突变量电流差动保护性能的极坐标分析方法

Analytical method of fault component current differential protection based on polar coordinates

目前对电流差动保护性能的分析基于差动电流-制动电流平面或复平面,存在一定的局限性。提出了一种极坐标平面下的电流差动保护性能分析方法,给出了电流差动保护判据在极坐标平面下的表示方法。利用该分析方法在极坐标平面比较了突变量电流差动保护不同判据的动作特征,为突变量电流差动保护在工程实际中的应用提供了依据。该方法能直观看出差动保护的动作特性,且能够表示电流幅值、相位对电流差动保护判据的影响。引入灵敏度系数比较各判据在区内、外故障时的性能。利用PSASP对110kV线路进行了仿真计算,仿真结果与理论分析一致。

To overcome the shortages of the analysis of the differential protection characteristic in the differential currents vs. resistant currents plane and complex plane at present, this paper proposes a novel method, which analyzes the differential protection characteristic in polar coordinate. The representation of fault component current differential protective criterions in polar coordinate is presented, and the comparison of characteristics of fault component current different criterions is described with this method which provides basis for the actual application. What＇s more, this method is convenient to analyze the influence on differential protection when both amplitude and phase of currents are changing. Sensitivity coefficient is introduced to contrast characteristic of criterions in both internal and external faults. The simulation results from the faults in 110 kV line by using PSASP are consistent with that of the theoretical analysis.