Research On Methodologies Of Planning And Operation Of Microgrids Under Uncertainty

Faced with increasingly severe energy,environment and climate issues,almost all the countries have reached a consensus on developing renewable energy.As a powerful approach to efficient utilization of distributed renewable energy sources,microgrids have been getting good opportunities for development.However,microgrids are exposed to a large number of uncertainties which significantly challenge them as well.This thesis focuses on planning and operation of microgrids under uncertainty.The main work is listed as follows:1)A two-stage robust planning method is proposed for a grid-connected photovoltaic battery microgrid,which considers the uncertainties of load demand growth and battery cost reduction.Firstly,to realize the flexible configuration of battery energy storage system within the planning period,a deterministic planning model is established integrating all the periods of microgrid operation.Then the robust counterpart of the deterministic model is built based on robust optimization theory and linear modeling methods and the corresponding solving algorithm is also presented.In the end,the effectiveness of the proposed method in determining the timing of energy storage investment and quantifying the impact of the uncertainties on microgrid configurations has been verified through an example analysis.2)A multi-state planning modeling method is proposed for a stand-alone microgrid,which takes into consideration the uncertainties of renewable energy and load as well as the equipment reliability.The change patterns of renewable energy sources and load demands and their correlation are analyzed by means of clustering techniques.Then a multi-state model is established to describe the uncertainties of resources and load based on the probability distribution estimation and discretization of the clusters.On this basis,a multi-state analytical model of energy storage considering the equipment failure rate is presented and further integrated with an optimal planning model with economic goals,which provides a convenient way to formulate a microgrid configuration with better performances in both economy and reliability aspects.3)Considering the day-ahead forecast uncertainties of renewable energy sources and load demands,an optimal scheduling strategy is proposed for a cooling and power integrated microgrid.Based on actual engineering backgrounds,the operation model of the integrated microgrid is established,which can reflect the actual working conditions.A two-stage robust model for optimal operation of the microgrid is further built to consider the day-ahead forecast uncertainties,and the introduction of budget of uncertainty provides a flexible way to adjust the robustness of the day-ahead operation plan.Compared with the deterministic optimal operation strategy,the proposed method can obtain better economic performance.In comparison with the model predictive control strategy,similar economic performance can be obtained by a single optimization operation using the proposed method.