基于波形相似度的小电阻接地系统高阻接地保护方法  

High Resistance Grounding Protection Method of Low Resistance Grounding System Based on Waveform Similarity

作　　者：李景丽[1] 杨旭晨 褚双伟 田凤兰 陈嵩 徐铭铭 时永凯 袁豪 LI Jingli;YANG Xuchen;CHU Shuangwei;TIAN Fenglan;CHEN Song;XU Mingming;SHI Yongkai;YUAN Hao(School of Electrical Engineering Zhengzhou Universitg,Zhengzhou University,Zhengzhou 450001,China;Zhengzhou Power Supply Company,State Grid Henan Electric Power Company,Zhengzhou 450000,China;Electric Power Research Institute,State Grid Henan Electric Power Company,Zhengzhou 450052,China)

机构地区：[1]郑州大学电气工程学院,郑州450001 [2]国网河南省电力公司郑州供电公司,郑州450000 [3]国网河南省电力公司电力科学研究院,郑州450052

出　　处：《电瓷避雷器》2023年第1期39-42,43-48,共10页Insulators and Surge Arresters

基　　金：国家自然科学基金(编号:51307152)。

摘　　要：零序过流保护是目前小电阻接地系统(NRS)常采用的保护方法,由于整定值过大,导致其在发生单相高阻接地故障时,易出现拒动的现象,不能对配电网系统进行可靠、灵敏的保护。针对该问题,首先由NRS发生单相接地故障的等值电路,计算可得故障、健全线路之间的零序电流幅值和相位具有较大差异,并通过在不同过渡电阻下线路之间零序电流波形的仿真对比图得到验证;然后采用了根据Pearson相关系数对各条线路零序电流波形进行相关性计算,得出每条线路与其他线路相似度的平均值,根据故障线路平均相似度最低,实现对故障线路选择的保护方法;其次搭建了NRS单相接地故障模型和控制论电弧模型,设置典型的故障条件进行仿真,验证了该方法在NRS发生高阻故障时的有效性。结果表明在不同的接地故障类型、过渡电阻、故障点距离、故障时刻相位角等典型故障工况下,本方法均能正确选择出故障线路,将系统的耐受过渡电阻值提高到1500Ω;而且对装置的要求不高,在实际工程上具有一定的应用价值。Zero-sequence over-current protection is a protection method often used in lowresistance grounding systems(NRS),due to itslarge setting value,it is easy to refuse to operate when a single-phase high-resistance grounding fault occurs,then the distribution network system cannot get the reliable,sensitive protection.To solve this problem,firstly,from the equivalent circuit of single-phase grounding fault in NRS,it can be calculated that the amplitude and phase of zero-sequence current between faulty and sound lines are quite different.It is verified by the simulation comparison chart of the zero-sequence current waveform between lines under different transition resistances.Secondly,a protection method is proposed to use the Pearson correlation coefficient to calculate the correlation of the zero-sequence current waveforms of each line,and obtain the average value of the similarity between each line and other lines.According to the maximum difference between the faulty line and the non-faulty line,that the average similarity is lowest,to choose the fault line;then the NRS single-phase grounding fault model and cybernetic arc model are built,and typical fault conditions are set for simulation,which verifies the effectiveness of the method for high-resistance grounding fault protection of low resistance grounding system.The results confirm that the method in this paper can select the faulty line correctly under typical fault conditions such as diverseground fault types,transition resistances,fault distances and phase angle.The method increases the protection withstand transition resistance capacity to 1500Ω;moreover,the requirement for the device is not high,which has certain application valuein practical engineering.

关 键 词：小电阻接地系统 高阻接地故障 相似度 电弧接地 

分 类 号：TM862[电气工程—高电压与绝缘技术]