A PRESENTATION ON ELECTRICAL TRANSFORMER MANUFACTURING PROCESS AT KOTSONS In partial fulfillment for the awa rd of degree B Tech in Electronics and Communication Engineerin g
Session 2010 Submitted To: Mrs. Vandana Shishoo (HOD of ECE)
Submitted By: Tanvi Gupta Year: 4th year Branch: ECE
Mr. Mr. Manish Sharma Sharma (Seminar Incharge)
Department Department Of Electronics and Communication Engineering Rajasthan College of Engineering for Women Bhankrota, Jaipur
COMPANY PROFILEu.
Kotsons is one of leading transformer manufacturing company in India. Kotsons plant was setup at Agra and Uttaranchal. KPL has in house facilities for conducting all routine test as per IEC, DIN, BS, ANSI, NEMA and IS. KPL Overseas customers are Central Electricity, Genera, ABB limited, Reliance Energy middle, BSES, JVVNL, DVVNL, AVVNL, Siemens Ltd. KPL is a Winner of highest prestigious award ´ NIRYAT SHREEµ for 2000-01. Kotsons transformer range 100 KVA to 1000 KVA are being type tested for temperature rise test and impulse test at world·s renowned testing laboratory.
T RANSFORMERu. A Transformer is based on two principles:
An electric current can produce a magnetic field (electromagnetism) and
secondly that a changing magnetic field within a coil of wire induces a voltage across the ends of the coil (electromagnetic induction). By changing the current in the primary coil, it changes the strength of its
magnetic field; since the changing magnetic field extends into the secondary coil, a voltage is induced across the secondary. The changing magnetic field induces an electromotive force (EMF) across each winding. Since the ideal windings have no impedance, they have no associated voltage drop, and so the voltages V P and V S measured at the terminals of the transformer, are equal to the corresponding EMFs. The primary EMF, acting as it does in opposition to the primary voltage, is sometimes termed the "back EMF". This is due to Lenz's law which states that the induction of EMF would always be such that it will oppose development of any such change in magnetic field.
IDEAL T RANSFORMERu.
T RANSFORMER MANUFAC T URING
PROCESS
CONS T RUC T IONu
CORE
Transformers for use at power or audio frequencies typically have cores made of high permeability silicon steel The steel has a permeability many times that of free space, and the core thus serves to greatly reduce the magnetizing current, and confine the flux to a path which closely couples the windings. Early transformer developers soon realized that cores constructed from solid iron resulted in prohibitive eddy-current losses, and their designs mitigated this effect with cores consisting of bundles of insulated iron wires.
W IN DINGu.
The conducting material used for the windings depends upon the application, but in all cases the individual turns must be electrically insulated from each other to ensure that the current travels throughout every turn. For small power and signal transformers, in which currents are low and the potential difference between adjacent turns is small, the coils are often wound from enameled magnet wire, such as Formvar wire. Larger power transformers operating at high voltages may be wound with copper rectangular strip conductors insulated by oil-impregnated paper and blocks of pressboard.
CORE AND W INDING ASSEMBLYu.
L.V. Windings are normally placed near core over insulating cylinder and oil ducts. HV Windings are assembled co-axially placed with respect to LV. Spacers between coils are 'T' shaped for added firmness. Coils are assembled with best insulating materials and are adequately clamped.
T APINGS AND T AP S W I T CHu.
Generally Taps are provided on HV Windings for HV Variation or LV Variation as specified by customer. These are brought up to a gang operated switch, suitable for external manual operation and can be locked in any desired position to avoid unauthorized operation. Tapping windings are carefully designed to keep unbalance to minimum. For large tapping range, separate regulating windings are used to maintain Ampere-Turn balance at all tap position.
SHOR T CIRCUI T CAPABILI T Yu.
In order to prevent deformation when subjected to short circuit forces, the windings are axially and radial supported. Solid block end insulation, adequate number of spacer rows and anchoring and bracing tapes, backed-up by substantial supporting frames are utilized. The axial end thrust under fault conditions is minimized by the suitable distribution of ampere turns over the length of the windings, by ensuring that the design dimensions are closely adhered to during manufacture.
DRYING OU T PROCEDUREu. For transformers up to 33 KV, drying is carried out in well ventilated, electrically heated oven for a period determined by electrical tests. The transformers are then immersed in freshly filtered oil and allowed to stand for a period until all trapped air is escaped.
For transformers with voltages of 66 KV and above, drying out treatment takes place in a vacuum drying oven. The core and windings assembly is placed in oven and initially heated at 80°C for a period. For bigger transformers, 25 MVA and above, Core coil assembly along with tank are in the oven and after completion of heating cycle, hot, degassed oil is then allowed into the transformer tank under vacuum.
T ANK CONS T RUC T IONu.
Tanks are fabricated from M.S. Sheet of best quality by electric welding. The tank is designed to withstand vacuum and pressure. A robust skid under base is provided, and guide bars are located inside the tank to securely fix the core and windings assembly in position, and to prevent any movement during transportation.
FINISHINGu.
Fittings and Accessories as per customer·s specification and drawing are checked. Air pressure test is subjected to avoid any leakage and seepage on all transformers. Transformers are filled with oil up to the minimum level marking, wherever necessary. Loose accessories like, earthing terminals, bimetallic connectors; dial type thermometers are also checked for proper fittings.
CONCLUSIONu.
Transformer provides us electricity in proper manner according to area distributing by electric board. Kotsons provides the equipment known as transformer that makes electricity distribution easier. It provides customers proper and regular supply of power.
T HANK YOU
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