Using singular perturbation model,by the example of a simple power system losing stability in big disturbance, this paper analyses the mid-long term instability mechanisms affected by slow dynamics.

• 采用奇异摄动模型,通过一个简单电力系统在大干扰下发生中长期失稳的实例,分析了慢动态对系统中长期失稳的影响。