1. A three-phase, three-wire AC system delivers 7 MVA at 12 kV and a power factor of 0.7 to a three-\phase balanced load. The system losses are specified to be 10% of the delivered power.\
(I) How much power is supplied by the three-phase system, accounting for the losses?\n(II) What is the per-phase cross-sectional area of the conductors?\n(III)How much more percentage of copper will be needed if we want to deliver 9 MVA to the load at\nthe same power factor, phase voltage, and power loss?\nFor this problem, assume the resistivity of copper, $\rho$=17.54×10$^{-9}$ ?·m, and transmission line length of\nl= 40 km.