selection of MV XLPE Cable 2

[MateenKhan]

Hi everybody
its first time for me to enter into this wonderful forum.i hope you peopole will help me in my querries. My question is that what will be the conductor size of MV 11KV XLPE Copper conductor cable for the load of 3100 KVA at a distance of about 3.5 KM?Is voltage drop be considered to select the cable conductor size?

 

[radeonforce]

Do you have access to the standards? I'm currently doing vacation work and have come across AS3008.1.1 which is the Australian standard for cable selection. There are three main things you should check when selecting a cable:
- full load current rating
- cable voltage drop
- short circuit rating

 

[magoo2]

Voltage drop and ampacity are the primary considerations for your MV cable installation.

There is a third - voltage stress, which should be considered when you look at the minimum possible conductor size.

Is the design tape shield or concentric neutral?

Why not aluminum conductor?

Why not TR-XLPE?

Is it North American practice or European?

Rather than leave you with no guidance, if it were North American practice, a 1/0 aluminum conductor with 175 or 220 mils (4.45 or 5.6 mm) of TR-XLPE would be a common rating to suggest. Smaller conductor sizes like #1 or #2 aluminum are used by a number of companies.

 

[7anoter4]

The first thing you have to state it is the minimum conductor cross section for the short circuit stability. For instance if the I"k3 =26 KA and the fault clearing time will be 0.15 sec. then you need 70 sqrmm copper in order not to overcome 250 degrees C [for XLPE].
Three 1/c conductors laid in the ground of 30 degrees C will support at least 200 A [you have only 163 approx.]
The voltage drop [for steady state of 163 A] will be only 133 V[1.21%].

 

[MateenKhan]

the most valuable post for my querry is from 7anoter4. thank you.