基于差分系数和参数辨识的配电网故障选线

Distribution Network Fault Line Selection Based on Differential Coefficient and Parameter Identification

针对暂态零序电流特征频段内包含的频率分量太少且不包含幅值较大的低频分量,不利于选线,由此提出一种基于差分系数和参数辨识的选线方法。通过对线路零序阻抗特性进行分析,得出了健全线路和故障线路的零序电流与其自身母线零序电压导数的比值在不同频率下存在差异,依据此故障特征可进行选线;为增强选线方法的准确性和适用性,引入了电容极性对判据加以补充,采用最小二乘法对线路电容进行识别,完善并形成了应用整个首次串联谐振频段故障信息且适用于不同中性点接地系统的选线判据。该方法可充分利用不同频段的暂态信息,理论分析和仿真结果表明,该方法能够准确、可靠的选线且适用性强。

Since the frequency component contained in the transient zero-sequence current characteristic band is too small and does not contain low-frequency components with large amplitude,it is not conducive to line selection.Therefore,a line selection method based on differential coefficient and parameter identification is proposed.By analyzing the zero-sequence impedance characteristics of the line,it is concluded that the ratio of the zero-sequence current of the healthy line and the fault line to the zero-sequence voltage derivative of its own bus line is different at different frequencies.According to the fault feature,the line selection can be performed;The accuracy and applicability of the line method introduces the capacitor polarity to supplement the criterion.The least square method is used to identify the line capacitance,and the fault information of the entire first series resonance frequency band is applied and applied to different neutral grounding system selection criteria.The method can make full use of the transient information of different frequency bands.The theoretical analysis and simulation results show that the method can accurately and reliably select the line and has strong applicability.