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:
Aug. 09, 2022
Filed:
Dec. 31, 2020
Schweitzer Engineering Laboratories, Inc., Pullman, WA (US);
Ritwik Chowdhury, Charlotte, NC (US);
Matchyaraju Alla, Pullman, WA (US);
Satish Samineni, Malvern, PA (US);
Normann Fischer, Colfax, WA (US);
Dale S. Finney, Little Bras d'Or, CA;
Schweitzer Engineering Laboratories, Inc., Pullman, WA (US);
Abstract
Detection of, and protection against faults within a restricted earth fault (REF) zone of a transformer or a generator is disclosed herein. Security of the REF protection element uses comparison of a negative-sequence reference quantity. The REF condition is only detected when there is sufficient ground involvement and a fault in the reverse detection has not been detected. Dependability of the REF protection element in low-impedance grounded systems is improved by ensuring that the element operates when a zero-sequence reference quantity and a neutral operate quantity are orthogonal to each other. The REF protection element further determines an open CT condition and blocks detection of an REF fault upon determination of the open CT condition. A tripping subsystem may issue a trip command based upon detection of the REF condition.