Make better use of Real-Time Energy Information to improve service reliability
Trouble Analysis
Another improvement that AMR would enable in outage management is reducing the reliance of
the OMS trouble analysis application on complete and accurate data of network and customer
connectivity. Trouble analysis involves predicting possible outage locations, or fault clearing
devices, and calculating the interrupted customers based on trouble calls received from
customers, outage notifications from power monitoring units and AMR, and telemetry data from
SCADA and Substation and Feeder Automation systems. The objective of trouble analysis is to
help the utility pinpoint the outage locations accurately and quickly, allowing faster crew
dispatch and less troubleshooting travel time, thereby reducing overall outage durations and
costs. While trouble analysis techniques of commercial OMS products have advanced in recent
years, their practical value in operations has been limited in many utilities for lack of quality
data, most notably the connectivity of customer service addresses to distribution transformers
and the network (Hatfield and Tram, 2000). AMR helps alleviate the data problem to improve
the practicality of the trouble analysis engines.
Trouble Analysis Based on Network Connectivity — AMR equipped with appropriate real-time
data communication and management capabilities can help lessen the impact of inaccurate
connectivity data on the trouble analysis results. The basis for this improvement is: the fact that
there are no customer trouble calls in an area would not as reliably tell the utility that the outage
location must not have affected that area as much as the fact that there are no service
interruptions detected from AMR meters in that area would. Furthermore, OMS can improve the
confidence level of its predicted outages by querying AMR meters in select locations on the
distribution network as part of the trouble analysis process. The select locations include, for
example, the customer meters immediately upstream and immediately downstream from the
current predicted outage location. This additional step is recommended because of potential
latency and loss of last gasp messages as explained above.
Trouble Analysis Based on Geospatial Information — Another improvement in trouble analysis
made possible by AMR is in areas where the confidence in the quality of customer/network
connectivity data is very low. To supplement the trouble analysis method based on
customer/network connectivity, which is most common among OMS products today, AMR
outage notification adds more data points to customer trouble calls, which can be combined with
the geocodes of customer premises and device location addresses to help the utility
operator/dispatcher pinpoint possible outage locations and dispatch trouble investigators.
Restoration Confirmation
Querying the AMR allows the utility to confirm that service has been restored without having to
call the customers back. The automated confirmation process can quickly identify power still-out
situations, which are common in storms due to cascading outages, and allow the utility to notify
the trouble crew before it leaves the area if problems still exist, thereby increasing operational
efficiency. Using AMR for the restoration confirmation function avoids the nuisance of calling
the customer in the middle of the night and reduces call center, dispatch, or Interactive Voice
Response (IVR) resources.
Switching Decision Support
In addition to outage monitoring as explained above, an OMS can leverage AMR capabilities in
near real-time monitoring of customer loads, and distributed generation if available, to help
utility operators develop more effective switching procedures and emergency load transfer
schemes.
Many OMSs today estimate transferred loads by using the connected kVA ratings of distribution
transformers. This method often leads to too conservative switching, and sometimes even
erroneous switching, for the obvious reason that transformer ratings do not accurately reflect
customer demands — some transformers may not have customers connected at the time of
switching and some may be overloaded. A few OMSs today use the transformer’s ratings or last
month’s customer kWh billing data at various load points to allocate the SCADA kW and kVAR
measurements at the substation to load points along the feeder to calculate line loading and
voltages for switching planning. While this method is much more accurate than the first one, it
does not consider the time-of-day variations of different types of customer loads. The near
real-time load data captured by AMR alleviates this deficiency and improves the accuracy of the
second method.
Summary
AMR and OMS systems have complementary but different roles, and integrating the two will
elevate the capability and ROI of both systems to new plateaus. Assuming that the real-time data
communication network supports AMR with adequate bandwidth, AMR can benefit outage
management in many areas: outage notification, outage confirmation, trouble analysis,
emergency switching design, restoration confirmation, and post-outage reliability analysis. AMR
helps the utility gage the outage extends quickly and ensure that all problems in the area are
fixed without having to wait for more calls from customers, often repeated calls hours later.
These benefits are particularly important during storm outages when there are often cascade
problems on the same circuit.
References
- Tram, H. and Engelken, L., 2000, “Improving Service Reliability in the Deregulated
Environment,” GITA Conference, March 2000.
- Benassi, F. E., 2001, “The Growing Value of Meter Data,” Energy IT, September/October 2001.
- Tram, H., 1999, “The Smart Way to Deliver Energy,” Utilities IT, July/August 1999.
- Brown, S. M., 2000, “Acquiring and Analyzing Customer Usage Data,” Utility Automation,
September 2000.
- Hatfield, M. and Tram, H., 2000, “Data for DMS/OMS – How Much Is Enough and Where to
Get It,” Utility Automation, September 2000.
