| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a directional protective relay device and a directional power relay device, capable of reducing the installation number of current transformers for protecting a three-phase AC circuit against short-circuit faults or reverse flows, and the numbers of directional protective relays and directional power relays. Ž<P>SOLUTION: An S-phase of a power transmission line is led through an annular iron core of a three-phase through current transformer 10 installed on a power transmission line so as to be in a reverse direction to that of the R-phase only one time, while the T-phase of the power transmission line is led through reversely to the R-phase two times. Upon detecting a short-circuit fault based on a short-circuit current I<SB>Ry</SB>inputted from the three-phase through current transformer 10 and voltage information of the power transmission line, a short-circuit directional relay 4 collectively interrupts first-third breakers 2<SB>1</SB>-2<SB>3</SB>installed on the R-phase, S-phase and T-phase of the power transmission line respectively. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
|
