Research on the structure of urban power network based on long-term planning of EHV network

In the procedure of urban electric network planning, many problems should be considered, such as how to adapt to the future load growth in the city, how to ensure coordinational development with future planning of higher voltage network, how to keep the N-1 structure of the lower voltage network as possible in the process of breaking up electromagnetic ring, and how to avoid the waste of huge investments due to breaking up electromagnetic ring and so on. The paper proposed the guiding ideology of planning urban electric network structure and corresponding technical principle: during the development of urban power network, the prospective planning of the higher voltage network should be considered and the timing and location to break up the electromagnetic ring should be reasonably determined; after breaking up the electromagnetic ring, the target network structure should keep the small ring structure as much as possible instead of the radial structure with power supply by single circuit. The guiding ideology of urban electric network planning and corresponding technical principle proposed in the paper were validated by a real case.