The Study On Island Microgrid System About Operation Strategies And Comprehensive Evaluation

In order to work out the problem about power supply in isolated islands,the paper presents an island microgrid system which includes abundant wind energy,solar photovoltaic energy and seawater resource.Firstly,the paper designs the composition structure of the island microgrid system,which includes an offshore wind farm,a rooftop photovoltaic plant,a seawater pumped storage power station,a micro-gas-turbine station,a storage battery,a load system and a control system.Secondly,the paper does the research on the modeling of the wind farm,the photovoltaic plant,the seawater pumped storage power station,the micro-gas-turbine station and the storage battery of the power system,according to their working principles.Thirdly,the paper presents a three-level operational control system about the island microgrid system,which includes ‘the single strategy’,‘the simple mixed strategy’ and ‘the complex mixed strategy’.In addition,according to the penetration of wind and solar power,the paper designs six kinds of operation strategies and their mathematic models.Fourthly,the daily operating cost,the permeability of renewable energy and the wind and light abandoning ratio are used as multi-objective functions.The system balance and the characteristics of each electrical equipment are the constraint conditions.Utilizing Genetic Algorithm,a model about dispatching optimization of the island microgrid is built.And using Lian Island of Lianyungang City as an example,the paper verifies the feasibility and validity of the optimization model with the help of MATLAB.Lastly,according to economical efficiency,environmental protection property,energy utilization rate and power distribution reliability,the paper presents a comprehensive evaluation index system of operating schemes in the island microgrid,which includes four first-level indexes and twelve second-level indexes.Utilizing Analytic Hierarchy Process and Entropy Weight Method,subjective weights and objective weights are decided.And the paper uses the combined weighting optimization model based on the maximization of variance to decide the optimal combined weight.The paper designs a multi-attribute decision model of island microgrids on the base of set pair analysis.The paper arranges the advantageous and disadvantageous orders of six operating strategies of Lian Island based on the close degree,and the best operating strategy is selected.The research results provide reference and guidance for future wind-light-seawater pumping micro-grid engineering construction in the Lian Island area.