中文摘要：

电压暂降是电力系统中最严重的电能质量问题之一，电压暂降源定位对协调由此引起的供用电双方纠纷具有关键性作用。在介绍三点法仙计系统参数的基础上，分析了上游系统参数和下游负倚参数变化与电压变化量之间的关系，并由此定义了上、下游对造成电压暂降的权重系数，从而定量地给出电压暂降源定位结果。与现有方法相比，该方法不仅适用范围较广，且给出的定量结果更有利于公平解决供用电双方的纠纷。算例结果表明，该方法能在简单辐射网和非辐射网中正确完成电压暂降源的定位，可应用于电能质量监测系统。

英文摘要：

Voltage sag is one of the most serious problems in power quality. Voltage sag source location is significant for the customers and suppliers to solve the issue between them. Three-point method was introduced for online tracking of power system parameters first. Then the relation between voltage variation and system parameters upstream, load impedance downstream was analyzed. Weight coefficients of them to voltage sag were defined respectively. Finally, the quantitative result was given for voltage sag source location. Comparing with current methods, the proposed method can be applied more widely, and its quantitative results are more reasonable to solve the issue between customers and suppliers. Testing results at radial networks and non-radial networks show that the method can locate the voltage sag source correctly. The method can be applied to power quality supervisory system.