1. Power Equipment School of Electrical Engineering, Xi'an Jiaotong University,State Key Laboratory of Electrical Insulation,Xi'an,China
2. Shandong Electric Power Dispatching and Control Center State Grid Shandong Electric Power Company,Jinan,China
3. Power Grid Technology Center State Grid Shandong Electric Power Research Institute,Jinan,China
4. State Grid Shandong Electric Power Company,Jinan,China