1. School of Electrical Engineering, Shanghai University of Electric PowerChangyang Road #2588Shanghai200090People's Republic of China
2. State Key Laboratory of Power Systems, Department of Electrical EngineeringTsinghua UniversityBeijing100084People's Republic of China
3. Department of Electrical, Electronic, and Information Engineering, ‘Guglielmo Marconi’University of BolognaViale Risorgimento 2Bologna40136Italy
4. Beijing Area Major Laboratory of High Voltage and Electromagnetic CompatibilityNorth China Electric Power UniversityBeijing102206People's Republic of China
5. ABB Switzerland LtdHigh Voltage ProductsZurichSwitzerland
6. Electrical Insulation Research Center, Institute of Materials Science, Electrical and Computer Engineering, University of ConnecticutStorrsCT06269USA
7. Kyushu Institute of TechnologyKitakyushuJapan