Reliability Evaluation Of Distribution System Containing Microgrids And Optimal Allocation Of Micro Power Supply

Micro-grid integrates renewable energy and load,which can realize local autonomous operation,promote local consumption of new energy,promote energy conservation and emission reduction,and realize sustainable development of energy.The connection of microgrid to distribution network changes the single attribute of distribution network and makes its reliability evaluation more complicated.In this paper,by establishing the power output model and time series load model of distributed power supply and energy storage devices in micro-grid,the reliability evaluation method of distribution network containing micro-grid is studied and verified in the reliability test system.Then the problems related to the optimal configuration of independent and grid-connected microgrids are studied,and the optimal capacity configuration with different types of power supply is obtained by simulation.In this paper,the wind and photovoltaic power generation system models are established,and the annual time-series load model in hours is established according to the typical load coefficient.This model reaches the peak load in summer and simulates the peak load in China.According to the established microgrid power model and the real-time monte carlo reliability evaluation method,the simulation calculation is carried out on the IEEE-RBTS Bus6-F4 system,and the influence of microgrid access on the distribution network system and load point reliability is analyzed.The research results show that the power supply reliability of the distribution network system has been significantly improved by the access of microgrid,especially for the important loads in the microgrid;The power configuration capacity of microgrid affects the power supply reliability of distribution network.This article researchs the operation strategies of independent and grid-connected microgrids.In the optimization configuration,the micro-power capacity and operation strategy are taken as the optimization variables,and the minimum netpresent value cost is taken as the objective function,and add constraints such as reliability constraints and environmental constraints.In addition,different power supply schemes were set up,and HOMER Pro software was used to simulate and optimize the configuration.The optimal configuration schemes of independent and grid-connected microgrids under different schemes were compared and analyzed.The wind speed and tie line power were set as sensitivity variables,and their influence on the optimal configuration was studied.The calculation results show that: in an independent microgrid system,energy storage combined with renewable energy generation,and configure diesel generator as a backup power supply program,which has the best reliability,economy,and environmental protection;In the grid-connected microgrid,the increase in the interactive power with the large power grid can reduce the system’s net present value cost and electricity cost,but it will reduce the self-balance of the system;In areas with abundant wind and solar resources,building a wind and solar hybrid microgrid can improve the system’s economic and environmentally friendly.