1. School of Electrical Engineering, Northeast Electric Power University, No. 169, Changchun Road, Jilin City 132012, P. R. China
2. Key Laboratory of Engineering Dielectric and Its Application of Ministry of Education, Harbin University of Science and Technology, Harbin 150006, P. R. China
3. Key Laboratory of Silicon Device Technology, Chinese Academy of Sciences, Beijing 100031, P. R. China
4. School of Mechanical Science and Engineering, Jilin University, Changchun 130022, P. R. China
5. Materials Physics Laboratory, Department of Physics, Faculty of Science, Prince of Songkla University (PSU), Songkhla 90112, Thailand
6. State Grid Liaoning Province Electric Power Company Limited, Electric Power Research Institute, Shenyang, 110181, P. R. China