EEAC与直接法的机理比较(二)壁垒点与观察点

A CRITICAL COMPARISON OF VARIOUS METHODS FOR TRANSIENT STABILITY ASSESSMENTPart Two Barrier Point and the Observation Point

讨论了长期困惑电力系统学术界的暂态稳定性理论和算法 ;归纳出 1 0个要素 ,即受扰程度函数、壁垒点、观察点、参考点、积分路径与被积函数、定性判据、轨迹稳定裕度、临界轨迹与参数极限值、迭代求解与初始轨迹、搜索策略与收敛判据。由 4篇短文组成的系列文章按照上述各要素 ,比较了 EEAC和直接法。作为第 2篇 ,文中阐述了同步有界稳定性和蠕步有界稳定性的不同概念 ,初步讨论了它们的关系 ,并分析了滑步与同步失稳之间的关系。文中还讨论了壁垒点与观察点这 2个要素 ,指出反映能量壁垒的点并不是不稳定平衡点 ,而是各保稳映象中首先遇到的动态鞍点 ,能正确反映系统实际受扰程度的观察点并不是故障清除点 ,而是实际受扰轨迹上的壁垒点。

Ten essentials for large-disturbance stability theory are abstracted. In terms of each of the essentials, Lyapunov direct methods, transient energy function (TEF) methods and extended equal-area criterion (EEAC) are critically compared in this four-part paper. A variety of viewpoints on the barrier point and the observation point are reviewed in the second part. The barrier point, which decides the critical value of the disturbed-measure function, might not be any unstable equivalent point, but the first-met dynamic saddle point among all complementary-cluster center-of-inertia images as EEAC does. The observation point, which represents the actual value of the disturbed-measure function for the disturbed trajectory, should not be the point at the fault clearing time but simply the same point as the dynamic saddle point.