Research On Optimal Scheduling Of Ac/dc Hybrid Active Distribution Network

Under the new energy situation,the healthy development of distributed power generation is increasingly valued by governments of various countries.The way in which distributed generation(DG)is connected to the distribution network is also increasingly concerned by many scholars.In order to cope with the current socio-economic and environmental protection development background,adapt to the future AC-DC hybrid distribution network structure of the distribution network,realize the transformation and upgrade of the distribution structure,improve the stability and efficiency of the access system,and improve the distributed power Permeability,hybrid AC / DC topology,power flow optimization,and economic dispatching have become important research topics in active distribution networks under the new energy situation.The access of distributed power makes the distribution network have active attributes.The AC and DC hybrid distribution network has gradually become a development trend due to its high efficiency in accepting DC source load,high reliability and high quality power supply.This is particularly important under the current microgrid development model.This article first introduces the basic concepts,operating characteristics,and research status of domestic and foreign research on distributed generation and AC-DC hybrid active power distribution networks.It describes the integration of distributed power into AC power distribution networks,DC power distribution networks,and AC power distribution networks.The impact of the topology of the DC hybrid distribution network,the current status of domestic and foreign research,and the development of distributed power sources after the grid connection on the entire distribution system.Then model the AC/DC hybrid power distribution system with distributed power.The three topologies of the AC/DC hybrid power distribution network are introduced.Studied the model of distributed power,The main component models are modeled,and three-phase models including transformers and loads are established,and the grid-connected control methods of AC-DC converters and DC-DC converters included in the DC distribution network are explained.The power flow calculation of AC/DC hybrid power distribution network based on power supply has laid the foundation.Based on the AC-DC hybrid power distribution model,the power flow calculation of the power distribution system with distributed power is described.The power flow calculation of the AC power distribution network is explained.Two power flow calculation methods of the AC power distribution network are introduced: Newton-Raphson method and forward pushback.Power generation method;then carry out power flow calculation of AC/DC hybrid distribution network,mainly elaborate on two typical power flow calculation methods,alternating iteration method and unified iteration method,and finally use the above power flow for AC/DC hybrid power distribution network with distributed power Computational tests were performed to verify that the power flow calculation can reach the convergence result,which can be applied to the power flow calculation of AC/DC hybrid active power distribution network.Finally,the optimal scheduling of AC/DC hybrid active distribution network is studied.Based on the above-mentioned AC/DC hybrid distribution network model and the application of power flow calculation,an AC/DC hybrid active power distribution based on mixed integer second-order cone programming is established.The network active-reactive multi-period collaborative optimization model considers multiple active control variables,and uses the second-order cone relaxation method to transform the mixed integer nonconvex nonlinear problem into a convex programming problem.The Cplex algorithm is used to obtain the optimal solution of the model and solve the voltage.The problem of over-limit is realized,and the power is quickly compensated.The validity of the proposed model is verified by the test results of the node system.