Once these
2976 IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 28, NO. 3, AUGUST 2013
probabilities are obtained, the probability of the top event can
be evaluated using (1)–(3). Next, the most critical sources of SA
errors can be identified and design improvements can be made
to enhance operators SA.
Even though this analysis provides a lower bound of the probability
of operator errors as it focuses on the modeling of a single
electrical substation, it can be used as the basis of the required
extended model for estimating the frequency of operator errors
with an adequate degree of accuracy.