TABLE III
ALLOWABLE TIME TO RELIEVE LINE’S OVERLOAD
is not “ ” secure after the generation units go offline for
maintenance. The operators’ insufficient SA increases system
stress and reduces security margins. Therefore, a single electrical
outage can result in line thermal overloads, increasing the
probability of cascading outages and loss of supply. The electrical
failure causes the transition of the system from S3 to S4.
Reference [18] provides three line thermal ratings: continuous,
long- and short-time emergency ratings (CON, LTE,
STE). Table III shows the time allowed to relieve the line
overloads based on these ratings.