The Planning Research Of Distributed Generation In Active Distribution Network

While the country takes more intention to the smart grid construction and the technology of energy saving and emission reduction,the distributed generation(DG)is getting more brand-new and vast development space.However,because of the large-scale connection of DG,distribution network changes from traditional passive mode of one-way power transmission to active distribution network of two-way transmission,which indicates that the DG connection will have a significant impact on the traditional power system.Under the comprehensive consideration of active management pattern of ADN,it is important to achieve an optimal allocation of DG in ADN with active management measures and improve the DG's initiative in the power operation,which has certain theoretical guidance meaning and engineering application value.Main contributions of this thesis ate listed as follows:Above all,the definition,classification and the grid-connected types of several typical DG are introduced and each types are unified by mathematical formula,which simplifies subsequent power flow calculation.Taking IEEE-33 node system as example,based on the simulation results of different DG grid-connected situations,the influence of DG connection on the node voltage and line loss is compared and analyzed.Then,according to the features and key technologies of ADN,the active management mode is proposed that control the tap of on load tap changer,control the active output of DG and the connection of reactive-load compensation equipment.Based on that,an objective function is set up to analyze the DG absorptive capability in each single node,to ensure that the large-scale DG connection will not affect the stability and security of distribution network.In order to enhance the comprehensiveness of DG configuration,the time series characteristic of some typical load and DG in different weather scenes are considered,while one day is divided into 24 parts,and a bi-level optimization model is established containing the DG environmental benefit index,in which the objective of upper-level model is to minimize the comprehensive cost of DG in a year,while the objective of lower-level model is to maximize the system voltage quality.The comprehensive cost of DG includes the DG investment cost,system carbon emission cost and so on,which turns the DG configuration issue into a single-objective programming problem with equality and inequality constraints.Aiming at the characteristics of bi-level model and the defect of shuffle frog leaping algorithm(SFLA)that it is easy to encounter local optimization and its search speed is slow,an improved frog leaping algorithm is applied to problem solving,which is integrated with the ides of genetic algorithm,overcoming the premature convergence.Finally,taking IEEE-33 node system as example,the optimal configuration scheme is obtained by simulation,based on the idea of control variable method,the specific indexes are compared with other schemes to verify the feasibility and superiority of proposed model and algorithm.