基于小波包频段分解及综合能量系数的小电流接地系统故障定段方案

Fault section location strategy of small current grounding system based on wavelet packet frequency band decomposition and comprehensive energy coefficient

针对小电流接地系统中单相接地故障定位这一难题,提出一种基于小波包频段分解及综合能量系数的小电流接地系统故障定段方案,根据故障发生的不同时刻对低频段与高频段能量比分配不同的权重,在最大程度上获取故障零序电流信号中的能量信息,避免频段选择不准确导致无法提取电流有效能量信息的问题,然后根据故障线路综合能量系数CEC与非故障线路CEC的差异确定故障区段。理论分析和基于ATP-EMTP的仿真模型验证了所提单相接地故障综合定段方案能有效辨识主馈线故障、贯穿线路故障及末级线路故障,且不受过渡电阻及故障发生时刻的影响,具有较高的准确性和可靠性。

Aiming at the problem of single.phase.to.ground fault location in small current grounding system,a fault section location strategy of small current grounding system based on wavelet packet frequency band decomposition and comprehensive energy coefficient(CEC)is proposed to allocate different weights for energy ratios of low-frequency and high-frequency bands at different fault occurrence moments,obtain the energy information in fault zero.sequence current signal to the maximum extent,avoid that the efficient current energy information could not be extracted due to inaccurate selection of signal frequency band,and the fault section is determined according to the CEC difference of fault line and normal line.The proposed single-phase-to-ground comprehensive fault section location strategy can identify the main feeder fault,penetrating line fault and terminal line fault,isn′t influenced by transition resistance and fault occurrence moment,and has high accuracy and reliability,which is verified by theoretical analysis and ATP-EMTP based simulation model.