1. Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen 518060, China
2. College of Information Engineering, Shenzhen University, Shenzhen 518060, China
3. State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049, China
4. Northwest China Grid Co. Ltd., Xi’an 710048, China