Inventory Optimization Study To Ensure Reliable Coal Supply Time For Thermal Power Peaking Units

As a major means to cope with load fluctuation of power grid and achieve peak shaving,peaking is of great significance to promote new energy consumption and optimize power structure.However,when participating in deep peaking tasks,the coal consumption and losses of thermal power peaking units will be higher than the basic operating condition due to load shedding or frequent start/stop,which affects the reliability of thermal power peaking units.From the perspective of coal combustion in thermal power peaking units,time requires timely supply of sufficient coal to cope with the fluctuation of unit load;economically,it requires saving coal-related costs.How to coordinate its time reliability and economy has been a challenge.At present,thermal power plants generally store large amounts of coal in advance in order to protect the normal generation needs of their units and to cope with fluctuations in demand due to peaking tasks,sacrificing some of the economics to improve their time reliability.In order to further improve the profit level while guaranteeing the time reliability of coal supply,this paper initiates a study on coal inventory optimization for thermal power peaking units.Combining the current situation of production and operation of thermal power peaking units and the current situation of coal supply,this paper investigates the coal inventory strategy under the situation of thermal power units participating in deep peaking,and the main research contents and results include the following four points.First,the literature research method is used to fully understand the current situation of domestic and international research on thermal power coal-fired inventory management and time reliability,to continuously clarify the researchideas,and to construct a reliable parameter system.Secondly,based on the system dynamics theory,a standard inventory optimization simulation model for coal combustion in thermal power peaking units is constructed.Meanwhile,according to the classical inventory control model,different simulation strategies of periodic ordering and quantitative ordering are designed.The standard inventory optimization simulation model is highly universal and can run most of the ordering strategies,which is easy to promote.Then,an improved simulation model is designed to adapt to the fluctuation of coal demand over time,taking into account the fluctuation of coal demand.By analyzing the probability distribution of coal demand data of thermal power peaking units,it is found that the coal demand probability density function is a combination of four normal distribution functions in time periods.The time-phased simulation model is designed based on the coal demand probability density function,in which the quantitative ordering strategy well solves the out-of-stock problem while reducing the average inventory level and total cost.Finally,considering the actual situation of unit participation in peaking,a safety stock calculation method that satisfies the maximum load fluctuation is designed and the ordering strategy is optimized.Meanwhile,considering the requirement of reliable coal supply time for thermal power peaking units,the evaluation index of coal supply time reliability for thermal power peaking units and the utility formula for coordinating time reliability and economy are proposed.Based on the time reliability evaluation index,the different simulation schemes designed in the full paper are analyzed,and it is found that the total utility of the improved quantitative ordering strategy based on the safety stock calculation method is the highest,and the level of time reliability and the level of economy are in the top.