Research On Dynamic Robust Reconstruction Of Distribution Network With Low-wind-speed Dispersed Wind Power Integrated

Under the influence of wind power brownouts in north of China,China's wind power development center has been transferred to the central and eastern regions with low-wind-speed,which promotes the development of low-wind-speed technology.The low-wind-speed technology greatly improves the wind energy utilization coefficient of wind turbine.Thus the dispersed access to the distribution network is not only conducive to the nearby absorption of the load in the central and eastern regions,but also greatly makes the distribution network's operation more economic.Therefore,the access of low-wind-speed dispersed wind power(LDWP)to the distribution network has become an inevitable trend.In order to further reduce network loss and improve voltage quality,LDWP can be used for distribution network reconstruction.Firstly,compared with conventional wind speeds,decentralized wind power output at low wind speeds has stronger randomness and volatility,which can easily lead to large voltage fluctuations and poor voltage stability in the distribution network.Therefore,the distribution network reconstruction scheme should be able to dynamically adjust in real time according to the high randomness and volatility of low wind speed distributed wind power,so as to obtain a dynamic optimal voltage distribution,power quality and minimum network loss.Secondly,the three-phase unbalanced load in the low-voltage distribution network is relatively common,which has an impact on the three-phase voltage,current imbalance and network loss of the distribution network.The distribution network should be able to implement the optimal reconstruction plan to obtain the smallest three-phase unbalance and network loss.Therefore,this paper aims to explore the multi-objective dynamic robust reconstruction method of distribution network with LDWP integrated.In this paper,based on the operation characteristics of low-wind-speed wind turbine,the establishment of DNR model is explored,as well as the solution and calculation method.The main work is summarized as follows:(1)Taking into account the uncertainty of low-wind wind power,photovoltaic power output and load as well as the behavioral characteristics of multiple types of users,the probabilistic uncertainty model of LDWP,photovoltaic power output and load is constructed.In the modeling process,the differences between low-wind-speed wind turbine and conventional wind turbine in operating characteristics are considered.(2)Based on the probabilistic uncertainty model,the dynamic robust reconstruction model of distribution network is established.The three-phase current unbalance degree and network loss are chosen as the optimization objectives.The switching operation times,node voltage opportunity constraints and branch power flow opportunity constraints are all considered.(3)The Latin Hypercube Sampling Monte Carlo Method(LHS-MCS)is used to obtain the objective function,and it is solved by using probabilistic power flow.The semi-invariant method using node voltage opportunity constraints combined with branch power flow opportunity constraints is used to achieve the relevant constraints.Based on the compound differential evolution algorithm(CDE),the dynamic DNR scheme is optimized.The optimal dynamic reconstruction scheme can not only significantly reduce the three-phase current imbalance and network loss,but also significantly reduce the node voltage imbalance,which can improve the overall voltage level of the distribution network,and improve the security and economy during distribution network operation.