极性反转条件下油纸界面电荷对沿面闪络电压的影响

Influence of Interface Charge of Oil Impregnated Pressboard on Surface Flashover Voltage Under Polarity Reversal

高压直流输电系统出现潮流反转时,换流变压器的油纸绝缘会承受极性反转电压,容易造成绝缘失效。基于油纸沿面绝缘结构的极性反转闪络试验平台,研究了油纸界面电荷对沿面闪络电压的影响以及直流极性反转条件下油纸绝缘沿面闪络电压与单极性直流电压下沿面闪络电压的差别,并分析了油纸绝缘沿面放电针板电极模型的界面电荷在极性反转条件下对油纸绝缘沿面闪络电压的影响,发现油纸积聚的界面电荷密度越大极性反转时发生沿面闪络的电压越低。

When HVDC systems are in the state of trend reversal,the oil-paper insulation of converter transformer will withstand voltage polarity reversal,which will cause insulation failure. Based on the test platform for polarity reversal conditions of insulation structure along the grease paper surface,the influence of interface charge on the flashover voltage along the oil-paper surface is studied,as well as the difference between the flashover voltage along the oil-paper surface under DC insulation polarity reversal and that under single polarity DC voltage. The influence of the interface charge of the oil-paper insulation surface in discharge needle plate electrode polarity reversal model on the surface flashover voltage is also analyzed,and it is found that the greater the interface charge density on the oil-impregnated pressboard,the lower the surface flashover voltage under the polarity reversal condition.