A transformer is a static machine used for transforming power from one
circuit to another without changing frequency. This is a very basic definition of transformer.
Generation of electrical power in low
voltage level is very much cost effective. Hence
electrical power is generated in low
voltage level. Theoretically, this low
voltage level power can be transmitted to the receiving end. But if the
voltage level of a power is increased, the
electric current of the power is reduced which causes reduction in ohmic or I
2R
losses in the system, reduction in cross sectional area of the
conductor i.e. reduction in capital cost of the system and it also
improves the
voltage regulation of the system. Because of these, low level power must be stepped up for efficient
electrical power transmission. This is done by step up transformer at the sending side of the power system network. As this high
voltage
power may not be distributed to the consumers directly, this must be
stepped down to the desired level at the receiving end with the help of
step down transformer. These are the uses of
electrical power transformer in the
electrical power system.