with the tender document. 2) Auxiliary AC and DC system AC system : AC380/220V - 3 phase 4 wire 50Hz with neutral point solidly earthed DC system : DC110V - 2 wire - 9 -

10 General Requirement for Mobile Substation Type of Mobile substation The following types of mobile substation are required MOE/45 MVA,132/33 KV/Mobile Substation Outdoor air-insulated type mobile substation with basic rating of 45 MVA 132/33kV Construction of Mobile substation 1) Design of mobile substation Mobile Substation shall be so designed that all necessary main equipment which are listed in clause shall be completely assembled and mounted on the trailers before shipment so that no assembling works of such equipment are required at site, except station earthing works, necessary connection works between main equipment, connection works to 132 kv connection point and cabling works between trailers, as well as minor adjusting works of equipment to the service position on the trailer. 2) Dimension of mobile substation Mobile Substation shall be designed compact sufficiently to reduce its overall dimension of traveling main body as much as possible for trouble-free transportation to almost any installation sites. Maximum permissible dimension for traveling main body shall be as follows: a) height from the ground to the highest top of equipment meter b) width including any protruding part of equipment meter c) longitudinal length including any protruding part of equipment meter Typical Component and materials for Mobile substation One mobile substation consists of two trailer-on board equipment, i.e., Trailer No.1 and Trailer No.2 with necessary installation materials. In addition to the above, materials and equipment for operation and maintenance activity such as spare parts, tools etc., are also required. 1) Component and materials as per each mobile substation: a) The Trailer No.1 consists of the following equipment. - 1 set of semi-trailer - 1 set of 145kVDisconnecting switch and Earthing switch - 1 set of 145kV Vacuum Circuit Breaker - 3 pcs. of 120kV Lightning Arrester for 132 kv line. - 1 set of 45MVA Power Transformer of 132/33 kv - 3 nos. of 145kV Current Transformer - 1 pc of 75kV Lightning Arrester for 132kV neutral point of power transformer. - 1 set of 75kVA Auxiliary & Earthing Transformer of 33 kv/ v - 1 lot of 132kV Connecting conductor and Safety fence - 1 set of Impact recorder mounted on the trailer floor b) The trailer No.2 consists of the following equipment - 1 set of semi-trailer - 1 set of Outdoor type 36 kv Air-insulated Metal-clad switchgear - 1 set of maintenance platform with traversing carriage in front of switchgear row - 1 set of Indoor Protection relay Panel with Numeric type relays. - 1 set of Indoor Supervisory control Panel including AC distribution circuit with mimic diagram and metering.

11 MOE/45 MVA,132/33 KV/Mobile Substation - 1 set of Outdoor type DC 110V Battery and Charger panel. - 1 set of 36kV power cables (for connection between Trailers No.1& 2) - 1 set of control cable with plug in type connectors (for connection between Trailers No.1 & 2) - 1 set of accessories for switchgears and panels necessary for maintenance. - 1 set of Impact recorder mounted on the trailer floor c) Consumable parts for each mobile substation - 1 set of Consumable spare pare parts 2) Equipment, materials and others for operation and maintenance as per the contract a) 1 set of Spare parts for 5 years b) 1 lot of Trainings Typical Traveling Conditions of Mobile Substation Maximum speed : for paved road 40 km/hour : for unpaved road 10 km/hour Cruising speed : for paved road 35 km/hour : for unpaved road 10 km/hour General Requirement of Trailer The trailers shall be designed and manufactured of semi-trailer type considering special service condition such as high ambient temperature, sand storm etc., encountered in Middle East. The trailers are the major part of mobile substation components and shall be a complete factory assembled flat bed type whose frame should have sufficient strength and rigidity to withstand a heavy load and a vibration in order to carry electrical equipment safely. Two types of trailer, trailer No.1 and No.2 shall be designed and provided for one set of mobile substation. A wheel plate and king pin system shall be provided for coupling with a tractor for transportation. Landing gears and jacking pads with necessary quantity of jacks sufficient to support overall weight of each trailer shall be also provided for installation of mobile substation at site. Each trailer shall be provided with one (1) set of mechanical type 3-axis accelerometer (Impact Recorder ) mounted on the trailer floor to record shock and impact experienced throughout transportation after shipment. The recording of all 3-directional measurement of Impact Recorder shall be continuous without any interruption throughout the overall route of shipping and transportation to the site after the shipment of the mobile substation. Unless explicitly stated, all the necessary provisions obviously required for proper and safe driving of the trailers such as spring system, braking system and signal lamps etc., shall be provided Design Temperature Rise Having regard to the service conditions, the limits of temperature rise of all equipment, determined in accordance with the relevant IEC, shall be reduced such that the final attained temperatures of site do not exceed the final temperatures imputed by the IEC reference temperature. Due regard must be taken of the effect of direct sunlight impinging on outdoor equipment and the effects of differential temperatures existing in equipment due to the impingement.

