基于分形理论与聚类分析的小电阻接地系统高阻接地保护方法

针对目前小电阻接地系统保护由于整定值过大而对高阻接地故障易出现拒动的问题,基于分形理论和聚类分析提出了高阻接地保护新方法。该方法提取故障线路和非故障线路零序电流的相似性特征,利用零序电流比值和分形维数对相似度进行量化计算,构建了接地故障特征矩阵,采用K-means聚类算法对接地故障特征矩阵进行分析,避免了保护整定困难的问题。经真型实验录波数据验证,所提方法将保护的耐阻能力提高到2000Ω,具有一定的应用价值。

Protection method based on fractal theory and cluster analysis for grounding fault with high resistance of low resistance grounding system

Because the setting value of the protection in low resistance grounding system is too large,the protection in low resistance grounding system easily refuses to operate when a high-impedance grounding fault occurs.Aiming at this problem,a novel protection method based on fractal theory and cluster analysis for grounding fault with high resistance of low resistance grounding system is proposed.The similarity cha-racteristics of zero-sequence current between fault line and normal lines are extracted.The characteristic matrix of grounding fault is constructed by the similarity of zero-sequence currents that quantified by ratio of zero-sequence currents and fractal dimension,and analyzed by K-means clustering algorithm.The pro posed method avoids the difficulty of protection setting.The true-mode experimental recording data verify that the high resistance capacity of protection is improved to 2000Ωby the proposed method,which has certain application value.