[1] North China Elect Power Univ, State Key Lab Alternate Elect Power Syst Renewabl, Beijing 102206, Peoples R China
[2] Tsinghua Univ, State Key Lab Power Syst, Dept Elect Engn, Beijing 100084, Peoples R China
[3] Univ Sydney, Sch Elect & Informat Engn, Sydney, NSW 2006, Australia