Research On Distribution Network Reconfiguration Combining Fuzzy Membership With Euclidean Distance

With the rapidly consumption of fossil fuels and deteriorate of climate and environment,the scale of new energy access to power system is increasing.Due to the output of the distributed generations(DG)is random and intermittent,may affect the stable operation of power system,therefore,it is necessary to research the distribution network reconfiguration to ensure the safe and reliable operation of the system.Based on system economy,reliability and safety,the multi-objective optimization reconfiguration method of the power distribution network is carried out from the static state and the dynamic aspect.The research content is as follows:(1)According to the graph theory correlation theory,a distribution network topology verification method is analyzed,and a system is subjected to layering processing,layered pre-push and back-generation solving of power flow of system when different types of distributed generations supply access systems are connected is achieved.The 14-node system is taken as an example for analysis and introduction,according to the method,parallel calculation of the same-level voltage and current can be realized,and the calculation efficiency is obviously improved.(2)An efficient method for multi-objective reconfiguration of radial distribution systems based on the membership function of fuzzy set and spatial geometry Euclidean distance is presented.The multi-objective model of distribution network reconfiguration is established from reduce network power loss and improve system static voltage stability these two aspects,get the reconfiguration optimal solution to reduce the power loss,improve the basic line stability and reduce the node voltage deviation at the same time.First of all,the membership function is used to convert multi-objective of different properties and dimensions into single goal satisfaction degree,combining with the Euclidean distance to determine the overall degree of fuzzy satisfaction,the multi-objective optimization problem is transformed into a single-objective nonlinear problem which avoids the inaccuracy of weight selection of traditional multi-objective problem.Secondly,an improved binary particle swarm optimization algorithm with particle position update and adaptive inertia weight is proposed to analyze the reconfiguration result which satisfies the constraints and achieves the comprehensive optimization of the objective function.At last,IEEE33 radial distribution network and the 10 kV distribution network of Taiyuan are taken as examples to verify that the method proposed in this paper is effective and useful.This method can further reduce the active power loss of the system after reconfiguration and effectively improve the voltage level of the whole network.(3)Based on the static reconfiguration,a multi-objective dynamic reconfiguration evaluation method for distribution network is proposed.The optimal dynamic reconfiguration scheme of the distribution network is determined by reducing the frequent operation of the switch and improving the operation economical efficiency of the system as the target.First of all,taking into account the characteristics of load continuously changing with time,BP neural network method is used to predict daily load.Secondly,Based on the proposed multi-objective static reconfiguration method,whether the FP is greater than Fk for the entire period of time to determine whether the reconfiguration is valuable,dynamically division the time interval and searching the optimal network topology which satisfied multiple targets in each subinterval.At last,through the IEEE 33 node distribution system with distributed generations,compare the results of enumerations to verify the efficiency of the proposed method.The dynamic reconfiguration method proposed in this paper can take into account all optimization goals.After the reconfiguration,the system economy,reliability and safety have been greatly improved,and the optimization results are more balanced.(4)Based on the basic theory of static reconfiguration and dynamic reconfiguration,the distribution network optimization reconfiguration software is developed to realize all the computing functions of each subroutine in the reconfiguration.