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CG Transformers has the capability to produce transformers from 400 to 900,000 kVA (300,000 kVA, 1-phase) in 3.3 kV to 500 kV class for various applications. |
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315MVA, 400 kV Transformer at NTPC
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Everything in Switching & Control for Substation Equipments |
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Manufactured ON LOAD TAP CHANGERS are an essential part of the Power Systems Network .We manufacture a complete range of OLTCs for use on transformers up to 66 kV at line end and 132 kV transformers at neutral end. Crompton Greaves started OLTC manufacturing in late sixties with "F" SERIES tapchangers in collaboration with M/S. FULLER ELECTRIC CO. -U.K. and being the latest technology of their times,they have been satisfying the needs of the customers even today. However as over the years certain features not covered by these tap changers gained importance,CGL developed the new "AT" SERIES OLTCs, in collaboration with M/S. ASSOCIATED TAP CHANGERS- U.K. These new tapchangers,being the successor of the "F" type design,offer all their features and also additionally satisfy the new challanges and requirements of the customers.
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Range Bushings upto 420kV. Technology The Condenser Bushings (i.e. Transformer Bushings) available from our plant are used for Air to Oil application. We use OIP (Oil Impregnated Paper) as the Main Insulation System in our Bushings. The Oil used by us is Napthene Based Mineral Insulating Oil (Free From Inhibitors). This oil is highly stable against Oxidation , Chemical & Electrical Ageing. Condenser Graded Bushings form the major part of the Insulation provided in Bushings. The use of Wide Band Bushing Winding Technic , enables a fine grading of the insulation. This ensures uniform stress control & thus provides highest reliability to the product. The Product Insulation undergoes a elaborate drying & impregnation cycle in the Autoclaves. The drying process is controlled by Vacuum Levels (monitored on Pirani Gauges) & the Vacuum durations. Salient Features
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High Voltage Power System experiences overvoltages that arise due to natural lightning or the inevitable switching operations. Under these overvoltage conditions, the insulation of the power system equipment are subjected to electrical stress which may lead to catastrophic failure. Broadly, three types of overvoltages occur in power systems: (i) temporary over-voltages,(ii) switching overvoltages and(iii) lightning overvoltages.The duration of these overvoltages vary in the ranges of microseconds to sec depending upon the type and nature of overvoltages. Hence, the power system calls for overvoltage protective devices to ensure the reliability. Conventionally, the overvoltage protection is obtained by the use of lightning / surge arresters . Under normal operating voltages, the impedance of lightning arrester, placed in parallel to the equipment to be protected, is very high and allow the equipment to perform its respective function. Whenever the overvoltage appears across the terminals, the impedance of the arrester collapses in such a way that the power system equipment would not experience the overvoltage. As soon as the overvoltage disappears, the arrester recovers its impedance back. Thus the arrester protects the equipment from overvoltages. The technology of lightning arresters has undergone major transitions during this century. In the early part of the century, spark gaps were used to suppress these overvoltages. The silicon carbide gapped arresters replaced the spark gaps in 1930 and reigned supreme till 1970. During the mid 1970s, zinc oxide (ZnO) gappless arresters, possessing superior protection characteristics, replaced the silicon carbide gapped arresters. Usage of ZnO arresters have increased the reliability of power systems many fold. Crompton Greaves Ltd. manufactures the zinc oxide lightning arresters for upto 420 kV systems, under a technical collaboration with M/S Hitachi, Japan. The unique features of CGL lightning arresters are as follows: (i) Protection: Superior non-linear characteristics allow the arrester to suppress the overvoltages faster & accurately. The energy handling capability of the elements is higher because of Doughnut type of design(for higher classes). (ii) Adaptability: Superior thermal stability characteristics allow the arresters to function at higher ambient temperature conditions. (iii) Safety: Arresters are known to sacrifice its life under vulnerable short circuit conditions. Usage of fibre glass tube around the ZnO element stack eliminate the possibility of shattering that can endanger to human life as well as to the near by equipment.
