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BRIEF DESCRIPTION High Voltage Capacitor Unit : (Ref. Fig. 1) The high Voltage Capacitor unit comprises of one capacitor unit upto 170 KV and two or more Capacitor Units for higher KV classes. The Capacitor Unit comprises of HV Capacitor (C1) and Intermediate Voltage Capacitor ( C2). These capacitors consist of oil impregnated series connected capacitor elements housed inside oil filled porcelain insulators. Each capacitor unit is independently hermetically sealed. Stainless steel bellow is provided inside each capacitor unit to compensate volumetric changes in oil due to ambient temperature changes. Aluminium HV Terminal is provided on capacitor unit as shown in Fig. 1. Bottom cover of the lowest capacitor unit forms the cover of the EM unit tank. Lifting Lugs are provided on the tank to lift the lowest capacitor unit and t he EM unit together. Intermediate Voltage Tap and high frequency Carrier Terminal (NHF) are brought from capacitor unit to EM unit through bushings. Electro Magnetic Unit (EMU) (Ref. Fig. 2) The EMU comprises of following electrical components: - Compensating Reactor (L) - Intermediate Transformer (Tr) - Damping Device (Zd) - Varistor (V) - HRC Fuses (F) / MCBs (M). The Varistor (V) and the damping device (Zd) are connected across an auxillary secondary winding (f-g). The varistor mounted inside secondary terminal box suppresses over voltages which may occur due to transients on the High voltage side or Low voltage side; whereas the damping device mounted inside EMU t ank damps the transient oscillations. The secondary winding leads and LV lead of the capacitor (NHF) are taken into secondary terminal box through a multilead epoxy block (monoblock). Surge Arrester is provided across NHF and earth which is rated at 1kVp. The compensating reactor (L) and intermediate transformer (Tr) are mounted inside the oil filled hermetically sealed EMU steel tank. A suitably dimensioned air cushion is provided in EMU tank to accomodate expansion of oil. For all service temperatures the oil level must be within min. and max. levels. On the bottom side of the terminal box a removable undrilled gland plate is provided in which suitable holes can be drilled at site. The HRC fuses (F) / MCBs (M) are fitted in the secondary terminal box. Optional Accessories 1) Terminal Connector 2) Cable Glands 3) Three Element Carrier protection device comprising of a) Drain Coil b) Lightning Arrester c) Earth Switch Items 1, 2 are packed seperately and 3 is mounted inside secondary terminal box.
PACKING, TRANSPORT AND UNLOADING CVTs upto 170 kV are packed in a single wooden packing crate. For higher kV classes base unit (comprising of lowest capacitor unit and EMU) and each capacitor unit is packed seperately. WARNING : BASE UNIT AND UPPER CAPACITOR UNITS SHOULD ALWAYS BE TRANSPORTED/ STORED IN VERTICAL POSITION. IT SHOULD NEVER BE TRANSPORTED/ STORED IN HORIZONTAL POSITION. (Except upper capacitor units of 800kV) For unloading, the packing crate should always be lifted from bottom. Immediately on receipt, the goods should be checked for transportation damage (if any). In case of externally visible damages, inform CGL and the insurance company immediately, preferably with photographs. Also mark the position of damage / oil leakage, if any on the CVT out line drawing enclosed with this manual and send it to CGL. Use nail puller while unpacking. While unpacking utmost care should be taken to prevent any damage to the CVT. Store the CVT only in vertical position on a hard, dry and even surface. For taking the base unit out of packing use lifting lugs provided on the EMU cover (Refer Fig. 3)and for taking top capacitor unit out of packing case, tie the rope in the neck of porcelain of this unit below Al. flange For lifting upper unit or middle unit, arrangement as shown in Fig.4 to be followed . CAUTION : 1) AVOID DAMAGE TO THE HV TERMINAL WHILE LIFTING THE UPPER CAPACITOR UNIT. 2) WHILE LIFTING THE BASE UNIT SAFETY ROPE HAS TO BE TIED AS SHOWN IN FIG. 3
