Distributed Generation Planning In Distribution Network Considering Uncertainties

Distribution networks can be divided into two categories according to whether the active management measures are used or not during the operation.One is the traditional distribution network(TDN),in which the active management measures are not considered.Another one is the active distribution network(ADN),in which the active management measures are used.With the integrating of wind turbine generator,photovoltaic generator and other intermittent distributed generation(DG),more and more uncertainties are arising in distribution network.The increasing of uncertainties will affect the index of distribution network,and the influence is closely related to the location and size of DG.This dissertation concentrates on the DG planning methodologies in distribution network considering uncertainties,and the main achievements are as follows:(1)A single-objective DG planning method in TDN considering correlations among the uncertainties(wind speed,illumination intensity and load)is proposed.Based on the chance constrained programming,a single-objective model for the optimal planning of DG in TDN is established,which can take into account correlations among the uncertainties.The objective function of the model is to minimize the annual comprehensive cost,and the constraints are the correlation restrictions,the DG investment restrictions and the electrical restrictions.The model is solved by a probabilistic power flow-based stochastic optimization method.The effects of correlations among the wind speed,illumination intensity and load on the results are studied.(2)A novel methodology for the multi-objective DG planning in TDN considering correlations among the uncertainties(wind speed,illumination intensity and load)is proposed.To minimize the annual comprehensive cost and system risk,a multi-objective DG planning model considering correlations based on the chance constrained programming is established.The model is solved by a probabilistic power flow-based multi-objective optimization method and the Pareto optimal solution sets are obtained for policy-maker to choose.The DG planning scheme can meet the load growth and risk control.(3)A methodology for the evaluation of available load supply capability in TDN considering uncertainties is proposed.A series of meaningful indices for the probabilistic evaluation of available load supply capability are defined,and they are used to evaluate the DG planning scheme in TDN.By calculating the probabilistic indices of available load supply capability,the technical adaptability of DG planning scheme for future load growth can be understood.The evaluation method can take into account the uncertainties and correlations.(4)A single-stage DG planning method in ADN considering demand side management and network reconfiguration is proposed.The uncertainties are handled by multi-scenario technology.On this basis,a novel DG planning model in ADN is established,whose objective function is to minimize the annual comprehensive cost,and the constraints contain active management measures,DG investment restrictions and various electrical restrictions.The model is converted to a multi-tier programming model according to the idea of decomposition and coordination,and the optimal DG planning scheme is obtained by a hybrid solving strategy.This planning methodology can fully simulate the operation of ADN in the planning stage.The effects of the unit cost of demand side management and network reconfiguration on the planning results are studied.(5)A novel multi-stage DG planning method in ADN considering demand side management and network reconfiguration is proposed.To meet the growing load in different planning stages,a multi-stage DG planning model in ADN with the objective function of minimizing the annual comprehensive cost during the planning period is established by multi-scenario technology.The constraints of the model not only contain active management measures,DG investment restrictions and various electrical restrictions,but also the relationship of DG installation in different stages.(6)A methodology for the evaluation of available load supply capability in ADN is proposed.The available load supply capability of ADN considering uncertainties is defined.On this basis,the evaluation model of available load supply capability in ADN considering the active management measures is established,which can be applied to evaluate the DG planning scheme in ADN.By evaluating the available load supply capability in ADN,the technical adaptability of DG planning scheme for future load growth can be understood.The effects of different combinations of active management measures on the evaluation results are studied.Case studies are carried out on a typical 33-bus distribution network and a practical 61-bus distribution network,and the results verify the feasibility and effectiveness of the proposed method.