馈电开关用电弧性单相接地保护方法的研究

Research of arc single-phase earth protection for feed switch protection

分析了电弧性接地故障时零序电压和零序电流暂态分量的特征,以及现有基于零序暂态分量分析的接地选线方法应用在馈电开关单相电弧性接地保护中存在的问题。提出了一种基于稳态零序电压和暂态零序电流首半波积分的馈电开关用电弧性接地保护新方法。该方法只需测量本馈电开关所载线路零序电压和零序电流,且不需计算暂态零序电流频率。经6kV实验电网多次模拟实验证明,该方法具有采样频率低、计算简单、判断准确的特点,可以有效解决现有馈电开关保护中电弧性接地故障动作不准确的问题。

Characteristics of zero-sequence voltage and zero-sequence current transient component are analyzed when arc-earth fault occurs. With the deficiency of fault line selection methods applied to feed switch single-phase arc-earth protection based on zero-sequence transient component, arc-earth protection for feed switch based on the first half wave integration of steady zero sequence voltage and transient zero-sequence current is proposed. The method does not need to calculate the frequency of transient zero-sequence current, and it only measures zero-sequence voltage and zero-sequence current of lines that the feed switch loads. The results of experiment show that the method has the characteristics of low sampling frequency, simple calculation and accuracy of judgement by several simulating of 6 kV experimental network, and can solve effectively the inaccuracy of existing switch according to action of arc-earth fault in single-phase earth protection.