Earthing switches are usually installed in combination with an isolator and the two should be interlocked electrically or mechanically to ensure that the isolator is open before the earthing switch is closed, and conversely that the earthing switch is open…
Isolators are simple devices with contacts invariably comprising a moving blade going into two parallel fixed contact faces. The fixed contact faces are usually made up of a number of spring-loaded fingers. The best isolators employ a roll-over action at…
The following basic types are available, typically rated at 350 or 500 MVA at 11 or 22 kV respectively: bulk oil minimum oil air break vacuum SF6 Circuit breakers are designed to deliberately create an arc, and thereafter to control…
The main four different switches used in a power system are: Circuit breakers are designed for controlled closing and controlled or automatic opening of load and fault current. Their duties are to close onto a fault and to automatically open…