基于不同时段内积投影的灵活接地系统高阻故障选线方法  

High Impedance Fault Line Selection Method Based on Inner Product Projection of Different Time Periods for Flexible Grounding Systems

作　　者：王晓卫 刘伟博 郭亮 梁振锋[1] Wang Xiaowei;Liu Weibo;Guo Liang;Liang Zhenfeng(School of Electrical Engineering,Xi’an University of Technology,Xi’an 710048,China;Electric Power Research Institute,State Grid Jiangxi Electric Power Co.Ltd,Nanchang 330000,China)

机构地区：[1]西安理工大学电气工程学院,西安710048 [2]国网江西省电力有限公司电力科学研究院,南昌330000

出　　处：《电工技术学报》2024年第1期154-167,共14页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金项目(52177114,61403127);国网江西省电力有限公司科技项目(521820220016,521820210005)资助。

摘　　要：针对灵活接地配电系统在发生高阻故障时,无法实现准确选线的问题,通过分析灵活接地系统故障特征得出中性点小电阻投入后故障馈线与健全馈线在零序电流幅值上存在差异,同时,小电阻投入后母线零序电压发生明显降低。由此,提出一种基于中性点小电阻投入前后不同时段下计算内积投影的高阻故障选线方法。首先,将小电阻投入后各馈线零序电流对投入前的母线零序电压做内积投影,由此构建判据1;其次,将小电阻投入后各馈线零序电流对投入前的中性点电流做内积投影,由此构建判据2;最后,当判据1与判据2判定的故障馈线结果一致时,得到故障馈线。大量仿真实验表明,在非同步采样、数据缺失与电弧等故障工况下,该方法具有良好的稳定性,与现有方法对比可知,该文方法判定时间短,且适应电流互感器反接工况。High impedance faults are a common form of distribution network faults,accounting for about 5%to 10%of medium voltage distribution network faults,often accompanied by arcing,which can easily cause safety hazards.Due to the weak fault characteristics of high impedance faults,most faulty feeder detection methods only have high accuracy for low-impedance faults.This is insufficient to support the principle of proximity and fast isolation of ground faults.Recently,some high impedance fault line selection methods have been proposed,but most of them suffer from complex principles,single criteria,and equipment measurement accuracy that does not meet the demand.To address these problems,this paper proposed high impedance fault line selection methods based on inner product projection of different time periods for flexible grounding systems.It can accurately detect the faulty feeder at high impedance faults through the characteristic quantities of voltage and current before and after small resistance input.Firstly,the inner product projection of each feeder’s zero-sequence current after small resistance input onto the bus zero-sequence voltage before small resistance input is constructed as criteria 1.Secondly,the inner product projection of each feeder’s zero-sequence current after small resistance input onto the neutral point zero-sequence current before small resistance input is constructed as criteria 2.Finally,when the results of the faulty feeder determined by criterion 1 and criterion 2 are the same,the final faulty feeder result is obtained.The fault detection method fully uses the fault characteristics under different time periods,solves the influence of bus zero-sequence voltage drop after small resistance input and a single criterion on the detection accuracy,and greatly simplifies the faulty feeder detection principle,resulting in a highly accurate faulty feeder detection method.The simulation results using a flexible grounding system show that.Firstly,the faulty feeder can be accurately determined under hi

关 键 词：灵活接地系统 高阻故障 不同时段 内积投影 

分 类 号：TM77[电气工程—电力系统及自动化]