电力系统保护与控制2025，Vol.53Issue(5)：59-68,10.DOI:10.19783/j.cnki.pspc.240302
计及电网参数不平衡的灵活接地系统高阻接地故障选线方法
A high resistance ground-fault line selection method for flexible grounding system considering unbalanced power grid parameters
摘要
Abstract
Zero sequence overcurrent protection adopted in the flexible grounding system faces the problem of low tolerance to transition resistance.The existing fault line selection methods also require high-precision current transformers and do not take into account the influence of grid parameter imbalances,increasing the risk of protection misjudgment.To address the issues,this paper first explores the relationship between the changes in electrical signals and line-to-ground parameters and unbalanced current before and after the introduction of a small parallel resistance,taking into account the unbalanced conditions of grid parameters.The research finds that the ratio of zero sequence current change and zero sequence voltage change of a healthy line is equal to the line-to-ground admittance,and the ratio of the change of the fault line is the sum of line-to-ground admittance and grounding admittance.On this basis,a method of line selection applicable to single-phase high-resistance ground faults in flexible grounding systems is proposed.This method is not affected by the unbalance of grid parameters and the zero sequence CT polarity reversal,effectively reducing the precision requirements of current transformers.In addition,the method can also utilize the fault information to measure transition resistance and the ground admittance of individual lines under unbalanced grid parameters.Finally,the correctness and effectiveness of the described method are verified in the simulation circuit model.关键词
灵活接地系统/电网参数不平衡/零序电压变化量/零序电流变化量/高阻接地故障Key words
flexible grounding system/unbalanced power grid parameters/zero sequence voltage variation/zero sequence current variation/high resistance ground fault引用本文复制引用
李晓波,张世乐,谢剑锋,彭超红,刘栩鹏,梁睿..计及电网参数不平衡的灵活接地系统高阻接地故障选线方法[J].电力系统保护与控制,2025,53(5):59-68,10.基金项目
This work is supported by the General Program of National Natural Science Foundation of China(No.52077215). 国家自然科学基金面上项目资助(52077215) （No.52077215）