12 Current Ratings Every current carrying part of the equipment, including circuit breakers, current transformers, disconnecting switches, busbars, connections and joints, etc., shall be capable of carrying its rated current continuously, and in no part shall the permissible final temperature be exceeded. In addition, all parts of the switchgear shall be capable of withstanding, without thermal or mechanical damage, the instantaneous peak and rated short time currents corresponding to the breaking capacities of the circuit breakers. All current ratings specified are the continuous values required under the service conditions Circuit Breaker Making and Breaking Capacities Each circuit breaker shall be capable of making and breaking short circuit faults in accordance with the requirements of IEC , three phase short circuit rating and to the rating of each type of circuit breakers. The break time for all breakers shall not be greater than 5 cycles. The tender documents shall include the certified type test report of making and breaking test in accordance with IEC , 36kV Circuit Breakers 1) 145kV circuit breakers The 145kV circuit breaker shall be of outdoor type vacuum circuit breaker or SF6. The breaking capacity of the circuit breaker shall be 40 ka. The proof shall be given that circuit breakers offered have been in use in similar climatic conditions to that prevailing in Iraq for at least five (5) years. Circuit breakers shall comply with the requirements of IEC Each circuit breaker shall be equipped with a local control cabinet which shall accommodate: a) the operating mechanism : trip free and motor charged spring operated type on 110VD.C b) a means of electrically operating the circuit breaker by a signal from remote control panel and protection relay c) a means of manually operating the circuit breaker for maintenance purposes d) operation counter e) a mechanically operated ON/OFF indicator f) provision for local manual charging g) Slow losing voltage trip device : when DC control voltage is losing, both electrical and electro-mechanical protection shall trip the 132kV circuit breaker. Circuit breakers with separate operating mechanism for each phase shall not be accepted. All breakers shall be fitted with lifting lugs or eyes. 2) 36kV circuit breakers The 36kV circuit breakers shall be in accordance with IEC and shall be of vacuum type. The breaking capacity of the circuit breaker shall be 31.5kA. The circuit breakers controlling the line circuits shall be arranged for double three phase rapid speed auto-reclosing in accordance with IEC They shall incorporate horizontal or vertical isolation facilities and be mounted on horizontal draw-out trucks

13 MOE/45 MVA,132/33 KV/Mobile Substation Rollers and their guide rails shall be designed to facilitate alignment and levelling with the enclosures of the trucks during re-instatement of the trucks into the breaker compartment. Circuit breaker closing mechanisms shall be of the trip-free type and motor charged spring operated type on D.C.110V. Each equipment shall be provided with a visual, mechanized indicating device. Lamp indication in place of mechanical one will not be accepted. In order to permit test purposes, circuit breakers shall be possible to complete the closing, tripping, indicating circuits when the circuit breaker is isolated. Means shall be provided for local manual mechanical tripping of circuit breakers, preferably by push-buttons, shrouded to prevent inadvertent operation. The mechanism shall be also provided with means for charging the spring by hand. Locking facilities shall be provided so that with the circuit breaker in any location it can be prevented from being mechanically closed when it is open and from being mechanically tripped when it is closed. This requirement shall be met by fitting a single padlock and shall not entail fitting any loose components prior to the insertion of the padlock. Provision shall be made for manually slow closing and slow opening of the circuit breaker for maintenance purposes, but it shall not be possible to this facility when the circuit breaker is in the service. In normal operation the recharging of the mechanism operating spring shall be commenced immediately and automatically, upon completion of the circuit breaker closure. The time required for such automatic recharging of the spring shall not exceed 30 seconds. Each circuit breaker shall be connected to the busbars and feeder circuit through plug and socket type isolating devices. The devices shall be of the offload type but shall be suitable for operation whilst the busbars or feeder circuits are alive. The isolating devices shall be interlocked with their respective circuit breakers to prevent their making or breaking load, but arrangement whereby attempted isolation of a closed circuit breaker trips the circuit breaker are not permitted. Where isolation is carried out by withdrawal of the circuit breaker, provision shall be made for rigidly locating the circuit breaker in the service. The main circuit isolating devices, and also all secondary circuit isolating contacts, shall be of the self-aligning type, mounted in accessible positions to permit maintenance. A set of metal shutters shall be provided to cover each 3 phase group of stationary isolating contacts. Each set shall be capable of being individually operated and individually padlocked when it is closed. The shutter shall open automatically by a positive drive initiated by the movement of the circuit breaker or voltage transformer carriage. The closing operation shall also be automatic, either by positive drive or by two independent means, each capable of operating the shutter alone. To facilitate testing, means other than locking shall be provided for securing the shutters in the open position. However, such means shall be automatically cancelled and the automatic operation of the shutters shall be restored upon reconnection of the circuit breaker or voltage transformer to the fixed isolating contacts , 36kV Outdoor Type Switchgear 145kV switchgear shall be an outdoor open structure type air insulated switchgear. Medium voltage (36kV) switchgears shall be an outdoor air insulated metal-clad switchgear.

