Research on High Voltage Circuit Breaker Mechanical Faults Online Monitoring

In power transformation and distribution system, unplanned blackouts caused by high voltage circuit breaker faults accounted for more than 60% of the total accidents [, most of the circuit breaker faults are caused by mechanical faults. Base on circuit breaker electrical characteristics, this paper present a method of circuit breaker mechanical faults on-line monitoring. Switching on-off of circuit breakers contacts can be equivalent to a time-varying capacitance, based on equivalent circuit model, the relationship between reactive component and time can be concluded. Processing circuit breakers contacts electric signals with orthogonal decomposition and least squares curve fitting method to highlight the main characteristics of the mechanical faults. These processed data collected from different running state can create a database, taking this database as diagnostic basis to diagnose whether mechanical faults occur to circuit breaker.