Research On Risk Assessment Of Power Ramp In Wind Farm Based On Copula Theory And Scenario Analysis

Wind power ramp refers to the phenomenon that there is drastic increase or decrease of active power output within a short time.The effect of wind power ramp on the steady operation of power system is increasingly prominent with the increase of wind power grid-connection capacity.At present,there are few studies on quantitative analysis of the risk of wind power ramp,and less research is made on the impact degree of power ramp.Based on these two aspects,a study on risk assessment of wind power ramp based on Copula theory and scenario analysis is presented.Specific research contents are as follows:(1)This paper analyzes the different recognition methods of wind power ramp event,and spinning door transformation algorithm is selected to identify wind power ramp.According to the characteristic quantity of identified ramp events—ramp amplitude and ramp duration,the fuzzy coordinate method was used to make a preliminary judgment on the level of wind power ramp events.(2)Applying Copula connect functions theory,this paper puts forward using copulas connect function to connect ramp amplitude and ramp duration edge distribution function for wind power ramp events that have been identified by the revolving door algorithm.The probability calculation model of wind power ramp event based on Copula theory is established,and calculates the probability of ramp events of different grades identified by the revolving door of algorithm.(3)Establish a calculation model for the risk loss of wind power ramp based on scenario analysis.First,this paper described the basic knowledge of risk theory.Then the distributed energy system is constructed,including wind power,gas turbine,energy storage device and uncertain load demand.Secondly,for different levels of wind power ramp events,Latin hypercube sampling and k-medoids clustering were used to construct the risk evaluation scenarios of wind power ramp in distributed energy systems.Finally,according to the established scenarios and knowledge of risk theory,the power deviation severity is proposed as the risk assessment index,and establishing the risk loss function calculation model based on CVaR to calculate the wind power ramp risk loss of ramp events with different probabilities in chapter 3.(4)According to the definition of risk assessment and the contents of chapter 3 and chapter 4,calculating the risk value of wind power ramp events in different levels,and assess and control the risk according to the value of risk.