基于并联电抗器引发拍频效应的特高压交直流碰线保护改进方案研究  

Improved Scheme of UHV AC-DC Line-touching Protection Based on Beat-frequency Effect Induced by Shunt Reactor

作　　者：李厚源 郑涛 黄少锋 倪钰翔 于欢昌 LI Houyuan;ZHENG Tao;HUANG Shaofeng;NI Yuxiang;YU Huanchang(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources(North China Electric Power University),Changping District,Beijing 102206,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京市昌平区102206

出　　处：《电网技术》2023年第8期3416-3425,共10页Power System Technology

基　　金：国家自然科学基金联合基金项目(U2166205)。

摘　　要：特高压交直流混联电网的迅速发展增加了交流线路与直流线路发生碰线故障的风险,现有交直流碰线保护存在无法区分瞬时性和永久性故障、直流系统无法自适应重启、交流系统重合于永久性故障时造成直流线路过电压等不足。据此通过优化直流系统的交直流碰线保护出口逻辑,利用交流系统两端装设并联电抗器的特点,提出了基于并联电抗器引发拍频效应的交直流碰线保护改进方案,并结合直流重启时交流系统的冲击电压特征,实现了故障类型的识别,直流系统的自适应重启以及交流系统的自适应重合闸,避免了交流系统重合于永久性故障时直流线路的过电压风险。在PSCAD/EMTDC平台中搭建了交直流碰线故障的仿真模型并进行了大量仿真实验,仿真结果验证了所提交直流碰线保护改进方案的可行性。The development of Ultra-high Voltage(UHV)AC-DC hybrid power grids has increased the risks of AC-DC line-touching faults.The existing AC-DC line-touching protection has some shortparts,for example,it cannot identify whether the fault is transient or permanent;the DC transmission line cannot adaptively restart;or an overvoltage in the DC system is caused by the reclosing of the AC system in a permanent fault.Based on these,by improving the exit of the AC-DC line-touching protection and using the advantages of shunt reactors in the AC system,an improved scheme of the AC-DC line-touching protection based on the beat-frequency effect induced by the shunt reactor is proposed.Combined with the DC impulse voltage of the AC system at the time of the DC restarting,the identification of fault types,the adaptive restarting of the DC system and the reclosing of the AC system are all realized.The overvoltage risks of the DC transmission line induced by the reclosing of the AC system in the permanent fault is avoided.The simulation model of the AC-DC line-touching fault is built in the PSCAD/EMTED and a large number of simulations verify the feasibility of the proposed AC-DC line-touching protection improvement scheme.

关 键 词：交直流碰线故障 交直流碰线保护 并联电抗器 拍频特性 直流冲击电压 

分 类 号：TM721[电气工程—电力系统及自动化]