ERECTION Upper Capacitor units belonging to the same CVT are marked at our works by the same serial number suffixed by U. For example : Serial number on the main rating plate fixed on the base unit - 1000 : Serial Number on the number plate fixed on upper capacitor unit - 1000/U : Similarly middle capacitor unit is marked by same serial no. suffixed by M. For example -1000/M. CAUTION : ENSURE CAPACITOR UNITS WITH SAME SERIAL NUMBERS ARE COUPLED DURING ERECTION OF CVT WITH TWO OR MORE CAPACITOR UNITS. The hardwares necessary for assembly of upper capacitor unit on the base unit are packed seperately. (Refer Fig. 4) for this assembly. Initially the base unit has to be mounted and fixed on the support structure. For fixing the base unit, four holes are provided on the bottom plate of EM Unit. (for mounting details refer to general arrangement drawing s upplied against order) The threaded studs used for coupling have to be first held into the through holes of the flanges, before the units are placed one above another. This assembly has to be done with utmost care, to prevent damage to the porcelain sheds. For handling of the base unit and upper capacitor unit during this erection process, use of crane is necessary. The studs used for coupling the capacitor units have to be tightened with a torque of 6 kg-m.
A C1 C2 NHF L Tr F Zd V S
- HV Terminal - Pri. Capacitor - Sec. Capacitor - HF Terminal - Compensating Reactor - Intermediate Voltage Transformer - HRC Fuse - Damping Device - Varistor - Surge Arrestor
Fig. No. 2
CAUTION : 1) UPPER AS WELL AS THE LOWER CAPACITOR UNIT HAS TO BE SHORT CIRCUITED AND CONNECTED TO EARTH UNTIL THE ERECTION AND COMMISSIONING WORK IS BEING DONE ON THE CVT. (The capacitors get charged by the electrical fields in the vicinity and they keep these charges for a long time, which will be dangerous to human life. Hence the shorting and earthing of capacitor units is necessary.) 2) DO NOT UNSCREW ANY OTHER SCREWED JOINTS OF THE CAPACITOR UNITS AND THE BASE UNIT.
Secondary Connection : While connecting the measuring instruments & protective relays to the secondary terminals, ensure the burden on respective secondary winding does not exceed. CAUTION : CVT SECONDARY WINDING SHOULD NEVER BE SHORT CIRCUITED.
COMMISSION AND MAINTENANCE
ELECTRICALS CONNECTIONS
The short circuit connection provided across the capacitor units has to be removed prior to commissioning. The CVTs do not require maintenance for a long period of time, owing to the foolproof hermetic sealing. Checks specified in the checklist given on page no. 4 are to be strictly followed. OUR CVTS DO NOT REQUIRE ANY ADJUSTMENTS AT SITE FOR MAINTAINING ACCURACY FOR THE SPECIFIED BURDENS. CVTS ARE CONSTRUCTED IN SUCH A WAY THAT THE REQUIRED ACCURACY CLASS IS MAINTAINED OVER THE ENTIRE BURDEN RANGE. CAUTION : 1) NEVER OPEN THE CAPACITOR UNIT AS WELL AS THE CLAMPING BETWEEN THE EMU AND THE CAPACITOR UNIT. 2) THE NHF TERMINAL WHEN NOT USED FOR CARRIER COMMUNICATION SHOULD BE FIRMLY CONNECTED TO EARTH. 3) THE TERMINAL BOX COVER SHOULD BE CLOSED USING NUT & BOLT SO AS TO COMPRESS THE DOOR GASKET ADEQUATELY THIS WILL ENSURE WEATHERPROOF SEALING.
