The lower-level problem is to maximize the loading margin under a load change direction and the upper-level problem is to find the closest critical point subject to the constraints of load change.

下层问题求解某个负荷变化方向上的最大负载裕度，上层问题考虑负荷变化方向的约束，寻找最近的电压稳定临界点。

youdao

The lower-level problem is to maximize the loading margin under a load change direction and the upper-level problem is to find the closest critical point subject to the constraints of load change.

下层问题求解某个负荷变化方向上的最大负载裕度，上层问题考虑负荷变化方向的约束，寻找最近的电压稳定临界点。

youdao