14 145kV switchgear shall consist of a disconnecting switch, an earthing switch, a circuit breaker, a set of lightning arresters, a set of current transformers and a set of bus conductors connecting the those equipment together to form a transformer feeder mounted on the trailer. The short-circuit current of the 145kV switchgear shall be 40 ka. Medium voltage switchgear shall consist of at least auxiliary, incoming and outgoing switchgears. Auxiliary switchgear shall contain a withdrawal type three-phase voltage transformer with power fuses as a main component. The incoming and outgoing switchgear shall accommodate each a withdrawal type vacuum circuit breaker, current transformers, an earthing switch and a set of busbars etc. A maintenance platform with a sufficient space shall be provided in front of medium voltage switchgear row for operation and maintenance purposes. The platforms shall be fitted with rails in a longitudinal way across the platform on which a carriage traverses in front of switchgear row in order to withdraw from or insert into the switchgear compartment the circuit breaker and /or voltage transformer truck Power Transformers 1) Types of transformers The transformers shall comply with the requirement IEC suitable for outdoor installation and service conditions. The changeover from ONAF/ODAF to ONAN cooling shall be entirely automatic but means of manual changeover shall be provided. 2) Continuous maximum ratings, temperature rise and overload All transformers shall be capable of delivering full capacity under steady load conditions without exceeding the limits of temperature rise specified in IEC ) Losses The losses of each transformer shall be stated in schedules. The tolerance on the losses of each transformer shall be in accordance with IEC The fixed losses shall be as low as consistent with normal design, reliability and economical use of material. 4) Insulation levels The first unit of each type of transformer manufactured in the contract shall be subject to the type testing to prove the impulse voltage withstand values specified in IEC ) Transformer fittings All transformers shall be equipped with the following fittings as typical items: a) Diagram plate b) Rating plate c) Earthing terminals d) Jacking lugs e) Lifting lugs f) Winding temperature relay g) Oil temperature relay h) Pressure relief device

15 i) Moisture-excluding breather of silica gel j) Buchholz relay k) Drain valve complete with sampling cock l) Oil level indicator m) Filter valves n) Conservator (Conventional type) o) Padlocks for each drain valve, and filter valve 6) Cooler control Each motor or group of motors shall be provided with a three-pole electrically operated contactor and with control gear of approved design for both of starting and stopping the motor by hand, and also automatically from the contacts on the winding temperature devices of the transformer. Over-load protection shall be provided but no-volt release shall not be fitted. Where small motors are connected in groups, the group protection shall be arranged so that it operates satisfactorily in the event of a fault occurring to a single motor. Each transformer shall be provided with an appropriate number of fans for sufficient cooling. 7) Tap changers On-load tap changers and accessories shall be supplied and shall be so designed as to give a large margin of security to operate from a 110V D.C. supply, and shall be capable of 100,000 tap changing operations, without the necessity of maintenance. The tap changer made by MR (Maschinenfabric Reinhausen, Germany) shall be provided. The tap-changer shall comply with IEC In addition, specific details of the required tap changer scheme shall be as follows: a) Tap change facilities shall be provided for each transformer to be automatically controlled or controlled by manual switching at the remote cubicle and controlled by manual switching at locally from the transformer. b) The tap changer shall be designed so that its operation with respect to selector & diverter switches, is carried out in an oil filled enclosure having with no communication with the oil of the transformer. c) All mechanical parts and all contacts shall be accessible via a cover on the separate tap changer tank and without having to interfere with the oil in the transformer. d) It shall not be possible to operate the electric drive when the hand operated gear is in use nor shall it be possible to engage the hand-operating gear when the electric operating drive is in progress. e) No two electrical control signals shall be in operation simultaneously. f) Operation of the remote or local control switch shall cause one tap movement only. subsequent tap movement on manual control shall be effective only after returning the control switch to the OFF position between successive operations. g) All control switches and local operating equipment shall be labelled to indicate the direction. (i.e. Raise or Lower of tap changing). h) The local control switches, together with the 110V D.C. contactors and terminal boards, shall be accommodated in a suitable weather-proof operating box mounted on the

