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Research On Robust State Estimation Of Active Distribution Network

Posted on:2020-10-20Degree:MasterType:Thesis
Country:ChinaCandidate:P HuangFull Text:PDF
GTID:2392330578455048Subject:Control engineering
Abstract/Summary:PDF Full Text Request
With the rapid development of new energy sources such as wind energy and solar energy,more and more distributed generation(DG)is integrated into the distribution network,which makes the traditional distribution network gradually supply power from one-way radial structure to multiple power sources of Active Distribution Networks(ADN)development.Compared with the traditional distribution network,with the increase of DG and the higher the power load,the active distribution network is particularly complicated in coordination optimization and active control management.The active power distribution system can regulate and optimize the distributed power supply and make rational use of existing resources.The network is balanced to maximize energy utilization,enabling the grid to operate stably at an efficient,reliable,and safe level.At the same time,a large amount of information data needs to be monitored and identified to ensure information reliability.Due to the uncertainty caused by DG output,data loss caused by communication equipment,etc.,it may bring bad influence to the dispatch center.State estimation can make full use of existing data under the conditions of the system to estimate the actual operating state of the system.In ADN,more and more information data needs to be processed.Therefore,in order to enable ADN to achieve optimal control and ensure the reliability of measurement information,it is practical to study the state estimation method suitable for active distribution network.In this paper,the robust state estimation of the active distribution network with distributed photovoltaic system is taken as the main research content,and the research work is carried out from the aspects of state estimation basic algorithm,photovoltaic cell model and photovoltaic system grid-connected estimation model.Firstly,it introduces the status of state estimation research at home and abroad,establishes the research objectives of this paper,and expounds the significance and application of the research.Secondly,it introduces the active power distribution system,analyzes the structural characteristics and key technologies of the active power distribution system;summarizes the basic algorithm of state estimation.The mathematical model of state estimation measurement is analyzed,and the state estimator based on Weighted Least Squares(WLS)and Weighted Least Absolute Value(WLAV)is introduced,and the measurement based on the node voltage method is derived.The mathematical expression of the function and the Jacobian matrix element describes the solution steps and flow of WLAV.Thirdly,analyze the working principle of photovoltaic cells,select the photovoltaic cell model and the state variables that can characterize the photovoltaic cells;build a two-stage photovoltaic grid-connected model,select the state variables in the photovoltaic grid-connected model,and use the WLAV state estimation method for small-capacity photovoltaics.The grid-connected model was used for simulation experiments.The simulation results show that the proposed method can estimate the state of the built-in grid-connected model and has certain resistance.Finally,the PV model is connected to the IEEE33 node power distribution system,and the WLAV estimator is used to estimate the active distribution network containing the PV system.The simulation results show that the proposed model can be used to estimate the actual running state by the WLAV estimator,and in the case of bad data,the algorithm can resist the influence of bad data and estimate the system state closer to the actual.It verifies the applicability of the algorithm and lays a foundation for future research.
Keywords/Search Tags:Active Distribution Network, Photovoltaic System, Robust State Estimation, WLS, WLAV
PDF Full Text Request
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