常规直流逆变站交流送出线路距离保护适应性分析与对策  

Adaptability Analysis and Countermeasures for Distance Protection of AC Transmission Lines Connected LCC-HVDC Inverter Station

作　　者：李会新 陈祥文 金明亮 刘阳 徐海洋 LI Huixin;CHEN Xiangwen;JIN Mingliang;LIU Yang;XU Haiyang(Central China Branch of State Grid Corporation of China,Wuhan 430000,China;Lamor Innovation Studio of Liu Huanzhang,Wuhan 430000,China;NR Electric Co.,Ltd.,Nanjing 211102,China)

机构地区：[1]国家电网有限公司华中分部,湖北武汉430000 [2]柳焕章劳模创新工作室,湖北武汉430000 [3]南京南瑞继保电气有限公司,江苏南京211102

出　　处：《中国电力》2024年第2期115-126,共12页Electric Power

基　　金：国家电网有限公司科技项目(SGHZ0000DKJS2200231,5100-202355035A-1-1ZN)。

摘　　要：常规直流逆变站交流送出线路故障通常会引发换相失败,存在故障电压和电流波形畸变等问题,可能导致工频相量距离保护性能劣化。首先,分析了工程中广泛应用的正序电压极化距离保护在常规直流逆变站交流送出线路中的适应性,分析结果表明,当逆变站运行于单回交流出线工况时,传统正序电压极化距离保护不再适用;然后,基于交流线路的RL模型,提出了基于波形相关系数的时域距离元件,可以不受逆变站非线性输出特性的影响,并针对时域距离元件存在的出口近区故障方向判别问题,利用电流畸变程度判断故障方向;最后,通过仿真验证了时域距离保护方案的有效性。The AC transmission line fault near the LCC-HVDC inverter station might lead to commutation failure.And fault voltage and current waveforms would be distorted.It will have an adverse effect on the performance of fundamental power frequency phasor based distance protection.Firstly,the performance of traditional distance protection based on positive-sequence voltage polarization which is widely used in practice is analyzed.If the LCC-HVDC inverter station only has the single AC transmission outgoing line,distance protection based on positive-sequence voltage polarization would no longer be applicable.Then,based on the RL model of AC transmission line,a time domain distance protection based on waveform correlation coefficient is proposed.It is not affected by the nonlinear output characteristics of LCC-HVDC inverter station.To solve the fault direction identification problem near the exit area,the index of current distortion is defined to identify the fault direction.Finally,the proposed time domain distance protection is verified by the simulation results.

关 键 词：逆变站 交流线路 时域距离保护 波形相关系数 电流畸变程度 

分 类 号：TM721.1[电气工程—电力系统及自动化]