The Closing Strategy of Vacuum Circuit Breakers to Suppress Inrush Current of Parallel Capacitor

In a 35kV medium voltage system, closing the parallel capacitor will generate high inrush currents, which will shorten the service life of electrical equipment such as capacitor banks and series reactors. This paper analyzes the transient process of closing capacitors theoretically and proposes a split-phase control strategy for vacuum circuit breakers. With the help of MATLAB/Simulink simulation software, by comparing and analyzing the closing inrush current and reactor transient overvoltage data of the proposed strategy and the traditional method of closing the capacitor bank, the selected closing strategy can limit the closing inrush current to 1.5p.u., the transient voltage of series reactor is limited to 2p.u. Further considering the dispersion characteristics of the vacuum circuit breakers, through comparative analysis, the selected closing strategy can still significantly reduce the inrush current and overvoltage during the capacitor closing process, and improve the closing safety of the reactive power compensation device.