Low-carbon Economic Dispatch Of Pumped Storage Assisting Coal-fired Units Considering Deep Peak Shaving

Currently.China’s energy power structure is still dominated by thermal power,about 90%of which are coal-fired units,and their carbon emission account for nearly 40%of the country’s total carbon emissions.Controlling the carbon emissions of coal-fired units has become the only way for China to achieve the "dual carbon" goal.In addition.due to the lack of flexible power sources in the power system,in the face of scenarios with a high proportion of new energy,especially small load and high wind power,coal-fired units need to operate frequently at low load rate,which will significantly increase coal consumption of units,leading to the decline in system operating economy and the rise in carbon emission intensity.Pumped storage has the advantages of clean energy,flexible mode conversion,and large peaking range,through its auxiliary peaking is expected to alleviate the depth peak shaving and emission reduction pressure of coal-fired units,but its current operating efficiency is still relatively low.Therefore,in order to achieve the low-carbon operation target of power system,it is of practical significance to study the low-carbon economic dispatch of pumped storage assisting coal-fired units considering deep peak shaving.The main research contents are as follows:1)Summarize the peaking mode,analyze the safety and technical performance of coal-fired units under low load operation.Considering the carbon emission and energy consumption influencing factors under different load rates,the carbon emission characteristics and energy consumption cost characteristics of coal-fired units under different peaking stages are studied from the system scheduling level,and a model of the overall carbon emission intensity and energy consumption cost of coal-fired units considering deep peak shaving is constructed.2)In order to reduce the carbon emission pressure caused by frequent deep peak shaving of coal-fired units,the daily carbon emission limit is determined on the basis of the system emission reduction target with the difference between peak and valley of net load of the system,and the total carbon emission control model of the system is established,and then the low-carbon economic dispatch strategy of deep peak shaving of pumped storage assisted coal-fired units based on the total carbon emission control is proposed.Taking the improved IEEE 39-node system as an example,the feasibility and effectiveness of the proposed strategy are verified by simulation.The results show that the proposed strategy can effectively reduce the frequency of deep peak shaving and carbon emissions of coal-fired units,and can reduce the emission pressure of coal-fired units under the peak-valley difference scenario.In addition,the proposed strategy is more effective as the total carbon emission limit of the system is continuously reduced,but it can seriously impair the economics of deep peak shaving of coal-fired units and lead to the increase of system operation cost.3)In view of the current situation of low utilization of pumped storage units,a low-carbon economic dispatch strategy based on low-carbon calling coefficient for deep peak shaving of pumped-storage assisted coal-fired units is proposed.Then,with the goal of minimizing the total operating cost the system,a low-carbon economic dispatch mode is established.Based on an improved IEEE 39 node example,simulation analysis is conducted to verify the feasibility of the proposed model in terms of pumped-storage utilization efficiency,emission reduction effect,and economy.The results show that the proposed strategy can effectively improve the utilization rate of pumped storage units,reduce the deep peak shaving energy consumption and carbon emissions of coal-fired units,and achieve the low carbon economic operation of the system.