Types of Tranformers

1. Step Up Transformer & Step Down Transformer - Generally used for stepping up and down the voltage level of power in transmission and distribution power network.
2. Three Phase Transformer & Single Phase Transformer - Former is generally used in three phase power system as it is cost effective than later but when size matters, it is preferable to use bank of three single phase Transformer as it is easier to transport three single phase unit separately than one single three phase unit.

3. Electrical Power Transformer, Distribution Transformer & Instrument Transformer - Transformer is generally used in transmission network which is normally known as power transformer, distribution transformer is used in distribution network and this is lower rating transformer and current transformer & potential transformer, we use for relay and protection purpose in electrical power system and in different instruments in industries are called instrument transformer.
4. Two Winding Transformer & Auto Transformer - Former is generally used where ratio between high voltage and low voltage is greater than 2. It is cost effective to use later where the ratio between high voltage and low voltage is less than 2.
5. Outdoor Transformer & Indoor Transformer - Transformers that are designed for installing at outdoor are outdoor transformers and transformers designed for installing at indoor are indoor transformers.