中国电机工程学报2024，Vol.44Issue(22)：8744-8758,中插5,16.DOI:10.13334/j.0258-8013.pcsee.230836
配电网相电压不对称动态变化下的高阻接地故障辨识
Identification of High-impedance Ground Faults Under Dynamic Variations of Voltage Unbalance in Distribution Networks
摘要
Abstract
In distribution networks,single-phase high impedance ground faults and dynamically varying asymmetric phase voltages exhibit similar waveforms of neutral point displacement voltage,which can lead to misjudgment of grounding protection.To address this issue,this paper establishes an asymmetric admittance vector model to analyze the causes of dynamically varying asymmetric phase voltages and reveal the changing mechanism of neutral point displacement voltage under non-fault conditions.A full-response fault circuit model is also developed to depict the variation trajectory of neutral point displacement voltage with respect to transition resistance,examining the overlapping steady-state region and transient feature differences between high-impedance ground faults and asymmetric admittance dynamic changes.While demonstrating the overlapping steady-state features of the two,the influence of the initial fault phase angle on the DC decay component of the neutral point displacement voltage during transients is revealed.Empirical wavelet transform is employed to extract the DC decay component and high-frequency component of the neutral point displacement voltage,and the DC decay component is utilized for fault identification.For scenarios where the specific initial fault phase angle renders the DC component undetectable,a centroid frequency distribution feature identification method based on variance contribution ratio is proposed to recognize grounding faults.Simulation analysis indicates that this method provides distinct distinguishing features for high-impedance ground faults below 5 kΩ and asymmetric admittance dynamic changes,offering a new approach for accurate identification of single-phase ground faults.关键词
动态不对称/高阻接地故障辨识/中性点位移电压/直流偏移分量/方差贡献率Key words
dynamic asymmetry/high-impedance ground fault identification/neutral point displacement voltage/DC offset component/variance contribution rate分类
信息技术与安全科学引用本文复制引用
李政洋,曹一家,陈春,李妍莎,李景禄..配电网相电压不对称动态变化下的高阻接地故障辨识[J].中国电机工程学报,2024,44(22):8744-8758,中插5,16.基金项目
国家自然科学基金项目联合基金(U1966207) （U1966207）
国家自然科学基金项目(52007009). Project Supported by National Natural Science Joint Foundation of China(U1966207) （52007009）
Project Supported by National Natural Science Foundation of China(52007009). （52007009）
