Circuits operation control and overloads protection: Power cables equivalent ampacities

The evaluation of the ampacity of electric power cables and the overload pr otection are currently based on criteria, to which the operation of the cir cuits will have to satisfy. each time Like the first time, without self-mem ory of the way of life, without discounts or debts correspondent to the act ual profile load, certainly different from a steady-state Line. The number and the duration of the emergency overload events are taken statistically i nto account (IEC rules) or are fixed in advance for an allowable average ti me per sear over the Life of the cable (ICEA approach). BZ To enhance these criteria, this paper suggests a method to define in the low-voltage range an equivalent prospective power cables ampacity, based on the global allowa ble cables life loss and considering the performance in the time. Since sti ll monitoring and memorizing the actual life of power cables are not possib le, the paper BE proposes a simple and quick evaluation method for the duty cycles characterized or approximated by load phases of continuous currents , The aim of this paper is to try to help the feeling of performance and be havior of insulated power cables. Ln reference to the prospective actual lo ad profile of each circuit or grouping of circuits, this feeling is very us eful for the designer to presuppose how much the power cable size will. be allowable and for the maintenance operator to presume during the life of th e circuits the real conditions of the power cables.