Improved Whale Algorithm For Solving Microgrid Operation Planning Problem

As energy demand grows and environmental concerns arise,the global focus on renewable energy is increasing.The continuous development of renewable energy sources,coupled with the maturity and decreasing cost of distributed energy generation technologies,has promoted the development of microgrids.A mini-grid system,a microgrid,is composed of multiple energy devices and energy storage devices that can be independently operated,connected unidirectionally,or connected to the main grid.This provides a dependable,secure,economical,and environmentally-friendly energy supply to a small community,building,or business.Microgrids have become an important means to solve energy supply problems,improve energy efficiency and promote energy transition.The key to guaranteeing the secure and effective output of every distributed energy source within the microgrid and the dependable running of the power system is the planning of the microgrid’s operation.This thesis focuses on the operational planning problems of microgrids in two modes of grid-connected operation and off-grid operation and the solution methods to solve the related problems.The main work is as follows.(1)A mathematical model of each distributed energy generation is formulated,taking into account the operational properties of wind,photovoltaic,battery bank,diesel,and fuel cell sources within the microgrid.Considering the differences in climatic environment throughout the year,the wind power,light radiation and load level vary in different degrees in each season,this thesis analyzes the differences in microgrid operation in four seasons with typical days in spring,summer,autumn and winter as representatives.(2)The operation planning problem of microgrid is a multivariate and multiconstrained complex nonlinear optimization problem,and the traditional optimization methods are not effective in the optimization process due to the influence brought by complex calculations.Therefore,the use of metaheuristic algorithms to solve complex nonlinear optimization problems can effectively improve the solution accuracy,such as the whale algorithm.The whale algorithm’s global search prowess,rapid convergence and immunity to initial parameters render it an ideal choice for tackling highdimensional problems.This thesis proposes an enhanced whale algorithm,based on the original one,with adaptive inertia weights and Levy flight trajectory,to augment its global search capability and precision of solutions.Additionally,a comparison experiment is designed to assess the efficacy of the upgraded whale algorithm.(3)The sum of operation and maintenance cost of each generation equipment,fuel use cost,interaction cost between microgrid and main grid,and pollutant emission cost in microgrid is the integrated operation cost,and the optimization objective is to minimize the integrated operation cost under the system operation constraint and equipment operation constraint,and the operation planning model of grid-connected and off-grid microgrid is established.By example simulation,the improved whale algorithm solves the model,yielding the results of grid-connected and off-grid microgrid operation planning for four seasons.