Voltage switchgear, a device to open and close the circuit, can be widely classified, ranging from a switcher for on and off in household lightings to a circuit breaker to interrupt fault load currents of many tens of thousands of amps in electric cables. The broad scope of switchgears variable depending on purpose, location and capacity means to call for appropriate selection for one's own sake, taken into account capability required and functionality available. Circuit breaker in power station is able to terminate current flow very quickly by isolating the defected part and at the same time switching it over to the normal part to safeguard the system when there occurs an accident of fault current in such a circuit board or something like that. According to IEC(International Electro-technical Commission) a switchgear is defined as "a construction conveying the current in normal state, while interrupting the flow of current in case of abnormal state like circuit breakage along with allowing the current to flow only in a preset duration."
The study aims at providing the classification of large-scaled industrial voltage switchgear used in a power generation station including its characteristics in operation and maintenance method in pursue of stable operation and prevention of troubles by way of analytical examination over exemplary accidents happened during operation.