Finite element analysis of positive streamer propagation with lightning impulse voltage

The response of lightning impulse voltage was tested in dielectric liquids employing the hydrodynamic modeling with three charge carriers by using the finite element method. To understand the physical behaviors of discharge phenomena in dielectric liquids, the response of step voltage has been extensively studied recently by using numerical techniques, but that of lightning impulse voltage was rarely seen in technical literatures. We, therefore, tested the impulse response with a sphere-plane electrode and a tip-sphere electrode which is explained in the IEC standard #60897 in detail. Before testing the lightning impulse response, we verified our numerical setup comparing with the previous results from the literatures. To stabilize our numerical setup, the artificial diffusion technique was adopted and the finer mesh distribution was generated along with the axial axis. We found that the velocity from the numerical result corresponded to that from the experimental result of lightning impulse breakdown testing in the literature.