| 摘要 |
<p>PURPOSE:To control surge voltage impressed on the corrosion preventing layer of a cable and to effectively protect the layer by installing a device for protecting the layer between the sheath of the cable and the ground at an intermediate point between the underground duct and the rising part led to the pylon. CONSTITUTION:A power cable 1 composed of a cable conductor 11 and a metal sheath 12 is covered with a corrosion preventing layer of PE, PVC, etc., and laid in an underground duct. One end of the cable is connected to a transformer 5 at the terminal connecting part provided with a device 6 for protecting the corrosion preventing layer. The other end is raised toward a pylon 7 and connected to the pylon 7 through the terminal connecting part 10 of the raised part provided with a built-in arrester. A device 20 for protecting the corrosion preventing layer is installed between the sheath 12 and the ground at a point A of transfer from the underground duct to the raised part leading to the pylon. Surge voltage impressed on the corrosion preventing layer is controlled to below a standard value related to breakdown strength and the layer is protected.</p> |
