At present there are demands for electrical power, to fulfill its requirements it requires to create bigger power generating stations. The power generating stations are thermal, atomic or hydro-electric; these are based on its availability of resources. The power generating stations are not near to the load center where the consumption of power takes place; these are then transported to the load centers. For this purpose high and voltage transmission network are required. If the power is transmitted at high voltage level then it is economical.
Electrical powers are distributed at lower voltage levels which are specified by the consumers. To provide stability and maintain the voltage level a number of switching stations and transformation or created between the consumer and generating stations. These switching and transformation stations are called as electrical substations.
The substations are classified in to different parts. Some of the substations are Step Down Substation, Step Up Substation, Industrial or Bulk Supply Substations and Outdoor Type Substations.