| 摘要 |
PURPOSE:To detect damages such as melting of metal strands, wire breakdown and the like, by providing electric insulating thin films around the entire surfaces of the metal strands, and performing continuity tests between the metal strands or between the metal strands and a metal pipe. CONSTITUTION:Electric insulating thin films 8... are provided around the entire outer surfaces of metal strands 6..., which form twisted wires 7 in a composite overhead earth wire (OPGW) made of optical fiber. The electric insulating thin films 8 electrically insulate parts between the metal strand wires 6 and between the metal strand 6 and a metal pipe 5. When the metal strand 6 is melted or broken due to thunderbolt, the electric insulating thin film 8 at that part is broken. Therefore, the insulating state between the metal strands 6 and the metal pipe 5 or between the metal strands 6 is broken. Then, a current is made to flow between the metal strands or between the metal strands 6 and the metal pipe at one end of the OPGW, and a continuity test is performed. Then, the damage of the metal strand 6 can be detected. The damage point can be detected with a fault locator.
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