ABSTRACT
Low Density Polyethylene (LDPE) has been widely used as insulating materials for high voltage and extra-high-voltage alternating current cables because of its excellent electrical and mechanical properties (Alapati & Meledath 2014; Rogti & Ferhat 2014). However, the space charge accumulation which causes local electric field distortion and finally leads to degradation of the polymeric dielectric is a problem and limits the polyethylene’s usage in high voltage direct current fields (Wang & Zhao 2014; Zhu & Zhang 2012). Therefore it has important scientific meaning and practical value to accurately characterize energy distribution of charge trap in polymer dielectric materials with the purpose of improving their properties and application (Zha & Dang 2010; Zhu & Zhang 2012; Mellinger & Camacho, Gonzalez 2004).
