基于相位差的小电阻接地有源配电网接地故障保护算法  

Grounding Fault Protection Algorithm of Small Resistance Earthing Active Distribution Network Based on Phase Difference

作　　者：李君 何敏[1] 黄守道[1] 刘君 刘志勇 Li Jun;He Min;Huang Shoudao;Liu Jun;Liu Zhiyong(College of Electrical and Information Engineering Hunan University,Changsha 410082 China;Weisheng Information Technology Co.Ltd,Changsha 410000 China)

机构地区：[1]湖南大学电气与信息工程学院,长沙410082 [2]威胜信息技术股份有限公司,长沙410000

出　　处：《电工技术学报》2024年第23期7418-7429,共12页Transactions of China Electrotechnical Society

基　　金：国家重点研发计划资助项目(2020YFB0906000)。

摘　　要：大规模分布式电源(DG)接入小电阻接地系统配电网后,故障电流产生明显变化,采用零序电流保护方法切除单相接地故障将出现误动作。为了解决以上问题,首先,提出基于相电压与零序电流相位差的小电阻接地系统有源配电网接地故障保护算法;然后,通过建立包含多个分布式电源的配电网接地故障电气系统结构与模型,对故障时刻相电压与零序电流相位关系进行理论推导与计算,分析得出不同接地故障位置的相位差区间,根据相位差区间进行接地故障判断与保护;最后,进行仿真验证,结果表明该方法在配电网中性点采用小电阻接地系统时,在多种过渡电阻,不同分布电源接入数量与容量,各类型电缆长度等情况下,负载波动,均能可靠判断接地故障,适用于DG中性点经小电阻接地和不接地两种方式。After the large scale distributed power supply is connected to the distribution network of the small resistance grounding system,the fault current changes significantly,which affects the original grounding protection accuracy of the system,zero-sequence current protection method is used to remove the single-phase ground fault.In recent years,experts and scholars have put forward the zero-order current phase differential protection scheme,pearson correlation protection method and zero-sequence current centralized comparison method,which is necessary to collect the zero-order current amplitude or phase of different monitoring points to upload it to the main station to calculate the fault location,which depends highly on communication and main station algorithm.In order to solve the above problems,the grounding fault protection algorithm of small resistance grounding system based on phase voltage and zero sequence current is proposed.By establishing the structure and model of the distribution network grounding fault electrical system containing multiple distributed power sources,we theoretically derive and calculate the phase voltage and zero sequence current at the time of failure,by calculating the phase difference between different grounding fault positions and different grounding transition resistances.Analyzing the phase difference interval characteristic value of ground boundary fault,outboundary fault and DG outboundary fault,according to the interval eigenvalue,the protection algorithm is implemented by:Real-time acquisition and calculation of zero-order current amplitude,when its effective value is 3In>Iset,start the protection calculation;real-time acquisition and calculating phase voltage amplitude,compare the three-phase voltage amplitude,select the phase with the amplitude drop as the fault phase;calculate the phase difference between the fault phase voltage and the zero-order current in real time,when the phase differenceθUC∈(-10°,40°),is the power side boundary fault,protect the instantaneous act

关 键 词：有源配电网 相电压与零序电流 相位差 小电阻接地系统 单相接地保护 

分 类 号：TM77[电气工程—电力系统及自动化]