| With the reform of the electricity market and the large-scale integration of renewable energy,the planning and operation of power system will face increasingly uncertainties,which makes the traditional deterministic power flow calculation and analysis method difficult to adapt to this situation.Therefore,in view of the uncertain influence of renewable energy and load in power grid planning,it is urgent to carry out the research of risk assessment model and method based on probabilistic power flow.The paper takes the uncertain impact of renewable energy and load in grid planning as the research basis,and adopts Copula theory and K-means algorithm to carry out related work.First,the paper has a summary on the models and algorithm of probabilistic load flow,and introduces the Monte Carlo simulation method of probability flow,including theoretical basis,calculation process and error analysis.Then,the paper establishes a mathematical model of wind power plant output based on a Weibull distribution of wind speed and IEC-Bin method.It also has a view on classical normal distribution,K-means and kernel density estimation of load probability model,and decide using the last to model.The paper comes up with using rank correlation coefficient to describe the correlation of input variables,and establish a method to generate the sample sequence of correlated variables based on Copula theory.Meanwhile,it puts forward risk assessment index from the aspects of probability and severity.At last,it had a test on IEEE-39 system by using MATLAB software,and get a good result of risk assessment. |
