基于脉冲电流的谐振接地系统单相接地故障选线方法研究

Line Selection Method for Single-phase Grounding Fault of Resonant Grounding System Based on Pulse Current

谐振接地系统单相接地故障的快速就近隔离是配网稳定安全运行的基础,短时改变中性点接地方式产生脉冲电流进行选线成为近年来研究的热点。本研究采用matlab&simulink搭建具有脉冲信号发生装置的谐振接地系统(架空线系统、电缆线系统、缆线混合系统)。在3种系统下,设置任意线路在不同条件下发生单相接地故障,提取各线路脉冲电流进行傅里叶分解,观察故障线路与非故障线路脉冲电流在频域分布上的差异,提出利用脉冲电流在频域分解的直流分量与基波分量之和作为选线依据;通过设置典型的故障点位置、故障相合闸相角、故障点弧道电阻作为故障条件,选线准确率均为100%,验证了选线依据的准确性。

The rapid and nearby isolation of single-phase grounding faults is the basis for stable and safe operation of distribution networks. Short-term changes to neutral grounding methods to generate pulse currents for line selection have become a hot research topic in recent years. The author uses matlab & simulink to build a resonant grounding system(overhead line system, cable system, cable hybrid system) with a pulse signal generator. Under the three systems, set any line to have a single-phase ground fault under different conditions, extract the pulse current of each line for Fourier decomposition, observe the difference in the frequency domain distribution of the pulse current of the faulty line and the non-fault line, and the sum of the DC component and the fundamental component of the current decomposed in the frequency domain is used as the basis for line selection;by setting the typical fault point position, fault phase closing phase angle, and fault point transition resistance as fault conditions, the line selection accuracy rate is 100%,which verifies the accuracy of the line selection basis.