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:
Dec. 16, 1986
Filed:
May. 07, 1985
Patrick Charles, Mareil sur Mauldre, FR;
Cgee Alsthom, Perret, FR;
Abstract
Apparatus for generating a signal indicative of a fault occurring in an AC electric circuit connected to an AC network (UW). The AC circuit (1) comprises a series connection of at least one inductance winding (L) and a two-way static switch having thyristors (5, 6) controlled by firing pulses .theta., and the capacitive impedance and the resistive impedance of said AC circuit are negligible relative to its inductive impedance L. The apparatus comprises a differential relay (15) receiving first and second input signals and providing an output signal (Id) when said input signals are unequal. The first input signal is a real image of the current flowing through said AC circuit as provided by the secondary winding of a current transformer (30) inserted in said AC circuit. The second input signal is a theoretical image of the current flowing through said AC circuit as provided by a theoretical image signal generator (16) which generates the theoretical image signal as a function of the said inductive impedance L, the firing pulses .theta., and the driving voltage across said AC circuit as indicated by the secondary winding of a voltage transformer (18), the voltage and current transformers being designed so that said two signals represent images to the same scale of the current of said circuit.