PROTECTIVE ACTION OF METALLIC CONDUCTORS UNDER THE EFFECT OF HIGH-VOLTAGE LINES

As is well known, extended metallic conductors and cables are widely used both in the USSR and abroad for protecting cable communications lines (CL) from dangerous effects of high-voltage lines (HVL) and direct lightning strikes. With magnetic effects of the HVL, the protective action of conductors and cables amounts to generation of back emf in the conductors of the communications line being protected by the current induced in them. The higher the current in the support cable, the greater its protective capability. This then gives rise to the basic requirement for the protective conductors - reliable grounding. The highest protective capability, the so-called "ideal" protection coefficient (PC), is that of an "ideal" grounded support cable, i.e., a cable connected to earth by a very-low resistance. A protective cable having direct contact with the ground, without external insulation, may be considered in the majority of cases an ideally grounded cable.