?-NSGA-? Based Many-objective Optimal Power Flow For Power System And Its Decision Support

Multi-objective optimal power flow(MOPF)has received more and more attention in the research of power system optimization operation.At present,most studies on MOPF have only considered two or three objective functions,such as total fuel cost,total emissions and active power loss.However,people rely more and more on electricity,and it is necessary for power companies to consider more optimization objectives in power system operation optimization with people's increasing demands on power quality and the development of power system.Thus,the MOPF problem gradually evolves into a many-objective optimal power flow(Ma-OPF,the objective function is usually more than three)problem.Focusing on the related problems of Ma-OPF and its decision support,this paper carries out research work,and the main contents are as follows:Firstly,this paper expands the MOPF problem to form Ma-OPF problem with consideration of minimizing five objective functions including the total fuel cost(TFC),total emissions(TE),voltage magnitude deviation(VMD),active power loss(APL)and Line-index(L-index).Furthermore,combined with NSGA-? which is designed for many-objective optimization problem,an improved NSGA-? is proposed to solve the established Ma-OPF problem.I-NSGA-? employs elimination mechanism to the reduce selection efforts in environment selection operation.An adaptive elimination strategy and a boundary and closer point preservation strategy are also introduced in ?-NSGA-? to obtain population diversity.The proposed?-NSGA-? and NSGA-? are compared and tested on IEEE 30/57/118 bus test systems with different cases and the experimental results demonstrate the competitiveness and effectiveness of proposed algorithm.Secondly,large-scale power systems generally adopt the mode of partition management.In this paper,a Ma-OPF method based on distributed power flow calculation(DPFC)is proposed for partitioned systems.DPFC is realized first.A simple model of DPFC is proposed based on node tearing and line disconnection.The DPFC is transformed into an optimization problem by taking the boundary node voltages of the network partition as decision variables and the boundary nodes power balance as objective function,and solved by pattern search method.And then,the Ma-OPF of partitioned system is realized based on DPLC and ?-NSGA-?.Multiple simulation cases based on IEEE 30/3 9/118 systems and actual power grid of Guizhou province verify the effectiveness of DPFC and DPFC based Ma-OPF method.Finally,in view of the fact that the actual power dispatch must be a certain solution,this paper takes the Pareto solution set of Ma-OPF problem as alternative scheme set,and takes multiple optimization objectives as multiple attributes to propose the multi-attribute group decision-making problem of power system.Three group decision making methods including 0-1 programming decision,grouping decision and clustering decision are proposed,based on the TOPSIS method and the Cook-Seiford social selection function.The comparison with the expert ranking results shows that the results of the proposed decision methods are reasonable.What's more,a many-objective optimization and decision-making support system of power system is established,based on MATLAB platform,which completes the optimization and decision support integration process,and realizes human-computer interaction.