| 摘要 |
<p>PURPOSE:To precisely measure a length of a power cable with ease before laying the cable by providing an optical fiber integrally with a measuring cable having the equal flexural rigidity as that of the power cable to be laid. CONSTITUTION:A plurality of element wires 12 are twisted together, thus obtaining a measuring cable 10, in the center of which an optical fiber unit 1 is located. The measuring cable 10 has the same size in the outer diameter and equal flexural rigidity as those of a power cable laid inside a conduit. The length of an optical fiber 18 of the optical fiber unit 15 is detected on the basis of an optical signal, and the actual length of the cable is measured with the measuring cable 10 housed inside the conduit. Otherwise, three cables are twisted together in the same manner as a triplex type cable 20 actually used inside the conduit, thereby constituting a triplex cable. Therefore, the length of the conduit is measured by using the optical fiber and an optical pulse tester.</p> |
