1. Department of Electrical Engineering Theory and New TechnologySchool of Electrical Engineering, Chongqing University Chongqing 400044 China
2. Chongqing Triloop Prospecting Technology Co., Ltd. Tongnan District, Chongqing 400044 China
3. Department of ElectricalComputer Engineering at the University of Tulsa OK 74104 USA
4. Technology DepartmentElectric Power Research Institute of Chongqing Chongqing 400044 China