Power systems play a significant role in every aspect of our daily lives. Hence, their continuation without any interruption (or with the least duration of interruption due to faults or scheduled maintenances) is one of the key aims of electrical energy providers. As a result, electrical energy providers need to check in great detail the integrity of their power systems by performing regular contingency studies of the equipment involved. Among others, line and transformer outage simulations constitute an integral part of an electrical management system. Both accuracy and calculation speed depend on the branch outage model and/or the solution algorithms applied. In this paper, the local constrained optimization problem of the single-branch outage problem is solved by intelligent methods: particle swarm optimization, differential evolution, and harmony search. Simulations of IEEE 14-, 30-, 118-, and 300 -bus systems are computed both by intelligent methods and by AC load flow. The results of the intelligent method -based simulations and AC load flow -based simulations are compared in terms of accuracy and computation speed.