CU/XLPE/CAS/PVC 38/66KV XLPE Insulated Underground Power Cable
Voltage grade is up to 220kv, cross-section area can be up to 2500 sqmm (copper or aluminiun conductor). Conductor long-time operating temperature is 90 degrees. In short circuit, conductor highest temperature should be not more than 250 degrees.
2. Brief Construction:
Single core
Copper or aluminium conductor
XLPE insulation
Corugation aluminum sheath
PVC or PE sheath
3. Laying conditions: For lyaing under ground with large different altitude, be able to bear external machanical force and moderate pulling force
4. MANUFACTURING FEATURES
Conductor
The conductor shall be round compact stranded copper or aluminum wires. The resistance of each conductor at 20ºC shall be in accordance with IEC 60228 standard. The surface of the conductor shall be clean and free from any foreign particles, which may contaminate the insulation or cause high electrical field stress in the conductor screen.
Conductor screen, Insulation and Insulation screen
Extrusion of conductor screen, insulation and insulation screen shall be by single pass, triple extrusion method. Conductor screen, XLPE main insulation and insulation screen shall be produced by triple extrusion and dry curing.
Conductor screen shall consist of semi-conducting tapes applied over the conductor and a continuous layer of extruded semiconducting XLPE compound covering the entire surface area of the conductor and firmly bonded to the inner surface of the insulation.
The insulation shall be XLPE and shall be applied by extrusion and cross-linked to form a compact and homogeneous layer in accordance with the Standards specified. The insulation material shall be of Super Clean polyethylene mixture suitable for cross-linking (XLPE).
Insulation screen shall consist of a layer of extruded non-strippable semi-conducting thermosetting compound.
After triple extrusion, the insulated cores shall be degassed to remove the by-product in the core from the cross-linking process.
Bedding
Semi-conducting water-blocking tapes (swellable tapes) over the insulation screen shall be applied to prevent longitudinal water penetration between insulation screening and metallic sheath. The swellable tape shall cover the entire surface area of the insulation screen.
Metallic sheath
Corrugation Aluminum sheath shall be applied over the semi-conducting water blocking tape to accommodate the required radical water tightness and protect the insulation core.
Outer sheath
The outer-sheath shall be of an extruded layer of black color PVC.It shall be highly chemical resistance and withstand the mechanical force during fabrication, transit,installation and operation.
Outer conductive layer
A coating of Graphite shall be applied over the over sheath to carry out D.C. Voltage Test.
1. The products are mainly complying with IEC 60840 standard, also can be produced according to OEM requirements and other standards, such as bs standard, DIN standard, ASTM standard, etc.
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