一种基于电流突变量的故障选相新方法

针对现有选相方法不能同时识别所有故障类型以及电流突变量选相在弱电源侧灵敏度不足的问题,提出一种新型电流突变量的选相方法。该方法首先根据保护安装处各相故障电流与其余两相故障差流之间的比例关系,构造故障相别选择系数,然后,通过分析该系数在各种故障情况下呈现的不同特征,实现故障选相。仿真结果表明,该方法能够在故障发生1个周波内快速准确地判断故障相别,对各种类型故障均具有较高的灵敏度,且不受故障位置、过渡电阻及负荷电流的影响,具有较高的可靠性。即使在发生发展性故障情况下,该方法仍具有较好的选择性。同时,该方法对弱电源侧选相具有足够的灵敏性。

A New Fault Phase Identification Method Based on Phase Current Difference

In accordance with the problems that single fault phase identification method existed can not identify all types of fault and the phase current difference identification devices had a low sensitivity in the weak infeed condition,a new type of fault phase identification method based on phase current difference was proposed in this paper.This fault phase identification method firstly used fault current measured at the protection devices setting place only to establish the fault phase identification factors based on the proportion relationship between the faulted phase current and the faulted line current.Then,the faulted phases can be identified fast and accurately by the different mathematical characteristics of fault phase identification factors in each fault types.Simulated results show that the proposed fault phase identification method can identify any types and phases of faults in a cycle and has a high sensitivity.Furthermore,the method which has high capability is not affected by the fault location and fault resistance and load current.It is also of interest to point out that this fault phase identification method has the capability of identifying the developing fault.Meanwhile,the method could work in the weak infeed conditions and has sufficient sensitivity.