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MAINTAINENCE OF POWER TRANSFORMER & TESTINGS
ABSTRACT
This project majorly deals with the performance, commissioning and testing of a POWER TRANSFORMER . It gives a brief idea of periodical maintenance of the power transformer in a 220/132/33-11 kv Renigunta substation. A practical power transformer is given here with all parts and its protective devices. The typical test results are also provided.
Transformer is a vital page link in a power system which has made possible the power generated at level of voltages (6600 to 22000 volts) to be stepped up to extra high voltages for transmission over long distances and then transformed to low voltages for utilization at proper load centers. With this tool in hands it has become to possible harness the energy sources at far off places from the load centers and connect the same through long extra high voltage transmission lines working on high efficiencies. At that, it may be said to be the simplest equipment with no motive parts.
At every step, whether the voltage level should have to be increased or decreased we need a transformer. If there is any fault or damage in the transformer then there will be heavy loss to the distribution system. So, periodical maintenance and testing is very important for a power transformer.
INTRODUCTION:
The Transformer is a device that which transfers electrical energy from one electrical circuit to another electrical circuit without change in frequency. It is electrically isolated and magnetically coupled. Actually, the transformer is an electromagnetic energy conversion device, since the energy received by the primary is first converted to magnetic energy and it is then reconverted in to useful electrical energy. Power transformer is one which step-up or step-down the voltage level based on requirement without change in the frequency.
Large-scale generation of electric power usually three phases at generated voltages of 11kv or higher. Transmission is generally at higher voltages of 132,220,400 and 750kv for which three phase transformers are necessary to step-up the generated voltage to that of the transmission line. Next at load centers the transmission voltage are reduced to distribution voltages of 66,33 and 11kv. Further at most of the consumers, the distribution voltages are still reduced to utilization voltages of 440 and 220V. Years ago it was a common practice to use suitably inter connected three single phase transformer instead of a single three-phase transformer.
PRINCIPLE:
A Transformer is a static device by means of which electric power in one circuit is transformed into electric power of another circuit without change in the frequency. It can raise or lower the voltage level in a circuit with a corresponding decrease or increase in current. The transformer mainly works on the principle of electromagnetic induction between two circuits linked by a common magnetic flux. It consists of two inductive coils which are electrically separated but magnetically linked through a path of low reluctance. The two coils posses high mutual inductance. If one coil is connected to a source of alternating voltage, an alternating flux is set up in the core, most of which is linked with other coil in which it produces mutually-induced emf based on Faraday’s laws of electromagnetic induction.