1. School of Economics and Management, North China Electric Power Univ., Zhu Xin Zhuang, Bei Nong Lu No. 2, Changping District, Beijing 102206, China (corresponding author).
2. Guiyang Power Supply Bureau of Guizhou Power Grid Company, Guiyang 550001, China.
3. Decision and Information Sciences Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439; and School of Economics and Management, Shanghai Univ. of Electric Power, Ping Yang Rd. No. 2103, Yangpu District, Shanghai, China.
4. School of Economics and Management, North China Electric Power Univ., Zhu Xin Zhuang, Bei Nong Lu No. 2, Changping District, Beijing 102206, China.
5. Professor, Dept. of Electronic and Electrical Engineering, Univ. of Bath, Bath BA2 7AY, United Kingdom.