| 摘要 |
PROBLEM TO BE SOLVED: To infallibly prevent the main relay and fault-detector relays in a main fail-safe protective relay system from operating erroneously or outputting error signals due to incoming waves and noises from the outside. SOLUTION: The main detector relay 7 and fault-detector relay 8 are provided with a sensitivity relay means (sensitivity relay 10) which compares the system current and voltage with the value a slightly smaller than the control- error suppression criterion and outputs a control-stop signal when it obtains a value smaller than the criterion, a communication means 12 to transmit the above output between the detector relays 7 and 8, and an output control means 14 to cutoff the relay control output based on the communication means 12 during the period the sensitivity relay outputs control-stop signal. |
