Power transformer is considered as a key element in any power distribution network. The capacities of the power transformers vary according to the power to be transported and transformed. There are voltage difference and current difference power transformers, starting form the huge transformers nearby the main power stations to the secondary transformers in the large substations of the distribution networks.

Al-Infiraj Group (Sunshine Co.) has long years experience of supplying the transformers from recognized origins to meet the needs of the industrial projects inland.

Due to the existence of a great number of inoperative transformers at the State and the private companies, within the intention of the group is to erect a workshop specialized in repairing the transformers of various capacities inland, in cooperation with the manufacturers. As repairing these transformers will support the electricity distribution network and reduce the need to import new ones.

Below is a summarized explanation on power transformers:

Transformer is a vital link in a power system which has made possible the power generated at low 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 possible to harness the energy resources 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. Nevertheless it has its own problems associated with insulation, dimensions and weights because of demands for ever rising voltages and capacities.

In its simplest form a Transformer consists of a laminated iron core about which are wound two or more sets of windings. Voltage is applied to one set of windings, called the primary, which builds up a magnetic flux through the iron. This flux induces a counter electromotive force in the primary winding thereby limiting the current drawn from the supply. This is called the no load current and consists of two components- one in phase with the voltage which accounts for the iron losses due to eddy currents and hysteresis, and the other 90° behind the voltage which magnetizes the core.

This flux induces an electro-motive force in the secondary winding too. When load is connected across this winding, current flows in the secondary circuit. This produces a demagnetizing effect, to counter balance this the primary winding draws more current from the supply so that

IP.NP = IS.NS

Where Ip and Np are the current and number of turns in the primary while IS and NS are the current and number of turns in the secondary respectively. The ratio of turns in the primary and secondary windings depends on the ratio of voltages on the Primary and secondary sides. The magnetic core is built up of laminations of high grade silicon or other sheet steel which are insulated from each other by varnish or through a coating of iron oxide. The core can be constructed in different ways relative to the windings.