1. Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, Jianghan University, Wuhan 430056, P. R. China
2. State Grid Xinjiang Company Limited Electric Power Research Institute, Xinjiang 830011, P. R. China
3. State Grid Electric Power Research Institute, Wuhan 430074, P. R. China
4. State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China