1. State Key Laboratory of Power Transmission Equipment and System Security and New Technology School of Electrical Engineering, Chongqing University, Chongqing 401331, China
2. Institute of Physics Academy of Space Technology, Lanzhou 730000, China
3. Jinzhong Power Supply Company of State Grid Shanxi Electric Power Company, Shanxi 030001, China
4. The China Southern Power Grid, Guangzhou 510080, China