16 transformer. A heater suitable for operation from a 220V single phase supply shall be provided in the motor drive unit for the tap changer in the operating box. The heater shall be provided with protective fuses of approved rating. i) The tap changer motor shall be designed for a 3-phase 380 V A.C. supply. j) The equipment shall be so arranged that once a tap change has commenced, it shall be completed even in case of failure of electrical supply to the mechanism drive motor. It shall not be possible to be left in an intermediate position. k) Indication shall be given, electrically at the remote control panel, and mechanically at the transformer, of the tap in use at any time. l) An operation counter shall be fitted to the tap changer. m) Limit switches shall be provided to prevent overrunning of the mechanism and shall be directly connected in the main circuit of the driving motor. In addition a mechanical stop or other approved device shall be fitted to prevent over-running of the mechanism under all condition. Limit switches may be connected in the control circuit of the driving motor provided that an approved mechanical declutching system is incorporated. n) Short circuit and overcurrent devices shall be included to protect all motors and control circuit. 8) Automatic Voltage Regulator (AVR) Each On-load tap changer of the main transformers shall be provided with an automatic voltage regulator relay (AVR). The AVR can be set by variable control and shall have facilities to keep the voltage constant on the secondary side of the transformer. The recommended preset range is between +/- 5% of rated line voltage of the secondary side of the transformer. Facilities to operate the tap changer with Automatic-OFF-Manual and Raise-Lower switches or push buttons shall be provided. Failure of AVR shall keep tap changer in position and give alarm. A full description of AVR and its controls shall be submitted with offer. 9) Parallel operation of transformers The two or three transformers ultimately will operate in parallel when the bus sectionalize is closed. Therefore the control of the tap changer shall be designed to enable parallel or individual operation of the two or three transformers as follows: a) Each transformer individually controlled automatic or manual. b) All transformers in parallel operation automatic or manual control with one of the transformers as master and the other transformers followers. The control and protection equipment associated with parallel-individual operation of the tap changes shall be also provided. A full description of parallel-individual system and control shall be submitted with the Tender

17 (Note: this clause is applicable to the Mobile substation with the bus sectionalize which intends to operate in parallel operation) 10) Cable boxes of transformers Cable boxes on the 33kV side shall be of the single core type cables and for full rating of the transformers. These boxes shall be of air insulated type. 11) 132kV Neutral point of main transformer The neutral point of 132kV system shall be solidly earthed. Therefore the main transformer with primary 132kV star connection shall be brought its neutral-point out for earthing purposes. The neutral point shall be provided with an earthing wire of not less than 100mm 2 (PVC sheathed of green colour) and a 75kV lightning arrester in parallel to connect the substation earthing grid. The earthing wire shall have an appropriate disconnecting means in order to avoid or reduce multiple points of earthing in 132kV system when necessary, but this disconnection of earthing wire shall not affect the connection of 75kV lightning arrester to the earthing grid which should be permanent Auxiliary and Earthing Transformer The transformers shall comply with the requirement IEC They shall be of self-cooled type and suitable for outdoor service conditions. The transformer shall be equipped with a primary zig-zag winding with its neutral point brought out so that, when the primary side of the transformer is connected directly to the secondary delta winding of the main transformer, it provides an earthing on the secondary side of the main transformer. The primary zig-zag winding shall be designed in such a way that not only its zero-sequence impedance restricts a neutral current up to 300A when an earth-fault happens, but also the winding can withstand such full current for not less than 10 seconds. The neutral point shall be provided with a bushing current transformer with a suitable current rating for a restricted earth fault protection for the secondary side of the main transformer. The transformer shall be also utilized as auxiliary AC power supply at low voltage side for station service. The low voltage winding shall be of star connection with neutral point brought out so that 3 phase 4 wire of V 50Hz AC distribution system is provided. AC distribution circuit shall be referred to the sub-clause The transformers shall be equipped with the following fittings as typical items: a) Rating plate. b) Earthing terminals. c) Lifting lugs. d) Oil temperature relay. e) Pressure relief device. f) Moisture-excluding breather of silica gel. g) Buchholz relay. h) Drain valve complete with sampling cock. i) Oil level indicator

