A utility can do a lot with advanced metering infrastructure (AMI): spot a problem downline from a transformer and trace it back upstream to find the fault; track and analyze power-use patterns to help shape demand; monitor and improve power quality and reliability; even provide consumers with information they can use to reduce their bills.
But as more smart meters and AMI systems find their way onto co-op lines, savvy technicians are finding an additional benefit: Advanced meters are great at detecting power thieves.
“They can’t hide from me very well,” says Nadine Hatch, the database programmer for Delta-Montrose Electric Association (DMEA) in Montrose, Colorado. “I’ll find them.”
DMEA launched its meter change-out program in 2009, and it now covers all 34,000 of the co-op’s accounts, says Steve Metheny, chief of power supply. He says the original selling point was remote-read capability.
“We have a very rural, mountainous service territory, and we had to go to every meter, every month, and take that reading,” he says.
Power theft is not a serious problem for DMEA, Hatch says, and detection was not among the co-op’s reasons for the change-out. Nevertheless, it’s not something they take lightly.
“It’s pretty rare,” says Andy Penfield, the co-op’s controller. “But it is nice to have an automated system that monitors use on a daily basis so we can address issues fairly quickly.”
The most common detection technique, according to Tony Thomas, an NRECA senior principal engineer, is to keep close track of brief power interruptions, or blinks, that smart meters report back to the co-op.
Power thieves often try the old-fashioned trick of flipping their meter upside down. With conventional that had the effect of running the meter backwards, which obviously would reduce the readings of power use, he says.
But not only do smart meters read correctly no matter which end is up, their blink monitoring and two-way communication abilities mean that the co-op gets an almost instantaneous report of any interruption.
“Modern AMI readers count those blinks and send that number to the utility,” Thomas says. “If you have a lot of blinks at one house and the neighbors don’t have any blinks at all, that’s a very good indication that you have power theft going on. It works beautifully.”
Some thieves, he adds, try a more dangerous alternative: bypassing the meter entirely with a conductor from the feeder line to the service drop. Smart meters talking to headquarters through an AMI system thwart that attempt too, Thomas says.
“First you have a lot of blinks, and then you have no usage,” he says. “Then the utility gets an alarm that says the consumer’s out of power. The first thing any utility does is compare that house to the next-door neighbor’s. If the place is showing no power but the neighbors have power, then you’ve got a problem.”
All of the major AMI system vendors include blink detection in their offerings, he notes.
Hatch agrees that the blink-count method would certainly work. But she takes a different route to get the same result.
“I’m actually looking at communications and the quality of communications with the meter,” she says. “If I’ve got something that’s not talking, that tells me something.”
DMEA’s meters take readings every two hours, and reports back to headquarters include a “quality code” assessing the communications signal, Hatch explains. “Maybe it made a partial response, not a complete response, and the system will give me a message about a problem with the meter.”
More than 34,000 meters sending back 12 readings a day will produce a lot of data to wade through, so as a further refinement, DMEA’s AMI system filters and flags the problems.
“That takes 34,000 down to a dozen or so and tells us that these few reads don’t balance,” Hatch says. “We’ll know something’s going on because the readings aren’t adding up how they should. For example, we can see when people install a PV [photovoltaic] system without going through proper procedures. Or if someone borrows a meter from one place and puts it in someplace else.”
As more co-ops transition their systems to use new technologies like SCADA and advanced metering, they’re being met with some trepidation by members. For co-ops like DMEA, it all boils down to member education and benefit.
“AMI systems do so much, it’s hard for an average member to really understand their value,” Metheny says. “It goes beyond meter readings, and it’s our responsibility to make sure our members understand that by using technologies like AMI, we’re able to improve the reliability and safety of our power systems. We are able to be more responsive to member needs and address outages quicker. And we are setting a solid foundation to respond to the changing dynamic of the energy industry that directly impact members, such as more distributed generation, real-time pricing, and demand response.”
Hatch has been at DMEA for three years, so she’s never worked without its AMI system providing constant information.
“I don’t know what we’d do without it,” Hatch says, adding that a thief could have gotten away with a lot in pre-AMI days. “Until the meter reader got there and actually looked at the meter, there’d be no way of knowing.”
And once again, Hatch hastens to add that most of the “dozen or so” AMI flags she looks over each day are the result of problems other than theft.
“But I’ve found a lot of power outages before anyone else has found them,” she says. “That’s what my job is, five days a week. And if we’ve had a big storm, it might be seven days a week.”