Natural disasters such as typhoons, lightning and ice disasters are difficult to predict and control. These catastrophic weather events not only seriously affect people's production and life, but also bring harm to the operation of the power grid, so an increasing amount of attention has been paid to them. Lightning strikes in the UK on August 9, 2019 caused a power outage. This once again sounded the alarm for the safety of domestic and foreign power grid operation. This paper first analyzes the development process of the 8.9 blackout in the UK, and reveals the chain reaction of system voltage drop and frequency drop caused by the lightning strike. Then the voltage stability and reactive power compensation capacity calculation method of a wind power-containing power system is studied. Taking a typical regional power grid as an example, simulation analysis of power grid stability under severe faults is made. This paper puts forward countermeasures to prevent system instability under catastrophic weather events. Finally, it provides relevant measures and suggestions for improving the safety and stability of power grid operation. This work is supported by Major Science and Technology Special Project of Hunan Province (No. 2016GK1003).