基于电晕笼的导线操作冲击电晕特性试验研究

Experimental Researches on Switching Impulse Corona Characteristics of Conductors Based on Corona Cage

随着电力系统的电压等级逐渐升高,操作过电压对输变电设备的绝缘水平影响越来越大,如何对输电线路操作过电压精确计算,使设备的绝缘设计更为合理广受关注。目前计算线路操作过电压中都忽略了导线的冲击电晕会对操作过电压产生明显的衰减畸变影响,计算结果往往过于保守。在中国特高压交流试验基地进行的试验对电力系统常用的导线进行了操作冲击电晕试验,获得了相应的导线冲击电晕伏库特性曲线。试验结果表明,导线参数对起晕电压影响较大。长波头操作冲击产生的空间电荷量比标准操作冲击更大,而正极性冲击电晕比负极性电晕更为激烈。基于试验结果,建议在输电线路中安装选相合闸断路器的,利用断路器的开断使线路的操作过电压都为正极性的,从而利用正极性冲击电晕降低线路操作过电压值。

As the nominal voltage of power transmission system rising,switching overvoltage has more and more important effect on the insulation of equipments.How to calculate the switching overvoltage accurately has attracted much more attention.At present,the attenuation and distortion of overvoltage caused by switching impulse corona are ignored in the calculations.Switching impulse corona experiments on the conductors of the type that commonly used in China are carried out in the UHV test base.The results show that the switching impulse corona incepts as the voltage exceeds the inception voltage.Long wave front time switching impulses generate more space charge than standard switching impulse.Positive impulses generate stronger corona than the negative impulses.In the end,controllable breaker is suggested to be used in the transmission lines.As a result,only positive switching corona will be generated and the switching overvoltage will be greatly decreased.