A design method is presented for the pressure relief hole of the metal-enclosed switchgear to avoid the explosion hazard of internal arc fault and ensure pressure release quick. This paper analyzes the Cassie arc model and the standard calculation method

and simulates the process of switch equipment internal arcing fault

pressure rising and releasing pressure based on MATLAB. The corresponding internal the greater pressure is calculated by gradually changing the pressure relief hole size. A suitable pressure relief hole is designed by combining the strength or contact pressure of gas tank

post insulator and dynamic seal ring

and experiment verification is made.The simulation results are close to experimental data

and type test is passed validation. Test result proves that the simulation and design method are reasonable

which can not only improve the safety of the equipment

but also shorten the development period of new products.