1. School of Electrical Engineering; Guangxi University; Nanning 530004 Guangxi Zhuang Autonomous Region China
2. Electric Power Research Institute; Guangxi Power Grid Corporation; Nanning 530023 Guangxi Zhuang Autonomous Region China
3. Nanning Power Supply Bureau; Guangxi Power Grid Corporation; Nanning 530031 Guangxi Zhuang Autonomous Region China