Calculation of transient radiation field from metallic enclosure of GIS based on surface-patch model

To improve the computation accuracy of the transient radiation fields in gas insulated substation (GIS), surface-patch model is proposed in this paper, and the method of vector fitting combining with recursive convolution is applied to substitute the method of fast Fourier transform (FFT) in the process of field calculation. The transient radiation fields of an actual 125-kV GIS are calculated to confirm the correctness of the model and the method. It is seemed from the simulation that the method of vector fitting combining with recursive convolution can overcome the conventional problems of FFT and reduces the computer memory and CPU time successfully, and the results from surface-patch model are more accurate than those from thin-line model.