| 摘要 |
PURPOSE:To detect the yield of abnormal temperature in the conduction of electric power cable directly, by displacing a configuration memorizing alloy material by the temperature increase in the electric power cable, bending optical fiber, and detecting the time change in reflection intensity of light pulses at this time. CONSTITUTION:A configuration memorizing alloy material 4 is inserted along a built-in optical fiber 3 in electric power cable. Light pulses are sent into the fiber 3. When the fiber 3 is in a normal state, the outputted pulses change approximately linearly. When the temperature of a conductor 1 is increased to a value exceeding the transition temperature of the alloy material 34, the alloy material 4 deforms each part of the fiber 3, and many bent parts 10 are formed. Therefore the outputted light pulses change in a small step shape. When the temperature of the conductor is partially increased in an abnormal phenomenon, the temperature of only the alloy material 4 in the vicinity of the abnormal location is increased to the value exceeding the transition temperature. Only a part of the fiber 3 is deformed. The outputted light pulses change in a step shape only at the specific part. By monitoring the outputted light pulses, the abnormal temperature of the electric power cable can be detected. |