Earthing :
Important Checks from Checklist
The CVT has to be firmly connected to earth by fixing substation earthing flat to the earthing pads provided on theEMU tank. The end (N) of high voltage winding of the intermediate voltage transformer which when brought inside the secondary terminal box has to be connected to the earthing screw provided in the terminal box has to be connected to the earthing screw provided in the terminal box. As despatched, the LV terminal of the capacitor unit (NHF) is connected to earthing screw by a cable link. CAUTION : ENSURE FIRM EARTHING OF (N) & (NHF).IF NOT EARTHED FIRMLY THESE LEADS AND OTHER LEADS IN THE TERMINAL BOX WILL ATTAIN EXCESSIVE VOLTAGES WHICH WILL LEAD TO PRODUCT FAILURE. One end of the secondary windings can also be earthed inside the terminal box by using the earthing screw.
a) Secondary Voltage : (item 5) Significant deviation in the secondary voltage from the rated value indicates that there is a fault. The product should be taken out of service immediately. Inform CGL for corrective action. b) Varistor : (item 6) Visual inspection of varistor (viz. check for bulging, burning) will indicate healthiness of the varistor. In case of any abnormality inform CGL immediately. c) Oil level Indicator : (item 7) : Since oil inside the indicator is directly exposed to the sunlight, a uniform or spotty brownish sediment can appear on the sight glass after few years of operation. However the oil should remain clear and become insignificantly darker. Otherwise check temperature rise of EMU as in d) and check oil characteristics as in e) below. d) Temperature Rise of EMU : (item 12) : if any fault develops in the EMU, the EMU tank temperature will rise. In such cases the temperature shall be measured below the within five minutes of taking the shut down. The recorded temperatures should be informed to CGL. e) Checking of oil in EMU : (item 13) : Owing to the foolproof hermetic sealing, the ageing of the oil is considerably reduced. An oil sample should be taken after first 10 years of service and subsequently every 5 years. Nevertheless the test on oil should be carried out when the oil becomes brownish in colour. The oil in the EMU should have a maximum dissipation factor of 10% at 40 deg. cent. and BDV of 40 kv (min.) For oil sampling procedure for this test and analysis of the test results contact CGL.
ESSENTIAL CHECK BEFORE COMMISSIONING : Low Voltage Ratio Check : For low voltage ratio check apply a voltage of 100 to 2000 volts between HV terminal and NHF, measure the voltage across the secondary terminals. The ratio should not significantly deviate from the rated value. In case of substantial deviation in this ratio, there is a possibility of an internal damage / loose connection during transport and apparatus must not be put into operation. Report the abnormalities to CGL immediately giving following details 1) Customer Site 2) Type designation 3) S. O. No. (On rating plate) 4) Sr. No. (On rating plate) 5) Date of receipt at site 6) Testing details 7) Contact person and Telephone number.
HV Connection : After confirming the low voltage ratio, connect the HV terminal to the line by terminal connector . While clamping the terminal connector proper torques should be applied to ensure firm connection. CVT HV TERMINAL BEING OF ALUMINIUM,BIMETALLIC STRIP IS NOT REQUIRED IF AL. TERMINAL CONNECTOR IS USED.
f) Inspecting the CVT for oil leakages : (item 8) : The CVT should be checked at following places for likely oil leaks. - Below each porcelain flange. - On EMU tank below and above. - On EMU tank at all welded joints. - Around monoblock in the terminal box. g) Check for capacitance : (item 14) : This should be conducted after 10 years of service at a temperature between + 15 and 30 deg. centigrade The capacitance value should not differ significantly from the routine test results, taking into account the accuracy of the capacitance meter. IN CASE OF DAMAGES AND FAULTS THE FOLLOWING SHOULD BE COMMUNICATED TO CGL : a) Customer Site b) Type designation of the CVT c) S. O. No. and serial number of the CVT d) Date of receipt and the date on which it i s noticed e) Details of damage and the date on which it is noticed. f) Details of the Low voltage ratio check before commissioning and results of other tests recommended by us 00
Check list Checks, which should definitely be carried out at specified times. .Additional checks, if further information is required, or if c onsidered necessary. F When EMU oil is dark. Checking Times : E After change of burden or of connections. Before reconnection to high voltage system. D If secondary voltage is doubtful C Before commissioning after transport of apparatus B After 10 years A Routine checking every year.
