Abstract: With the rapid development of economy, there will be more in the upgrading of the level of automation in petrochemical engineering and petrochemical enterprises in China in the future. In solving the impact of the power shaking, the impact of the grid connected to the system will have a higher and more specific requirements. In order to deal with this phenomenon, a new type of integrated fast cutting device is proposed. Then, by combining with the actual operation situation, the computer simulation is carried out. Finally, the simulation results are used to analyze whether the frequency, power angle and voltage change meet the grid connected condition during the process of fault switching.