POWER August 2013 - 47

SMART GRID AWARD
1. Outage mitigation. The direct savings in customer outage minutes since EPB began
integrating smart grid technologies on its distribution system are dramatic. Data for 2013 are
through March 31. Source: EPB
45
40
35
30
25
20
15
10
5
42,054,788
utes gained because the crews can go straight
to Tier 3 work, " explained Manager of Smart
Grid Development Jim Glass.
Improvements in Operational Efficiency.
" Even at this early stage of implementation,
we're seeing efficiencies in operations
that amount to roughly $10.5 million per
year, " said Assistant Vice President of Electric
System Ryan Keel. " Examples include
meter-related trip costs, demand reduction,
asset management, and reduction in storm
restoration cost. "
When the average person thinks about the
7,667,509
4,435,120
2011
2012
Includes direct savings only
metrics: reduction in outage duration and
other direct benefits to electric power customers,
improvements in utility operational
efficiency, and availability of next-generation
communications services.
Reduction in Outage Duration. A University
of California, Berkeley study indicates
that power outages account for roughly
$80 billion annually in total losses to communities
across the U.S. Based on that calculation,
EPB estimates that community losses
in its service area are roughly $105 million
annually. But it is seeing outage reductions of
50% and higher thanks to its smart grid work,
which means the community avoids $50 million
or more each year in lost productivity,
lost product, and lost sales.
The system continues to outperform the
utility's 40% improvement goal. Here are
some recent results of direct customer impacts
of storm events:
■ July 5, 2012: 55% improvement, 42,000
fewer customers affected
■ Jan. 14, 2013: 100% improvement, 11,258
fewer customers affected
■ Jan. 17, 2013: 70% improvement, 8,056
fewer customers affected
The story of the Jan. 14 event-when, at
6:51 p.m., a tree fell on a high-voltage 46
kV power line just outside of the Pine Ridge
Substation-is becoming legendary. Here's
the timeline:
■ The fallen tree causes a fault serving three 12
kV distribution substations and knocks out
power to 11,258 homes and businesses.
■ A mere 28 seconds later, the automation
system restores service to 10,000 homes
and businesses.
August 2013 | POWER
■ Another 15 seconds later, automation restores
power to another 800 homes and
businesses.
■ Three minutes later, a dispatcher remotely
opens and closes switches, restoring power
to 289 more homes and businesses.
■ Two minutes and 43 seconds later, a
dispatcher remotely operates the final
switches to restore power to the remaining
customers.
Within 6 minutes, more than 11,000 homes
and businesses were restored-an effort that
would have taken about 4 hours before Chattanooga's
smart grid.
As Figure 1 shows, EPB avoided over 50
million customer outage minutes from July
2012 through March 2013.
But Figure 1 only represents direct savings.
Consider a traditional multi-day outage restoration
scenario for a significant storm, which
generally has three ordered tiers of work:
1. Identifying areas of damage.
2. Switching around damage.
3. Making repairs to damage.
In a traditional multi-day storm restoration
scenario, utilities may spend the first 20
hours on Tiers 1 and 2-sending crews to
manually look for damage and to manually
open/close switches to energize customers
around the damage. These are the steps that
have been largely replaced with automated
switching. Next, crews begin work on the areas
with damage. " We refer to direct savings
in customer minutes of interruption (CMI) as
the minutes saved specifically and directly
by the quick identification of damage and
automated switching. Just as important and
significant are indirect CMI savings: the minwww.powermag.com
2013
smart
grid, the first thing that comes to mind
is a meter that enables bidirectional communication.
That capability has helped EBP
provide improved customer service. For example,
it is common for customers to report
an outage that a field crew later finds to be a
tripped breaker box. Intelligence at the meter
can allow EPB staff to troubleshoot that call
remotely instead of sending out a lineman in
a truck to repair a perceived problem. " Now
that our software can see what's happening at
the meter, we know that roughly 10% of our
outage calls are not outages at all and can be
resolved with the customer quickly and remotely, "
said Keel.
But network intelligence is where EPB has
realized even greater gains. Reliability has been
significantly enhanced by its 1,170 S & C Electric
Co. IntelliRupter PulseClosers (pictured in
the photo at the top of this story), which have
enabled dramatic outage duration reductions,
which in turn led to EPB winning Greentech
Media's best-in-class award for distribution automation
two years in a row.
" Where we used to have intelligence on
each end of a multi-mile feeder, we now
have intelligence (smart switches) every
3,300 feet, " Glass noted. " The time saved by
only having to search 3,300 feet for damage
(versus up to 36 miles) represents very real,
though indirect, savings in CMI. "
Next-Generation Communications
Services. Though the smart grid communications
backbone, which EPB Electric
Power owns, was installed first to shorten
power outages for customers and improve
operational efficiencies for the utility, that
fiber-optic asset can also be used as a revenue
stream and is " leased " by the EPB Fiber
Optics brand to offer next-generation
communications services for a monthly
subscription.
The company currently has almost
50,000 homes and businesses connected
to an Internet speed of at least 50 Mbps-
that's 10 times the national average, according
to Bailey, and the largest concentration
of existing connections that fast anywhere
in the country. Customers do not have to put
down a deposit and do not have to commit
47
Millions of minutes

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POWER August 2013

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