الفهرس 
TRANSFORMER PROTECTIONOnly 14 pages are availabe for public view
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Abstract
Electricity or Electrical power has become a major part of our daily life and without electricity we cannot imagine a . life today. Most of our household appliances work on electric current. Sometimes our home appliances malfunction due to voltage problems. We face various power problems due to voltage fluctuations. The solution for• all these problems can be rectified only through a transformer. Power transformers or a transformer is an electrical device that is used to change an alternating current and voltage from one electric circuit to another through electromagnetic induction. These transformers are employed in various mechanisms to reduce the incoming voltage or increasing the voltage of electrical equipments. These transformers have two or more windings wounded on a laminated iron core and the number of windings is based on the requirement of electric voltage that the transformer is used to supply.
There are many types of transformers. like power transformers, electrical transformer, audio transformer, current transformer, high voltage and low voltage transformers, step-up and step-down transformers etc. Each of these kinds has its own properties and usages in tr~sferring voltage based on the appliance it is attached with.
A major application of transformers is to increase voltage before transmitting electrical energy over long distances through wires. Wires have resistance and so dissipate electrical energy at a rate proportional to the square of the current through the wire. By transforming electrical power to a high-voltage (and therefore low-current) form for transmission and back again afterward, transformers enable economic transmission of power over long• distances. Consequently, transformers have shaped the electricity supply industry, permitting generation to be located remotely from points of demand. &&All but a tiny fraction of the world’s electrical power has passed through a series of transformers by the time it reaches the consumer.
Transformers are also used extensively in electronic products to step down the supply voltage to a level suitable for the low voltage circuits they contain. The transformer also electrically isolates the end user from contact with the supply voltage.
. Power transformers are one of the most expensive components of electrical power plants.
For this reason, transformer condition assessment and management is a high priority task. If a transformer fails, it would have a significant negative impact on revenue and service reliability. Failures of such transformers can result in serious power system issues. So fault diagnosis ahd detecting at an early stage for power transformer is very important to insure the whole power system run normally. Based on fault attributes oftransformers, there are a few works have been done on transformer fault diagnosis using such methods as neural networks.
Failure can occur in a transformer due to different reasons. Some failures can be limited or prevented by tests during commissioning, energizing and maintenance of transformer.
. In this Report, we aim at studying the performance of power transformer especially for Nubaria Power Station from the ~iewpoint of protection, commissioning, energization and practical case (report about the accident). An accident has been occurred to this transformer on tap-changer which led to the stopping of the. generation part that was supplying the transformer CTG-3B for eight months. This problem is very impact economically on the electrical power plant (Nobaria Power Station) and reduced the efficiency and preformed through this period.
This report includes the following:-
Chapter 1
Chapter 2 Chapter 3
Chapter 4
Chapter 5 Chapter 6
This chapter presents an introduction about basics of the transformers as to kinds and construction.
This chapter discusses general information about transformers’ protection.
This chapter presents practical steps for preparing transformers before starting
operation as it is called transformer commissioning. .
This chapter presents a practical experiences about transformer energizing in service as it is illustrated in Nubaria Power Station for Electricity Production. This chapter presents practical study case about a failure of transformer.
This chapter draws conclusion and recommendation throughout the report.
This study aims at presenting the correct procedure tests that should be employed, in-site on power transformers. The application of such tests leads to maintain the stability of the plants as well as increasing the efficiency of the electric power generation sector.