Weld lines in power cable insulation

Seams were observed in the XLPE insulation of power cable. The type and intensity of the cables varied due to the melt temperature and homogeneity in the extrusion. Electrical needle tests performed with four cable samples manufactured with two separate methods indicated that the weld line-containing sector of the cable is measurably weaker than the insulation in general. Conical extrusion was able to modify, level out, and reduce the seam effect. These results lead to the conclusion that the traditional extrusion process can be considered a less robust solution than the rotating mass distributor with respect to the seams.