1. Hubei Engineering and Technology Research Center for AC/DC Intelligent Distribution Network, Wuhan University, Wuhan 430072, China
2. School of Electrical and Automation, Wuhan University, Wuhan 430072, China
3. China Electric Power Research Institute, Haidian District, Beijing 100192, China
4. State Grid Huaining Power Supply Company, Huaining 246121, China
5. Department of Electrical & Computer Engineering, University of Denver, Denver, CO 80208, USA