1. Economy & Technology Research Institute, Gansu Electric Power Corporation , Lanzhou 730050 , China
2. China Aero Geophysical Survey and Remote Sensing Center for Natural Resources, China Geological Survey , Beijing 100101 , China
3. Anhui Nanrui Jiyuan Electricity Grid Technical Co. Ltd, State Grid , Hefei 230088 , China
4. Hangzhou Power Supply Company, State Grid , HangZhou 310000 , China