1. College of Electrical and Information Engineering, Hunan UniversityChangsha410082People's Republic of China
2. College of Electronic and Information Engineering, Yili Normal UniversityYili835000People's Republic of China
3. School of Automation, Guangdong University of TechnologyGuangzhou510012People's Republic of China
4. Equipment Condition Assessment CenterHunan Electric Power Research InstituteChangsha410000People's Republic of China