1. School of Electric Power Engineering, South China University of Technology,Guangdong Key Laboratory of Clean Energy Technology,Guangzhou,China,510641
2. School of Electric Power Engineering, South China University of Technology,Guangzhou,China,510641
3. Guangzhou Panyu vocational and technical college,Guangzhou,China,511483
4. Metrology Center Guangdong Power Company Grid,Qingyuan,China,511500