1. State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Shaanxi 710049, China
2. State Grid Electric Power Research Institute, Wuhan, 430074, China
3. CAS Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
4. University of Chinese Academy of Sciences, Beijing, 100049, China
5. School of Engineering, University of Warwick, Coventry, CV4 7AL, United Kingdom