Salt contamination from Hurricane Wilma combined with a light rain last
night to start a Keys-wide power outage at 8:52 p.m. Both transmission
lines serving the Florida Keys were affected. In addition to the salt
contamination, a high voltage lightning arrester also failed in the Marathon
substation at some point during the night. This equipment failure prevented
power from being restored to the Lower Keys until the arrester was
discovered and isolated. The transmission line to the Lower Keys was the
last to be restored at 6:45 a.m. this morning.
The outage began when a drizzling rain combined with a coating of salt on
the main transmission line insulators, creating noticeable arcing and
surface tracking as the insulator surfaces became conductive. This problem
is being seen by FPL and other utilities in the path of Wilma, which was a
big wind event with little rain. The Card Sound transmission line went off
three times and is still out of service this morning.
"Contamination conditions like these are rare, and we only occasionally
experience problems of this magnitude," said FKEC CEO Tim Planer. "A dry
salt layer doesn't cause a problem, but when it is moistened by a light
rain, the system begins experiencing pole top arcing and outages until it
rains hard enough to wash off the salt."
The last time FKEC experienced this type of problem was after the "super
storm" in March 1993. Heavy rains will eventually wash the salt off the
insulators and solve the problem.
In addition to the salt contamination, a high voltage lightning arrester
also failed in the Marathon substation last night. Once FKEC was able to
restore the transmission line between the mainland and the Upper Keys, it
began troubleshooting the line in the Middle and Lower Keys. Attempts to
re-energize the line failed until the faulty equipment was found.
"The good news is that the bad lightning arrester was isolated and the
transmission line has now been restored to the Lower Keys," Planer said. "We
appreciate the patience of everyone affected by the outage while we worked
to find and correct the problem."
