Quantitative Analysis On Energy Storage Capacity Of Thermal Power Units

Power grid has higher and higher requirement for the rate of thermal power unit response, to meet the requirement, a well-coordinated control system is necessary, requirement of designing a well-coordinated control system is to obtain the accurate controlled device model. Storage capacity is one of the significant parameters of controlled device model of coordinated control system, quantitative analysis on thermal power unit storage capacity lays the foundation for building model. In this paper, the combination of mechanism analysis, data analysis and finite element analysis method is applied for quantitative analysis of boiler steam-water system and condensate water system storage capacity.Analyzing boiler steam-water system storage capacity is based on design data of centralized control operating procedures as well as thermal properties of water and steam. Divide steam-water system into several parts by finite element analysis method, calculate storage capacity of each part, the sum of components is boiler steam-water system storage capacity. Taking ND 660 MW supercritical Power Plant and LPS 330 MW power plant as an example, steam-water regenerative heat storage coefficient and metal regenerative heat storage coefficient are calculated by method above, the coefficients result in boiler regenerative heat storage coefficient, according to the analysis of result, come to the conclusion about boiler steam-water system regenerative factor trends.Condensate system storage utilizes the self-balance relationship between the condensate water flow and low pressure steam extraction flow, by rapid changes in the condensate flow, thereby changes the heater into the low pressure turbine extraction flow and the generation unit power. Firstly, through the mechanism analysis of the thermal power regenerative heating system of low pressure heaters, deaerator and high-pressure heaters, establishes quality-energy balance equation of each heater, combined with the equivalent enthalpy-drop method, obtains static correspondence between changes in condensate system condensation water flow and load variation of unit. Secondly, make use of design data and operating parameters of PS power plant 600 MW sub-critical water-cooled unit, ZX power plant 1000 MW ultra-supercritical water-cooled unit, DT power plant 600 MW subcritical air-cooled unit, the ND power plant 660 MW supercritical air-cooling unit, take the methods and examples mentioned above into calculations. Finally, the results are analyzed by calculating the difference between the condensate system storage capacity trends and air-cooled and water-cooled units Units Condensate System storage capacity.In summary, this paper studies on thermal power systems and condensate storage capacity of steam-water systems in depth, obtains method to calculate the energy storage capacity of the two systems respectively and provides a significant basis for determining the parameters of the storage capacity of the controlled device model of coordinated control system, which can design a favorable control system to improve the response rate of the unit load.