基于零序电流幅值比倍增系数的灵活接地系统故障选线方法  

Fault line detection method for a flexible grounding system based on a zero-sequence current amplitude ratio multiplication coefficient

作　　者：周宇 汤涛 曾祥君[1] 罗春辉 杨忠毅 ZHOU Yu;TANG Tao;ZENG Xiangjun;LUO Chunhui;YANG Zhongyi(School of Electrical and Information Engineering,Changsha University of Science and Technology,Changsha 410114,China;Hunan Electric Power Transmission and Transformation Engineering Co.,Ltd.,Changsha 410114,China)

机构地区：[1]长沙理工大学电气与信息工程学院,湖南长沙410114 [2]湖南省送变电工程有限公司,湖南长沙410114

出　　处：《电力系统保护与控制》2022年第23期112-120,共9页Power System Protection and Control

基　　金：国家自然科学基金项目资助(52207075,52037001);湖南省自然科学基金项目资助(2020JJ5584);湖南省教育厅重点实验室创新平台项目资助(19K003)。

摘　　要：针对灵活接地系统高阻接地故障选线困难的问题,提出一种基于零序电流幅值比倍增系数的灵活接地系统故障选线方法。首先,分析了系统单相接地故障时并联小电阻投入前后中性点与线路零序电流幅值比的变化特征,即:中性点与健全线路零序电流幅值比增大,而中性点与故障线路零序电流幅值比减小。其次,通过引进倍增系数定量刻画幅值比变化趋势,继而构造故障选线自适应判据。此外,利用中性点电感和电阻间接求解小电阻投入后零序电流幅值微弱的健全线路倍增系数,有效降低因零序CT精度限制所导致的选线误判概率。理论分析和仿真结果表明,该方法耐过渡电阻能力可达3000Ω,无需零序电压信息,可靠且适用性强。It is difficult to select a fault line when a high impedance grounding fault occurs in a flexible grounding system.Thus a fault line detection method for such a system based on zero-sequence current amplitude ratio multiplication coefficient is proposed.First,the variation characteristics of amplitude ratio of zero-sequence current at neutral point to zero-sequence current of line before and after a parallel small resistor is put into use in the single-phase grounding fault of the system are analyzed.This means that the amplitude ratio of zero-sequence current at the neutral point and the zero-sequence current at sound line increases,while the amplitude ratio of zero-sequence current at neutral point and zero-sequence current at fault line decreases.Second,by introducing the multiplication coefficient,the changing trend of amplitude ratio is quantitatively described,and then the adaptive fault line detection criterion is constructed.In addition,the neutral point inductance and resistance are used to indirectly determine the multiplication coefficient of the sound line with weak zero-sequence current amplitude after the input of a small resistance.This effectively reduces the misjudgment probability of line selection caused by the limitation of zero-sequence CT accuracy.The theoretical analysis and simulation results show that the proposed method can withstand a transition resistance up to 3000Ωwithout zero-sequence voltage information,and is reliable and applicable.

关 键 词：灵活接地系统 高阻接地故障 幅值比 倍增系数 故障选线 

分 类 号：TM862[电气工程—高电压与绝缘技术]