Characterization of the effect of the insulating material of covered cables on the impulse breakdown behavior of single- and three-phase compact distribution lines

•Larger withstand levels for HDPE covered cables are reported.•Differences up to 60% on minimum breakdown voltages are noted.•HDPE-covered cable presents shorter time for disruption.•The disruptive voltage is influenced by the pinhole location along the cable cover. This paper aims to characterize the influence of the insulating material of covered cables on the impulse breakdown behavior of typical single- and three-phase compact distribution line configurations. Based on high voltage tests with standard lightning impulse voltages, three main features are investigated: (i) minimal values of breakdown voltage, (ii) time for disruption, and (iii) pinhole location. The results indicate larger withstand levels for the single- and three-phase structures when high-density polyethylene (HDPE) is used instead of crosslinked polyethylene (XLPE) in the insulating layer of the cables. Differences up to 60% are reported. Also, HDPE-covered cable presents a shorter time for disruption. Typically, voltage breakdown was observed in the wavefront for HDPE-covered cables and in the wavetail for XLPE-covered cables. Finally, tests with punctured samples showed that the value of the disruptive voltage is influenced by the pinhole location along the cable cover.