The figure below shows a one-line diagram of a simple power system containing a single 480 V generator and three loads. Assume that the transmission lines in this power system are lossless, and answer the following questions.
a. Determine the per unit model for this problem assuming a 100 kVA base.
b. Assume that Load 1 is Y-connected. What are the phase voltage and currents in that load? Solve in per unit and convert to real volts and amps
c. Assume that Load 2 is ?-connected. What are the phase voltage and currents in that load? Solve in per unit and convert to real volts and amps.
d. What real, reactive, and apparent power does the generator supply when the switch is open? Solve in per unit and convert to real watts, VARS and Vas
e. What is the total current IL when the switch is open? In per unit and real amps
f. What real, reactive, and apparent power does the generator supply when the switch is closed?
g. What is the total line current IL when the switch is closed? In per unit and real amps
h. How does the total line current IL in per unit compare to the sum of the magnitude three individual currents I1 + I2 + I3?
If they are not equal, why not?
