Study On Distribution Network Reconfiguration With Distributed Generation

With the rising permeability of distributed generation(DG)in distribution network,the structure and operation mode of the distribution network will change,which will affect the power flow distribution and reactive power balance of the original distribution network.The distribution network reconfiguration can find the optimal operation structure by changing the location of the interconnection switch,so as to demand the safe,reliable and economic operation of the distribution network.Therefore,it is of great significance to study the safe,reliable and economic operation of the distribution network with DG through multi-objective reconfiguration.In the thesis,a mesh adaptive direct search(MADS)algorithm for multi-objective reconfiguration of distribution network with DG is proposed.Firstly,in the study on power flow calculation of distribution network with DG,the average voltage fluctuation rate is used as the quantitative index to evaluate the influence of DG access location,capacity and type on voltage.The calculation results show that the influence degree of DG access location and capacity on voltage changes with the change of access location.Secondly,in the study on reconfiguration graph generation and radiation constraint judgment,according to the connection model of IEC 61970,the mapping function is constructed,the simplified rules are generated,so as to obtain the reconfiguration graph.The radiation constraint judgment method based on independent loop is proposed,and it is used in the distribution network reconfiguration based on MADS algorithm,which speeds up the calculation speed and verifies the efficiency.Thirdly,in the study on reconfiguration algorithm,the MADS algorithm.is improved,and the logistic chaos variable is introduced,which makes the step factor of algorithm change in real time,speeds up the efficiency of algorithm iteration in the middle and later stages.Finally,according to UML,the object-oriented model of connection model,reconfiguration graph,and MADS algorithm is carried out.Then,reconfiguration program with C++programming language is written to verify the validity of the design model.Taking 35kV high-voltage distribution as an example,multi-objective reconfiguration is carried out to verify the performance of the reconfiguration algorithm.Compared with the function values under the initial structure,the operation indexes are optimized,and a group of optimal reconfiguration schemes satisfying the constraints can be obtained,which verifies the effectiveness and validity of the improved algorithm.