1. Department of Electrical Engineering, Xi’an University of Technology, No. 5 South Jinhua Road, Xi’an, Shaanxi Province 710048, People’s Republic of China
2. State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, No. 28 XianNing West Road, Xi’an, Shaanxi Province 710049, People’s Republic of China
3. State Grid Anhui Electric Power Research Institute, Hefei, People’s Republic of China