减小电压暂降深度的三相重合闸时序研究

In order to reduce voltage sag depth of sensitive load when three-phase circuit breaker reclosing is failed, a method determining three-phase reclosing sequence is proposed. When faults occur on a transmission line, the relays act and the three-phase circuit breakers trip on both sides of the line. According to fault component theory, a faulted network is built. Additional source is added on each end of the line and then the fault component voltage of sensitive load node is calculated for two cases. Based on the amplitude of fault component voltage of sensitive load, the three-phase reclosing sequence is determined. The side with smaller amplitude of fault component voltage is determined to checking non-voltage. An IEEE 39 System model is established in PSCAD/EMTDC for simulation, and the influence of different fault types, fault locations and transition resistances on reclosing sequence is considered. Results show that the method can effectively reduce voltage sag depth of sensitive load in case of three-phase circuit breaker reclosing failure, able to improve voltage quality without additional investment.