1. New Energy (Photovoltaic) Industry Research Center, Qinghai University, Xining 810016, China
2. School of Electrical and Automation, Wuhan University, Wuhan 430072, China
3. Electrical Department at College of Engineering in Wadi Al-Dawasir, Prince Sattam Bin Abdulaziz University, Wadi Al-Dawasir 11991, Saudi Arabia
4. Power Dispatch and Control Center, Guangxi Electric Power Company, Nanning 530013, China