Reconfiguration Of Distribution Network With The Distributed Generation

Nowadays,the energy crisis and environmental problems are becoming more and more prominent.Thus as the representative of clean pollution-free energy,the development of DG has made remarkable achievements.Meanwhile,the proportion of the DG in distribution network is also growing.Although the DG could bring about much positive influence on the distribution network,the highly penetration rate of the DG in network will also introduce much negative influence at the same time.The distribution network reconfiguration can decrease the network power loss,improve the voltage quality,balance the network load and improve the network reliability.Thus the negative influence of the DG on network will be decreased greatly.Therefore,a thorough study of the distribution network reconfiguration considering the DG can improve the safety and reliability of the distribution network operation.According to the analysis of wind power generation and photovoltaic power generation,the mathematical models based on their characteristics can be established.And the PV nodes and PI nodes can be obtained by translation.Then the network's power flow can be calculated by applying the forward-backward sweep method considering the DG.Finally,through the simulation calculation of IEEE-33 node distribution network,the effects of distributed generation's number and location on the distribution network can be obtained.In this thesis,a mathematical model is established,taking the minimum operation cost and node voltage deviation as the objective function.The system index is proposed and processed,thus the evaluation index sequence can be formatted.Then the standard deviation is introduced to classify the reconfiguration time interval.Finally,by analyzing the harmony search algorithm's advantages and disadvantages,the harmony annealing algorithm is proposed to reconstruct the distribution network combining the simulated annealing algorithm and the harmony search algorithm's strong global search ability.The decimal coding scheme is applied in this thesis,whose superiority is demonstrated comparing with the binary coding scheme by the IEEE-16 nodes distribution network.Then the limit and the generalized branch is introduced to repair a large number of infeasible solution in the network reconfiguration,so the search scope of feasible solution will be reduced and the search efficiency of algorithm will be improved.Then several examples are taken to demonstrate the feasibility of the method and algorithm proposed in this thesis.The following three aspects are mainly considered when progressing the dynamic reconfiguration simulation.The first one is the static reconfiguration with the DG.The second one is the network dynamic reconfiguration without the DG.The last one is network dynamic reconfiguration with the DG.Meanwhile,other methods and algorithm are also introduced to compare with the method and algorithm proposed in the thesis,so as to verify the superiority of method and algorithm proposed in this thesis.