灵活接地系统电弧接地故障建模与特征分析  

Modeling and characteristics analysis of arc grounding fault in a flexible grounding system

作　　者：田君杨 沈梓正 李海勇 蒋连钿 王小帅 薛永端[2] TIAN Junyang;SHEN Zizheng;LI Haiyong;JIANG Liandian;WANG Xiaoshuai;XUE Yongduan(Guangxi Power Grid Power Dispatching Control Center,Nanning 530023,China;New Energy College,China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]广西电网电力调度控制中心,广西南宁530023 [2]中国石油大学(华东)新能源学院,山东青岛266580

出　　处：《供用电》2024年第9期90-97,共8页Distribution & Utilization

基　　金：中国南方电网有限责任公司科技项目(046000KK52220008)。

摘　　要：灵活接地系统发生电弧接地故障时,并联小电阻投入后,系统接地方式由小电流接地方式转变为大电流接地方式,故障点电流进一步增大,并联小电阻的投入对电弧故障特征的影响需进一步明确。传统黑盒模型难以精确计算电弧的非线性故障特征,即不易获得故障状态方程的解析解。为解决这一问题,可将电弧黑盒模型转化为受控源等效模型。首先,建立了灵活接地系统电弧接地故障等值电路。然后,给出母线零序电压与各线路零序电流的解析表达式,并分析灵活接地系统并联小电阻投入前后的电弧性故障特征。研究发现并联小电阻投入后,零序电压中电弧引入的谐波更为明显,而故障线路零序电流的电弧特征被削弱。最后,通过仿真验证了所得结论的正确性,为后续灵活接地系统电弧接地故障保护的研究提供了理论依据。When an arc grounding fault occurs in a flexible grounding system,after the parallel small resistor is put into operation,the system grounding mode is changed from the small-current grounding mode to the large-current grounding mode.The current at the point of fault further increases,and the effect of the input of the parallel small resistor on the fault characteristics of the arc needs to be further clarified.The traditional black box model is difficult to accurately calculate the nonlinear fault characteristics of the arc,that is,it is not easy to obtain the analytical solution of the fault state equation.To solve this problem,the arc black-box model can be transformed into a controlled source equivalent model to establish the arc-grounding fault equivalent circuit of a flexible grounding system.Then the analytical expressions for the zero sequence voltage of the bus and the zero sequence current of each line are given to analyze the arc fault characteristics of the flexible grounding system before and after the shunt resistor is put into operation.It is found that the harmonics introduced by arcing in the zero-sequence voltage are more obvious after the shunt small resistor is put into operation.In contrast,the arcing characteristics of the zero-sequence current of the faulted line are weakened.Finally the simulation verifies the conclusions’correctness and provides a theoretical basis for the subsequent research on the arc-grounding fault protection of the flexible grounding system.

关 键 词：灵活接地系统 电弧接地故障 模型简化 故障特征 等值电路 

分 类 号：TM71[电气工程—电力系统及自动化]