Solution of phase-interchange faults

A PHASE-INTERCHANGE FAULT on a power system occurs when two of the three conductors are interchanged. If the portion of the power system involved is a radial branch that has a voltage source at only one end, the consequences are reversed phase rotation in the branch beyond the point of phase interchange. Although the physical consequences may be serious, the calculation of the resulting currents and voltages are relatively simple. If the portion of the power system involved has voltage sources on both ends, as in a loop or network, the phase interchange has the effect of causing large currents to flow in the power system, and their analytical determination is more difficult and complex.