柔性励磁提升受端电网暂态稳定特性研究

Research on flexible excitation system applied to improve transient stability characteristics of the receiving-end power grid

目前同步机采用的传统励磁系统暂态强励能力有限且无法有效维持,而柔性励磁系统能有效提升机组的暂态强励顶值,并通过直流母线电压的控制维持其故障期间及故障清除后的强励能力,因此针对关键机组应用柔性励磁系统以提升局部电网暂态稳定特性进行了研究。介绍了柔性励磁的硬件拓扑结构及控制方法,分析提升机组暂态稳定特性的柔性励磁控制目标。在存在暂态稳定问题的受端实际电网有针对性地对关键机组进行柔性励磁应用,并在仿真中验证应用实施后该电网暂态稳定提升效果。结果表明,有限的关键机组应用柔性励磁后,能有效提升电网的暂态稳定特性。

The transient forced excitation of the traditional excitation system used for synchronous condenser is limited and unmaintainable. A flexible excitation system can improve the crest value of transient forced excitation and maintain the forced excitation capacity during and after faults through DC bus voltage control. Therefore,a study is conducted on applying a flexible excitation system for critical units to improve the transient stability characteristics of local power grids. The hardware topology and control method of flexible excitation are introduced,and the flexible excitation control objective to enhance the transient stability characteristics of the units is analyzed. The flexible excitation is applied to the critical units in the actual grid at the receiving end with transient stability problems. The transient stability enhancement effect of the grid is verified in the simulation after the application. The results show that applying flexible excitation to a limited number of critical units can effectively improve the transient stability characteristics of power grid.