1. State Grid Anhui Electric Power Research Institute, Hefei 230601, China
2. State Grid Anhui Ultra High Voltage Company, Hefei 230051, China
3. State Grid Hefei Power Supply Company, Hefei 230061, China
4. Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China