热电联产机组柔性控制仿真研究

Simulation study on flexible control of cogeneration unit

随着新能源发电大规模发展,热电联产机组需要灵活运行以平抑新能源接入电网带来的波动。为了满足机组灵活运行时控制要求以及机组运行安全性,设计了一种基于灵活性评价的热电联产机组柔性控制策略。首先,根据机组电负荷、热负荷和机前压力的响应特性,提出一种可以表征机组负荷适应能力以及运行安全性的灵活性评价指标的计算方法,并以此作为最优柔性因子选取的依据。然后,仿真分析了单一工况下柔性因子对控制系统性能的影响。最后,在确定不同工况最优柔性因子的基础上,设计了随工况变化的自适应柔性因子并应用到柔性控制中。仿真结果表明:该控制策略不仅在机组大范围工况变化时可以取得较好的控制效果,也可以对低压缸切缸后的机组实现较好的控制,满足机组灵活运行的控制要求,保证机组运行安全性。

Large-scale grid connection of new energy power generation makes cogeneration units need flexible operation to smooth out the fluctuation brought by new energy access. In order to meet the control requirements of flexible operation of the unit and the safety of the unit operation, a flexible control strategy for cogeneration units based on flexibility evaluation is designed. Firstly, according to the response characteristics of electrical load,thermal load and throttle pressure of the unit, a calculation method of flexibility evaluation indexes which can represent the load adaptability and operation safety of the unit are proposed, and these indexes are used as the basis for selecting the optimal flexibility factors. Then, the influence of flexibility factor on the system performance under a single working condition is simulated. Finally, on the basis of determining the optimal flexibility factors under different working conditions, the adaptive flexibility factors that changing with working conditions are designed and applied to the flexible control. The simulation results show that, the control strategy can not only achieve a better control effect when the unit runs under large-scale conditions change, but also achieve a better control for the unit after the low-pressure cylinder is cut off, which can meet the control requirements of flexible operation of the unit and ensure the safety of the unit operation..