A Multistep Dynamic Equivalent Method for Urban Power Grid Based on District Dividing

With the increasing demand of electricity, the development of the urban power grid has drawn a lot of attention in China. In order to focus on the analysis of an urban power grid, the remaining part of the large-scale power grid used is to be reduced. The accuracy of the equivalence is key to urban power grid research. In this paper, a multistep dynamic equivalent method based on district dividing is proposed. Based on the electrical distance, voltage level, and geographic location, the external system is divided into outer layer, inner layer, and buffer subsystem. Each district is separately reduced by different methods. The proposed technique is illustrated by a real large-scale power grid in the south of China.