11kV/400V Pole mounted sub-station

1. Lightning arrestors- It provides a low-impedance path to ground for the current from a lightning strike or transient voltage and then restores to a normal operating condition.

2. Isolator-  Isolator is mechanical switching device operated on No load condition. It is capable of opening and closing a circuit when small or negligible current is flowing.

3. Fuses/Air break switches- It is overcurrent protection device used to protect the circuit.

4. Transformer- It is used to step down 11kV voltage level to 400 V.

5. Circuit breaker- It is used as a protection and switching device to interrupt fault currents automatically and may be used to switch loads on and off, or to cut off a line. Its basic function is to interrupt the current flow and prevent the risk of fire during fault condition and during maintenance activities.

6.Function of DO – Drop Out Fuses are protection devices that protect networks and equipment from current surges and overloads. An over current will melt the fuse element in the carrier disconnecting the line or equipment. They also provide network isolation points when manually operated with a hot stick.