小电流接地配电线路弧光高阻接地故障电压特征分析

Analysis of the arc high impedance grounding faults voltage characteristics in non-effective grounding feeders

中性点非有效接地系统单相弧光高阻接地故障检测的难点在于如何实现灵敏启动。现有的检测方法以零序电压的幅值越限作为启动判据,但是由于对越限门槛值的整定直接影响着检测的灵敏性和可靠性,在实际运行中往往难以同时兼顾。针对该问题,基于现场实测故障录波数据,采用数值统计、傅里叶变换、图形对比等方法从时域、频域角度分析了单相弧光高阻故障的暂态电压特征。搭建了弧光高阻接地故障暂态模型,仿真验证了所提取的暂态电压特征的正确性,为后续故障选线装置应对单相弧光高阻故障的灵敏启动判据开发提供了基础。

The difficulty of single-phase arc high impedance grounding fault detection in neutral ineffectively grounded system lies in how to realize sensitive start.The current detection methods use the zero sequence voltage amplitude limit as the starting criterion,but the setting of the limit value directly affects the sensitivity and reliability of detection,it is often difficult to take into account both in practical operation.Aiming at this problem,based on the field wave recording data,this paper analyzes the transient voltage characteristics in the event of the single-phase arc high impedance grounding fault by means of numerical statistics,Fourier transform and graph comparison from the time domain and frequency domain.Meanwhile,the transient model of arc high impedance grounding fault is established,which verifies the validity of the transient voltage characteristics features extracted.It lays a foundation for the subsequent development of sensitive start criterion of faulty line selection device when single-phase arc high impedance grounding fault occurs.