1. State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
2. Zhuhai Power Supply Bureau, Zhuhai 519000, China
3. College of Information Engineering, Taiyuan University of Technology, Taiyuan 030024, China e-mail:
4. Key Lab of Field Bus and Automation of Beijing, North China University of Technology, Beijing 100144, China
5. The Beijing Key Laboratory of New and Renewable Energy, North China Electric Power University, Beijing 102206, China