I. Introduction
Demographic and economic expansion of countries have led to an increase in demand for electrical energy, thus requiring larger and more complex power systems. This complexity has a direct toll on inspection and maintenance and the occurrence of blackouts in different electrical networks worldwide exposes the vulnerability of these power systems. A clear example of the fragility of power systems occurred on September 24th, 2011, in Chile, due to a fault in the transformer 500V / 230V from electrical substation in Ancoa, causing a blackout of the national power system. It affected approximately 9 million people and interrupted normal operations in several copper mines which immediately impacted on the local economy of Chile [1].