基于单端口网络内电阻极性的电压暂降追源方法

Voltage sag source location method based on the polarity of single port network internal resistance

电压暂降追源即确定电压暂降扰动源相对于监测装置的位置。以对电网故障的分析为切入点,应用端口网络理论,将任何复杂电网在电压暂降源监测装置安装处等效为2个"有源单端口网络"。视电网故障为"有源单端口网络"的外部扰动,测量并计算出"有源单端口网络"的内电阻,依据"有源单端口网络"的内部电阻的极性,对电压暂降源相对于电压暂降源监测装置的位置进行判断。内电阻为正,电压暂降源与参考方向相反,即上游。内电阻为负,电压暂降源与参考方向相同,即下游。给出了内部电阻的计算方法。所提出的电压暂降源定位方法具有坚实的理论基础。仿真结果表明,该方法对辐射式、非辐射式,以及中性点有效接地和非有效接地的混合电网的电压暂降源定位准确率达到100%,是一种非常实用的电压暂降源定位法。

Locating the voltage sag source is to determine on which side of a monitoring device the voltage sag originates. This paper takes the analysis of power grid faults as an entry point and applies the port network theory, and then any complex power network at both sides of voltage sag source monitoring devices can be equivalent into two active single-port networks respectively. Grid faults are regarded as external disturbances of ＂active single-port network＂, meanwhile the internal resistance of the ＂active single-port network＂ will be measured and calculated. Based on the sign of internal resistance in these two active single-port networks, the voltage sag source location relative to the monitoring devices can be identified accurately. If the sign of internal resistance is positive, the location of volthge sag source is opposite to the reference direction, that＇s upstream. If the sign of internal resistance is negative, the location of voltage sag source is consistent with the reference direction, that＇s downstream. Calculation method of internal resistance is given. The proposed method has a solid theoretical basis. Simulation results show that this method can locate voltage sag source with an accuracy of 100% in power networks with various topologies, such as radial or non-radial power systems as well as the network adopted neutral grounded effectively or ineffectively. It is a practical and effective method for voltage sag source location.