Distribution Transformer:

Distribution transformers are commonly used in electrical power distribution and transmission systems.  That class of transformer has the highest power, or volt-ampere ratings and the highest continuous voltage rating. A power rating is generally determined through the category of cooling methods the transformer might use.  A few generally-used methods of cooling are through using oil or a few other heat-conducting materials.  Ampere rating is raise in a distribution transformer through increasing the size of the primary and secondary windings; voltage ratings are increased through increasing the voltage rating of the insulation used in making the transformer.