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:
Jan. 31, 1978
Filed:
Jun. 21, 1976
Applicant:
Inventors:
Assignees:
Tokyo Shibaura Denki Kabushiki Kaisha, Kawasaki, JA;
Chugoku Denryoku Kabushiki Kaisha, Hiroshima, JA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02H / ;
U.S. Cl.
CPC ...
361 64 ; 361 66 ; 361 68 ;
Abstract
In a protective relaying system wherein a carrier wave frequency modulated by an electric quantity is transmitted to a receiving station for operating a relay and an abnormal condition of the transmitted signal is detected by detecting the frequency variation of the carrier wave, there is provided an abnormal condition detector which compares the lengths of contiguous or closely adjacent periods, or functions thereof, of the received carrier wave.