考虑线路参数非线性特征的零序电流增益分析

Analysis of Zero-Sequence Current Gain Considering Nonlinearity of Line Parameters

单相接地是电网的常见故障,线路发生单相接地故障时,保护动作三相跳闸后,后跳开侧零序电流有时出现突变的现象。故障波形分析表明,这种零序电流增益在一定程度上受线路参数非线性特征的影响。为此,在考虑线路参数非线性特征基础上,分析线路非线性参数和故障点位置参数与零序电流的定量关系,为更好地解释故障过程及理解故障后的保护行为提供依据,仿真结果表明了该理论分析的准确性。

Single-phase earthing faults occur commonly in a power grid.While a single-phase earthing fault happens following the three-phase tripping in transmission line,the zero-sequence current at the later tripped side usually has a sudden change.According to the analysis of fault waveforms,the gain of zero-sequence current may be affected by the nonlinearity of line parameters to some degree.Taking into account the nonlinearity of transmission line parameters,the relationship among line parameters,fault points and zero-sequence current is analyzed quantitatively.The study results are helpful for better understanding the action of relays after faults.The simulation results verify the accuracy of the theory analysis.