DC-arc Motion Characteristics and Influencing Factors of Arcing-time on Ice-covered Outdoor Insulators
To enhance the prediction technology for flashover risk in ice-covered insulators,we analyzed the motion characteristics of DC arcs on high voltage suspended ice-covered insulators and investigated the factors influencing arc duration by using DC icing flashover tests.Firstly,the leakage current and arc dynamic characteristics of DC icing flash-over test were analyzed cooperatively,and the difference of arc dynamic behavior under positive and negative DC voltage was studied in detail.Then,the correlation between arc time and arc characteristics and leakage current was analyzed,and a multivariate fitting model for arc time was established.The results show that the changes of leakage current and arc length can effectively distinguish the arc development stage,in which the arc under negative DC voltage produces fre-quently,the initial local arc is densely distributed and the duration is short.The new discharge path generated by DC arc extension leads to contact and non-contact arc attenuation,and the development direction of the new discharge path is oppo-site under different polarity voltages.In addition,the cumulative charge and the average length of the DC arc are positively correlated with the arc time.The distribution ranges of data dispersion and charge accumulation of the average negative DC arc length are lower,and the established multivariable fitting equation has higher prediction accuracy for arc duration.