Distribution Automation
Plans in AEP Texas
Overview
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AEP Texas is deploying smart meters to roughly
1,000,000 customers
The meters utilize Landis + Gyr UtiliNet radio
technology
UtiliNet mesh network requires regular placement
of routers on utility poles throughout the system
Routers can be used for more than strictly AMI
traffic
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If they’re there, why not use them?
Very limited in scale and scope so far
Deployment
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Total of twelve smart switches deployed so far
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Installed in sets of three
Locations: Two sets in San Angelo, one set in Abilene,
and one set in Corpus
Up to ten additional locations (30 additional smart
switches) may be chosen before the end of 2011.
They will most likely be deployed in the Rio
Grande Valley, Corpus Christi, Laredo, Victoria,
Abilene, and/or San Angelo.
Organizational
Responsibilities
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Reliability Engineering: Selects location,
performs studies as necessary, program the
devices
AMI construction group: Installs routers for
AMI deployment
Information Technology: Creates the links
between the UtiliNet system and SCADA
Dispatch: Operates and monitors the status
of the devices
Switch Specification
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Using S&C IntelliRupter
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15.5kV models to support our mostly 7.2/12.47kV
system
Interrupting rating: 12500A
Continuous current rating: 630A
Uses “pulse closing” technique
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Standard reclosing could be used for fuse saving
strategies, but we’ve opted not to use it
Ensures less damage to distribution equipment by
limiting the amount of energy in a fault
Switch Specification (cont’d)
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Modular communications
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Vendor installs Landis + Gyr UtiliNet module
SpeedNet and other radios available and possible for
future use
Communications infrastructure
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UtiliNet mesh network
Very scalable, but not very high bandwidth
DA takes much higher priority in signals than AMI
Proprietary UtiliNet signals converted at station to
DNP3 for SCADA master control device
Latency is expected to be measured in seconds as
opposed to milliseconds or minutes
Mounting/Installation
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Switches are mounted on 45 ft, Class 3 or
better poles
Only overhead installations on wood poles so
far
No location restrictions beyond engineering
judgment
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Everybody knows of the story of the switch right
next to a drainage ditch…
AMI routers must generally be installed in an
area before DA schemes are installed
Maintenance
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S&C IntelliRupters have a life span of about
30 years or more
Batteries should be replaced on a 5 year
cycle
Bypass switches are installed on both load
and source side
Thus far, testing is performed live
Modular communications and control module
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Control module can be accessed via Wi-Fi for
programming and to check error logs
AMI Integration
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Leaning heavily on AMI communications system
Communications to the substation shares routers
and protocols with AMI system
DA gets top priority in communications along mesh
At the station, switch signals are translated to DNP3
and sent to the SCADA master control device
Switches do not communicate directly with meters
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UtiliNet mesh latency would be too high for something
like this to work
Safety
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For loop-automation, the “middle” device
must be placed into non-reclose mode before
work begins
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A non-reclose order or hot line tag may be used
on the source side device as well
The S&C IntelliRupter has an interlocking
visual open
To accommodate contractors/out-of-town
crews, dispatchers will let crews know they
are on an automated system when they logon
Operations
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Real-time visual representations of the status
of the devices (open/closed/non-reclose/etc)
are provided via SCADA
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Also allows remote control of functions – can be
overridden by field using physical levers
Non-switch smart nodes (such as intelligent
volt-var controls) are not anticipated at this
time
Operations (cont’d)
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Alarm points are used on abnormal switch state
Outage tickets are still manually generated by
dispatchers
Switches can be used to gather outage
information, isolate faults, and re-energize the
line – similar to breakers using SCADA
Due to the limited scope of deployment,
switches will only be marginally useful in load
estimation and planning functions
Budgeting/Cost Recovery
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Costs of systems is broadly imbedded in
rates until a more timely recovery mechanism
is in place
Limited scope of projects means no special
projects have been created; they are lumped
in with general sectionalizing and reliability
budgets
AMI communication devices (routers) are
paid for by smart meter surcharge, and AMI
remains their primary function
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DA is along for the ride!
One Caveat
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Some of the equipment
may not stand up to
highly corrosive
environments….
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Installation was on North
Padre Island, only a few
months old
ALL future installations
will use our own external
disconnects
Questions?