HomeMy WebLinkAboutMemo - Mail Packet - 12/18/2018 - Memorandum From Tim Mccollough Re: November 27, 2018 Electric Outage Follow UpUtilities
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700 Wood Street
PO Box 580
Fort Collins, CO 80522
970.221.6700
970.221.6619 – fax
970.224.6003 – TDD
utilities@fcgov.com
fcgov.com/utilities
M E M O R A N D U M
DATE: December 6, 2018
TO: Mayor Troxell and City Councilmembers
FROM: Tim McCollough, Deputy Director, Utilities Light & Power
THROUGH: Darin Atteberry, City Manager
Jeff Mihelich, Deputy City Manager
Kevin R. Gertig, Utilities Executive Director
RE: November 27, 2018 Electric Outage Follow-up
BOTTOM LINE
On November 27, 2018 at 5:18 pm, 4,986 Light & Power (L&P) customers on the west side of
Fort Collins experienced an electric outage that lasted approximately 50 minutes. The outage
was caused by a malfunctioning protective relay at a substation. The malfunction caused two
substation breakers to open inadvertently. The device has been replaced with a spare unit and a
full replacement of this type of protective relay across the electric system is planned in the
2019/2020 funded Capital Budget (Offer 8.6).
OUTAGE DETAILS
L&P staff, assisted by Platte River Power Authority (Platte River) staff, were performing
required testing of protective relays at our substations the day of the outage.
Before the event, the device that later malfunctioned was removed from service and tested as a
part of routine compliance testing. The unit successfully passed all tests and was placed back in
service. After crews left the substation, the device operated inadvertently and caused two
substation breakers to open.
There were three potential causes that were investigated during the outage response.
1. The relay testing was suspected as a potential cause.
2. L&P crews received reports of a transformer fire on the west side of town from the Fort
Collins Police Department. The fire turned out to be an incinerator on the Colorado State
University Foothills Campus that was observed and reported by a caller to 911.
3. There was a dig-in on an electric duct bank earlier in the day that contains the same
circuits served by the breakers that opened. It was suspected there was additional
damage to these circuits caused by the dig-in. No evidence of circuit damage was found.
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The protective relay was removed from service and the breakers were closed back in restoring
power after 50 minutes once the other two causes were ruled out.
The relay that malfunctioned was tested again after the outage and it failed the tests. A spare
unit was installed and put in service without incident. L&P Staff has confirmed that there has
not been a similar relay malfunction that has occurred in the history of our system. Fortunately,
all relays of this type are planned for replacement in our 2019/2020 capital improvement plan
in the budget just approved.
Even considering the impact of this outage, Fort Collins L&P customers enjoy one of the lowest
outage rates in the nation. With an outage frequency of about once every three years per
customer on average.
We received feedback from customers who received busy signals, or had their calls
disconnected while trying to report the power outage. The high call volume received during this
outage caused our after-hours emergency line to reach capacity and the calls above the line
capacity were disconnected.
Staff has identified several improvements to implement as a result of this outage.
NEXT ACTIONS
• Evaluate the after-hours phone system capacity and explore improvements to prevent
future issues with high call volumes.
• Continue to manage the implementation of the public facing electric outage map that
will be published on our website to inform customers about outages and restoration
efforts.
• Complete the budgeted upgrades to our substation’s relays in 2019 and 2020.
BACKGROUND & JOINT WORK WITH PLATE RIVER
In 2002 The North American Electric Reliability Corporation (NERC) mandated testing be
performed on substation equipment every 6 years to verify performance of the protective relays
that support the reliability of the bulk electric system. Testing is done jointly with Platte River
under strict NERC guidelines, the same tests being performed the day of the November 27
outage.
Through an intergovernmental agreement (IGA) with Platte River, L&P has the option of
utilizing Platte River equipment and personnel to perform specific testing or construction work.
In addition, L&P relays that are a part of Platte River’s NERC underfrequency program are
tested on an annual basis when revised underfrequency settings are received from Platte River.
L&P also performs regular inspections and maintenance of all substation equipment to insure
the exceptional reliability of L&P’s substations.
Currently, L&P has three substations that fall under NERC requirements. L&P’s next audit will
be in the spring of 2020. To date, NERC audits were successfully completed in 2008 and 2014
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with no sanctions or penalties. (Documentation and presentations specifying the NERC testing
requirements available upon request.)
JOINT PROJECTS WITH PLATTE RIVER TO FOLLOW:
• Replacement of 115/230 KV motor operated switches with circuit switchers
• Richard’s Lake Substation XFMR1 – 2019
• Harmony Substation XFMR1 – 2019
• Linden Tech Substation XFMR1 & XFMR2 – 2019
• Harmony Substation XFMR3 – 2020
• Harmony Substation XFMR2 – 2021
• Harmony Substation XFMR4 – 2022
• Periodic NERC Testing
MAJOR L&P PROJECTS FOR 2019 AND 2020:
• Load Tap Changer maintenance
• Substation SCADA equipment and feeder relay upgrades
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