Lightning protection of cable-connected high-voltage distribution substations by surge diverters

For devising a general guidline on lightning protecting of distribution substations connected to overhead lines through cables, the surge voltages at both ends of the cable are derived for various types of incident lightning surges. The substation is represented by an open-circuited cable, which would result in surge voltages at the cable terminations equal to, or more severe than, the surge voltages for practical installations. The results are used to assess: (i) whether protective devices are needed (ii) when they are needed, whether surge diverters at one end of the cable provide adequate protection. Attention is paid to the surge strength of the line insulation, as on it depend the types of incident lightning surge to be used in devising general guidelines.