交直流预电压下导线-棒间隙的冲击特性

Air breakdown in conductor-rod gap with direct or alternating voltage switching impulses

通过实验研究了导线棒间隙在直流和交流预电压作用下的操作冲击特性。交流预电压对其冲击击穿特性影响取决于操作波叠加在交流上的位置。在正操作电压作用下 ,不论是直流预电压还是交流预电压 ,其冲击击穿 U50 % 电压都有提高。操作波的波长越长 ,直流预电压值越高 ,其击穿电压提高越明显。对交流预电压而言 ,当操作波叠加在交流电压 180°,135°上时 ,操作击穿电压随着操作波的波长和交流预电压值的增加而显著增加 ,增加值最大可达 70 %。通过电晕检测表明 ,对导线棒间隙而言 ,预电压的存在主要改变了棒头部的负流注活动强弱 ,从而引起 U50 % 击穿电压的不同。

The air breakdown in the conductor rod gap was analyzed for alternating or direct switching impulse voltages. The effect of the alternating pre stressing voltage on the impulse spark over voltage depended on where the switching impulse is superimposed on the AC waveform. For positive switching impulse cases, both the DC and AC pre stressing voltages significantly increased the impulse spark over voltage, and the longer time to peak of the impulse voltage was the higher spark over voltage was. With...