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.

• 归纳出10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。