换流阀换相过冲电压理论计算及运行方式影响研究  

Study on Theoretical Calculation of Commutation Overvoltage of Converter Valve and the Influence of Operation Mode

作　　者：乐波 唐英杰 厉璇 徐政[2] YUE Bo;TANG Yingjie;LI Xuan;XU Zheng(State Grid Economic and Technology Research Institute Co.,Ltd.,Beijing 102209,China;College of Electric Engineering,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]国网经济技术研究院有限公司,北京102209 [2]浙江大学电气工程学院,杭州310027

出　　处：《高电压技术》2020年第4期1250-1259,共10页High Voltage Engineering

基　　金：国家重点研发计划(2016YFB0900805)。

摘　　要：换流阀最大峰值持续运行电压(peak value of continuous operating voltage, PCOV)是换流站绝缘配合工作的重要参考数据,明确PCOV对应的运行工况有助于缩小计算范围,降低计算时间。建立6脉动整流器的阀电压波形的分时间段表达式,根据换相过冲电压计算原理分析阀电压跃变与阀电压峰值之间的关系,论证了计算PCOV时所参照的跃变时刻和运行工况。同样对逆变器的电压跃变情况进行分析,发现逆变器内换相过冲对阀电压峰值的影响远小于整流器。进一步对实际工程中使用的12脉动换流器中邻桥换相过程对阀电压波形的影响进行推导,明确了12脉动换流器阀PCOV不受邻桥换相过程的影响。以3个不同电压等级的实际工程为例,计算出额定工况和长期过负荷工况下决定阀电压峰值的阀侧线电压值和跃变电压值。提出在计算阀PCOV时推荐以长期过载方式作为直流输电工程运行方式,以整流模式作为换流器运行模式。The peak value of continuous operating voltage(PCOV) of converter valve is an important reference datum for insulation coordination of converter station. Defining the corresponding operating conditions of PCOV is helpful to narrow the calculation range and reduce the calculation time. Consequently, the expression of valve voltage waveform of 6-pulse rectifier is established in different time intervals, and the relationship between valve voltage jump and peak value of valve voltage is analyzed according to the calculation principle of commutation overvoltage. Then the jump time and operation condition for calculating PCOV are demonstrated. The same method is used to analyze the voltage jump of the inverter and it is found that the effect of commutation overshoot on valve peak voltage is much smaller than that of the rectifier. The influence of the adjacent bridge commutation process on the valve voltage waveform of the 12-pulse converter is further deduced. It is clear that the PCOV of the 12-pulse converter valve is not affected by the adjacent bridge commutation process. The side voltage value and jump voltage value of the valve which determine the peak value of valve voltage under a rated working condition and long-term overload working condition are calculated by taking three practical projects with different voltage grades as examples. The conclusion can be drawn that long-term overload mode is recommended as the operation mode of HVDC transmission project and rectification mode as the operation mode of converter when calculating the PCOV of valve.

关 键 词：换流器 换相过冲 最大峰值持续运行电压 电压跃变 运行方式 

分 类 号：TM721.1[电气工程—电力系统及自动化]