1. Department of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin, China
2. Key Laboratory of Smart Grid of Ministry of Education and the Key Laboratory of Smart Energy and Information Technology of Tianjin Municipality, Tianjin University, Tianjin, China
3. Center of Electric Power and Energy, Technical University of Denmark, Kongens Lyngby, Denmark
4. Department of Energy Technology, Aalborg University, Aalborg, Denmark