On cable, in the socalled “mask”, essentially a measure of improvement of electric field distribution. Conductor by multiple wires twisted together, easy to form air gap between it and insulation, not smooth on the surface of the conductor creates electric field concentration. Surface shield plus one layer of semiconducting material, and unshielded conductor equipotential bonding and good contact with the insulation layer, so as to avoid partial discharge occurs between conductor and insulation.
This a layer shield for within shield layer; also in insulated surface and nursing sets contact Department also may exists clearance, is caused local discharge of factors, so in insulated layer surface plus a layer half conductive material of shield layer, it and was shield of insulated layer has good contact, and metal nursing sets, potential, thereby avoid in insulated layer and nursing sets Zhijian occurred local discharge.
This a layer shield for outside shield layer; no metal nursing sets of squeeze package insulated cable, except half conductive shield layer outside, also to increased with copper with or copper wire around package of metal shield layer, this metal shield layer of role, in normal run Shi through capacitor current; Dang system occurred short-circuit Shi, as short-circuit current of channel, while also up to shield farm of role. If the outer semiconductor layer and this layer of copper in cables shielding does not exist, in a three-core cable insulation breakdown occurs between the core and the core is a distinct possibility.
