基于变电抗的接地选线新方法

针对中性点经可控消弧线圈接地电网单相接地故障选线困难的情况,提出零序电流比幅接地选线新方法。分析了影响小电流接地选线的原因,归纳出小电流接地选线主要要能够捕获暂态信息并作出正确判断。给出了零序电流比幅接地选线法理论推导,得出了小电流接地系统在正常运行和发生单相接地故障时系统主要物理量的计算公式。利用Matlab仿真软件对所提方法的仿真结果表明,该方法运算速度快、抗干扰能力强、选线准确;特别是当单相接地故障发生在故障线路对地电压最小时所提方法也适用。

Faulty line selection based on variable reactance

Aiming at the difficulty of faulty line selection for the single phase grounding of the network with neutral point earthed via controllable arc suppression coil,the ZSCR(Zero-Sequence-Current-Ratio) method is presented.Factors influencing the faulty line selection for small-current earthing power system are analyzed.The key techniques are the transient information acquisition and the correct judgment.The theoretical deduction of ZSCR is given and the calculation formulas for the main parameters of small-current earthing system are presented for both normal and single-phase grounding conditions.Simulations with Matlab show that the proposed method has fast calculation speed,good performance and high correctness,even when faulty-line-ground voltage is the smallest.