中性点直接接地系统的相控重合闸研究

Research on Controlled Reclosing for Solidly Earthed Neutral Systems

重合闸是区分永久故障和瞬时故障的有效方法,但重合于永久故障又会对电力系统造成很大的冲击。为减小重合电流的峰值和持续时间,针对中性点直接接地系统的特点,分析了重合闸时电流的特点,提出了一种相控重合闸策略,即在特定的电压相位先依次进行单相重合,利用电流参数快速辨识算法计算出重合电流的周期分量幅值,并与整定值进行比较以判断是否存在接地故障,然后再依次进行两相同步重合,判断是否存在相间短路故障;并提出利用真空触发开关实现相控重合闸的快速重合器方案。仿真结果表明,提出的重合闸策略能明显降低重合电流峰值和持续时间,判断出故障性质。

Reclosing is an effective method to distinguish instantaneous faults from permanent faults, but there will be an enormous shock for power systems when reclosing in a permanent fault. To reduce the reclosing current peak value and to decrease the current duration time for solidly earthed neutral systems, the relationship between the reclosing current and the voltage phase angle was analyzed, and then a new controlled reclosing strategy was proposed. Three phases were reclosed in turn in a specific line-to-earth voltage phase angle, and the periodic component amplitude of the reclosing current was calculated by a fast identify algorithm for current parameters and compared with a setting value to find the earth fault. Then the pair combinations in three phases were reclosed synchronously in turn in a specific line-to-line voltage phase angle to find the phase-to-phase fault. A new fast recloser using triggered vacuum switch was proposed to implement the proposed controlled reclosing strategy. The simulation results show that the proposed controlled reclosing strategy can reduce the current peak value and duration time and can determine the fault type.