| 摘要 |
<p>PURPOSE: To provide a highly reliable accident point spotting device by preventing the erroneous spotting of the device when an accident happens. CONSTITUTION: A ground-fault over-voltage monitoring means 11 detects a ground-fault over-voltage. An AC under-voltage monitoring means 12 detects a voltage drop across a bus caused by a ground-fault. A bus-phase voltage monitoring means 13 detects the occurrence of a power failure caused by the tripping of a circuit breaker. A ground-fault detection locking means 10 discriminates whether an accident happens inside or outside of the container of insulating equipment by logically combining the signals from the means 11, 12, and 13 by means of circuits 14-19 and further discriminates whether or not the rise of gas pressure in the container is caused by the tripping of the circuit breaker. In case the possibility of erroneous spotting of a ground-fault exists as a result of the above-mentioned discrimination, the locking means 13 inhibits the ground-fault detecting operation of a ground-fault detecting arithmetic means by outputting a ground-fault detection locking signal to the arithmetic means.</p> |
