PROCESS FOR DETECTING FAULTS OR FAULT DIRECTION IN ELECTRICAL LINES AND MEANS FOR CARRYING IT OUT

摘要

A method and apparatus for detecting a fault and also the direction of a fault in electric lines, wherein voltage (Su) and current step signals (Si) corresponding to the transient components in the line voltage and line current are derived; the instantaneous values of these step signals (Su, Si) define, in a co-ordinate system formed by the step signals (Su, Si) themselves, a point which passes through a line of motion (B) after the occurrence of a fau and if the point transgresses a triggering boundary (AI, AII, AIII, AIV) in the co-ordinate system the fault is detected. In this event the direction of the fault is found from the quadrant (QI, QII, QIII, QIV) in which the transgression takes place. At a predetermined time after entry of the point into a boundary zone provided in one quadrant, located in the line of motion ahead of a triggering boundary in next adjacent quadrant, a triggering boundary in at least the next adjacent quadrant is adjusted to a greater distance from the origin of the co-ordinate system which is located in the same semicircular space bounded by the axis of the voltage step signal (Su). This measure considerably increases the reliability of detection with respect to fault direction and, in addition, reduces the time required for fault detection.