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CTs 24kV to 420kV : IVTs 24kV to 245 kV : CVTs 72.5 kV to 420kV : *CT -
Current Transformers Range of Products Instrument Transformers : CTs, IVTs, CVTs up to 420kV. We also manufacture Coupling Capacitors (CCs) & Grading Capacitors (GCs) (for use on Multibreak Circuit Breakers). Technology We use OIP (Oil Impregnated Paper) as the Main Insulation System in our ITs & Bushings. The Oil used by us is Napthene Based Mineral Insulating Oil (Free From Inhibitors). This oil is highly stable against Oxidation, Chemical & Electrical Aging. In CVTs, CCs, GCs, the capacitor technology used by us is either All Paper or Paper+Film (Mixed Dielectric). Condenser Graded Bushings form the major part of the Insulation provided in CTs, IVTs. The use of Wide Band Bushing Winding Technic, enables a fine grading of the insulation. This ensures uniform stress control & thus provides highest reliability to the product. This Wide Band Bushing (wound on a special purpose microprocessor controlled machine) & other premade insulation (Prepared on special purpose machines) account for more than 60% of the major insulation used in the CTs, IVTs. The Product Insulation undergoes a elaborate drying & impregnation cycle in the Autoclaves. The drying process is controlled by Vacuum Levels (monitored by Pirani Gauges) & the Vacuum duration. Stainless Steel Bellows are used in our CTs, IVTs, CVTs, CCs, GCs for compensating the oil volume variations due to changes in ambient temperature. SS Bellows thus provide foolproof hermetic sealing & thus the internal dielectric is maintained factory fresh during the service. The use of SS Bellows ensures isolation of Oil in the product (thus the OIP Insulation) from Ambient Air/Gases. The "Gas Bubbling" phenomenon doesn't exist in our products & the Partial Discharge inception voltages are maintained High. Hence a lower aging & higher product life is ensured. In CVTs, Zinc Oxide Varistors are used for providing Overvoltage Protection. These overvoltages are caused by the Ferroresonance. These varistors are connected across an auxiliary secondary winding & are mounted in the secondary terminal box. Thus it is easily possible for the user to routinely monitor the condition of the varistor. In CTs, All Aluminium Primary Winding is used for Current Ratings higher than 200 Amps & where the number of primary turns required by design are less than four. The all aluminium primary winding formed by use of rigid extruded sections of Aluminium. All the joints in the primary winding are welded. Thus a consistent & reliable Short Circuit Performance is ensured on each CT.
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Indoor applications
Technology Power System is a complex network used for generation,transmission and distribution of electric power from the point of generation to load points located elsewhere. The Power System Network comprises of a wide range of equipment used for switching ,measurement and protection during normal and abnormal conditions of operation.All equipment's associated with the fault clearing process are covered by the word "SWITCHGEAR". A circuit breaker is a switching and current interrupting device in a switchgear.The circuit breaker serves 2 basic purposes:
The existence of both the technologies (SF6 and Vacuum) up to 36 kV is mainly due to the application needs of power systems and both the technologies score over each other in one or the other application areas. Crompton Greaves Limited has always kept pace with the latest development in the field of Switchgear for over 50 years and is a pioneer in introducing SF6 gas circuit breaker in India way back in 1983 in Technical Collaboration with M/s Mitsubishi Electric Corporation,Japan and more than 9000 CG SF6 GCBs with puffer type interrupters up to 400 kV have been put into service in various environments,in many countries where they are operating satisfactorily. The Vacuum circuit breakers have been indigenously developed and fully type tested as per latest IS/IEC specifications to meet the application needs of tropical countries.Crompton Greaves has an independent manufacturing plant of Vacuum Interrupters manufactured in technical collaboration with M/s Westinghouse,USA. The design of VCBs is compact and rugged to meet the stringent operating conditions in medium voltage switchgear. |
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Features: The assembly
of the interrupter is made in a dust free clean room.
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Experience
: The TRIDENT range of oil ring nmain
equipment has a 25 year service history of trouble free operation with
more than 1000,000 units in service world wide. The equipment is suitable
for use in some of the world's more difficult climatic conditions
including : Compact Design : The TRIDENT range is designed to provide a compact arrangement but still offer ease of installation. This has been achieved using well known combination of insulating oil and epoxy resin bushings/mouldings. Ease of Operation : All switching and earthing operations can be carried out from the front of the unit. Position indicators are clear and conveniently located in line with the switching positions. Interlocks : The switches are fully interlocked to prevent any possible mal-operation and subsequent dangerous operations. Mechanism : The operating mechanisms are of the independent manual spring type for both main and earth switches ensuring speed of operation is independent of operator. Ring/Feeder : Ring Switches are fault make, load break three position type 'ON', 'OFF' and 'EARTH'. |
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FEATURES : IMPROVED
MECHANICAL CONSTRUCTIONS : ENHANCED
IMPREGNATION AND OIL CIRCULATION : IMPROVED
TRANSIENT OVERVOLTAGE ENDURANCE : HIGH
INRUSH & DISCHARGE CURRENT WITHSTANDING CAPABILITY : LOW
DIELECTRIC LOSSES: CORONA
RING DESIGN: This design gives an additional advantage of improvement in partial discharge inception voltage. TYPES OF CAPACITORS :
We can supply Capacitor Banks with External or internal fuses depending on customer's specific requirement. External or Internal fuses have their own merits and demerits. However, the trend world over is from Internal fuses to External fuses to fuseless Capacitor Banks. |
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184 Elgin Road ( RD7 ) Ashburton
Phone 03 302 3023 Fax 03 302 3093 WEB www.adaptnz.com
Steve Offord Regional Manager Mobile 021 507 831 email sofford@adaptnz.com
Ruth Offord Manager Major Accounts Mobile 021 507 832 email rofford@adaptnz.com |
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