Research On Modeland Method Of Microgrid Optimal Scheduling With Multi-distributed Generation

The energy crisis and environmental pollution problems are becoming serious nowadays and the usage of renewable clean energy generation of small power transmission and distribution systems – micro-grid has been widely developed.The optimal scheduling of micro-grid is to solve the economic,environmental and other optimized problems by using the appropriate distributed power supply,a reasonable optimal scheduling strategy and an efficient intelligent algorithm,which can improve economic benefits,reduce environmental pollution problems,and promote sustainable development of society.Therefore,research in micro-grid optimal scheduling is of great significance.The working characteristics of photovoltaic cell,wind turbine,micro turbine,fuel cell and storage battery and corresponding mathematical model of these five generating units were analyzed and established separately in this thesis.Optimized model with the lowest economic cost,least pollution gas treatment cost and optimum comprehensive benefit determined by dualistic factor contrast method were established in this thesis.Constraints of power balance,ramp rate and battery charge state of micro-grid were considered as well then a scheduling strategy with grid-connected and grid-disconnected operation of micro-grid was developed under time-of-use price mechanism with charging and discharging of battery.In view of traditional intelligent algorithm shortcomings and new type of biological heuristic swarm intelligence algorithm-the bird swarm algorithm(BSA)suffers from poor population convergence precision and even trap into local optimized solution due to the early evolution of the population lack of diversity and the changes of the cognitive and group behavior parameters when solving a small number of multi extreme functions.The BSA algorithm is improved and a Levy self-adaptive BSA algorithm(LSABSA)is formed.Ten typical test functions were used to simulate and compare the LSABSA algorithm,particle swarm optimization(PSO)algorithm,improved particle swarm optimization(GPSO)algorithm and BSA algorithm and then the feasibility and superiority of the improved algorithm are verified.Finally,the thesis used a typical day in summer for a micro-grid system including cold and electric loads as an example and it used the established operational strategy and LSABSA algorithm to solve the optimal output of economic,environmental and multi-objective models under grid-connected and grid-disconnected operation of micro-grid.The operating costs and environmental costs of different objective functions for micro-grid under different operation modes,cost details and economic cost of different operational modes under objective function of optimum comprehensive benefits were simulated and calculated,the results verified the feasibility of the improved algorithm and effectiveness of multi-objective optimization and it showed the necessity of renewable clean energy generation use.Meanwhile,it showed that the economic cost of micro-grid grid-disconnected operation is higher than the economic cost of grid-connected operation.