Research On Probabilistic Power Flow Calculation Method Of Distribution Network With Distributed Generation

With the continuous improvement of people’s quality of life and the increasing number of ways to use electricity,people’s demand for electricity and electricity is also increasing.Nowadays,distributed energy has become an important part of smart distribution network.The development of distributed energy technologies such as photovoltaic,wind power and natural gas is an important measure to solve the energy supply and improve the structural problems on the supply and demand sides of energy.However,with the gradual increase of grid-connected scale of distributed power sources such as photovoltaic and wind power,intermittent and uncertain operation of the power system will become increasingly prominent,and the randomness of the power grid will become increasingly obvious,which will bring greater challenges to the operation,planning and safety assessment of the power grid.The increase of power system uncertainty is bound to lead to the increasingly complex and changeable operation mode As a calculation method that can comprehensively and systematically describe the distribution characteristics of various random variables,Probabilistic Load Flow(PLF)is of great importance in the study of power system uncertaintyIn order to evaluate the influence of distributed generation(DG)connected to the grid on the probabilistic load flow(PLF)of the power system,in this paper,based on the section of Sampling(Slice from the SS)of the Markov Chain Monte Carlo(MCMC)simulation method on the basis of the introduction of improved Latin hypercube Sampling(ILHS),through to the Slice Sampling(SS)to get the initial samples again processing to improve the efficiency of calculation,and then using the Copula theory connect input random variables correlation probability model is established,Kendall rank correlation coefficient was used to measure the correlation between input random variables.For the final sample,the deterministic power flow calculation is carried out After the calculation,the SS-based MCMC simulation method and the traditional MCS probabilistic power flow calculation method are compared to verify the reliability and efficiency of the method used in this paperAlso studied different correlation between wind power and pv output of system trend(voltage magnitude and phase Angle,line power,system network loss rate),the influence of the results show that the different correlation of wind-photovoltaic forces will not have a great influence on mean values of power load flow,but the voltage magnitude,probability distribution and the standard deviation of the line power can be affected seriously,will increase the volatility of the system,but the scenery complementary output(negative correlation)can improve the relevance of the economy and reliability of the system.Secondly,the influence of distributed generation with different capacity on the node voltage magnitude,line power and system network loss is analyzed,which indicates that a large amount of distributed generation will increase the instability of the system,but will greatly improve the economy of the power grid with a small amount of system network loss.Finally,the difference of the influence of the same proportion of DG on the system power flow in different scale systems is analyzed,which proves that the large system has a more stable compatibility with the access of DG,and the network loss rate is relatively smaller,indicating better economic benefits.