Research On High-voltage Circuit Breaker Mechanical Characteristic Online Monitoring

Circuit breaker is an important control and protection equipment in power system which has the most frequent mechanical and electrical actions in substation. Therefore, the performance of a circuit breaker during its operation has great impact to the power system security. The statistical analysis showed that most of the circuit breaker failure is due to bad mechanical properties and occurs mainly in the circuit breaker actuator.After decades research and development of circuit breaker fault diagnosis, there are already many new technologies for engineering practice. The parameter extraction methods of circuit breaker mechanical properties mainly include contact travel/time curve analysis, vibration signal analysis and operation coil or energy storage motor current curve analysis. Applied by the current mainstream technology, direct monitoring of the actuator method can reflect the mechanical condition better. However, it is still hard to avoid problems such as sensor installation difficulties, wiring and operation complexity, etc. Monitoring of auxiliary system approach focuses on the diagnosis of mal-tripping and other faults caused by transmission system. Image measurement just beginning to be used for circuit breaker fault diagnosis, the method is still under research and development.A new non-contact monitoring method to evaluate a circuit breaker based on the voltage and current waveform during its operation is presented in this paper. It can effectively avoid the difficulty of sensor installation, which make it easier to achieve on-line monitoring and not limited to the circuit breaker type.