After the three-phase short-circuit of the impedance of the infinite power supply, what components are included in the transient current? How did it all happen? Can the transient process be analyzed using the phasor method? why? b) Is it possible for a phase to have no aperiodic component after a three- phase short circuit? Is it possible that none of the three phases has an aperiodic component? Why? c) Why does the maximum possible instantaneous value of the short-circuit current appear about half a cycle after the short circuit? Why does the maximum effective value of short circuit current appear in the first cycle after short circuit? d) Why is the per unit value of the short-circuit power equal to that of the short-circuit current? e) What is the use of calculation of impulse current, short-circuit capacity. and maximum effective value of short-circuit current in engineering? why? f) please draw the phasor diagram of the infinite power supply through the impedance three-phase short circuit, and explain the phasor diagram on the understanding premise.