18 j) Filter valves. k) Conservator (Conventional Type). l) Padlocks for each drain valve, and filter valve. The minimum capacity of the auxiliary power supply shall be 250 kva including a spare capacity of 15kVA earmarked to MOE s own use. The contractor shall submit a calculation sheet of his proposed AC capacity for MOE s approval Current Transformers Current transformer shall comply with the requirements of IEC (IEC ) Current transformer shall be capable of withstanding without damage the peak short time current breaking capacity. All current transformers shall have rated secondary current of 5 Amps. The rated volt-ampere output of each current transformer shall not be less than the connected burden as installed in service plus some extra burden. The burden of cable connection shall be taken into account. The secondary windings of each set of current transformer shall be earthed at one point only. Current transformers used for energizing indicating instruments shall be of accuracy class 1.0 and those for protective purposes shall be of accuracy class 5P10, except a special requirements (i.e., class x etc.) to the current transformers by some of relays are taken into account. The connection and the ratio in use shall be indicated on all connection diagrams. The contractor shall submit the characteristic of each current transformer including its calculated maximum burden and/or knee-point voltage for MOE s approval Voltage Transformers Voltage transformers shall comply with the requirements of IEC Voltage transformers shall be of accuracy class 1.0 for energizing indicating instruments and 3P for protective purposes. They shall be so designed that saturation of the cores does not occur when times normal voltage is applied to each winding. They shall have outputs 50% in excess of the burden in use when design. The voltage transformer secondary circuits shall be complete in themselves and metal cases shall be individually earthed. Secondary fuses shall be provided as close as possible to each voltage transformer and labelled to show their function and phase colour. Relevant documents shall be submitted for approval for each type of voltage transformer Lightning Arresters Lightning arresters shall comply with the requirements of IEC Lightning arresters shall be of metal-oxide gapless type. 1) Lightning arrester for 132kV system a) 132kV line Lightning arresters to be used on 132kV line terminals shall be mounted as closely as possible to 132kV line bushings of the transformer and shall be rated as follows: - Rated voltage : 120 kv - Nominal discharge current : 10 ka (peak value) - Line discharge class : 3 - Energy absorption capability : 7.5 KJ / kv one min

19 Lightning arresters shall be provided with one (1) surge counter for all three (3) arresters for 132kV line as well as with one (1) surge recorder to the arrester of each line. b) 132kV neutral point Lightning arresters to be used at neutral point of 132kV winding of the transformer shall be rated as follows: - Rated voltage : 75 kv - Nominal discharge current : 10 ka (peak value) - Line discharge class : 3 - Energy absorption capability : 7.5KJ / kv one min. 2) Lightning arrester for 33kV system a) 33kV line - Rated voltage : 39 kv - Nominal discharge current : 10 ka (peak value) - Line discharge class : 2 b) 33kV neutral point - Rated voltage : 21kV - Nominal discharge current : 10kA (peak value) - line discharge class : kV Disconnecting Switches 145kV disconnecting switches shall comply with IEC The short time current of the disconnecting switch shall be 40 ka/ 3sec. 145kV disconnecting switches installed at all mobile substations shall be of outdoor manual operation type and shall be operated from ground level. The operating mechanisms shall open and close all three phases simultaneously and shall be self-locking in both the open and closed positions. All disconnecting switches shall be fitted out with hand operating device Earthing Switches of 145, 36kV Earthing switches shall comply with the requirements of IEC The short time current of the earthing switch of 145, 36kV shall be 31.5kA/ 1sec. Each incoming and outgoing line and cable feeder circuits shall be provided with an earthing switch. The earthing switches shall be hand operated and shall comply with the requirements for disconnecting switch. 145kV earthing switch shall be annexed to 145kV disconnecting switch and so arranged that the earthing switch and disconnecting switch are each other interlocked mechanically in compliance with the requirement of sub-clause a). Earthing switch for 36kV switchgear shall be integrally a part of each cubicle cable head and shall be so designed that it is operational only when the circuit breaker is withdrawn. The earthing switch installed at 33kV cable side shall have a fault making capability corresponding to the rated peak short time current

