Advanced metering infrastructure (AMI) and outage management systems (OMS) have operated in tandem for some time. When utilities deployed fixed-network AMR systems a decade ago, using data from the AMR system for the OMS was one of the big drivers for AMR, according to Kevin Cornish, executive consultant with Enspira Solutions.
While the concept of furnishing the OMS with meter-related outage information isn't new, one challenge is that the utility never received all the meter's relevant information. It got just enough to properly identify outages and locations. Today's AMI systems feature a robust communication network, a meter that can repeat outage information to increase the probability of being received, and the ability to forward power-on or restoration information automatically.
AMI allows operators to quickly see where outages have occurred, and improved communication decreases dispatchers' response time during outages. For example, when a call enters the OMS, AMI technology can analyze the outage information and then check surrounding meters. This advancement eliminates the need for more customers to call in before operators can determine an outage location. In addition, periodic “sweeping pings” by AMI can alert the OMS to outages in the system before any customers call. AMI also can confirm outage restorations, providing positive verification via reads of meters or “pinging.”
To fully take advantage of the link between AMI and OMS, utilities are exploring opportunities to link the technologies with their supervisory control and data acquisition, customer information systems (CIS), interactive voice response and geographic information systems (GIS), all of which can generate additional useful information during outages. For instance, CIS and GIS are base data systems that feed into OMS. They help to determine where all the meters are and which customers are associated with which meters. This doesn't help the OMS determine outages. However, as AMI data flows into the OMS, it includes a tag, such as the meter or premise ID, so the OMS knows which customer should be assigned the outage.
Getting Beyond the “Last Gasp”
Most meters used in AMI systems have a “last-gasp” capability, which is a high-priority message transmitted by the meter that service is out. With a large outage, the last-gasp functionality can overwhelm an AMI system because of message collisions in the communication network.
New technology is able to overcome such problems, said Cornish. Some AMI systems don't just send a single last gasp, he notes. Rather, they send a series of “power out” status messages. Some mesh networks also combine outage information. As a result, instead of having 100 distinct outage messages, a utility might only have a packet with outage information. The same amount of information makes its way through the network, but it is more efficient. Furthermore, some AMI systems have the ability to filter or throttle the amount of outage information that is making its way to the OMS, so that it doesn't overwhelm the OMS.
AMI and OMS in Action
Peterborough Utilities (Ontario, Canada) implemented its smart meters in mid-2009. While the company hasn't yet used them for time-of-use, it is using them for billing.
While the information is useful for meter reading, the system also provides additional information that the utility can use, such as outage management. The utility doesn't have an actual OMS, but with its AMI technology, the company can tell which meters are attached to which transformers.
When there is an outage, the utility receives outage notification from the meters themselves. This lets the company know which transformers are potentially out, even before customers call. “We call this our ‘poor man's outage management system,” said David Whitehouse, manager, customer service. “When service is restored, the meters provide us with a restoration notification.”
Another utility moving in the direction of AMI and OMS integration is Philadelphia, Pennsylvania, U.S.-based PECO, which installed an automatic meter reading (AMR) system in 2000. Currently, PECO is on a journey to replace its AMR system with a true AMI system, including bidirectional communications on the meters. PECO expects to begin installing these meters in 2012. One of the new enhancements for the utility's OMS will be the ability to monitor voltage at the meters. Since low voltages often precede outages, the company will be able to dispatch on this problem and either reconfigure a circuit or reroute power before the outage actually occurs.
Over the years, AMI has begun to play a more significant role in outage management. By capitalizing on the benefits of this technology, utilities can help to streamline power restorations and minimize outages in the future.
Joel Hoiland (firstname.lastname@example.org) is the CEO of Utilimetrics.