Switchgear

Abstract

This chapter discusses the basic design and construction of industrial low voltage and medium voltage breakers and switchgear. Circuit breakers and switches are used to provide isolation points for the electrical system in the plant. Circuit breakers can be operated for control purposes to isolate equipment in the station for operation and maintenance and they can also be operated for protection purposes to isolate equipment in the event a fault is detected in the equipment. Circuit breakers are designed with a mechanical device to provide the mechanical force to both close and open or trip the circuit breaker. Like all electrical equipment, breakers are design with insulating systems and must be able to withstand both the normal power system voltages as well as transient voltages the breaker may see during operation. For safe and reliable operation of the breaker, there are several mechanical interlocks that are used.