Power cables

I will suggest him/her to refer any vendor catalogue.

hai kamal, thanks for your reply. how do measure current in XLPE Cables.

by

K.Mani maran

hi

What are you requesting ?

To measure the current flow in a cable, there is no differance between PVC and XLPE.Just put a Tong Tester in one of the cores,the Tong Tester will indicate the current carried by that core of the cable.

dear

thanks

could you send me a sfot ware for short cuituic calculatins if any?

best regards

thansk

dr sabry

No need. Just use the electrical code applicable in the country of installation; in the UK it is BS7671, for example.

If you intend to calculate the maximum short-circuit current which a cable insulated in XLPE could withstand or the minimum cross section area of the conductor for a given short-circuit current then you need to know some data:

the ambient temperature, the initial load current or the temperature, the short-circuit duration[trip time] if there is only one-time fault or total duration if there are more than one time, the maximum permissible temperature in short-circuit case [for instance for XLPE it is 250 oC] and the conductor material [copper, aluminum or else]

If the duration it is less than 10 seconds then you may use an adiabatic case-that means all the heat produced in the conductor by electric losses is used only for increasing conductor temperature [no heat evacuated to ambient]

If the duration it more than 10 seconds then you have to reduce the maximum temperature to what is called "emergency load temperature" for XLPE it is only 130oC and since you have to consider the heat evacuation to the ambient the calculation takes into consideration different medium-free air, underground, duct, conduit and other.

As is explained above the are many standards for these calculations for instance British Standard7671 [C 4.4.5 Circuits without overload protection] IEEE, VDE,EDF,GOST and others. IEEE 80 present a formula for conductor cross area calculation [see attached] However, you need also the conductor data from the tables.

The material constant table from IEEE 80/2013

For more than 10 seconds short-circuit duration as per IEEE 242/2001

Note : actually θK it has to be θ/K where θ it is duration in hours.

A simplified formula according to STD-ICEA P-32-382 for XLPE or EPR

For current-carrying capacities for cables [ampacity-in USA] for low-voltage cables see IEC 60364-5-52 Selection and erection of electrical equipment –Wiring systems and for medium voltage cables up to 30kV IEC 60502-2 Cables for rated voltages from 6 kV (Um = 7,2 kV) up to 30 kV (Um = 36 kV)

One can always measure it with one of these: