Research on Optimal Planning of Distribution Network with Multi-microgrids Based on the Improved Minimum Spanning Tree Algorithm

Aiming at the planning problem caused by microgrid access to the distribution network, an optimization planning method for a distribution network integrated with microgrids based on an improved minimum spanning tree (MST) algorithm is proposed to improve the reliability and economy of the distribution network. Firstly, we analyzed the microgrid's internal characteristics, and the microgrid's external equivalent model was obtained. Based on this, the substation location and load zoning problem in the planning stage I is optimally solved based on the minimum load moment principle. In planning stage II, a multi-objective grid planning model is developed on the basis of the first stage, taking into account the economy and power supply reliability. The model is optimally solved based on the improved MST algorithm. The results of the distribution network planning without and with microgrids are compared, and the impact of the inclusion of microgrids on the line investment, network losses, and supply reliability of the distribution network is analyzed. The example analysis results indicate that the inclusion of microgrids can effectively reduce the substation's construction investment, improve the substation's power supply level, and improve the economy and reliability of the grid planning scheme. It provides a reference value for subsequent planners to do proper planning.