直流滤波器对±800kV直流线路单极接地故障过电压的影响

Influence of DC filter parameters on single-pole grounding fault overvoltage in ±800 kV UHVDC transmission line

基于极线间的电磁耦合作用和波过程,分析了直流滤波器参数对直流线路单极接地故障过电压的影响机理、直流滤波器电容值和电感值对该过电压的影响以及电容值对该过电压的影响规律。研究表明,直流滤波器电容值会对直流线路单极接地故障过电压产生影响,其中主电容对该过电压的影响最为显著,是控制线路过电压的关键,随着电容值增加,该过电压的增大趋势逐渐趋于平缓,而电感值对该过电压影响不大。将直流滤波器主电容限制在2μF以内,基本可以保证线路过电压幅值不超过额定电压的1.7倍。

The influence mechanism of DC filter parameters on single-pole grounding fault overvoltage was studied based on the electromagnetic coupling between two pole lines and the wave process.The influences of DC filter parameters including capacitance parameters and inductance parameters on the overvoltage as well as the influence regulation were analyzed.The research showed that,the DC filter capacitance parameters had certain influence on single-pole grounding fault overvoltage,and the main capacitor of DC filter influenced the overvoltage most significantly,which was the critical factor to limit the overvoltage on transmission line,while the DC filter inductance parameters had little effect on the overvoltage.The increasing trend of overvoltage tended to be slow with the increase of capacitance parameters.The overvoltage of transmission line could be basically limited within 1.7 times of rated voltage as the main capacitor of DC filter was limited within 2μF.