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:
Sep. 10, 1991
Filed:
Mar. 12, 1990
Leland L Kessler, American Township, Allen County, OH (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
A differential protection circuit includes a pair of current transformers each having a secondary winding and each being inductively coupled to a power conductor at a different location. The secondary windings of these transformers are electrically connected in series with each other in a loop in a bucking arrangement. A resistor is connected in parallel with the secondary winding of each transformer. Control circuits are connected to sense a voltage signal appearing across the resistor and to take appropriate action when the sensed voltage reaches a predetermined level. An additional winding on one of the transformers provides isolation between the loop and one of the control circuits to prevent false tripping of the differential protection circuit.