Voltage Level Requirement

The next one up is 33kV.

Why do you think you need a voltage higher than 11 kv?

You need to talk with your power provider to see what capacity they have left to provide you for your increased power demand on the 11kV supply. They should advise you if you need to switch to a higher voltage to reduce the strain on their network.

Post 3 is correct.

20MVA/11kv=1800A. That's a lot of current, meaning a lot of losses in the feed lines.

Triple the voltage, and you cut the required current to 1/3. That's why!

For that size of factory, you should have your own substation...

Thanks for replay, we have already a 132/11kv switchyard. Now we start a expansion, we have a spare capacity for expansion. New expansion voltage level is 22kv. so i think its not create any problem.

Post3(Mr.Jack) and post4(Mr. dkwarner) are definitely right. My experienced in Midle East Elect. Companies, we prefered to utilized 33kv up in short distance transmission line(25km), 133kv(medium range x'mission), and 230-500kv for Long distance x'mission system accross the region (1200km). Then we utilized 13.80kv MV to consumers thru' MV/LV S/S @ 13.8Kv/380V 3-phase. Advantage of HV transmission system is low current, impedance, power losses from receiving end(Ern) to sending end(Esn) which is economical. I don't know what is the power demand of your place or how long is your transmission line. My opinion is better use the next higher standard Medium voltage 33kv for you x'mission lines if not more than 25km long.