DIGITAL PROTECTION RELAY, DIGITAL PROTECTION RELAY TEST DEVICE, AND METHOD FOR TESTING DIGITAL PROTECTION RELAY

摘要

A digital protection relay according to an embodiment of the present invention has: an auxiliary converter (2) for reducing the voltage of an electrical signal from a main-circuit converter (1); a detection resistance circuit (20) connected on an output side, the input side being the auxiliary converter (2), the detection resistance circuit (20) formed in the shape of the letter &pgr; or T; an analog detection circuit (3) attached to the output side of the detection resistance circuit (20), and used for detecting the electrical level of the electrical signal from the auxiliary converter (2); an A/D conversion circuit (4) connected to the analog detection circuit (3); a central processing unit (5) connected to the A/D conversion circuit, and used for performing protective actions; and a trip output contact point (9) operating based on the processing of the central processing unit (5) for operating an external breaker (21). The digital protection relay provides, between the detection resistance circuit (20) and the analog detection circuit (3), an input contact-point terminal (11) for inputting a test signal using a fixed voltage from an external test device (13) to the analog detection circuit (3) as a signal corresponding to the output of the auxiliary converter (2).