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:
Mar. 29, 2005
Filed:
Aug. 26, 2002
Applicants:
Takahiro Kase, Tachikawa, JP;
Hidenari Amo, Fuchu, JP;
Yasutaka Sonobe, Koganei, JP;
Inventors:
Assignee:
Kabushiki Kaisha Toshiba, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02H003/18 ;
U.S. Cl.
CPC ...
Abstract
In a protective relay system according to an aspect of the present invention, a direction of a fault is correctly determined during system oscillation using one of a negative-phase-sequence relay and a zero-phase-sequence relay. A circuit breaker is tripped only when an internal fault is determined at both terminals to be protected using a carrier signal. Thus, even though a fault occurs during system oscillation, the circuit breaker can be tripped against the internal fault.