负极性方波下介质阻挡对电晕放电重复率的影响

Influence of Dielectric Barrier on Repetition Rate of Corona Discharge with Negative Square Pulse Wave

电晕放电产生的空间电荷会在周边固体绝缘介质表面积聚,为了研究在介质阻挡下的电晕放电机理以及空间电荷对电晕放电重复率的影响,搭建了针板介质阻挡电晕放电模型。使用负极性周期脉冲方波对放电起始前8个周期中放电重复率的变化规律进行分析,建立数学模型分析电晕放电下放电重复率、放电次数与电压的函数关系。通过对比无介质阻挡、PE、PTFE、PC、PVC、pressboard等片状绝缘材料阻挡以及FEP电缆绝缘层阻挡下电晕放电情况,得到以下结论:无介质阻挡时,放电重复率与电压呈指数关系,且指数常数主要由针尖直径与几何结构决定;绝缘介质阻挡时单周期内放电重复率呈负指数递减并趋于某一饱和值;各周期放电次数和放电重复率的变化与材料表面电阻率有相关性;改变脉冲间隔能改变放电重复率的变化趋势和放电次数的最终稳定值;绝缘几何结构会改变指数分布情况但不改变趋势。

Space charge generated by corona discharge will accumulate on the surface of solid dielectric.To study the mechanism of corona discharge with dielectric barrier and the influence of space charge,a needle-plane dielectric barrier corona discharge model was built.The negative square pulse wave was used to analyze the repetition rates of the first 8 cycles,and the mathematical models were established to analyze the functional relationships between repetition rates,discharge numbers and voltage levels.By comparing different cases of corona discharge including no dielectric barrier,5 kinds of dielectric barriers,and FEP cable insulation barrier,this paper draws the conclusions as follows.When there is no dielectric barrier,the repetition rate has an exponential relationship with voltage level,and the exponential constant is mainly determined by tip diameter and geometric structure.Secondly,the repetition rate decreases exponentially in a single cycle with dielectric barrier and the discharge number of each cycle decreases gradually to saturation.Thirdly,the discharge number and repetition rate share the similar trend with surface resistivity,and it is able to change the repetition rate and the final stable value of discharge number by changing the time interval between each two pulses.Finally,the geometric structure of insulation can change the distribution of indexes but will not change the trend.