Evaluation Of Transmission Reliability Margin Of Interconnected Power System Considering Wind And Solar Power Incorporated Into Grid

With the gradual opening of the power market,the Transmission Reliability Margin(TRM)of the interconnected power system is not only an important indicator to measure the adequacy of system operation,but also an important reference for optimizing the allocation of resources in the power market.It is of great significance and value to the stability and economic operation of the system.In the development process of the transition to environmental protection and clean energy,wind power and photovoltaic have become important sources of electricity supply in China and even the world due to the advantages of green,environmental protection,clean and sustainable.However,the wind-solar power system has been affected by the randomness and volatility of wind and solar power output,the environment in which the system operates has become more complex and uncertain.Therefore,although more achievements have been made in TRM research,at present,how to reasonably and comprehensively consider the uncertain factors such as wind power and photovoltaic in the calculation of TRM is still a hot topic of relevant research.Under the background of wind-solar power incorporated into grid,in order to accurately evaluate the transmission reliability margin of interconnected power systems,this paper proposes a TRM evaluation method that takes into account the time-varying correlation characteristics of wind-solar output.First of all,wind and solar power output modeling and scenario analysis are necessary conditions for the stable operation of interconnected power systems.This paper takes full consideration of wind-solar output characteristics,including time-varying correlation characteristics,seasonal characteristics and uncertainties,combining K-means clustering and other methods,a wind-solar 24-hour combined output scene generation method based on time-varying Copula function is proposed.The scene generated by this method can provide a basis for subsequent evaluation of TRM.Furthermore,after setting TRM,the risk of transmission capacity shortage that may still exist in the system is defined and studied,and its size is accurately measured with the help of GlueVaR tools.In order to ensure the economy and reliability of the system operation,and make the maximum expected net profit of the system as the optimization goal,a TRM evaluation model that can distinguish the different risk preferences of decision makers is constructed,the time scale is also taken into account in TRM assessment.In order to ensure accuracy and speed of the solution,the expected net income model of TRM is solved by the sequential Monte Carlo simulation method and the improved particle swarm optimization algorithm,and the algorithm solution principle and solution process are introduced.Finally,this paper selects the actual measurement data of a neighboring wind farm and photovoltaic power station in a certain place of China,and generates the operating scene set in time series by using sequential Monte Carlo simulation method based on the wind-solar 24h combined output scenario set generated by the method in this paper,combined with the operating status of the components.After generating the operating scene set in time series,the modified IEEE-RTS system is used as the solution background,and the optimal value of TRM is obtained by solving the model using the optimization algorithm.Comparing with previous methods,the results verify that the proposed evaluation method can not only improve the accuracy of wind-solar output scenario generation,but also provide the necessary guarantee for the reliable and economic operation of the interconnected power system.At the same time,it also realizes the differentiated evaluation of TRM.