1. Institute of Electricity Science and Technology of Guizhou Power Grid Co. 1 , Guiyang 550000, China
2. Guizhou Power Grid Company Limited, Xingyi Power Supply Bureau 2 , Xingyi 562400, China
3. Guizhou Power Grid Company Limited, Liupanshui Power Supply Bureau 3 , Liupanshui 553000, China
4. School of Electrical Engineering, Chongqing University 4 , Chongqing 400044, China
5. School of Materials Science and Engineering, Chongqing University 5 , Chongqing 400044, China