Lightning protection wiring of oil switch on pole a

Lightning protection terminals of pole oil switches.
    Pole oil switches are mostly used for line segmentation or transformer matching . Due to its small phase distance and low insulation level, it must
be protected with a pavilion-type arrester or protective gap. Its wiring is shown in the figure. Figure (a) is suitable for oil switches that are often closed ; Figure (b) is suitable for oil switches
that are often open . The grounding resistance is not greater than 10,0.