1. Substation Overhaul Center, State Grid Hangzhou Power Supply Company, Hangzhou, China
2. School of Electrical Engineering, Shandong University, Jinan, China
3. Substation Operation Center, State Grid Hangzhou Power Supply Company, Hangzhou, China
4. Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, U.K
5. College of Electrical and Electronic Engineering, Institute of High Voltage and Insulation Technology, North China Electric Power University, Beijing, China