基于灰色关联度的谐振接地系统单相接地故障检测方法

Single-phase Ground Fault Detection Method of Resonant Grounding System Based on Gray Correlation Degree

谐振接地系统的单相接地故障难以检测,主要是由于谐振接地系统的电流非常小。针对故障相和非故障相之间瞬时零序电流波形的相似性小于两个非故障相之间的相似性,提出了一种基于曲线间灰度关系的馈线检测保护方案。选择斜率关系度作为一种灰色关系度来表示一个馈线与其他馈线之间暂态零序电流波形的相似性,并建立表示所有馈线之间关系的坡度关系矩阵。利用坡度关系矩阵建立的保护准则可用于单相接地故障馈线的检测。本文所提出的方法目前适用于至少有三个或更多馈线的系统。EMTP仿真结果和适应性分析验证了该方案的有效性和可靠性。

The single-phase grounding fault of resonant grounding system is difficult to detect,mainly because the current of resonant grounding system is very small.For the similarity of instantaneous zero sequence current waveform between fault phase and non-fault phase is less than that between two non-fault phases,a feeder detection protection scheme based on gray level relationship between curves is proposed in this paper.The slope relation degree is selected as a grey relation degree to represent the similarity of transient zero sequence current waveform between one feeder and other feeders,and the slope relation matrix is established to represent the relation between all feeders.The protection criterion based on slope relation matrix can be used to detect single-phase ground fault feeders.The method presented in this paper is currently suitable for systems with at least three or more feeders.The effectiveness and reliability of the scheme are verified by EMTP simulation results and adaptability analysis.