数十厘米长间隙真空绝缘研究进展

Research Progress of Vacuum Insulation With Tensof Centimeters of Long Gaps

综述了西北核技术研究所在微秒数十厘米长间隙真空绝缘领域的研究进展,包括:总结了数十厘米间隙下同轴电极真空绝缘阈值的经验公式,发现真空击穿电场强度同时受电极间隙和电极面积两个因素影响,并存在经验公式;总结了电极间隙为4 mm~4 m时,平板电极真空绝缘阈值的经验公式;总结了脉冲宽度为1 ns~1 ms时,真空绝缘阈值随脉冲宽度变化的经验公式;总结了长间隙真空击穿的物理机制,发现粒子碰撞理论更适合解释长间隙条件下的真空击穿现象;给出了几种常见的可提高真空绝缘阈值的方法,包括粗糙度合适和研磨,及在首次放电电压与微放电电压之间的老炼。

Vacuum insulation is a common insulation form in pulsed power field.The recent research progress for the vacuum insulation long gaps with tens of centimeter under microsecond pulses in Northwest Institute of Nuclear Technology is reviewed,including five aspects.First,the empirical formula for vacuum breakdown field(E b)of coaxial electrodes with a gap of tens of centimeters is proposed,it is found that E b is affected by both the electrode area(A)and electrode gap(g),which can be expressed as E b=C 1 g-1/3 A-1/6.Second,the E b for plain-plate electrodes with a gap of several meters is proposed,i.e.,E b=C 2 g-1/3,where g ranges from 4 mm to 4 m.Third,the relationship between E b and the pulse width(τ)forτfrom 1 ns to 1 ms is proposed which can be expressed as E b=C 3τ-1/6.Fourth,the long-gap vacuum breakdown mechanism is summarized,it is found that the clump theory is more suitable to explain the long-gap vacuum breakdown phenomenon.Fifth,the methods which can enhance the E b for long gap are put forward,which include polishing at a reasonable roughness and aging at a moderate degree.