(The following is a reformatted version of a press release
issued by Con Edison and received via electronic mail. The
release was confirmed by the sender.)
September 30, 2013
Statement by Con Edison
Re: Metro-North Restoration Update/Initial Findings of Feeder
Over this past weekend, Con Edison successfully constructed
alternate power sources to the Metro-North New Haven line, which
allowed some electric trains to begin running this morning. We
continue to work around-the-clock to reconnect the 138kV feeder
that had been removed from service several weeks ago to
accommodate Metro-North’s system upgrade work. The reconnection
is expected to be completed by October 7th and will provide full
service to the line.
Our primary focus has been on establishing temporary feeders in
Harrison, reconnecting the 138kV feeder that was taken out to
accommodate Metro-North’s upgrade work, and repairing the second
138kV feeder that faulted on Wednesday morning. Given this
focus, we do not know with certainty the cause of the feeder
failure at this time. A preliminary review indicates that the
feeder fault is likely related to work that was performed to
disconnect the feeder for Metro-North’s upgrade work.
High-voltage transmission feeders are housed in oil-filled
pipes. Removing these feeders from service is a complex process,
which involves freezing the insulating oil in the pipe within a
“freeze pit.” These freezing operations are conducted routinely
while working with high voltage transmission lines, and we
perform numerous operations each year without incident.
In this case, we have confirmed that the fault is located just
outside of the “freeze pit” work area. In addition, the ground
surrounding the work area was found to be frozen, and this
unusual condition likely contributed to the feeder failure. We
cannot recall a condition of this nature developing during any
of our previous freeze operations.
We will be conducting a thorough review of the cause of the
feeder failure once restoration activities are completed. The
review will include a thorough examination of the failed cable
once it is removed from the pipe as part of the restoration
process, and will focus on understanding how this incident
occurred to avoid future such incidents.
We also plan to have extensive discussions with the MTA
regarding contingency planning.
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