5.2. ERMUSR 02-12-2013 v ,
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Elk River k
Municipal Utilities UTILITIES COMMISSION MEETING
TO: FROM:
Elk River Municipal Utilities Commission Wade Lovelette-Superintendent of Technical
John Dietz, Chair Services
Daryl Thompson, Vice Chair
Allan Nadeau, Trustee
MEETING DATE: AGENDA ITEM NUMBER:
February 12, 2013 5.2
SUBJECT:
2012 Electric Reliability Report
BACKGROUND:
Minnesota Rules Chapter 7826 Public Utilities Commission Electric Utility Standards cover
safety, reliability, service, and reporting requirements. Per 7826.0100(A), municipal utilities are
exempt from these requirements. However, the Elk River Municipal Utilities Commission
adopted a number of parts of this chapter as a Distribution Reliability Standard policy requiring
annual reporting on system reliability.
DISCUSSION:
Even with the weather issues during 2012, our reliability index numbers are excellent. These
reliability index numbers reflect the condition of our robust electrical system as well as the
superb response time from our local line crews. This also reflects the local accountability, long
term visioning on system design, and ongoing system maintenance. The table below reflects the
number of customer outage minutes from 2003 through 2012.
Year # of Customers # of Outage Minutes # of Outages
2003 7193 39,285 54
2004 7773 393,926 84
2005 8398 558,140 59
2006 8804 314,510 73
2007 9163 67,845 47
2008 9067 155,768 57
2009 9170 46,706 49
2010 9207 526,144 77
2011 9576 297,359 51
2012 9285 71,496 57
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Page 1 of 3
�NATURE�
Reliable Public
Power Provider p P O W E R E D T o S E R V E
A number of reliability indexes are used in the electric industry to make it easier to compare
performance of electric utilities. These reliability indexes are:
1. ASAI (average service availability index)
ASAI is a measure of the average availability of the sub-transmission and distribution
systems to serve customers. It is the ratio of the total customer minutes that service was
available to the total customer minutes available in a time period. This is normally expressed
as a percentage.
ERMU's 2012 ASAI is 99.999% Availability. Last year was 99.994% Availability.
2. CAIDI (customer average interruption duration index)
This is defined as the average length of an interruption weighted by the number of customers
affected. It is calculated by summing the customer minutes off during each interruption in
the time period and dividing this by the number of customers experiencing one or more
sustained interruptions during the time period. The resulting unit is minutes. The index
enables utilities to report the average duration of a customer outage for those customers
affected.
ERMU's 2012 CAIDI is 66 minutes. Last year's CAIDI was 105 minutes.
3. SAIDI (system average interruption duration index)
This is defined as the average interruption duration for customers served during a specified
time period. It is determined by summing the customer minutes off for each interruption
during a specified time period and dividing that sum by the average number of customers
served during that period. The unit is minutes. This index enables the utility to report how
many minutes' customers would have been out of service if all customers were out at one
time.
ERMU's 2012 SAIDI is 7.7 minutes. Last year's SAIDI was 31.1 minutes.
4. SAIFI (system average interruption frequency index)
This is defined as the average number of timers that a customer is interrupted during a
specified time period. It is determined by dividing the total number of customers interrupted
in a time period by the average number of customers served. The resulting unit is
"interruptions per customer."
ERMU's 2012 SAIFI is 0.117. Last year's SAIFI was 0.296.
Another statistic staff gets concerned about is the average length of any outage. Elk River
Municipal Utilities' 2012 average length of outage is 119.32 minutes. Last year the average
length of outage was 126.00 minutes. Electric utilities with a high percentage of underground
facilities will exhibit higher length of outage time than electric utilities with more overhead
facilities.
P O W E R E D et 1 I
Page 2 of 3 NATURE
Reliable Pablic
Power Provider P O W E R E D T o SERVE
Staff reviews these statistics in detail to find ways to continually improve our system. These
statistics are very good compared to other utilities. Birds and animals caused the greatest
number of outages. Birds and animals resulted in 38.60% of our outage incidents, and
contributed to 36.24% of total outage time. Outages resulting from branches and/or trees make
up 7.02% of our outage incidents and contribute to 2.18% of our outage time. This low
percentage is a reflection of the good tree trimming our crews do during the winter. Overall,
weather related outages account for 12.28% of the incidents and 4.49% of our outage time.
Many investor owned and cooperative run utilities "storm normalize" their reliability numbers
by removing "major outages" due to storms from their reliability index number calculations.
Our reliability numbers have not been storm normalized. Our numbers reflect these major
outages and represent what our customer actually experienced in 2012. Overall, our electric
distribution system is robust and our reliability is very high.
ACTION REQUESTED:
No action is required.
ATTACHMENTS:
• SAIFI, SAIDI, and CAIDI Interruption Frequency
• Number of Outages By Cause
• Outage Minutes By Cause
• Number of Outages by Month/Year
■'l �' Page 3 of 3 P O M 1 R t 0 a r
�NATURE
Reliable Public'
Power Provider POWERED To SERVE
Elk River Municipal Utilities Page 1 of 1
217/20138.35:53 AM SAIFI SAIDI CAIDI
Starting date 01/01/2012
Ending date 12/31/2012
SAIFI System Average Interruption Frequency Index 0.11696
SAIDI System Average Interruption Duration Index 7,70016
CAIDI Customer Average Interruption Duration Index 65.83425
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Reliarrait; Elk River Municipal Utilities Page 1 or 1
2/7/2013 8:47 47 AM Number of Outages By MonthlYear
ou2012
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14
I 3 02/2012
13 06120121 10 0312012
3 04/2012
12 1 08/2012 10 05/2012
11 06/2012
11 py20121 05/20121 _ I 14 07/2012
12 0812012
10 i 7 0912012
71012012
0 1 ; 311/2012
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8 I 1 09/20121 1 1020121
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02/2012 03/2012 04)2012 052012 0612012 07!2012 082012 09/2012 102012 11/2012
Starting date D1lD1l2D12
Included Outage Detail : Include All
Note : Multiple outage detail records may be only counted once.
Ending date 12/31/2012