Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education，Shandong University，Jinan250061，China

The1000kV/500kV electromagnetic loop or1000kV/500kV/220kV electromagnetic loop may appear in Chinese power grid.A new method for electromagnetic loop partitioning based on quantitative analysis of network community structure characteristics is presented.According to the distribution of center substations and the topology structure of the network，several parts are separated from the low voltage level network in the operational mode of electromagnetic loop using GN dividing algorithm.The partition scheme set is formed in accordance with the sequence that every part separated from the network in the dividing process.And the modularity index of community structure is employed to evaluate the quality of the dividing results.Case studies demonstrate that the proposed method can effectively reflect the community structural characteristics and provides theoretical bases for electromagnetic loop partitioning.