Study On Optimal Power System Dispatch With Wind Power Integrated Based On Conditional Value-at-risk

Wind power generation is the most mature technology and the most promising renewable energy power generation form,and wind power integration into power system has eased the pressure on China's energy consumption and brought huge economic and environmental benefits.However,due to the fluctuation and uncertainty of wind power,wind power integration brings risks to power system operation and control.Accurate assessment of risks brought by wind power and making power system dispatching strategy comprehensively considering the safety and economy of the system,has become an important issue for the future power system with the high proportion of renewable energy integrated.To solve this problem,this dissertation studies wind power scenario modeling and generation scheduling optimization modeling.This dissertation will combine generation dispatching problem and the theory of conditional value-at-risk(CVaR)into the analysis of system operation risk,which can accurately reflect the influence of system operation risk and decision-making risk attitude on generation dispatching.The main research is as follows:(1)A scenario generation method and a scenario reduction method are proposed,which take into account the conditional distribution characteristics of wind power variability and prediction error.The accurate quantification and modeling analysis of wind power fluctuation and uncertainty are very important for the development of system scheduling plan.Based on the dynamic scenario generation technology,a new method of wind power scenario generation considering the conditional distribution characteristics of wind power fluctuation and prediction error is proposed.Aiming at the shortcoming of the conventional clustering algorithm,an improved K-medoids clustering algorithm is introduced into scenario reduction,by which the representative wind power scenarios can be got reflecting fluctuation and uncertainty of statistical characteristics.(2)A coordinated generation and reserve dispatching model based on probabilistic scenarios and conditional value-at-risk is proposed.Representative scenarios can accurately describe the stochastic process of the system and evaluate the system's ability to regulation and reserve requirements.In this dissertation,the power generation and reserve coordination optimization model considering the fluctuation and uncertainty of wind power is established based on the probabilistic scenarios.As the evaluation method based on the expectation regard commensurate with high loss events of low probability and low loss events of high probability and cannot reflect the decision maker's risk attitude to operation risks and the range of losses the decision-makers might particularly concern about.In order to accurately evaluate the risk of generation scheduling,conditional value-at-risk is introduced to measure the economic loss of wind curtailment and load shedding.The influence of different risk attitude on generation scheduling and reserve allocation is analyzed.(3)Based on the theory of conditional value-at-risk,a coordination optimization model of generation and reserve considering energy storage and demand response is established.In view of the future power system with a high proportion of wind power only relying on conventional unit to accommodate wind power will cause too much regulation cost,the energy storage system and demand response is introduced into day-ahead generation dispatching model.Based on scenario analysis,an energy storage model considering energy storage capacity restriction is established.And a demand response model based on user satisfaction constraint is established.This dissertation introduces the theory of conditional value-at-risk to measure risk,and compares and analyzes the influence of different risk attitudes toward system dispatching under different dispatching modes.The simulation results show that the coordinated scheduling model considering energy storage and demand response can effectively improve the wind power acceptance level and realize the economic operation,and also significantly reduce the risk of extreme scenarios to the system dispatching.