Research On Flexible Scheduling Of Integrated Energy System Considering Wind And Solar Power Output And Load Uncertainty

With the gradual promotion quality and demand for energy in social,the global total energy consumption and per capita energy consumption has continued to "double" situation,and the mode of energy supply is single,clean energy effective utilization rate is low,resulting in obvious energy shortage,serious environmental pollution problems become more and more obvious.In this context,CCHP system has developed rapidly,not only realizes the complementary utilization of energy,but also controls the amount of pollutant emissions.Liquefied Natural Gas(LNG)has developed rapidly in recent years,and 1 ton LNG theoretically available cooling capacity is about 230kWh in vaporization process.It is of great significance to research LNG cold energy utilization,especially the use of LNG cold energy power generation in energy saving,environmental protection and economic benefits.However,the traditional CCHP system did not make full use of the distributed renewable energy such as wind energy and solar energy into power grid to generation,abandoned wind and solar phenomenon is more serious,and not on the LNG comprehensive complementary use,resulting in a great waste of energy.Thus,an integrated energy system is built in this paper,using LNG as the input fuel and a large number of cold release in gasification process through the organic Rankine cycle method for low temperature power generation,accessing to wind energy,solar energy and energy storage devices to achieve ladder cold energy complementary use and improve wind and solar power generation efficiency.The thesis is based on the ladder complementary of multiple energy sources,which promotes the combined use of wind,solar,electricity and gas,and provides a powerful guarantee for the construction of the next generation of green,intelligent and efficient grid.First of all,the paper focuses on an integrated energy system structure consisting of LNG,cold,and distributed energy sources.Expounding the generation model of the renewable energy,the energy storage device and the power to gas technology,and analyzes the operation characteristics of the integrated energy system.By considering the distributed renewable energy and load demand uncertainty.The paper uses a theory of random forest algorithm that to decide the outcome of multiple combinations with simulating vote method.A forecasting model of the integrated energy system renewable energy output and load demand based on random forest algorithm is proposed.The number of trees and the number of candidate variables of the split node have an important influence on the prediction accuracy of the model.By setting up the two parameters,achieving accurate forecast of renewable energy output and the cold and heat load demand.To discuss the renewable energy output and load probability distribution in the different real-time price,the probability density of renewable energy output and load forecast,gives the probability of wind speed,photovoltaic units output and electrical load distribution curve.Finally the root mean square error,the mean absolute percentage error and mean bias error are evaluated and forecast,decision tree and support vector machine algorithm were compared to verify the accuracy of random forest algorithm prediction.Secondly,in view of the uncertainty of wind and solar power output and load forecasting error,Monte Carlo sampling method is used to generate multiple scenes.Each scenario corresponds to a feasible scheme of the integrated energy system wind and solar power output and load.Through the optimal operation of the operating cost of the integrated energy system,a variety of modes of operation can be obtained.In a single scenario,the integrated energy system targets the minimum operating costs of the LNG purchase cost,the purchase cost and the carbon emission cost.The power generation of the gas turbine,the electrical power purchased from the large grid and the power delivered to the large grid are taken as decision variables.The constraints of power balance,the balance of supply and demand of thermal and cold energy,the storage constraints of energy storage devices and the operation constraints of system units are taken into account.When the integrated energy system is converted from a number of different scenes,the mode of operation is adjusted accordingly.At the same time,aiming at the minimum operating cost is adjusted between the multiple scenarios of the system and a flexible optimal scheduling model of integrated energy system with wind and solar power and loads is proposed.In the multi scenarios,the multiple decision path transformation method is used to solve the model.Finally,the paper compares and analyzes the operating cost of the system's multiple scenes and the impact of LNG cold energy generation on the system operation cost.The optimal operation strategy of integrated energy system under different electricity price scenarios is proposed.Numerical results show that the flexible operation can effectively reduce the operation cost of the system adjustment.The integrated energy system can choose the corresponding operation plan according to the different electricity price,and it proves that the LNG cold energy utilization has a good optimization effect on the system operation cost.