For equilateral spacing of conductors of an untransposed $$3$$-phase line, we have

During a disturbance on synchronous machine, the rotor swings from A to B before finally settling down to a steady state at a point C on the power angle curve. The speed of the machine during oscillation is synchronous at point(s)

For an unbalanced fault, with paths for zero sequence currents, at the point of fault

Resistance switching is normally employed in