Preventive Maintenance of the Electrical Equipment of HANARO

Electrical equipment deterioration is normal, but equipment failure is not inevitable. As soon as new equipment is installed, a process of a normal deterioration begins. Unchecked, the deterioration process can cause a malfunction or an electrical failure. Preventive maintenance is defined as an activity undertaken regularly at preselected intervals while a system is operating satisfactorily, to reduce or eliminate an accumulated deterioration, while a repair is an activity to bring a system to as a good as new status after a failure has occurred. Electric equipment of HANARO such as high and low voltage switchgear and motor control centers, etc., have been operated since they were installed in 1993. We have conducted a periodic and surveillance test on these equipment. And the equipment go through an inspection by the Korea Electrical Safety Corporation (KESCO) every two or three years. We planned to overhaul the major components, such as the protective device (vacuum circuit breaker, air circuit breaker and protective relay), transformer and high and low voltage switchgear bus as a preventive maintenance (PM) and conducted the overhaul in 2007. The overhaul was conducted in two ways. One was an inspection and maintenance of the major components, and the other was an electric system analysis. This paper describes the overhaul activities and their results