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. 26, 1985
Filed:
Sep. 29, 1982
Tokyo Shibaura Denki Kabushiki Kaisha, Kawasaki, JP;
Abstract
A protective relaying system is disclosed 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 an input conversion/unit adapted to receive a first and a second input signals corresponding to said current and voltage, for converting the magnitude and/or the phase of the first and second input signals to produce least two electrical quantities a first electrical quantity and a third electrical quantity, and for outputting the second input signal without conversion as a second electrical quantity. The protective relaying system also includes a comparing unit connected to receive first, second and third electrical quantities from the input conversion unit for comparing the first and second electrical quantities to produce a first logical state and comparing the third and fourth electrical quantities to produce a second logical state signal cyclically. The protective relaying system further includes a digital data processing unit for judging whether a specified logical condition between the first and second logical state signals holds for a predetermined number of times corresponding to a predetermined electrical angle, and for producing a protection relay output signal based on the judging result. The protection relay output signal is adapted for using to trip the circuit breaker.