特高压交流单回线路操作过电压等值风速系数的计算分析

Calculation and Analysis on Equivalent Wind Speed Coefficient of Switching Overvoltage for UHV AC Single Transmission Lines

运行经验表明超/特高压输电线路在大风下还未出现过由操作过电压所导致的风偏闪络。由于操作过电压的持续时间较短,所以高幅值的操作过电压和大风恰好一起发生的概率很小。为此,分析了典型地区的气象数据,结合特高压交流单回线路操作过电压的沿线分布和幅值分布,研究了特高压交流单回线路部分地区的操作过电压等值风速系数取值。结果表明：不同地区的操作过电压等值风速系数取值不同,由最大平均风速大小和风速分布概率这2者共同决定;若将特高压交流单回线路在操作过电压下的风偏闪络率控制值设为0.005次/（100 km·a）,则可将多数地区的操作过电压等值风速系数取为0.4,根据设计风速的不同,可将操作过电压所决定的塔头间隙值降低1.3~1.7 m。

Operating experience shows that windage yaw flashover between tower and conductor caused by switching overvoltage has not happened in UHV＆EHV transmission lines. For switching overvoltage, because of its short duration, the probability that high amplitude overvoltage and high wind simultaneously happen is very small. Therefore, we ana- lyzed the meteorological data of typical regions.Moreover, combining with switching overvoltage along the line distribution and amplitude distribution of UHV AC single transmission lines, we studied the evaluation of switching overvoltage equivalence wind speed for UHV AC single transmission lines. The results show that, the evaluation of switching overvoltage equivalence wind speed coefficient is different in different areas, which is co-determined by max- imum average wind speed and velocity distribution; if the windage yaw flashover evaluation is 0.005 times/（100 km.a） of switching overvoltage in UHV AC single transmission lines, the evaluation of switching overvoltage equivalence wind speed coefficient is 0.4 in most areas, according to the different design wind speed, the gap distance of tower head deter- mined by switching overvoltage can be reduced by 1.3~1.7 m.