Modelling of Streamer Propagation Velocity in Ester Group Insulating Oil by Considering Electron Velocity Saturation

Ester group insulating oil is an environmentally friendly dielectric liquid. Its physical, chemical and electrical properties can meet the requeirements of transformer oil. In order to understanding the formation and development mechanism of streamers in ester group insulating oil, the simulation analysis of streamer discharge is an essential research method. However, a major drawback of the existing positive streamer photocharge drift models is the overestimation of electron velocities. In this paper, we use a nonlinear electric field-dependent electron velocity model that more accurately describes streamer velocity. The results show that under the voltage amplitudes of 50kV, 70kV and 90kV, the average propagation velocities of streamers are 2.08km/s, 3.2km/s and 4.53km/s, respectively, which are consistent with experimental findings in the literature.