Study On Automatic N-1 Verification For Urban Distribution Network Planning

With the rapid development of national economy, the research on urban power system planning is attracting more and more attention in order to meet the rapidly increasing demand on electric power. Aiming to the characteristics of city electric network, the requirement about higher reliability, security and economy of distribution system is getting more and more intensive. According to the requirement of "Planning and Designing Guideline for Urban Power Network", the N-1 verification on distribution network planning gets more and more attention. For a long time, most of the studies for N-1 verification are focused on the safety analysis of the power system. Although some quantity standards have been presented, these standards have not been applied to practical planning engineering due to the complex structure of distribution network.This paper has launched a study on the application of N-1 theory on different situation and equipment based on fundamental theory of N-1 verification and the method of depth and breadth-first local topology, and launched the principle of finding the load transfer path is based on the minimum switching operation. Power flow calculation is used to verify whether equipment has case of overload or voltage off-limit. Improvement and complement have been made on the method of N-1 verification of planning of distribution network, and it also offers different N-1 verification methods on high-voltage and medium-voltage distribution network.The model in this paper has been programmed. Under the software platform of"computer-aided decision-making system for urban power network", the visual user interface has been designed and the program usability has also been verified via calculation samples.