Optimal Time Division Reconfiguration Of Distribution Network With Distributed Generation

In recent years,with the rapid development of new energy and electric vehicles,the requirements for construction planning,and operation management of distribution network have also been gradually improved,whereas,the traditional distribution network has failed to adapt to the situation of large number of distributed generators.The distributed power supply and the power grid supply alternate each other,which can effectively minimize the impact of the power grid accident on the user.A large number of distributed power can reduce the operation cost of distribution network,improve the efficiency of power transmission,and bring energy saving benefits.The multi power supply cooperative power supply scheme can effectively solve the problems of insufficient power transmission and distribution capacity in regional power grid and so on,and ensure the reliable operation of the power grid.However,due to the fluctuation of the output power of distributed generation and the incompatible operation with the load of distribution network,the voltage fluctuation and flicker of the grid will be caused.Through the close / open distribution network switch and section switch to adjust the topology structure,can improve the voltage level of the node,reduce the power loss of the network,to prevent overload and improve the distribution network on distributed power consumptive capacity under certain security constraints.Therefore,it is of theoretical and practical significance to study the dynamic reconfiguration of distribution network.On the basis of the analysis of network topology,this paper briefly introduces several mainstream methods of power flow calculation,such as the bull pull method,the Zbus method and the forward back generation method.The processing methods of different types of DG grid connected nodes are analyzed,the forward and backward generation method based on node layering is chosen as the calculation method in this paper.Finally,an example is given to verify the practicability of the forward back generation algorithm based on node stratification in the distribution network with distributed power.Taking the IEEE33 node system as an example,the effects of different types of DG grid connected to the system voltage level and network active loss are analyzed.When determining the type of DG grid node,comparing the voltage quality and the network active loss in different injection capacity and access position,which can provide the reasonable layout of the distributed power supply.Aiming at the limitation of binary particle swarm optimization in the application of distribution network reconfiguration,an improved adaptive BPSO algorithm is proposed.The BPSO algorithm is used to verify the IEEE33 and IEEE69 node systems.By comparing the network loss and node voltage trend before and after reconstruction,the superiority of the BPSO algorithm is verified.With regard to the decrease of network loss caused by switching operations is relatively small,the switching mode of the system will be avoided.To solve the problem,a method of resolving the optimal time interval based on the correction of network loss threshold is proposed in this paper,moreover several dynamic time interval reconstruction schemes are given through chain principle.Finally,the IEEE33 node system and the IEEE69 node system are used as examples to verify the validity and practicability of the algorithm.