By use of a new differential algebraic equation (DAE) model and direct method of reduction, the authors calculate the saddle-node bifurcation (SNB) point and the calculation amount is reduced.

• 这使鞍结分岔分析方法可应用于直流线路较多的交/直流系统。为判别系统发生的失稳模式，还引入了相关因子法。