kVA = kW/0.8P.F
kVA = 15/0.8
kVA = 18.75kVA
I = kVA/(1.732x415V)
I = 18.75/718.78
I = 0.0260kA
I = 26A
I = 26A x 1.2 (overload factor)
I (MCCB,TP) = 32A Icu = 10kA and Ics = 6kA will be more then enough.
32A MCCB, TP as Incoming breaker
Further outgoing breakers for 220V system could be MCCB's, DP or SP as per requirement.