基于相对保护熵与名义过渡电阻的电网故障在线检测方法

为了实现故障元件的在线检测,提高其准确性与容错性,提出了利用7类广域保护动作信息定义保护熵与相对保护熵概念。给出了相对保护熵阈值的确定方法、检测故障的两个判据,分析了其对某些保护信息出错情景的敏感性,尤其是故障线路上保护拒动、相邻非故障线路上保护误动位数较多情景。在有保护拒动与误动的大多数情况下,采用相对保护熵能够准确判断出故障线路。研究了基于有限同步相量测量单元的线路名义过渡电阻的求解方法,将它作为相对保护熵接近于阈值的疑似线路的补充判断。IEEE 14节点系统的多组算例结果表明,采用保护熵能够使3位保护误动与拒动的故障检测正确率达到100%,将相对保护熵与名义过渡电阻两者结合,能够对较多位保护误动与拒动情景进行有效检测,有着较高的准确性与容错性。

Online Fault Detecting Method Based on Relative Protection Entropy and Nominal Transition Resistance

To implement online detection of fault component and improving accuracy and tolerance, the protection entropy is proposed using seven types of wide-area protection actions, as well as the relative protection entropy. Meanwhile, the acquisition of threshold for relative protection entropy is discussed. Its sensitivity to some situations of protection action errors is studied, especially those of quite a few protection rejections on fault line and protection misoperations on adjacent lines. In most situations, the fault line can be accurately detected by protection entropy with simulation test. The method of nominal transition resistance based on limited phasor measuring unit (PMU) is studied, which is used as a supplement to situations in which the protection entropy of suspected line is near to the threshold. The simulation results on IEEE 14-bus system show that, by combining relative protection entropy with nominal transition resistance, the proposed algorithm has higher accuracy and tolerance. This work is supported by National Natural Science Foundation of China (No. 51377137).