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:
Jul. 03, 1984
Filed:
Sep. 20, 1982
Ivan De Mesmaeker, Windisch, CH;
BBC Brown, Boveri & Company, Limited, Baden, CH;
Abstract
The invention relates to a low impedance excitation system for use in distance relays. In such a system the low impedance check is carried out by comparing the phases of signals (U.sub.D,U.sub.S) which are obtained by forming the sum and the difference from an image voltage signal (U.sub.A) and a line voltage signal (U.sub.K). The triggering characteristic is formed in the complex impedance plane by means of the combination of at least two different triggering characteristics, mainly a circular (K) and a lenticular (L) characteristic, in order to avoid overlapping between the triggering area and the active load area (W) and in order to achieve an adequate arc reserve on the whole length of line to be monitored. The switching over between the different triggering characteristics (K,L) takes place as an operational function of the phase difference (.beta.) between the image voltage signal (U.sub.A) and the line voltage signal (U.sub.K).