Check Items : 1.
Check of Earthing
A EMU tank, NHF (L V terminal of capacitor)
B
C
O
O
D
E
F
N (Neutral end of HV winding of Int. VT) 2.
Low voltage ratio
Check for correctness
O
3.
Secondary circuits
Check if not short circuited
O
O
4.
Connections
Check for firmness of connections
O
O
O
Check for corrosion .
O
5.
Secondary Voltage
Check with regard to rated value
6.
Varistor Visual
check (Bulging or burning)
7.
Oil Level Indicator
Check if completely filled with oil
O
O
O
O
O
O
O
O
O
Check oil colour 8.
Oil leaks
Check for oil traces
9.
Terminal Box
Check for cleanliness and
O
O
O
O
O
O
O
door gasket sealing 10.
Porcelain Insulator
Check for dust accumulation
O
11.
Metal Parts
Check for corrosion
O
12.
Temperature rise
Check for tank temperature
13.
Oil in Tank
Checks on the oil
O
14.
Capacitor
Check capacitance)
O
O
A
B
O
C
D
E
F
Fig. No.3
SAFETY : 7.1 Instructions for Disposal of Material Material used in Instrument Transformers & Condenser Bushings to minimize depletion of natural resources : After unpacking of product at site, packing wood & steel to be recycled. Keep wood & steel at dry place to avoid soil & water pollution. After the useful life of product is over, disassembled the job. Collect oil & oil soaked paper to avoid soil & water contamination. The disposal action for various materials is as follows :
For disposal of Hazardous waste, refer to local regulation.
7.2 Instructions for Mitigation Control In case of abnormal & emergency conditions during life cycle of Instrument Transformers & Condenser Bushings to minimize environmental pollution : Storage of packing wood for long duration in humid condition will cause land pollution. Incinerate / bury the Infected wood as per local regulation. Rusting of steel used in packing will cause contamination of water & soil. Take action as per local regulation. In case of rusting of steel component used in product, clean the rust with suitable solvent & apply paint to prevent further rusting.Ensure masking of insulating surfaces while painting.Contact manufacturer & refer local regulations for use of solvent & procedure for painting. During transportation / storage / operation, if any oil leakage is detected suspected, following actions are
to be taken : If the product is in operation, de-energized & disconnect the suspected product. Clean the product. Find out source & severity of leakage. If leakage is at bolted joint, ensure tightness of bolt. If the leakage is minor on surface, apply sealant to stop the leakage. If the leakage is major, raise the level of leaking portion to reduce leakage. Avoid spreading of oil. Arrange for oil collection. Collect the leaked oil, oil soaked soil, oil soaked cotton waste / wooden dust, etc. Incinerate as per local regulations. Contact manufacturer for further action & before recommissioning. In case of fire / explosion of product, immediately de-energize the HV circuit, if not already tripped. Extinguish the fire. Take actions as per local regulations. Contact manufacturer for further action.
