Conventional transient stability analysis is performed on the basis of
a balanced system representation. However, a power system may be unba
lanced due to a variety of and the computations of sequence quantities
due to these unbalances is necessary in order to facilitate the appli
cation of countermeasures. This paper presents an algorithm for the si
mulation of large scale power system dynamics under unbalanced operati
ng conditions. This algorithm finds potential application in the simul
ation of systems with abnormal loads such as are furnace and traction,
and also in the realistic simulation of unbalanced faults in bulk pow
er transmission systems.