电极表面光滑程度对水介质高电压击穿的影响

 采用水介质同轴实验装置，改变电极表面的光滑程度，在μs级充电时进行水介质击穿实验，并对实验结果进行了分析和解释。结果表明：抛光电极表面可有效提高水介质耐高电压击穿能力；表面粗糙度为0.4～0.8 μm的抛光电极表面的击穿场强比表面粗糙度为1.6～3.2 μm的粗糙抛光电极表面，更符合Martin公式。电极表面光滑程度的改善，使阴极场致发射电流减弱进而击穿延迟时间变长，气泡也更难以附着在光滑的电极表面，从而可以提高水介质耐高电压击穿能力。

Influence of polished surface of electrodes on high electrical breakdown for water dielectric

A coaxial electrode experimental apparatus with water dielectric capacitor was set up, high voltage breakdown experiments for polished and unpolished surface of electrodes with microsecond charging were respectively carried out. The experimental results are shown as follows: (1) polished surface of electrodes effectively improves the capacity to maintain the high electrical voltage for water dielectric; (2) breakdown stress for surface polished electrode of roughness (0.4~0.8 μm) is in better agreement with Martin formula than roughly polished one(1.6~3.2 μm); (3) primary mechanism to increase the breakdown stress of water dielectric is that, field emission currents to heat the bubble become weak on the cathode for polished surface of the electrodes and the time lag to breakdown is increased, moreover, it is more difficult to rusult in bubbles on the polished surface of electrodes.