Switchgear / Circuit breaker

There are various types of switchgear and controlgear used in power generation and distribution networks as protective devices. Switchgear also perform the function of controlling, protecting, and isolating various electrical equipment and machinery used in industrial applications. The different kinds of switchgear and controlgear are circuit breakers, isolators, gas insulated switchgear (GIS), on load tap changers (OLTC), load break switches (LBS), earth switches, ring main units (RMU), contactors, relays, bus bars, etc.

Some switchgear, especially the low power ones are manually operated, while all high power switchgear are operated electronically with the help of motors. Switchgear can be either AC or DC. With increase in power, switchgear are insulated either by air, oil, vacuum, or gas (SF6), which allow larger power and currents to be managed safely. Air insulated switchgear require a large amount of space for the contacts to operate safely and the arc to get extinguished, while the same can be managed in a smaller space by using gas insulated switchgear (GIS). By using oil insulated switchgear, there is always the risk of oil spillage.