计及换相失败的输电线路单相接地故障熄弧时刻识别

Identification of Arc Extinguishing Time Under Single-phase Grounding Fault in Transmission Line Considering Commutation Failure

针对含直流馈入交流输电线路单相跳闸后换流阀换相失败导致重合闸判据失效的问题,提出基于故障相时移电压能量比的熄弧时刻识别策略。首先,基于换流器开关函数理论,研究逆变侧换相失败时换流阀两侧电压电流相互作用关系。然后,对带并联电抗器交流故障相端电压特征进行分析,得到熄弧前后的电压幅值波动差异。最后,计算故障相电压能量分布,利用时移电压能量比确定单相接地故障二次电弧熄弧时刻。在PSCAD/EMTDC平台的仿真结果验证了所提识别策略的有效性。

Aimed at the reclosing criterion failure caused by the commutation failure of a commutator valve under singlephase grounding fault in an AC transmission line with DC feed-in,an identification strategy for arc extinguishing time based on a fault-phase time-shifted voltage energy ratio is proposed.First,according to the switching function theory for converters,the interaction between voltage and current on two sides of the commutator valve is studied when the invert⁃er-side commutation fails.Then,the voltage characteristics at the AC fault terminal with a shunt reactor are analyzed,and the difference in voltage amplitude fluctuations before and after arc extinguishing is obtained.Finally,the faultphase voltage energy distribution is calculated,and the time-shifted voltage energy ratio is used to determine the extin⁃guishing time of secondary arc under single-phase grounding fault.Simulations are performed on the PSCAD/EMTDC platform,and results verify the effectiveness of the proposed identification strategy.