暂态电流保护选择性的研究(Ⅱ)--考虑阻波器的故障暂态过程分析

针对保护出口处发生金属性或小电阻短路故障时，暂态电流保护完全失去选择性的严重缺陷，提出了使用阻波器保证暂态电流保护选择性的改进方案，并进行了改进方案的故障暂态分析和仿真研究。研究结果表明，在线路出口经小电阻或金属性故障时，受阻波器的影响，故障暂态过程的基本特性将发生根本的变化，从而使其奇异性出现较大差异，并由此可实现故障线路的识别。在线路上使用阻波器，是保证在线路出口经小电阻或金属性故障故障时暂态电流保护选择性的重要措施，因而是实现暂态电流保护的必要条件。

Study on the Selectivity in Transient Current Protection(Ⅱ)--Transient Analysis of Fault with Line Trap

For the severe limitation that the selectivity of transient current protection will lose when the fault with small resistance or without resistance takes place at the end of transmission line, this paper proposes an improved line-trap method to ensure the selectivity of transient current protection. The transient analysis, EMTP simulation studies show that the line trap will completely change the basic characteristic of the fault transient process when the fault with small resistance or without resistance takes place at the end of transmission line, therefore the transient current singularity of fault line and non-fault line will be obvious difference, which allows to identify the fault line reliably,and it's an important step to use the line trap in transmission line to ensure the selectivity of transient current protection.