考虑发电机磁链衰变动态的暂态稳定性研究

Transient stability research considering flux decay dynamics

基于结构保持电力系统模型,研究了发电机磁链衰变动态对暂态稳定性的影响,指出一些被证明能有效阻尼系统振荡的非线性励磁控制策略,可能缩短临界切除时间。通过对故障时磁链衰变动态在转角-暂态电动势平面变化轨迹的比较分析,得出临界切除时间缩短是故障时交流暂态电势减小造成的。通过能量函数法,以直观的图形方式给出了稳定边界,并分析了负载变化时稳定边界相应的变化情况。提出优化LgV控制器设计方法,既能保持原有的阻尼效果,又能延长故障切除时间,增强了系统的暂态稳定性。仿真结果表明了所提方法的正确性与有效性。

Based on the structure preserving power system model,the influence of flux decay dynamics of generators on transient stability is studied. Some of the nonlinear excitation control strategies proved to be effective in damping the post-fault system oscillation may reduce the CCTs（Critical Clearing Times）. The trajectory comparison of different flux decay dynamics in the rotor angle- Eq＇ plane during a fault is provided,showing that the shorten Eq＇ causes the CCT reduction. With the help of energy function method, the stability boundary is demonstrated in figures. The variation of stability boundary with the increase of load power is analyzed. An optimal method of LgV controller design is applied,which maintains the damping effect and prolongs the CCTs to improve the transient stability and dynamic performance of power system. Simulative results show the correctness and effectiveness of proposed method.