| 摘要 |
<p>In the construction of an electric power transmission cable for medium voltage distribution (up to 60 kV), a metal (copper) screen, located a paper cover on a multistrand core cable having crosslinked polyethylene (XPE) insulation between extruded semi-conductor screen layers, is made of strip material previously impressed with transverse grooves and laid up helically to a short pitch. The grooved metal strip is overlaid with a helically wound textile tape and further layers of insulating rubber with an interlayer of steel braiding. The grooves in the metal layer increase its radical elasticity to compensate for the relatively high coefficient of thermal expansion of the crosslinked polyethylene layer, allowing heat cured rubber external insulation to be used on lay-ups involving both metal and (XPE) layers. The short radial pitch also improves the longitudinal flexibility of the composite cable.</p> |
