The Operating Transient Process Analysis and Synchronous Switching Strategies Research of Vacuum Breaker

Abstract

Circuit breaker switching operation will generate transient voltage and inrush current. The synchronous switching control strategies research can effectively reduce the transient effect and improve power quality. The transient operation process of vacuum circuit breaker is analyzed by deriving the system voltage and current expressions when vacuum circuit breaker switching reactive compensation capacitor bank. The theory switching phases without transient transition process are obtained by referring to the voltage and current expression. The optimum switching capacitor banks phase and new synchronous switching control strategies of different connections capacitor bank are given by synthetically considering closing action time dispersion, pre-strike characteristic and opening arcing time of vacuum circuit breaker. The voltage and current waveforms when vacuum circuit breaker randomly, according to traditional and new synchronous switching strategies switching ungrounded Y capacitor banks connection are simulated in the article. Simulation results show that the inrush current under the new synchronous switching control strategies can be reduced 1.2p.u.and closing voltage has no oscillation transition process, that is, directly accesses to steady-state. So the theoretical analysis and synchronous switching control strategies in the article are verified correctly.