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Reconfiguration Of Distribution Network Considering DG With Time-varying Output

Posted on:2018-04-01Degree:MasterType:Thesis
Country:ChinaCandidate:L ZhangFull Text:PDF
GTID:2322330515969801Subject:Power system and its automation
Abstract/Summary:PDF Full Text Request
Distribution network reconfiguration is an effective method to optimize the operation mode of distribution network,which can change the structure of distribution network by changing the states of the switches in the network to achieve the goal of reducing the network loss and improving the quality of power supply.With the development of distribution automation and the rapid growth of distributed generation(DG)in distribution network,the requirement of distribution network reconfiguration is higher and higher.In the actual system,load and distributed generation output both have the characteristics of time varying.Only static reconstruction of a system at a certain moment can not solve the problems encountered in practice.Therefore,the dynamic reconfiguration of distribution network based on the temporal variation of system data is also studied in this dissertation.The difference between static reconfiguration and dynamic reconfiguration of distribution network is that static reconfiguration is based on one moment,while dynamic reconfiguration is based on a time period.Consequently,the dynamic reconfiguration can be equivalent to a number of static reconfiguration problems with switching constraints.At the aspect of static reconstruction,improved Particle Swarm Optimization algorithm is proposed in this dissertation.The model for static reconfiguration is build at first.Then,the improved particle swarm optimization algorithm is proposed and test,which uses the inertia weight of the nonlinear change and the learning factor of the asymmetric asynchronous change,also using the Gauss white noise to creat twice disturbance variation.Concerning the huge number of infeasible solutions in the reconfiguration of distribution network,a decimal coding based on the position of the loop matrix and strategies repairing and punishing the restricted particle are presented.Through two examples,the feasibility and effectiveness of the proposed method are verified,and the influence of reconfiguration and distributed power supply on distribution network is analyzed.Then,on the basis of static reconfiguration,a dynamic reconfiguration method based on Fisher optimal partion method is proposed.The model of dynamic reconfiguration is established.Based on the characteristics of the temporal variation of the system data,the Fisher optimal partion method is used to segment the time period.The static reconfiguration is carried out in each load center.If the number of switching times goes beyond the limit,the optimal number of segments will minus 1,and then the segmentation and reconfiguration will be carried out again.This method does not need to set the threshold value of time merging or the number of segments in advance.The simulation results show that the proposed method can effectively reduce the number of reconfiguration and limit the number of switching times in the allowable number of times.And in the segmentation of the system's multidimensional load,a method for obtaining approximate load curve is provided,which is to use principal component analysis method to fit the load curve,and is verified by calculating the segment loss function changes.
Keywords/Search Tags:distributed generation, static reconfiguration of distribution network, improved particle swarm optimization, dynamic reconfiguration of distribution network, Fisher optimal partition method
PDF Full Text Request
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