When the local high voltage discharge occurs in the internal area of a converter transformer oil tank,the transformer oil in the discharge area will be vaporized instantly and explosion pressure wave will be generated.In order to study the propagation characteristics of the pressure wave in the transformer tank and elevated seat area in the above process,a three-dimensional geometric model was established and divided into polyhedral meshes according to the actual experimental situation.For numerical simulation,a fluent software was used.During the calculation,the actual discharge energy curve was loaded in the discharge area through the profile file,and the compressibility of gas and liquid was considered through the gas-liquid two-phase flow model.The results show that when the arc energy is 4.929 MJ and the duration is 58.6 ms,the peak pressures at the monitoring point on the top of the elevated seat,on the left and right top of the oil tank are 1.21 MPa,4.62 MPa and 3.79 MPa,respectively.The pressure peak in the elevated seat area decreases with the increase of the distance from the fault point.The simulated pressure peak and pressure variation trends obtained by simulation at different monitoring points display a satisfied consistence with the experimental results,which verifies the effectiveness of the simulation calculation model.By establishing and solving the arc fault discharge simulation model in the oil tank through numerical simulation,the detailed pressure variation curve and the pressure wave propagation law in the three-dimensional space can be obtained.It can greatly reduce the loss of manpower and material resources caused by the discharge experiment,and provide an effective theoretical basis for the prevention of arc explosion accident in the transformer oil tank.