A 3-phase 230 V, 9 kVA, 0.9 PF (lagging) load is supplied by 10 kVA, 1330/230 V, 60 Hz three-phase transformer connected in Y. The equivalent impedance of transformer referred to the low-voltage side is 0.12 + j0.25. Determine the required supply voltage if the load voltage is 230 V.