Small Network Solves Big Problem

By Jerry Bonser,
Xcel Energy

Imagine you’re a meter reader for Xcel Energy. Your job got a lot easier when Xcel automated 1.5 million meters in the Denver area with a van-based mobile automated meter reading (AMR) system. Now, to read meters, you hop in the van and drive your route, using the van’s on-board computer to “wake up” the meters, which then send the data through radio frequency communication back to the computer in the van. Piece of cake, except for one thing-high-rises. You pull up to a 41-story building to collect your reads, but the van can only read meters up to the sixth or seventh floor. So, you climb out of the van with a handheld unit, take the elevator to the 41st floor, and start to work your way down, floor by floor. On some floors, you can get access to the meter room; on others you can’t. It’s not a very efficient way to collect data.

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Xcel Energy provides electricity, natural gas and other services to 4.6 million customers in 12 states. When it comes to reading meters in these buildings, you might say Xcel Energy had a high-level problem. The utility automated the electric and gas meters throughout its Metro Denver-area service territory and was reading them with a mobile van system. The system works beautifully, with the one exception-high-rise buildings. Xcel Energy was missing 43 percent of the meter reads in high-rises.

Excel Energy Becomes Beta Test Site

Nearly two years ago, the utility agreed to be a beta test site for a new network product from Itron Inc.-the MicroNetwork, a low cost, network AMR solution that can be selectively deployed to provide more frequent meter reading capability for any combination of electric, gas and water meters. Because the MicroNetwork makes use of existing public communication networks to deliver data from locally installed concentrator devices to the host processor, it can be strategically and cost-effectively deployed in a surgical manner.

“It’s unlikely that a single technology solution alone will meet all the various needs and accommodate changes over time,” said Tim Stone, Itron’s MicroNetwork marketing manager. “Xcel Energy is a perfect example of that. The van-based mobile system they had in place worked well for the vast majority of their territory-with the major exception of high-rise buildings. Dropping in a MicroNetwork was ideal from both the performance and cost standpoints. The important lesson here for utilities is that they don’t have to choose a single technology and force it to fit every set of circumstances. This integrated approach can save a great deal of money for a utility because it can implement the lowest-cost system to meet different needs within the territory.”

A MicroNetwork system, or “cell,” typically consists of up to 15 “concentrator” units that serve a designated population of Itron radio-equipped meter modules called ERTs. Itron ERTs are the endpoint devices that encode and transmit meter data to the collection device. Information is gathered by the concentrators, forwarded to a base concentrator and sent over radio frequency to the mobile system or telephone lines to the head-end processor. One MicroNetwork cell can handle up to 1,200 endpoints.

During the beta test, Xcel Energy installed 11 concentrators in three buildings-a 28-story structure, a 31-story building and a 42-story structure. These three structures housed a total of 958 meters. Prior to the installation of the MicroNetwork system, the utility was missing the vast majority of those 958 high-rise meters on a regular basis due to the height limitations of the mobile system and/or the inability to access and read the meters manually with a handheld computer. With the MicroNetwork installed, Xcel Energy now can automatically and efficiently collect the reads without having to access the building.

When the production model of the product was developed, the utility began installation in other buildings. Today, Xcel Energy has 17 additional concentrators located in 11 buildings, and it typically misses less than one half of one percent of the reads in these buildings during any given month. It is also installing the system in four additional buildings.

The software includes scheduling functions to control the timing of tasks, status windows to provide a single point of reference to determine status of concentrator interrogations, table viewers, daily task tables, reading log tables, a task monitor and a concentrator dialer.

The concentrators can collect data on any schedule desired-hourly, daily, monthly or off-cycle. In Xcel Energy’s case, the mobile AMR system is used to collect the data from the MicroNetwork. It takes about 30 seconds for the van to stop outside a high-rise with more than 500 meters and collect all the data. The utility is currently performing just monthly consumption reads at these locations.

Added Benefits

The system can also help with off-schedule reads, such as move in/move out. Presently, Xcel Energy doesn’t perform special move in/move out reads because its automated meter reading system provides correct reads on cycle billing dates before and after a move, so it is easy to accurately prorate the bill. But the system does allow the flexibility necessary to perform on-request reads if needed, as well as to collect tamper information. The system detects and reports tampering from a variety of sources, including meter removal and reverse rotation of meter counters, cut cables and remote module counter tampering. Tamper status information is stored in the concentrator unit and delivered to the host processor on request.

The benefits of the system include reduced costs, increased information, improved operations and the potential to offer new services and generate new revenues. Reduced costs come from the elimination of estimated reading costs, reduced requirements for field visits, reduced numbers of hazardous-to-read meters and reduced theft investigation costs. Xcel Energy receives more information because it can read meters more frequently, perform selected reading functions without specialized or advanced meters, collect and report tamper information more frequently, and track billing questions or abnormal consumption patterns. The system also allows the utility to gather daily reads for gas daily balancing and electric system load balancing and forecasting. It can also provide submetering information and aggregate reading from multiple meter locations. Operations are improved by eliminating estimated reads, while reducing field visits and call volume to the customer service department. Customer calls can also be resolved more quickly through ready access to accurate data. New revenue generation possibilities include data aggregation, submetering, offering meter reading services to other utilities, gathering and selling data, consumption monitoring, vacation monitoring and consolidation of information for key customers.

Xcel Energy is also experimenting with submetering applications using this system and sees a great potential in that prospect. For instance, the utility could offer property managers submetering information based on daily reads. In addition, Xcel Energy plans to begin reading water meters and has a major project in the planning stage to submeter between 3,000 and 5,000 units, including gas, electric, domestic hot water and chilled water.

Xcel Energy’s experience with the MicroNetwork has been extremely positive. Of course, each new project is a learning experience and there are things the utility would do differently if it could start over, such as use more directional antennae on concentrators. It cabled several concentrators together, using directional antennae only on the highest locations.

Xcel Energy recommends this technology to any utility that has a mobile system and needs to expand capabilities without a system-wide conversion to a fixed network. This technology fits into a migration strategy as well, because the data can be read by a larger fixed network as well as by a mobile system.

That image of the meter reader trudging down 41 flights to try to capture meter data is long gone at Xcel Energy. The new system is better for everyone-customers who receive accurate, timely reads, and the utility, which reaps the benefits of increased efficiency and operational improvements.

Jerry Bonser is the manager of measurement technology and services at Xcel Energy.

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