The question is whether the 380 V is measured line to neutral or line to line. If it is line to line, then it is only 219 V line to neutral.
I will assume it is line to neutral
30 kW/380 V = 78.9 A
That is the sum of the three phase currents, each phase is 26.3 A, assuming the load is balanced.
(It may need higher current during starting.)
Edit: It is actually more likely that it is 219 V line to neutral and 380 line to line.
30 kW/219 V = 137 A, 45.7 A in each phase (assuming balanced load)
A three phase induction motor would be running phase to phase (no neutral required). The calculation is: 30,000W/380V/1.73 (sqrt of 3) or45.58028441
Amps. That being said, overcurrent protection will have to be sized to carry momentary starting load of about 250%. This could be even higher in an application with large inertial loading. The calculation is assuming 100% efficiency as well, so you need to know if 30kW is the size of the motor or the consumption under load and divide the current figure by efficiency.
Note that the square root of the phasing is used as actual voltage (an hence current) in a three phase circuit is 120 electrical degrees apart so the actual currents peak 1/150 of a second apart in 50 Hz or 1/180 of a second at 60 Hz.
Motor name plate data should indicate FLA (full load amps) and LRA (locked rotor amps). Local code requirements or good engineering practice will dictate wire size and overcurrent protection.
Sounds like you are looking at wire in the #6 AWG range (~15 sq mm) with an increase in size of (~5 sq mm) for each 30m increase in length.
Of course that's looking at it from half a world away.
I am looking to put a capicitor on my a/c units how much will i sve per month if the follow are assumed.
3 phase 280 volt
when i do a ready on of a test unit i am saving 2 amps
my kilowatt per hour rate is .0983 from my utitlity bill the ac units run aproxiamatley 20 hours per day
here is my calculation did i do it right
amps(2) * 280 volts = volts 560 =kilo watts .56 * kwh cost of $.0983 =.055 * 22 hours a day * 30 days a month = $33.00 per month in savings