area where the electricity is transmitted by the underground cable and it is safe because of no external exposure of power part and it is produced as a structure which is able to attach protective device to the primary, the secondary. It is able to use as power saving type transformer and pad mounted transformer of high efficiency with a built-in amorphous transformer? According to bushing arrangement- Radial Feed type : It is supplied with an electricity from one side of power source, the same as a general transformer- Loop Feed type : For the increasing of the reliability in power transmission and distribution, it is supplied with an electricity from both sides of power source