Study On Distributed Supervisory System Of Circuit-breakers Electrical Endurance

High voltage circuit-breakers are the most broadly applied high voltage electric devices in power systems. The status of breakers directly influences power system's stability and reliability. So it is of great significance to enhance the maintaining of circuit-breakers and to convert from planning maintenance to condition based maintenance. In accordance with the current condition of maintenance in our country, the necessity of exerting the condition based maintenance to H.V. Breaker is discussed. Through the analysis and study of the electric erosion theory, the dissertation demonstrates the theoretic foundation on which the judgement standard of the contacts wear due to the accumulated breaking current and corresponding breaking times is based. Furthermore, a distributed supervisory system of H.V. circuit-breakers electrical endurance is developed based on this principle. The supervisory system is applied to all kinds of transformer substations. Its main functions include: supervising the electrical endurance of contacts, judging the contacts wear according to the breaking current, and putting forward appropriate suggestion of maintenance. Besides, the system carries out the statistics and analysis of breakers operation reliability. Some topics are highlighted: the sign and judgment of breaker electrical erosion condition and electrical endurance status, the sample and calculation precision on the condition of the large-scale change of breaking current, the judgement of breaking time and breaking type, communication and data transmission among units, and anti-interference in substation environment. The whole framework and function designment are expatiated in the dissertation. And it also presents the hardware and software designment of the locale supervisory and the communication and administration unit. The choice of the subject comes from practical requirement. The application of the system will provide basis for the maintenance of H.V. circuit-breaker. There is great significance to enhance breakers operation reliability and to save maintenance cost. The application foreground should be very broad.