| 摘要 |
PURPOSE:To inspect a protective relay, and to protect a main circuit even if a trouble occurs in a main circuit during an inspection by varying the set value of at least one protective relay. CONSTITUTION:A main circuit current is converted into a secondary current by a main circuit current transformer 1, and input to parallel-connected two protective relays A, B. The outputs of the relays A, B are used as a trip signal of a breaker through an AND gate, and used as an inspection output through an OR gate 16. When a test is executed, a lower set value than the set value of a setter 9 is set to an outer set interface 10 via a signal line 18, one of signal lines 20, 21 is set to 'H', the other is set to 'L' to set either protective relay A or protective relay B to a testing state. If it is normal, an output is exhibited in the OR gate 16 by an output from its protective relay, thereby performing an inspection. |
