Study On Vacuum Circuit Breaker Switching Overvoltage

Vacuum circuit breaker is to play an important role in middle and low electricity implement of power system for its particular characteristic and degree with no substitution. Then the problem of vacuum circuit breaker switching overvoltage will be more outstanding along with its wide applications. To avoid accidents and hidden trouble, the study on interrupting transformers and capacitor group and countermeasures must be carried through by the numbers.On the base of practical transformer substation main connection, electric components and system circuit model are first formed in the paper; analyze vacuum arc characteristic and medium resume are analyzed, then, according to vacuum chamber physical process of switching AC arc, resume process are divided into three stages: sheath development, neutral particles diffusion and static characteristic, with that, calculating model of medium resume strength is erected and applied in the computing of vacuum circuit breaker interrupting transform overvoltage; In the paper, Saber software is used to simulate a whole switching process; As follows, overvoltage characteristic of vacuum circuit breaker switching no load and load transformers, kinds of influence factors are analyzed in detail; At last, vacuum circuit breaker switching capacitance group overvoltage formative causes and electrode refining for lessening reignition are discuss.Saber simulation software has the function of disposing mix signal, mix technology and mix administrative levels, Saber simulation models builded expediently by MAST VB could simulate regular electromagnetism, electromechanical, electric power, electron component and its' controlling signal. In the paper, vacuum circuit breaker switching transformers process is simulated with Saber software and parameters are analyzed The results indicate that overvoltage peak value of switching no load transformers is not much high, especially for switching load transformers. Yet, reignition overvoltage might do harm to transformer coils by cumulative effects for its surge steepness. The measures lies in setting parallel connection capacitance in practice working. For switching capacitances group overvoltage, vacuum circuit breaker refining technics requires strengthening, and chamber reignition probability might be confined in minimum extension.