电负性气体对局部放电特性的影响

Effect of Electronegative Gas on Partial Discharge Characteristics

电负性气体的存在会对局部放电过程产生重要影响,为此,以低密度聚乙烯薄膜内的人工气隙作为研究对象,研究了不同氧气与氮气比例、不同湿度等条件对局部放电特性的影响,得到了不同气体成分和湿度条件下气隙中局部放电的谱图及放电量随时间变化的关系。研究表明,虽然同为电负性气体,但气隙中平均放电量随O2、N2混合气体中O2的体积分数的增加而减小,随湿度(H2O)的增加而增大,这是由于电负性气体对自由电子的吸附作用与附着电子在电压作用下的释放过程相互竞争决定的。兔形谱图与电负性气体无关,可能与N2有关,在气隙中气体为纯N2时,实验中容易出现兔形谱图;在气隙中湿度很高时,实验中容易出现类似正弦曲线形状的谱图,并对这些现象做出了分析和解释。

The process of partial discharges（PDs） will be affected by electronegative gas.Using the void inside low density polyethylene （LDPE） as the object,we focused on the change of the partial discharge characteristics with the electrical aging time,and also on the effects of the partial pressure ratio of O2 and N2 as well as the humidity.The experimental results show the mean partial discharge magnitude decreases with the increase of the mixture proportion of O2,and increase with the increase of humidity.This can be recognized as the interaction of the effect of attachment of the electronegative gas as well as the release of the attached electron through the electrical field.The rabbit like patterns show easily when the void is filled with pure N2,it is considered that the electronegative gas has no inevitability with the conformation of the rabbit like patterns.And the sine-shaped like patterns show easily when the humidity is high.This phenomenon is explained.