1. School of Electrical and Electronic EngineeringNorth China Electric Power UniversityChangping DistrictBeijing102206People's Republic of China
2. Bradley Department of Electrical and Computer EngineeringVirginia Polytechnic Institute and State UniversityBlacksburgVAUSA
3. Condition Based Maintenance DepartmentChina Electric Power Research InstituteHaidian DistrictBeijing100192People's Republic of China