[1] Digital Grid Research Inst China Southern Power Gr, Guangzhou 510700, Peoples R China
[2] South China Univ Technol, Guangdong Key Lab Clean Energy Technol, Guangzhou 510630, Peoples R China
[3] Guangdong Univ Technol, Sch Automat, Dept Elect Engn, Guangzhou 511400, Peoples R China