定子过电流限制与过励限制的协调性研究

Research on Coordination of Stator Current Limit and Over-Excitation Limit

励磁系统定子过电流限制和过励限制的协调控制一直是业内讨论的热点,但相关的研究文献较少,文章建立了某一600MW机组的仿真模型,模型不仅包含了励磁系统主环,也包括了定子过电流限制和过励限制环节模型。基于搭建的仿真模型深入研究了两个限制的协调性,从研究结果可见,两个限制器均具备存在的价值,其在系统电压下降过程中,抑制转子过电流和定子过电流方面作用明显,有效地延长了故障过程中机组的在网时间,提高了机组对电网的电压支撑作用。而通过不同故障下的仿真表明,定子过电流限制在系统电压下降过多时应闭锁运行,避免机组的无功不足,导致机组稳定性能下降。文章结论对于励磁系统参数整定、逻辑设计具有重要意义。

The coordination control of stator current limit and over-excitation limit has been a hot topic of discussion in the industry, but less related research literature, this paper establishes the simulation model of a 600MW unit, which not only includes the excitation system main loop, also includes the stator cur-rent limit and over-excitation limit model.The coordination of two limits is researched based on the simu-lation model, the study result shows, the two limiters are useful, when the system voltage drops, have obvious effect on the inhibition of the rotor over current and stator over current, to effectively prolong the time of the unit in the network during the failure process, to improve the voltage supporting effect of unit on the grid.Through the simulations under different fault conditions show that, the stator current limit should run with blocking when the system voltage drops too much, to avoid the insufficient of reactive power, and resulting the decline of the system stability.The conclusion has the significance for the exci-tation system parameter setting and the logic design.