特高压交流110kV并联电容器组相对地过电压研究及避雷器能量选择

Phase to Ground Overvoltage Analysis and Lightning Arrester Energy Selection of 110 kV Shunt Capacitor in UHV Transformer Substation

特高压交流工程110 k V并联电容器装置采用避雷器作为相对地过电压保护设备,避雷器的吸收能量需要根据电容器组结构形式和运行工况确定。以110 k V/240 MVA并联电容器装置为研究对象,利用电力系统过电压理论分析了开关正常分闸及重击穿时电容器组的相对地过电压水平,采用电压电流积分法推导出分闸重击穿时注入避雷器的能量,并采用EMTP软件进行了仿真计算,仿真计算结果与理论分析结论一致。研究表明:对于110 k V并联电容器装置,当某相开关发生重击穿时,相邻相避雷器吸收能量最大,建议特高压工程110 k V并联电容器装置用避雷器吸收能量不小于1 MJ,2 ms方波通流容量不小于1 500 A。

Since 110 kV shunt capacitor of UHV AC project uses lightning arrester as a phase-to-ground overvoltage protection device, it is necessary to evaluate the lightning arrester absorbing energy under the specific conditions. Consequently, taking the 110 kV/240 MVA shtmt capacitor device as the research object, firstly, we analyzed the switch normal tripping and restriking capacitor group phase-to-ground overvoltage level with power system overvoltage theory, then, we derived the energy of the surge arrester by using a voltage and current integration method, finally, we performed the si- mulation calculation by using the EMTP software. Calculation results were consistent with the theoretical analyses. It is shown that, for I 10 kV shunt capacitor device, when one phase is restriked, the arrester of the other phase will absorb the maximum energy. According to research results, it is proposed that the recommended value of the arrester absorbing energy would be above 1 MJ, and 2 ms rectangular impulse capacity of 110 kV shunt capacitor installation should be no less than 1 500 A.