The use of shear responsive stress control mastics as void fillers in medium voltage cable accessories

摘要

In the majority of polymeric medium voltage cables the outer conductive insulation screen (shield) is connected to earth (ground), and this contains the radial electrical field within the insulation. The status quo is disrupted when the screen is removed during jointing or terminating and the screen cutback is left untreated. The stress at the screen cut will be much higher than the design stress of the cable (Figure 1), and cable accessories are designed to control this stress to a workable level [1]. The example illustrated in Figures 1 and 2 shows this effect with a nongeometric stress control method, but similar effects will occur with geometric systems. Use of an effective stress control system ensures that the stress lines are redistributed to reduce the highly localized stress at the screen cut.