XLPE Cable Current Rating Calculator
Choose cable size ( mm2) and Get current rating of 11 kv / 33 kv XLPE cable rating.
What is XLPE Cable
XLPE or cross-linked polyethylene cable is made from polyethylene plastic which is a thermoset insulation material. cross-linked polymers material have a special chemical property of the molecular structure of atomic chains that are very strongly and tightly bound together, due to which great dielectric strength and high insulation resistance can get through it. As temperature increases due to electrical heating, it provides excellent insulation and maintains electrical properties.
XLPE provides excellent resistance to abrasion and this special resistance to abrasion works excellent in both high and low-temperature types of situations. Cross-linked insulation is also low-cost insulation that why it can be affordable and economical to use. one more property that makes it unique insulation increase as voltage increases.
Current Rating of 11 KV XLPE Cable
Definition: The current rating of an xple cable is defined as the maximum current carrying capacity of the cable under normal conditions. The current rating of the xlpe cable is decided by the maximum power transfer by the cable. The current Rating of an xlpe cable depends on mainly two factors first one is the insulation temperature and the second one is the electrical resistance of the conductor. The current rating of xlpe cable can be categorized in three ways.
Types Current Rating of XLPE Cable
- Normal maximum continuous current rating.
- Over-current rating
- Short- Circuit rating
Normal or safe current rating
When the current flows within range of its maximum capacity through cable then Normal current carrying capacity depends on three-factor-
1- Heat dissipating properties of the cable
2- Minimum conductor operating temperature
3- Condition of installation means how the cable is laid underground or in the air.
During Normal current carrying capacity calculation, thermal resistivity of the sheath and cable is ignored. And the heat generated in the core of the cable is occurred due to various losses in the conductor. These heats are conducted to air or ground through bedding of resistance, metallic armor and finally passes into atmosphere air or ground depending on the type of installation.
|Serial no.||Size of XLPE cable(MM2)||Normal current rating (cable in ground)||Normal current rating (cable in air)|
Over Current Rating
The overcurrent rating depends on the thermal status of the xlpe cable if overloading increases means current increases in the heating also increase proportionally that causing more thermal energy must be dissipated along the way. further operational temperature of the wire and the insulation also get a rise. Overcurrent rating depends on the depth of laying, ground temperature, air temperature, etc.
Short Current Rating
As we know during a short circuit a heavy current flows through the conductor so the conductor size in xlpe cable a for electrical use is also decided by its capacity to carry the short circuit current during fault. Short circuit rating of xlpe cable is based on it is assumed that the duration of the short circuit is too short and there is no flow of heat, produced during a short circuit, through the insulation of xple and the whole of it is absorbed by the conductor of the cable. The short circuit current ratings (r.m.s. values) of XLPE insulated cables with aluminum/copper conductors for the one-second duration. These ratings have been calculated using the following formula.
Ish = (kA) /√ t
Where Ish = it is RMS. value of short circuit current (kA) during fault
k = constant (forAluminium-0.094,for Copper-0.143)
A = cross sectional area of each phase conductor ( mm² )
t = duration of short circuit in (sec)
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3 thoughts on “XLPE Cable Current Rating Calculator”
Thanks for this information.
It is possible to have 1core x500mm² 1.1kv xlpe/pvc amored?
Good afternoon. Can you please provide a formula to calculate current rating of a 3 core, 11kv, XLPE cable laid on under ground from a 11 KV switchgear to a transformer having distance 1 KM.
In my case transformer capacity is 1 MVA. What should be ideal size of cable to load the transformer 80%.