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Advanced Metering Infrastructure (AMI)


AMI refers to all components of the infrastructure relating to electric metering and communications. This includes smart meters capable of two-way communication1.

Description of AMI technologies

AMI meters are sometimes called interval meters and in that sense are closely related to automated meter reading (AMR) devices. The notion of an interval meter comes from the fact that the meter (AMI and AMR) can capture electricity usage information on a periodic basis and transmit that data to the utility company. The key difference between AMI and AMR is that an AMR device only provides a one-way communication path. Demand response, price, and other operational signals cannot be transmitted from the utility company to an AMR meter as it can with an AMI meter.

AMI’s role in outage prevention and service restoration

In the face of a catastrophic weather event, AMI devices will not have much of a role in outage prevention, but they can be a tremendous help in service restoration. When a power outage occurs, smart meters have the ability to send a “last gasp” message to the utility outage management system (OMS). It would alert the utility of the event, allow the OMS to ascertain the extent of the outage, and begin making conclusions about the affected areas in mere seconds’.

Without AMI, service restoration is a function of the utility call center in a process that takes much longer (e.g., customers struggle to locate account information in the dark, or they must be manually identified by the call center agent) and is less complete. Also, during the restoration process the absence of the signal from an interval meter would indicate a secondary outage that the utility might not otherwise be aware of.

Illustration

In August 2011, Hurricane Irene moved along the eastern coast of the U.S., eventually making landfall as a Category 1 storm on the coast of New Jersey. It then passed over several northeastern states as a tropical storm/tropical depression. As Tom Evslin, a Vermont Electric Co-op customer and author living in New England, noted on his blog, Fractals of Change2.

“At 8:15 p.m., with the wind still raging, the lights came back on for most of us. It’s likely some intrepid person went up in a cherrypicker in the storm and made a repair (thank you!). Immediately, the outage website showed that 199 South Hero customers were still without power; something must have happened downstream from the original break. Without smart meters, the crews probably wouldn’t have known about the second break for quite a while, since the people who were cut off by it would have just assumed that the original problem hadn’t been fixed yet and wouldn’t have called in again until they lost patience or saw their neighbors’ lights on.”

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1 Berst, Jesse; Smart Grid 101, Everything you always wanted to know about grid modernization in 5 easy lessons; © 2011 by Smart Grid News, pp. 17.

2 blog.tomevslin.com/2011/08