Research On Probabilistic Power Flow Calculation Of Distribution Network Considering The Correlation Of Wind/Solar Power Output

Due to the randomness and volatility of wind energy and solar energy,there is uncertainty in the output of wind turbines.In recent years,more and more intermittent energy sources such as wind power generation and photovoltaic power generation have been connected to the distribution network,and there have been problems such as the voltage limit of the power system nodes.Aiming at this problem,the probability distribution characteristics of the node voltage and the branch flow are obtained by the probabilistic load flow calculation,and the voltage running state of the distribution network is analyzed.In this paper,a method based on quasi-Monte Carlo sampling(QMCS)to obtain semi-invariants of input random variables is proposed.This method improves the classical Monte Carlo sampling(MCS)method and inherits the advantages of the MCS method.In addition,the efficiency reflected in some practical problems is usually hundreds of times faster than the MCS method.The feasibility of QMCS sampling combined with semi-invariant is verified by an example.For the multi-wind farm output with wind speed correlation,the calculation method based on the Nataf transformation principle and wind speed correlation is introduced to obtain the wind speed related output samples,and the correlation between wind farms is analyzed by the probabilistic power flow calculation.The influence of tidal characteristics.The simulation data shows that the stronger the wind speed correlation,the larger the fluctuation range of node voltage and branch power when multiple wind farms are connected to the system,which provides an effective basis for grid dispatchers.Aiming at the correlation of wind and light output,a method based on Frank C-QMCS combined with semi-invariant method is proposed.The Frank Copula function is used to construct the correlation random variable probability model,and the spatial complementary structure between wind and light output is fitted.The adjacent wind farms and photovoltaic power plants with relevant correlations are sampled,and the wind turbine generators are mainly analyzed.The correlation of theprobabilistic trend characteristics of its access to the distribution network.The simulation results show that if the output correlation between intermittent energy sources is not considered,the judgment of system power quality and power supply stability is too optimistic,and the impact of accessing the distribution network on the system is more serious than expected.This paper provides an effective reference for the safe and reliable operation of the actual power system.