Research On Reconfiguration Of Distribution Network With Distribution Generation And Energy Storage

Reconfiguration is one of the main methods to optimize the operation of distribution network,which not only can reduce power loss and voltage deviation,but also can improve the reliability and economy of distribution network.In recent years,with the rapid development of global economy and the improvement of people living standards.And the depletion of traditional fossil fuels such as coal and oil,distributed generation(DG),represented by wind power and photovoltaic power has been widely utilized in the word.However,DG increases the uncertainty of distribution network planning and operation because of their inherent randomness of DG output when integrated distribution system.Fortunately,energy storage device can balance the DG intermittent output of stochastic volatility under a certain extent.And can increase the power of the DG acceptance ability,but also makes the structure of distribution network is complicated,which leads to big challenges to the optimization of distribution network operation.Therefore,this paper researches distribution network reconfiguration problem considering uncertainties including wind power and photovoltaic power.The specific work is as follows:First,in order to analyze the influence of DG uncertainty for distribution network operation.This paper proposes a mean-variance-skewness based expectation maximization(MVSb EM)model based on portfolio theory.Which aims to balance the risk and benefit brought by the random uncertainty of distributed generation to the operation of distribution network.In addition,the Latin hypercube sampling(LHS)method is adopted to sample uncertain DG,which can reduce the computational burden of repeated samples.The simulation result obtained based on a modified of IEEE 33 bus to measures the uncertainty of DG integration network from economic and risk indicators.The results verify the reliability and effectiveness of the MVSb EM model for measuring random optimization problems of distribution network.Secondly,in order to study the impact of DG uncertainty on the distribution network reconstruction results,the aforementioned risk assessment model that takes into account the DG uncertainty was embedded into the reconstruction process of the distribution network,and a risk-based distribution system was established.The network static reconfiguration optimization model obtains the optimal distribution network reconfiguration solution by balancing the benefits and risks brought by the DG uncertainty.In addition,based on the integer coding rule of basic loops,a methodology of judging and repair the invalid solutions in the process of distribution reconfiguration through the distribution branch group vector is proposed.And an improved binary simulated annealing algorithm is used to find the optimal solution for the reconfiguration of distribution network under the uncertainty of DG.Take the improved IEEE 33 bus of network distribution system as an example,the analysis of example shows that the distribution network reconstruction model considering risk assessment can not only effectively reduce the network loss of the distribution network,increase the voltage level,but also take into account the impact of DG uncertainty on the distribution network reconstruction.Finally,the dynamic network reconstruction of the distribution network with microgrid is studied in response to the changes in DG and load over time,and the power backflow caused by the large number of DGs connected to the grid.Aiming at the uncertainty of microgrid,a risk measurement method based on credibility theory was proposed to simultaneously evaluate the randomness and ambiguity of DG.On this basis,the dynamic reconstruction model of microgrid is established with the aim of economic optimization.Simulation results show that the distribution network with microgrid can not only reduce the running cost and energy loss of the reconstruction of the distribution system,but also play the role of peak load shifting.