Characteristics XLPE
• permissible operating temperature
– For permanent (normal) operation 90°C
– short circuit +250°C
– overload operation and
damage sea +130°C
• Specific heat resistance 3,5 m/W
• Dielectric constant 2,4
• Specific resistance (20°C) min.
Insulation
– Cross-linked polyethylene (XLPE), compound
type DIX8 according 620 S2.
– Copper cross-section according 620 S2.
Outer sheath
– compound DMP2 according 620 black or
– PVC compound DMV6 according 620 red
– Wall-thickness 2,5 mm,
for 500 mm2
/30 2,6 mm
Continuation
▲
MEDIUM VOLTAGE POWER CABLES
XLPE-insulated 6/10 kV, 12/20 kV, 18/30 kV
.
Semi-conducting type
– Over the outer semi-conducting layer, semi-
conducting tape must used. 200%
• Tensile strength min. 0,5 10–3
• Density 0,92 g/cm3
• Breaking strength min.
Moreover, better dielectric constant value has an
effect the low mutual capacitance, the short-circuit
to ground and the charging current XLPE-insulated
cables.
In comparison PVC and paper-insulated cables, the
advantage XLPE-insulated medium voltage power
cables that they possess low dielectric factor, such as
it 100 times smaller than PVC-insulated cables.
– Semi-conducting compound, cross-linked,
wall-thickness 0,3 0,6 mm. 12,5 N/mm2
Conductor
– Copper aluminium, round, multiwire stranded
and compact, according VDE 0295.
Separator
– Over the screen well under outer sheath,
a separating layer must used (e.
Inner semi-conducting layer
– Semi-conducting compound, cross-linked,
mini-mum wall-thickness 0,3 mm.
The good properties XLPE-insulated cables remain
constant through wide temperature range.
Screen
– Screening copper wires must have minimum
diameter 0,5 and over that copper tape
applied helically with minimum thickness of
0,1 mm. The XLPE-insulation possesses very good
electrical, mechanical and thermal characteristics in
medium voltage networks.
In order prevent the penetration moisture and
also extend the duration life, the XLPE-insulated
medium voltage cables are designed with longitudinally
water-proof screen including additional swell tape
and outer sheath. taping). Due the heating and pressure the
molecule chains are joined each other, assuring the
transition from thermoplastic elastic condition.
The manufacture this sheath based high density
polyethylene (HDPE), which additive organic
peroxide mixed.
– Insulation nominal wall-thickness
for 6/10 3,4 mm
12/20 5,5 mm
18/30 8,0 mm
Outer semi-conducting layer
– Outer semi-conducting layer extruded together
with the inner semi-conducting layer and the
insulation one working process and are spliced
with each other. This type insulation very
chemically resistant and also resistant cold. Due to
various advantages, the XLPE-insulated type has vastly
displaced the traditional classical paper-insulated types
in many sectors.
Concentricity conductor
– The difference between the maximum and
mini-mum value 0,5 should not be
exceeded.Q
583
Since about 1970 the cross-linked polyethylene
(XLPE)-insulated power cables have been used in
Germany. 1016
Ohm cm
• Loss factor (tan (20°C) max
