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:
Apr. 16, 1985
Filed:
Sep. 29, 1982
Fumio Andow, Hachiohji, JP;
Masuo Nakashima, Urawa, JP;
Tokyo Shibaura Denki Kabushiki Kaisha, Kawasaki, JP;
Abstract
A protective relaying system which detects a fault in an electric power system having a circuit breaker by using a current and a voltage of the electric power system. The protective relaying system includes input conversion unit adapted for connecting the electric power system to receive a first and a second input signals corresponding to the current and the voltage and for converting the magnitude and/or the phase of the first and second input signals to produce a first, a second and a third electrical quantities. The protective relaying system also includes comparing unit connected to receive the first, second and third electrical quantities, for comparing the first and second electrical quantities to produce a first logical state signal, and comparing the third and a fourth electrical quantities to produce a second logical state signal cyclically, and for producing a logical state signal including the first and second logical state signals cyclically. The protective relaying system further includes digital data processing unit connected to receive cyclically the logical state signal, for producing a first and a second serial logical state signals and for judging whether a phase-rotation sequence of the first and second serial logical state signals equals a predetermined sequence to produce a protection relay output signal. The protection relay output signal is used to trip the circuit breaker.