Problems needing attention in field insulation resistance test of medium voltage XLPE cable

- May 04, 2018-

  into the plate in the XLPE cable before the factory, manufacturers are electric saws will be cut at both ends of the neat, with a hot shrink cap for sealing treatment. It is unavoidable to attach some copper slag and copper powder to the insulating surface of the cut at the end of the cable cutting process. If the copper residue and copper powder are not cleaned up during the process of measuring the insulation resistance after the goods are inspected or laid down at the customer's site. will result in the whole cable insulation resistance is zero or low, resulting in the cable production suppliers of product quality misjudged.

The author has several times on the customer reflects the 10kV, 35kV cable insulation resistance to zero or low to the scene for the view, are due to the cable end of the end of the surface adhesion of copper slag and copper powder clean up. The above problems reflect some customers lack of understanding of the material and structure of the medium voltage power cable, and make some common mistakes in the detection. Medium Voltage Three-core XLPE power cable mainly has conductor, conductor shielding (also known as the inner half conductive shielding) layer, insulation, insulation shielding (also known as the outside half conductive shielding layer), metal shielding layer, filling, tape, internal protection layer, steel tape armored, external protective layer and other materials. The insulation core is mainly conductor, inner half conductive shielding layer, insulation, the outer half conductive shielding layer is through the 0+3 three-layer coextrusion cross-linked production line of a continuous extrusion, the half conductive shielding layer and the outer half conductive shielding layer material color black, are conductive material; the insulation is dark white, metal shielding layer is generally copper belt The coating is tightly wrapped in a half conductive shielding layer outside the insulating line core.

As some customers use the conventional view of low voltage cables when they first used the medium voltage XLPE cable, it is mistaken to think that the half conductive shielding layer of insulated core is black insulating material, and the stolen goods and copper residue and copper powder attached to the insulating section of the cable end head are inspected and cleaned carefully, which leads to the wrong inspection and misjudgment of the insulation resistance of the cable. In order to avoid customers in the use of the roll table to the medium voltage Xlpe cable in the field insulation resistance test to make some unnecessary common mistakes, recommended cable manufacturers in the cable to provide customers with the use of instructions, to the insulation resistance test before the middle voltage xlpe cable end how to correctly handle and correct test steps to write clearly, So that customers can scientifically correct acceptance and use of medium voltage XLPE cable.