Fallas de alta impedancia en los sistemas de distribución eléctrica

Abstract

Most of the time, a fault in an electrical power system presents a much higher current than the current that flows in the system during. normal conditions. This fault current is harmful for the components of the system because they were not designed to sustain the fault current for a long Hm» For this reason, the electrical system is mainly protected against over-currents. In some instances, a fault in the primary conductors of the distribution system may exhibit such a low current that the over-current protection devices can not detect. This type of fault may persist indefinitely, possibly causing damage. to private property, animals and humans by contact with energized llw-s. A fault which presents this behaviour is called a high impedance fault. Many research efforts have been made into high impedance detection, which employ various strategies. Until 1989, no technique had gained industry-wide acceptance for an effective and reliable operation. Some products developed for the detection of high impedance faults were launched to the market during 1991, but it is still too early to discuss their effectiveness. This document describes the conventional over-current protection system, high impedance faults and the new technology available detect them.