| 摘要 |
PURPOSE: To enhance reliability of the operation of a relay and the safety of a protective system by distinguishing an internal trouble and an external trouble. CONSTITUTION: If a trouble is generated in an A-phase, a comparator circuit not illustrated, generates an output signal by a trouble currentΔiAt and generates an operation signal O1 meaning that the A-phase trouble has been generated within the protective range of a relay. Similarly, an input comparator 424 generates an output signal. The operation signal meaning that it has been generated within the resistance range of a relay is generated from a comparator 428. A tripping signal is generated from an AND gate 250 by the operation signals O1 and O2 .
|
