SELF-POWER CIRCUIT FOR PROTECTING RELAY

摘要

A self-power circuit for a protecting relay includes: a rectifying circuit section rectifying an AC current from an electric power system; a power source circuit section includes: a comparator comparing whether an output voltage from the rectifying circuit section exceeds a reference voltage and a semiconductor switch configured to be switched by an output from the comparator, and supply the output voltage from the rectifying circuit section, as a constant voltage to a microcomputer unit of the protecting relay; an inductor configured to, when a DC current supplied from the rectifying circuit section is rapidly increased, gradually increase the DC current to flow to thus have an increased voltage thereacross; and a bi-directional diode connected between the power source circuit section and a ground and turned on to form a bypass path of a current when a DC voltage supplied from the power source circuit section is rapidly increased.

主权项

1. A self-power circuit for a protecting relay, the self-power circuit comprising:
a rectifying circuit section configured to rectify an alternating current from a current transformer that detects amount of an electric current flowing through an electric power line of an electric power system; a power source circuit section connected to an output terminal of the rectifying circuit section and configured to include a comparator comparing whether an output voltage from the rectifying circuit section exceeds a reference voltage and a semiconductor switch configured to be switched by an output from the comparator, and supply the output voltage from the rectifying circuit section, as a constant voltage to a microcomputer unit of the protecting relay; an inductor connected to the semiconductor switch of the power source circuit section in series and configured to, when a direct current supplied from the rectifying circuit section is rapidly increased, gradually increase the direct current to flow to thus have an increased voltage thereacross; and a first bi-directional diode connected between an output terminal of the power source circuit section and a ground and turned on to form a bypass path of an electric current when a direct current voltage supplied from the power source circuit section to the microcomputer unit of the protecting relay is rapidly increased.