±1100kV特高压直流输电工程直流滤波器过电压与绝缘配合

Overvoltage and Insulation Coordination of DC Filter in± 1 100 kV UHVDC Power Transmission Project

直流滤波器是直流输电工程直流场的重要设备之一。详细分析了直流滤波器避雷器配置方案及参数选择过程,给出了避雷器参数选择的具体表达式。研究了对直流滤波器绝缘水平起决定性作用的故障工况:直流极线接地短路、直流极线侵入操作波;建立了这2种故障工况计算模型,模型中需要考虑故障点到直流滤波器高压端之间的故障电感。基于具体±1 100 kV特高压直流输电工程,对直流滤波器设备进行过电压计算。计算结果给出了滤波器各设备的最大暂态过电压,进而根据绝缘裕度确定了该特高压直流工程直流滤波器各设备最终的绝缘水平,为设备选型和制造提供依据。

DC filter is one of the critical devices in HVDC power transmission project. The configuration scheme and parameter selection process of arrester in DC filter were analyzed in-depth, and the specific expression of arrester parameters was presented. Two typical fault conditions which played decisive roles on the insulation level of DC filter were studied： ground fault on DC line and incoming switching surge on DC line; meanwhile the calculation model of these fault conditions were introduced, in which fault inductance between fault point and high-voltage side of DC filter should be considered. Based on the practical ±1 100 kV UHVDC transmission project, the overvoltage of DC filter devices was also calculated. The maximum transient overvoltage of all the DC-filter devices was presented in the calculation result, and then the final insulation level of DC-filter devices in this UHVDC project was determined according to their insulation margin, which could provide the basis for the selection of equipment and manufacturing.