20 Interlocking Equipment All disconnecting switches and earthing switches shall be provided with interlocking features of mechanical sequential locking type or electro-mechanical bolt type, and the scheme of interlocking shall be subject to approval of engineer and shall cover the hand operation of apparatus which is normally electrically operated. All mechanical interlocks shall be applied at the point at which hand power is used, so that stress can not be applied to parts remote from that point. Where key interlocking is employed, tripping of the circuit breaker shall not occur if any attempt is made to remove the trapped key from the mechanism. Any local emergency tripping device shall be kept separate and distant from the key interlocking. All electrical interlocks shall not produce or permit faulty operation. Electro mechanical bolt interlocks shall be energized only when the handle operating of the mechanism is brought into the working position. Means shall be provided whereby the bolt can be operated in emergency or a failure of interlock supplies. When made of malleable iron, operating boxes handles, rods, tubes and other fitting for outdoor equipment shall be galvanized. Basic operating condition for interlocking scheme shall be as follows: 1) 145kV switchgear: 145kV disconnecting switch connected in series with 145kV circuit breaker shall only be operated when the circuit breaker is open and none of the adjacent earthing switch is closed. 145kV earthing switch shall only be operated when 145kV disconnecting switch is open and vice-versa. Interlocking between the disconnecting switch and the circuit breaker shall be achieved by an electrical means and the interlocking between disconnecting switch and earthing switch shall be of mechanical type. 2) Medium voltage(36kv) switchgear: It is not possible for circuit breaker to insert into the service position unless the earthing switch mounted at the cable side of the same cubicle is open, but possible to insert only when the earthing switch is open. It is not possible for earthing switch to close unless the circuit breaker in the same cubicle is in the isolated condition (disconnected position or withdrawn condition), but possible to close only when the circuit breaker is in the isolated condition. Interlocking between the circuit breaker and the earthing switch shall be of mechanical type. 3) Between 145kV and Medium voltage switchgear across the main transformer: 145kV disconnecting switch shall not be operated unless the circuit breaker in the medium voltage incoming switchgear is open. 145kV circuit breaker shall not be closed unless the earthing switch in the medium voltage incoming switchgear is open. The earthing switch in the medium voltage incoming switchgear shall not be closed unless 145kV circuit breaker is open. Interlocking between 145kV and medium voltage switchgear across main transformer shall be of electrical type kV Bus bars and Connections ACSR or copper busbars and connections shall comply with the applicable clauses of IEC

21 MOE/45 MVA,132/33 KV/Mobile Substation requirements. The design shall be such that no conductor is, under the most adverse conditions that can arise in service, be stressed to more than 40% of its elastic limit. Phase arrangement and colour identification shall be in accordance with sub-clause kV bus bars and connections Busbars and connections shall comply with the applicable clauses of IEC recommendation. The equipment shall be of single bus bar type. The busbars and connections shall be covered with suitable insulating materials having a sufficient die-electric strength link silicone rubber etc. Bus bars shall be of constant cross sectional area throughout their length with connections as short and straight as possible. The resistance of any length shall not be greater than that of an equal length of section of conductor, without a joint. The resistance of any length shall not be greater than that of an equal length of similar section of conductor, without a joint. Access to bus bars and the connection directly connected thereto shall be gained only by the removal of covers secured by bolts or screws. Such covers shall be clearly and indelibly marked Bus bars. Phase arrangement and colour identification shall be in accordance with sub-clause Phase arrangement and Colour identification of electrical conductors and equipment 1) Phase arrangement The phase designation of AC circuit shall be assigned as R for the first phase, Y for the second phase, B for the third phase and N for the neutral phase. The polarity designation of DC circuit shall be assigned as P for the positive polarity and N for the negative polarity. N shall be also designated for earthing circuit for both AC and DC circuit. The standard phase arrangement viewed from the front of the switchgear and panel shall be as follows: a) AC circuit three-phase single phase - from left to right R-Y-B-N R-B-N - from top to bottom R-Y-B-N R-B-N - from far to near R-Y-B-N R-B-N b) DC circuit - from left to right P-N - from top to bottom P-N - from far to near P-N All relays, instruments, others devices, conductors and equipment shall be arranged and connected in accordance with the standard phase arrangement where possible. 2) Colour identification a) Colour of internal wiring Colour of insulation of all internal wiring for control and auxiliary circuit as well as the sheath colour for low voltage power cables except earth circuit shall be black and that for earth circuit shall be green. b) Colour scheme for phase identification of AC circuits Identification of the phases of conductors and power cables for AC circuits shall be attained by collared ferrules or other durable materials at their ends as follows: