Teaching fault studies using symmetrical components

Symmetrical component methods are reviewed for calculating currents in three-phase electrical power systems following asymmetrical faults. Solution of the load flow problem in evaluating component currents and voltages in network elements is also discussed. First, development of a digital fault studies program of use in undergraduate teaching, highlighting aspects of program design, is described. The calculation of network element quantities with display of results is then explained. Also discussed are modified routines which use complex impedances to represent system elements and use of the program on the more common PCs. Phase voltages and currents for circuit elements in a model power system comprised of generators and transmission lines are illustrated for the more common shunt and series faults. Both reactances and complex impedances are used in computing theoretical values