1. State Key Laboratory of Reliability and Intelligence of Electrical EquipmentHebei University of Technology No. 8, Guang Rong Street, HongQiao District Tianjin 300130 China
2. Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei ProvinceHebei University of Technology No. 8, Guang Rong Street, Hong Qiao District Tianjin 300130 China
3. State Grid Jibei Electric Power Co., Ltd.Zhangjiakou Power Supply Company No. 131, Wuyi Road, Qiaodong District Zhangjiakou City Hebei Province 075001 China