| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of reporting the condition of current loading to the remote end side of a power cable, without using any special signal wire or wireless facilities. SOLUTION: Along with fitting current transformers to the grounding wires at both ends of a power cable, blocking coils are inserted between these CTs and the ground. A circuit capable of controlling an alarm device fitted to the vicinity of the remote-end side CT by detecting a signal put in from the CT at one end (measuring end) of the power cable with the CT fitted to the other end (remote end) side of the power cable, using the shielding layer or external semiconductive layer of the power cable as a signal wire, is constructed. The alarm device is controlled by putting a high-frequency pulse signal of a specific pattern into the grounding wire on a measuring side of the power cable through the CT fitted to the grounding wire, and detecting the signal at the remote end side of the power cable through the CT. Along with it, the condition of the remote end side alarm device is monitored in real time, by putting a high-frequency pulse signal of a specific pattern representing the condition of the alarm device into the grounding wire at specified intervals also from the remote end side of the power cable, and receiving the signal at the measuring end of the power cable.
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