Power Transformer:

Power Transformer are given a variety of different names, depending on their use in power systems. A transformer connected to the output of a generator and used to step its voltage up to transmission levels(110 + kv)is sometimes called a unit transformer. The transformer at the other end of the transmission line, which steps the voltage down from transmission level to distribution levels ( from 2.3 to 34.5 kv), is called a substation transformer, finally the transformer that takes the distribution voltage and step it down to the final voltage at which the power is actually used (110, 208, 220 V etc) is called a distribution transformer. All these device are essentially the same – the only difference among them is their intended use.