Field distortion by a single cavity in HVDC XLPE cable under steady state

Electric field distribution in high voltage direct current (HVDC) cross-linked polyethylene (XLPE) cable at steady state is researched in this study. Under the condition that no cavity exists, equations describing the critical temperature difference for field reversal, and electric field distribution at steady state are proposed. When the cable with cavity is studied via the finite element analysis method, 2D and 3D model can be two possible choices. The comparison between these two models provides the reference for model selection so that the problem can be solved correctly. To study field enhancement by a single air-filled cavity at steady state, some possibly influenced factors are considered, including the cavity location, cavity size, cavity shape, temperature difference and material type. The equation describing field enhancement is given in the study.