Dynamic Behavior Of Surface Charge And Tracking Failure Of Epoxy Nanocomposite

As an insulating material, epoxy plays an important role in the power system. Oncethe insulation failure occurred, it may leads to short circuit, blackouts, fire, explosionaccidents a nd ot her s erious c onsequences. A fter modified b y doping inorganicnanometer pa rticles, t he i nsulation of e poxy will c hange greatly. T herefore, t hepractical application of the modified epoxy has a very important significance. As thevoltage levels increase, more and more epoxy in high voltage equipment suffered withsurface c harge a ccumulation a nd t racking failure phe nomenon. T herefore, t heinvestigation of t he s urface c harge be havior a nd t racking f ailure of e poxynanocomposites is of great theory and practical significance.Epoxy/TiO₂made in our laboratory was employed as the test sample in this paper.The el ectrostatic v oltmeter w as u sed t o s can t he s urface p otential w ith r espect t osurface ch arge ac cumulation a nd de cay. Based o n t he n eedle-board e xperimentmethod, t he t racking f ailure phe nomenon un der dc a nd pul se c ondition w asinvestigated. U sing no nlinear m ethod a nd t hermal br eakdown m echanism, t hetracking f ailure p henomenon w as an alyzed. The m ain research w ork an dachievements are as follows:（1） Under high DC voltage environment, the insulation performance of epoxydegraded for s urface charge accumulation w as i nvestigated b y w ay o f n eedleelaectrode charging. The surface charge accumulation and decay with the voltage,polarity and time were observed. The mechanism changed by the nanoparticles wasalso discussed in the high dc voltage environment. The surface charge accumulationand decay behaviors were obtained.（2） Pulse voltage on a needle electrode for single corona charging was adopted inthis s tudy. T he pul se corona w as i nvestigated b y w ay of t he s urface chargeaccumulation an d d ecay w ith ch anges o f t he r ise t ime an d ch arge p olarity. T hemechanism c hanged b y na noparticles w as a lso di scussed i n t he pul se v oltageenvironment. The surface charge accumulation and decay behaviors were obtained.（3） The i nfluence o f na no-scale TiO₂particles o n t racking f ailure o f ep oxynanocomposites in contaminated environment was analyzed. The erosion depth andthe w eight lo ss of e poxy n anocomposites w ith di fferent c oncentrations of TiO₂particles were investigated. We measured the discharge current and the distribution ofdischarge l ight b y us ing a recursive pl ot a nalysis a nd f ractal di mention m ethod. Results showed that the resistence to tracking failure of the nanofilled epoxy wasimproved.（4） The t racking failure phe nomenon of Epoxy/TiO₂under pul se voltage w asinvestigated. It i s concluded t hat t he TiO₂particles d etermine th e resistence totracking f ailure. T he m echanism f or t he i nfluence on t racking f ailure w as a lsoanalyzed.