Research On Rapid Variable Load Strategy Of Thermal Power Unit Based On Condensate Throttling

With the rapid development of the world economy and technology,the energy structure of China’s power system is also showing a trend of diversification.Although the total installed capacity of new energy generation has also increased significantly,the randomness and the uncertainty of the new energy make it difficult to be connected to the grid.How to effectively use new energy is still a big problem in front of us.The thermal power unit has a certain flexible operation capability,which can also solve certain problems for the large-scale consumption of new energy in China.However,with the increasingly stringent requirements for peak and frequency regulation of the power grid,the traditional coordinated control method of thermal power units has failed to meet demand for variable load capacity of grid units.The variable load capacity of thermal power units must be further improved.The rational use of the internal energy storage of the unit can improve its own load-changing capacity.Therefore,this paper conducts research on the strategy of rapid variable load control for condensate throttling of thermal power units,as follows:1.The principle of variable load for condensate throttling using the energy storage of the unit’s regenerative heating system is introduced,and the mechanism analysis of the regenerative heating system of the thermal power unit is performed.The model finally calculates the increment range of condensate throttling power of a 350 MW unit,and the maximum sustainable time of condensate throttling by using related parameters,which provides a reference for the design of the control scheme described later.2.In order to overcome the non-linear factors existing in the condensate throttling control,the condensate throttling object model combination obtained under each typical working condition is used to form a condensate throttling model,and the condensate throttling system control is realized through fuzzy gain scheduling control strategy.So that the designed condensate throttling control system can still maintain a good control effect under the conditions of variable operating conditions.The controller parameters of each typical working condition are set by using particle swarm intelligent algorithm.Compared with the effect of traditional PID control,the effectiveness of the control system is verified.In addition,the differences between the impact of condensate throttling by frequency conversion throttling of condensate pumps and throttling by water gate of deaerator are also compared.3.In order to safely and rationally use part of the energy storage of the condensate system of the unit,a multi-loop structure of the condensate throttling system is designed,and the condensate throttling is coordinated with the coordinated control according to the variable load characteristics of the coordinated control system and the condensate throttling control system,and jointly participated in the control of the unit load,thereby forming a new coordinated and optimized control scheme.The simulation verification shows that the designed new coordinated optimization control system can effectively improve the dynamic performance of the unit while ensuring the safe operation of the unit,and makes up for the shortcoming of the slow response rate of the coordinated control system in the initial stage of variable load of the unit.