High Voltage Circuit Breaker Condition Monitoring And Fault Diagnosis

High voltage circuit breaker is playing a very important role in power system. It has dual task of control and protection power system. In the trend of the connection of the global power grid, the scale of the power grid is larger and larger. So the high voltage circuit breaker become more and more important in power system, and it also made the normal operation of increasingly high demands. In order to improve the reliability of normal operation of power system, it has important practical significance to study the high voltage circuit breaker condition monitoring and fault diagnosis technology to improve the level of operation and maintenance of circuit breakers.First, this paper analyses the summary of CIGRE 13.06 working group world wide reliability data and the status of circuit breaker in China from China Electric Power Research Institute. It gives the items and characteristic parameters of condition monitoring based on analyses of the common fault of circuit breaker resist-operation, mal-operation, insulation, breaking and closing, current-carrying and so on. In the research of the characteristic parameters signals of circuit breaker which include the current of opening (closing) coil, mechanical vibration, interrupting current, travel and speed of contact, temperature and so on, the corresponding relation between the monitoring signals and the fault is finally find out.As the circuit breaker failures have imprecise and uncertain characteristics, this paper gives a method which is combined by the Rough Set Theory and the Bayesian Network to diagnose the fault of high voltage circuit breaker. In this paper, a diagnostic model of high voltage SF6 circuit breaker is established based on the research of LW6B-126 SF6 circuit breaker. The discernible matrix algorithm of attribute reduction in the Rough Sets Theory is used to reduce the attribute of this fault diagnosis decision table and eliminate the redundancy knowledge. Then the minimal diagnostic rules can be obtained after simplify the expert knowledge. The complexity of BN structure can be decreased effectively based the minimal rules. Finally, probability reasoning can be realized by Bayesian Network, which can be used to analyze fault reasons of circuit breaker fleetly. This method is proved to be feasible and effective for the HV SF6 circuit breaker by the result of practical fault diagnosis examples.The high voltage circuit breaker condition monitoring system is developed in Visual C++6.0 environment. The main function include the real time circuit breaker condition monitoring data and waveform displays, circuit breaker database management, real time calculation of circuit breaker's electrical life and fault diagnosis. This system tests the various functions of the software based on Altai's USB2002 data acquisition card. Finally, this paper introduces the overall interface of this monitoring system simply.