Research On Optimal Scheduling Strategy Of Generalized Power Sources In Active Distribution Network

With a large number of Generalized Power Sources(GPS)connected to the power grid,the operation mode,management mode and control mode of traditional distribution network have been changed greatly.The traditional distribution network is gradually transited to Active Distribution Network(ADN).The existing optimal dispatching strategy of distribution network is no longer suitable for ADN,so the research on ADN optimal scheduling strategy is extremely important.Firstly in this thesis,the internal mechanism of GPS is analyzed in detail,and the mathematical model of active power output of GPS is established including the active power model of controllable Distributed Generation(DG),the interaction criterion of Micro-grid(MG)and ADN,and the active power model of Energy Storage System(ESS).Then,the basic principles and implementation steps of the general Firefly Algorithm(FA)adopted in the follow-up optimization scheduling strategy are introduced in detail,and the defects of the general FA are improved by using the advantages of chaotic mapping,therefore the improved Chaos Firefly Algorithm(CFA)is formed.On the basis above,the fundmental idea of solving problem is proposed,that is,the Analytic Hierarchy Process(AHP)is combined with Entropy Method(EM)to determine the weight of each objective function in the multi-objective function,and the solution of multi-objective function problem is transformed into single objective function problem.After that,aiming at the optimal scheduling problem of ADN,a multi-objective optimal scheduling model is built with the minimum of the system active network loss and the node voltage deviation as the objective function along with the active output of the controllable DG and the active output of MG as the control variables.Similarly,another multi-objective optimal scheduling model is established with the minimum of the system active network loss and the mean variance of the load curve as the objective function,and along with the active output of the controllable DG and the active output of ESS as the control variables.So the CFA is used to solve the above models.Finally,in order to prove the feasibility and rationality of the proposed algorithm and the two optimal scheduling models,one example of IEEE 33-node system with a GPS access in and another example of practical ADN are verified.The results show that,with the combination of AHP and EM,the weight coefficients of the sub-target functions in the multi-objective function are reasonably determined in the process of converting the two multi-objective functions into a single objective function on the basis of combining the two factors of subjectivity and objectivity,and the optimal scheduling strategy is obtained by using the CFA to solve the two models,the optimal output plan of each schedulable unit in the complete scheduling period is given.