含直配式新能源的配电网接地故障协同处理与区域辨识  

Collaborative Fault Handling and Area Identification of Grounding Faults in Distribution Networks With Directly-coupled Renewable Energy Sources

作　　者：李政洋[1] 曹一家[1] 陈春[1] 李妍莎 李景禄[1] 赵龙 LI Zhengyang;CAO Yijia;CHEN Chun;LI Yansha;LI Jinglu;ZHAO Long(State Key Laboratory of Disaster Prevention&Reduction for Power Grid(Changsha University of Science&Technology),Changsha 410114,Hunan Province,China;Cyg Sunri Co.,Ltd.,Shenzhen 518057,Guangdong Province,China)

机构地区：[1]电网防灾减灾全国重点实验室(长沙理工大学),湖南省长沙市410114 [2]长园深瑞继保自动化有限公司,广东省深圳市518057

出　　处：《中国电机工程学报》2025年第6期2145-2159,I0009,共16页PROCEEDINGS OF THE CHINESE SOCIETY FOR ELECTRICAL ENGINEERING

基　　金：国家自然科学基金项目(U1966207,52007009)。

摘　　要：直配式新能源电站接入配电网后,源网中性点接地方式间存在兼容性及内过电压防护问题,给配电系统安全运行和故障区域辨识带来新的挑战。为此,建立直配式新能源逆变装置并网模型,分析谐波对中性点接地装置的影响原因,揭示谐波过电压在中性点装备的发展机理。通过构建源网中性点零序回路模型,分析接地故障处理时的兼容性问题,探明故障电弧重燃的原因。提出配电网单相接地故障协同处理方法,采用经验小波变换分解中性点位移电压和馈线及节点零序电流,得到故障处理过程中自由分量的衰减方向特征,感知接地故障的同时排除不对称干扰,实现高阻接地故障下的故障馈线以及故障区域准确辨识。仿真表明,该方法在故障过渡电阻小于等于5 kΩ时,能够准确定位接地故障发生馈线和区域。在智能断路器广泛应用背景下,为单相接地故障的诊断辨识提供了新思路。After the integration of direct-connected renewable energy power plants into the distribution network,compatibility issues and internal overvoltage protection challenges arise between the grounding methods of the source and the network neutral points.This presents new challenges for the safe operation of the distribution system and the identification of fault areas.To tackle these challenges,a model of the direct-connected renewable energy inverter unit is established for grid connection.The impact factors of harmonics on the neutral point grounding device are analyzed,revealing the development mechanism of harmonic overvoltage on the neutral point equipment.By constructing a model of the neutral point zero-sequence loop in the source and network sides,compatibility issues during ground fault handling are analyzed,and the reasons for fault arc reignition are elucidated.A method for coordinated processing of single-phase ground faults in distribution networks is proposed.The empirical wavelet transform is used to decompose the neutral point displacement voltage,feeder,and node zero-sequence current to obtain the attenuation direction characteristics of the free components during fault handling.This method enables the perception of ground faults,exclusion of asymmetric interference,and accurate identification of fault feeders and areas under high-resistance grounding faults.A series of simulations show that the method can accurately locate the occurrence of ground faults in feeders and areas when the fault transition resistance is less than or equal to 5 kΩ.In the context of widespread application of smart circuit breakers,this provides a new approach for diagnosing and identifying single-phase ground faults.

关 键 词：直配式新能源 内过电压防护 接地方式兼容性 故障协同处理 高阻接地故障辨识 故障区域辨识 

分 类 号：TM77[电气工程—电力系统及自动化]