构建基于零序电流差异化指标的灵活接地系统单相接地故障选线方法  

Single-phase to ground fault line selection method based on zero sequence current differentiation index in flexible grounding system

作　　者：黄亚峰[1] 贾宝华 王浩天 王汝田[1] HUANG Yafeng;JIA Baohua;WANG Haotian;WANG Rutian(Department of Electrical Engineering,Northeast Electric Power University,Jilin 132012,China)

机构地区：[1]东北电力大学电气工程学院,吉林吉林132012

出　　处：《电气应用》2023年第9期91-100,共10页Electrotechnical Application

基　　金：国家自然科学基金项目(52277170)。

摘　　要：针对配电网非有效接地系统发生故障接地电阻大时故障信号弱、故障线路的选取效果不理想的难题,提出了一种构建基于零序电流差异化指标的灵活接地系统单相接地故障选线方法。针对发生单相接地故障时并联电阻投入前、投入后同一母线上的正常运行线路和故障线路的零序电流以及系统的零序电压特征进行分析,发现:正常运行线路在并联电阻投入前后,零序电流幅值减小,并且在零序电压方向的投影差为零;故障线路零序电流幅值增大,并且在零序电压方向的投影较大,据此引入比值法与相位法相结合的选线方法,可以可靠、准确地判断出故障线路。分析结果表明,此方法能够适用于过渡电阻在3000Ω以内的高阻接地故障。利用PSCAD建模仿真,验证了所提故障选线方法的准确性及可靠性。In order to solve the problem of weak fault line selection when high resistance ground fault occurs in low current grounding system of distribution network,this paper presents a method of single-phase to ground fault line selection for flexible grounding systems based on zero sequence current differentiation index.Based on the analysis of the zero sequence voltage and current characteristics of non-fault line and fault line on the same bus before and after the operation of shunt resistance,it can be con-cluded that:the non-fault line has the following characteristics before and after the operation of shunt resistance,the amplitude of zero-sequence current decreases and the amplitude of zero-sequence current increases,and the projection difference of ze-ro-sequence current in zero-sequence voltage direction of all non-fault lines is close to zero before and after the shunt resistor is put into operation,the projection difference of zero-sequence current in zero-sequence voltage direction of fault line is large,and the phase difference between zero-sequence current of fault line and zero-sequence voltage of bus line changes after the shunt resistor is put into operation,according to this,the ratio method can be used to judge the fault line more reliably and accurately.The method of combining projection ratio and phase is used to form the fault line selection flow.The analysis results show that this method can be applied to high resistance ground fault with transition resistance less than 3000Ω.The accuracy and reliability of the proposed fault line selection method are verified by PSCAD modeling and simulation.

关 键 词：配电网 单相接地故障 零序电流差异化指标 灵活接地系统 故障信号 比值法 

分 类 号：TM862[电气工程—高电压与绝缘技术]