基于电容序列近似熵的消弧线圈接地选线方法

针对零序电流互感器极性不明确导致选线失败的问题,分析了选线失败的原因,提出一种基于对地电容近似熵的选线方法。提出利用差分方法改进矩阵束,解决分量湮没问题,从而准确提取复频域极点信息。分别求取每条线路对地电容序列,由于消弧线圈补偿作用故障线路电容序列近似熵将超过阈值,则判断该条线路为故障线路。仿真实验结果验证:该方法摆脱了由于零序互感器极性不同而导致选线错误的限制,且适用于两出线系统,适应性强,选线准确率高。

Fault line selection approach of extinction coil based on capacitance sequence approximate entropy

Anti-polarity of zero sequence CT leads to the failure in NES fault line selection, after analyzing the reason, a new selection approach using approximate entropy of ground admittance is proposed. Difference method is used to improve matrix pencil and solve the problem of component annihilation, therefore the pole information of complex frequency domain is got accurately. Evaluating the approximate entropy of distribution capacitance of each feeder under arc suppression coil compensation effect, then it is discriminated as fault feeder when the numerical value is beyond a threshold value. The method eliminates the error due to the limitation of anti-polarity of zero sequence CT and can also be applied to system with two feeders. Experimental results show that it can increase the accuracy and dependability of fault line detection effectively.