7.3 Material safety data sheet (MSDS) Indentification of the substance / preparation & the company : Product : “Electrol” uninhibited transformer oil conforming to IEC 60296 - 2003 Class I and IS335 - 1993 Product Grade : Transformer oil type IEC : 60296 - 2003 Class I Raj Petro Specialities Pvt. Ltd. 146/2/3 Karad Village, Madhuban Dam Raod, Silvassa 396 230 UT OF D & NH Composition : Refined mineral oil Typical Properties : � Physical State @ 25 C: Liquid O Kin Viscocity @ 40 C : 9.34 CST Appearance : Bright & Clear Oil Density @ 20OC : 0.820 Kg/L Solubility in water : Negligible Storage, Handling and Protective Measures : Stability / Reactivity Stable. Hazardous Nature : Hazardous Nature not required. Storage Container Materials : New steel drums made out of CRCA sheet confirming to IS 1783 specification or in bulk, in EP coated steel drums or in SS tanks. Storage Condition : Store in cool, clean, dry place with adequate ventilation. Avoid heat naked flames and strong oxi dizing agents. Individual Protective Measure : Skin : Use oil resistant gloves that overalls to minimize skin contact and contamination of personal clothing. Eye : Wear safety glasses Respiratory : Avoid inhalation of mist. When handling drums of this product safety boots or shoes should be worn. Ventilation : General or local exhaust ventilation should be provided if oil mists are generated in any event threshold limit value of 5mg/m3 for oil mist should not be exceeded. Toxity : Non Toxic in normal conditions. Irritation : Non irritating. Electrol : A transformer oil is manufactured from Mineral Oils of types shown to be Non-carcinogenic in lifetime animal skin painting studies. Electrol : A transformer oil is expected to be of a low o rder of acute schematic toxity. In normal use it is not expected to be associated with irritation of either skin or e yes and it is not expected to be a skin sensitizer. No long term toxic effects are to be expected.
First Aid Measures : Skin contact : Remove oil soaking clothing. Wash affected parts of the body thoroughly with soap and water, kerosene, gasoline or organic solvents must not be used. Oil soaked clothing, including footwear, must be thoroughly cleaned before being worn again. Eye contact : Hold eyelids open and flush eye with water. Inhalation In the event of dizziness or nausea, remove casualty to fresh air. If symptoms persist obtain medical attention. If breathing stops give assisted respiration by mouth to mouth or mouth to nose method. Ingestion : Oil products must not be siphoned by mouth. Ingestion is an unlikely even however if it does occur DO NOT INDUCE VOMITING. No emergency measures are needed but if adverse health effects follow, refer for medical attention. Fire and Explosion : Flash point, PMCC : 156OC Auto-ignition temperature : Expected to be greater than 320 OC (ASTM method) Flammability Limits : Petroleum vapours are flammable (explosive) in proportions between approximately 1 percent and 10 percent of vapour in air by volume at ambient tempreature and pressures. The vapour pressure of this product is expected to be too low ambient temperatures for the lower explosive limit to be reached. Extinguishing Media : Recommended : Foam, carbon dioxide (Co 2), dry chemical and extinguishers. Sand or earth may be used to another small fires. To be avoided : Water jets should not be used since product will float and spread out on top of w ater and may re ignite. Action in case of spillage : Absorb a small spillage with sand or earth. Sweep up and contain absorbent and then remove it to an appropriate facility for disposal in compliance with local regulations. Large spillages should be prevented from spreading by t he use of sand or earth. If possible transfer the spilled oil to a salvage tank, otherwise treat as for a small spillage. Disposal of used product and container (where applicable) Used oils may contain harmful impurities, which present risks to health that are not present when handling the new oil. It is not possible to be more specific since the presence and absence of harmful impurities is use dependent therefore ALL use oil should be allowed to contaminate soil or water and should be disposed of in accordance with prevailing regulations, preferably to a recognized collector or contractor. The competence of the collector or contractor to satisfactorily deal with waste oil should be established beforehand. This information is based on our knowledge as of and is intended to describe the product for the purposes of health and safety requirements only. It should be not therefore be construed as guaranteeing any specific property of the product.
S.O. No. of the Product………………….. Sr. No. of the Product………………….
IN CASE OF TRANSIT DAMAGES MARK THE LOCATION OF DAMAGE / OIL LEAKAGE ON THIS DRAWING AND SEND IT TO CGL (ADDRESS IS GIVEN OVERLEAF)
Crompton Greaves Ltd., Switchgear Division (S1) A-3, MIDC, Ambad, Nasik - 422 010. India. Tel. : +91 253 2301271, 73 Fax : +91 253 2381247 Email :
[email protected] Registered Office CG House, 6th Floor, Dr. Annie Besant Road, Worli, Mumbai- 400 030. Visit us at : www.cgglobal.com
