1. State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China
2. Xi’an Jiaotong University Suzhou Institute, Suzhou, Jiangsu 215123, China
3. Key Laboratory of Smart Grid of Shaanxi Province, Xi’an, Shaanxi 710049, China