Insulators and Earthing Switches
Earthing switches are provided at several locations to facilitate maintenance. Main blades and earth blades are interlocked along with both electrical and mechanical means. The earthing switch has to be capable of withstanding short circuit current for little duration as applicable to the isolator.
An electrical insulator resists the flow of electricity. Application of voltage difference across a good insulator results within negligible electrical current. Adequate insulation is of prime importance for obvious purpose of reliability of supply, safety of equipment and personnel, etc. The insulators in use at substations are post insulators of pedestal type. The station design should be such in which the number of insulators is remain at a minimum at the similar time ensuring security of supply. In the fields where the problem of insulator pollution is expected (such as near the sea or thermal station, railway station, industrial area and etc.) special insulators along with higher leakage resistance should be used.