On-line temperature monitoring of power distribution equipment

Continuous on-line temperature monitoring provides the means to evaluate current condition of equipment and timely detect abnormality. It provides information on the energized equipment´s response to normal and emergency conditions. On-line temperature monitoring helps to coordinate equipment specifications and ratings with specific application, to determine the real limits of the monitored equipment and to optimize facility operations. Wireless technique eliminates any need for special cables and wires with lower installation costs then other types of online condition monitoring equipment and works well under difficult conditions in strategically important locations. Wireless condition monitoring of energized equipment is applicable both as standalone system and with an interface with power quality monitoring system. The paper presents the results of wireless temperature monitoring of switchgear at a power plant over a two-year period and development of statistically reliable mathematical model describing relationship between observed temperature of electrical contacts and load current with the parameter depending on contact condition. The model provides an algorithm for development of diagnostic tool for determining contact condition, which should support decision making, regarding maintenance procedures, and empower the facility management to accomplish more effective assets management.