Risk Assessment Of Generation And Transmission System With Wind Power Grid-connected

The global energy shortage crisis and environmental pollution problems are receiving more and more attention from all over the world,making the development and use of green renewable energy become the direction of global energy development.As the most promising green clean energy power generation method,wind power has developed rapidly in recent years.However,the randomness and volatility of wind power have a great impact on the safe operation of power systems.Especially in the context of increasing wind power grid-connected scale,the uncertainty factors of wind power will bring huge challenges to power system risk assessment.In order to comprehensively analyze the impact of wind power grid-connected on the risk assessment of power generation and transmission system,this thesis studies the operational risk and economic risk assessment of power generation and transmission systems with wind power grid-connected.The main research contents are as follows:Firstly,the component outage model of power generation and transmission system is established.By analyzing the influence of line power flow factor,aging failure and accidental failure factors on component shutdown,the outage model of system components such as lines,transformers and circuit breakers is established;Then by analyzing the influence of real-time operating voltage and frequency on the outage of conventional generators,the fault and shutdown model of conventional generators,the outage model of conventional generators based on voltage and frequency is established;Finally,by analyzing the outage rate of wind turbines under three weather conditions,a wind turbine outage model considering weather factors is established.Secondly,aiming at the problem of poor fitting effect and low fitting accuracy of wind power measured data with single distribution,this thesis uses weighted Gaussian mixture distribution to fit the wind power measurement data,and establish the wind farm output probability model based on this distribution.At the same time,aiming at the EM algorithm is easy to fall into the local optimal defect when estimating parameters of weighted Gaussian mixture model.The ECM algorithm is proposed to estimate unknown parameters of the model,which improves the accuracy of parameter estimation and the fitting effect of the model obviously.Thirdly,in the selection of probabilistic analysis method,the Markov Chain Monte Carlo(MCMC)simulation method with high computational accuracy is adopted,and aiming at the high cost defects for the commonly used Gibbs algorithm,a MCMC method based on Slice Sample algorithm combined with Latin Hypercube Sampling algorithm is proposed.Because the Slice Sample algorithm is more flexible than the Gibbs algorithm,the computational complexity is smaller,at the same time,the Latin Hypercube Sampling algorithm can reduce the correlation between the sampled values,thus greatly improving the computational efficiency and accuracy of the MCMC method.In this thesis,the method is applied to the risk assessment of the generation and transmission system with wind power grid-connected.The simulation results show that the proposed method has better stability and accuracy when the sampling times are the same.Fourthly,a risk assessment model based on optimal power flow is established,and operational risk assessment indicators and economic risk assessment indicators are given to accurately assess the risk of the generation and transmission system with wind power grid-connected.This thesis incorporates the wind farm into the IEEE-RTS79 test system for simulation analysis.The results show that the wind power grid-connected will have a certain degree of impact on the system risk assessment results,and the appropriate grid-connected capacity and reasonable grid-connected location will reduce the risk of the power generation and transmission system.