Research On Multi-Objective Optimal Allocation Of Distributed Generation In Distribution Network

With the large-scale utilization of clean energy and the advancement of intelligent distribution network research,more and more distributed generation(DG)is connected to the distribution network.DG has obvious benefits for voltage reliability,but it is influenced by different locations,different capacities and different types.At the same time,the uncertainty of DG output and load demand also brings risks to the network operation.Therefore,how to choose distributed generation reasonably has become a hot research at present.In this thesis,the optimal allocation of DG will be studied in three aspects: the multi-objective optimal allocation of distributed generation,the combinational schemes selection of distributed generation under different load scenarios,and the design of small micro-grid with distributed generation.The thesis explores the influence of node voltage and total network loss under single-point and multi-point access conditions,different location access conditions and different capacity access conditions,and takes the IEEE-33 nodes distribution network as an example,which lays a theoretical foundation for the next research.Considering the decreasing trend of distributed generation subsidy price,the thesis constructs a multi-objective optimization model,which takes the total project profit,total network loss and total node voltage deviation as objective functions.An improved multi-objective Particle Swarm Optimization(MOPSO)algorithm is proposed in this thesis.In the strategy of population updating,self-adaptive speed updating is achieved by comparing the mean size of the population.In the strategy of cross-border processing,the second opportunity of cross-border particle is given.In the strategy of nondominated sorting,considers the influence of surrounding environment.In the strategy of external archives updating,keeps the updating synchronization of archive and population.Taking the IEEE-69 nodes distribution network as an example,the DG optimal configuration model is constructed and solved by using the improved MOPSO algorithm.According to the time series characteristics of wind power output,photovoltaic power output and load demand,a price revenue rule based on real-time absorptive capacity is proposed.In order to solve the evaluation problem of distributed generation combination schemes in different scenarios,a multi-objective decision model with investment cost,electricity price income and loss reduction rate as decision attribute is constructed.In view of the disadvantage that prospect theory can not adequately reflect the quantitative relationship among objectives in multi-objective decision-making,a comprehensive prospect decision-making system is established by incorporating grey correlation coefficient.A practical investment example is given to verify the scientificity and objectivity of the system for multi-objective decision-making with unknown weight.Taking the IEEE-69 nodes distribution network as an example,and the best distributed generation combination scheme under different load scenarios is determined by using the comprehensive prospect evaluation system.The thesis presents a microgrid design idea which aims at minimizing the net present value of system cost.Taking residential and industrial distribution network in a certain area of China as an example,the micro-grid is designed and simulated by using HOMER software,and the optimal configuration results of each component of microgrid and the energy flow in the system are obtained.