power = 1.73 * V* I
V = 380 v
I = ?
power = 315 kva = 315 * 1000 = 315000 va
I = power / 1.37 * v = 315000/1.73 * 380 = 315000/657.4 = 479.16 A
and from my experience you can know the Ampere direct by this
if you have KVA and output volt is 380
you can do that
KVA * 1.5 = Ampere
if you have the power be KW you can do that
KW * 2 = Ampere
about your load and you hvae pool pump motor 3 phase
you must know her we have a power factor not unity
and you must make a palance on the three phase
Engniee
Ali younes