The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 21, 1986
Filed:
Jun. 21, 1983
Michael Vitins, Zurich, CH;
BBC Brown, Boveri & Company Limited, Baden, CH;
Abstract
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 fault; 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.