柔直电网机械式高压直流断路器分闸过电压问题分析及改进措施  

Analysis and Improvement Measures for Overvoltage Problem of Mechanical HVDC Circuit Breaker in Flexible DC Grid

作　　者：李金卜 刘宪辉 张晓飞 田凯哲 陈思宇 LI Jinbo;LIU Xianhui;ZHANG Xiaofei;TIAN Kaizhe;CHEN Siyu(State Grid Jibei Electric Power Co.,Ltd.EHV Power Transmission Company,Beijing 102488,China)

机构地区：[1]国网冀北电力有限公司超高压分公司,北京102488

出　　处：《内蒙古电力技术》2023年第2期64-68,共5页Inner Mongolia Electric Power

摘　　要：针对张北柔性直流电网机械式高压直流断路器在分闸过程中引起直流母线过电压保护动作事件,基于柔性直流电网的特点、机械式高压直流断路器工作原理、直流母线过压保护原理分析,发现在分闸过程中,机械式高压直流断路器转移支路电容电压叠加直流线路电压,导致直流母线过压。针对上述问题,通过调整机械式直流断路器转移支路电容充电回路中的整流二极管方向,改变了转移支路电容极性,解决了直流母线过压问题,并通过仿真验证了该措施的有效性,提高了柔性直流电网运行的可靠性。Aiming at the DC bus overvoltage protection event caused by the mechanical high⁃voltage direct current(HVDC)circuit breaker of Zhangbei flexible DC grid during the opening process,the characteristics of the flexible DC grid are introduced.The working principle of the mechanical HVDC circuit breaker and the DC bus overvoltage protection principle are analyzed.It is found that in the process of switching,the transfer branch capacitor voltage of mechanical HVDC circuit breaker superimposes the DC line voltage,resulting in DC bus overvoltage.In response to the above issues,by adjusting the direction of the rectifier diode in the transfer branch capacitor charging circuit of the mechanical DC circuit breaker,the polarity of the transfer branch capacitor is changed,and the problem of DC bus overvoltage caused by the mechanical high voltage DC circuit breaker in the process of breaking is solved.The effectiveness of the measure is verified by simulation,which improves the reliability of the flexible DC grid operation.

关 键 词：柔性直流电网 机械式高压直流断路器 过电压保护 转移支路 

分 类 号：TM77[电气工程—电力系统及自动化]