Global Energy Interconnection Development and Cooperation Organization Xicheng District Beijing 100031 P. R. China;
ABB (China) Ltd. Beijing Eco. & Tech. Development Area Beijing 100176 P. R. China;
State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi Province P. R. China;
State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi Province P. R. China;
The University of Melbourne Parkville Victoria 3010 Australia;