Accurate and Rapid 3D Full-Maxwell Simulations of Very Fast Transients in GIS Based on a Novel Busbar Voltage Setting Method

In 3D full-Maxwell simulations of very fast transients (VFTs), both accuracy and simulation efficiency pose challenges. The existing method cannot set simulation conditions appropriately, resulting in subpar simulation accuracy for the VFT process and unnecessary time consumption. Moreover, for the very fast transient overvoltage (VFTO) waveforms estimated by simulations, there is still a lack of specific analysis on waveform characteristics and appropriate verification methods. In this paper, a novel method that significantly improves both the accuracy and the time efficiency of the 3D full-Maxwell simulation of the VFT process is proposed. The wave process generated by breakdown is also analyzed to obtain the VFTO waveform characteristics for subsequent verification. Simulation cases, based on both a simplified GIS model and an actual GIS model, are demonstrated and discussed. Furthermore, a specially designed field test on the typical 1100 kV GIS, taking into account the residual voltage, is conducted for the simulation verification for the first time. The simulation and field test results align well in both the time domain and the time-frequency domain. Additionally, the novelty of this proposed method is demonstrated by comparing it with other existing method in case studies. The accuracy of the method has been shown to improve significantly, and the simulation time consumption can be reduced with the same computational machine and simulation configuration.