A balanced three-phase distribution line has an impedance of 1+j8 I per phase. This line is used to supply 3 balanced three-phase loads that are connected in parallel. The 3 loads are L1= 120 kVA at 0.96 leading pf, L2= 180 kVA at 0.8 lagging pf, and L3= 108.8 kW and 15.6 kVAR. The magnitude of the line voltage at the terminals of the loads is 2400√3 V. Note: All 3 loads given are the overall load across the three-phases, not per-phase loads.
a) What is the magnitude of the line voltage at the sending (voltage source) end of the line?
b) What is the proportion of real power delivered to the load from the source? This is called the efficiency of the system with respect to real power.