直流馈入对工频变化量距离保护影响分析及改进  

Analysis and Improvement of DC Infeed on Power-Frequency Variation Distance Protection

作　　者：刘江山 李凤婷[1] 解超 陈睿康 LIU Jiangshan;LI Fengting;XIE Chao;CHEN Ruikang(School of Electrical Engineering,Xinjiang University,Urumqi Xinjiang 830047,China)

机构地区：[1]新疆大学电气工程学院,新疆乌鲁木齐830047

出　　处：《新疆大学学报（自然科学版）（中英文）》2021年第6期753-763,共11页Journal of Xinjiang University(Natural Science Edition in Chinese and English)

基　　金：国家自然科学基金(51877185);国家电网公司科技项目(SGXJJY00GHJS2000011).

摘　　要：为研究直流馈入对工频变化量距离保护的影响,建立了直流系统等值工频变化量阻抗模型,基于不同故障程度下直流控制策略的切换,分析了直流系统等值工频变化量阻抗的变化特性及其对工频变化量距离保护的影响.在过渡电阻较大的情况下,直流系统等值工频变化量阻抗呈容性,会造成工频变化量距离保护正方向保护范围减小.基于此,提出了工频变化量阻抗继电器与全阻抗继电器配合的改进方法,有效改善了由于直流馈入造成保护拒动的问题.最后,基于PSCAD/EMTDC的仿真结果验证了理论分析的正确性和改进措施的有效性.In order to research the influence of DC feed on power-frequency variation distance protection,the equivalent power-frequency variation impedance model of the DC system is established.Based on the switching of HVDC control strategies under different fault levels,the change characteristics of the equivalent power-frequency variation impedance of the DC system and its influence on the power-frequency variation distance protection are analyzed.It is concluded that when the fault resistance is large,the equivalent power-frequency variation impedance of the DC system is capacitive,which will cause the protection range of the power-frequency variation distance protection to be reduced in the positive direction.Based on this,an improved method for the coordination of power-frequency variation impedance relays and impedance relays is proposed,which can solve the problem of the reduction of the protection range in the positive direction caused by DC feed.Finally,the simulation results based on PSCAD/EMTDC verify the correctness of the theoretical analysis and the effectiveness of the improvement measures.

关 键 词：直流馈入 工频变化量距离保护 换相失败 控制策略 保护范围 改进措施 

分 类 号：TM773[电气工程—电力系统及自动化]