1. Economic and Technical Research Institute of State Grid Shanxi Electric Power Company, Taiyuan 030000, China
2. School of Electrical and Electronic Engineering, North China Electric Power University, Beijing 100000, China
3. State Grid Shanxi Electric Power Marketing Service Centre, Taiyuan 030032, China
4. State Grid Shanxi Electric Power Ultra High Voltage Substation Branch, Taiyuan 030032, China
5. College of Electrical and Power Engineering, Taiyuan University of Technology, Taiyuan 030024, China