Research On Power System Operation Optimization Based On Flexible Modification Of Conventional Coal-fired Power

The output of my country’s power system is mainly thermal power,and coal-fired units account for a large proportion.Retrofitting conventional coal-fired power plants with steam extraction and dual heat storage will not only improve their flexible operation capabilities,but also have better energy storage efficiency.After the transformation,the internal structure of the unit will become complicated,and the original operating model will no longer reflect the operating characteristics of the unit.Therefore,this article focuses on the related problems after the steam extraction and dual heat storage retrofits of coal-fired power plants.First of all,from the perspective of three technological transformations,the principles of improving the flexibility of coal-fired power plants and the restrictive factors affecting their performance are analyzed.The flexibility mechanism of coal-fired power generation units is explained.First,the internal structure and energy relationship of the units are briefly introduced,and then they are modified from two aspects to improve their flexibility.Finally,comparing the three technical angles,it is concluded that it is more cost-effective and effective to adjust the flexibility of coal-fired power plants by improving the ability of the units to operate at low loads.In addition,the low-load operation capacity transformation methods of the unit are analyzed and compared,and it is concluded that the operation cost of the unit using extraction steam and heat storage is lower than that of using the stabilizer.Secondly,the internal structure and thermal cycle structure of the coal power unit before the transformation are introduced,the six processes of the water vapor cycle are analyzed,the thermal cycle structure of the transformed unit is introduced,and the high-temperature heat storage device and the low-temperature heat storage device are introduced.The structure of the dual heat storage system is analyzed and introduced.Starting from the energy flow conversion between the systems after the transformation,the operation mode of the coal power unit is analyzed and introduced in three different working conditions,and its restrictive factors are analyzed.From the three modules of boiler,heat storage,and power generation,the operation mode of the unit after the transformation is modeled,and the corresponding constraint conditions are given.Finally,in order to make it closer to the actual dispatching operation mode,based on the two models of unit combination and intraday economic dispatch,the combined operation of the reformed coal power unit and wind power generation is simulated through the historical forecast of wind power generation and actual data.A method for evaluating the benefits of combined operation of coal power generating units and wind power generating units is proposed.Through the simulation of related calculation examples,the impact of the transformation on the start-up cost of the coal-fired power plant and the system wind abandonment rate was analyzed,and the correctness and effectiveness of the established model was verified.The simulation results can quantitatively reflect the extraction of the coal-fired power plant.After the steam and dual heat storage transformation,the combined operation benefits of coal power generating units and wind power generating units have been significantly improved.At the same time,through the establishment of different wind power permeability and heat storage capacity of heat storage devices to analyze their impact on the benefits of combined operation of coal power plants and wind power plants.