By Jim Roche, Cooper Power Systems/Cannon Technologies
The advent of automatic meter reading (AMR) came about in the mid-’80s, and more prominently in the early 1990s as an automated way to collect basic meter-reading data. The term and technology behind advanced metering infrastructure (AMI) began showing itself around 2005, evolving from the foundations of AMR. As not uncommon in this industry, we often hold on to the label that came first or use two terms interchangeably, even if the actual meaning or definition is slightly different. All AMI systems contain AMR functionality (although it’s not the core of its purpose), but all AMR systems are not AMI systems.
According to the Demand Response and Advanced Metering Coalition, AMR is defined as a “system where aggregated kWh usage, and in some cases demand, is retrieved via an automatic means such as a drive-by vehicle or walk-by handheld system.” A more expanded definition likely includes all one-way systems, drive-by and walk-by systems, phone-based dial-up systems, handheld reading entry devices and touch-based systems. These systems tend to be collection only, without means for broadcasting command or control messages. In addition, data from AMR systems is typically gathered only monthly or, at most, daily.
AMI is typically more automated and allows real-time, on-demand interrogations with metering endpoints. The Federal Energy Regulatory Committee (FERC) defines AMI as “a metering system that records customer consumption hourly or more frequently and that provides for daily or more frequent transmittal of measurements over a communication network to a central collection point.”
AMI requires requisite bandwidth to supply more than merely metering and power-quality information. AMI systems need to have appropriate bandwidth and broadcast capabilities to allow for demand response/load management as well as distribution automation.
Because of the inherent differences in AMR and AMI, the data available from each system differentiates them.
AMR systems can typically provide the kWh reading and possibly peak kW demand for the month. Other limited data may also available, depending on the system deployed.
AMI typically provides a substantial payload of information. The list of detailed information that can be supplied via AMI systems includes: cumulative kWh usage, daily kWh usage, peak kW demand, last interval demand, load profile, voltage, voltage profile, logs of voltage sag and swell events, voltage event flags, phase information, outage counts, outage logs, tamper notification, power factor, and time-of-use kWh and peak kW readings. With high-end AMI systems, nearly all of this information is available in real time and on demand, allowing for improved operations and customer management.
AMI systems can also be used to verify power outages and service restoration, perform remote-service disconnects and reconnects, allow automated net metering, transmit demand-response and load-management messages, interrogate and control distribution-automation equipment and facilitate prepaid metering.
When studying the list of available information, one easily sees the differences. The functionality available in AMI has caused many utilities throughout North America to invest in AMI systems, including utilities that previously invested in AMR systems. Utilities have various reasons for wanting to increase their AMR systems’ functunality.
Because of the differences in available information, the number of departments that can benefit from the system is vastly different (see Figure 1).
The beneficiary list from AMR is short, with only the metering and billing departments benefiting. AMI can benefit groups ranging from engineering and operations to asset-management and planning departments. In addition, AMI has the built-in tools to enhance customer service and satisfaction.
The drivers for AMR are typically limited to improved billing accuracy and a reduction in the time and expense to read and bill meters.
While AMR systems were advanced in their day, they just don’t have the capability to deliver most of these goals to electric utilities. This is not a slight on AMR; those systems were designed in a different time for a different purpose. There are options that allow utilities to migrate from existing AMR systems to a more powerful and flexible AMI system.
While AMI systems also read meters, it’s no longer a primary driver for most utilities.
In 2007, the Cooperative Research Network, the research arm of the National Rural Electric Cooperative Association, identified its top two dozen applications for AMI systems. Meter reading didn’t make the list.
As highlighted above, there are numerous drivers for utilities to implement AMI systems. Some are touched on below by utilities that have embarked on AMI system implementations.
Bob Brennan, president and CEO of Manitoba Hydro, remarked at the kickoff of Manitoba Hydro’s implementation, AMI will allow the utility to “ … achieve key objectives set forth in our corporate strategic plan, particularly in the areas of conservation and stewardship, delivering customer value, financial performance and employee safety.”
Southern Pine EPA in Taylorsville, Miss., implemented AMI because it says it will give the company the ability to achieve its mission, “ … to provide reliable, safe and efficient services at a competitive price to all our customers.”
According to Dwight Duncan, Ontario minister of energy, “Smart meters will empower consumers to better manage their electricity costs and respond to pricing incentives that encourage both conservation and load shifting to off-peak periods.”
The U.S. Energy Policy Act of 2005 (also known as EPAct 05) encourages the use of time-based rates to enable consumers to manage their electric energy use and costs through AMI and its associated communications technologies.
Tools for E&O Professionals
AMR’s limited functionality and flexibility offers little in engineering tools. But what can AMI mean for utility-distribution engineers and operations personnel? When used at its fullest potential, there is much to be gained.
Improved system-voltage monitoring can lead to better regulation, improved capacitor and regulator placement and more accurate voltage-drop analysis. Improved load information leads to better load studies and analysis, resulting in improved planning and system design. Improved reliability monitoring can lead to improved outage response, proper system-protection analysis and ultimately, a decrease in outages and outage time, raising reliability indices. Improved monitoring and information flow can also lead to better management of critical assets such as transformers and capacitors. Distribution-automation tools implemented via AMI networks provide for real time interrogation and control of remote intelligent electronic devices (IEDs). The information and reporting tools available within AMI systems can allow for targeted vegetation management and line patrol, prioritizing and controlling maintenance spending. Last, engineers can use the systems to pinpoint system losses, and once identified, reduce them.
Opinions & Conclusions
Uncertainty in power-supply and generation markets is likely to lead to additional costs being passed to distribution utilities. AMI provides the tools and flexibility to pass these charges on to consumers as needed. In addition, the demand response and pricing programs that can be implemented via AMI systems allow the utility and customers a number of options to manage their usage.
AMR systems are good doing what they do: reading meters. Nevertheless, as they prepare for the future, it will likely be harder for most utilities to justify the expense of a system to provide meter reading alone. The benefits of AMI tend to provide a more palatable and sensible return on investment (ROI) for today’s utilities. This also tends to be true for utilities that invested in early AMR technologies, as manageable and cost-effective migration plans can be set into action.
So, what does AMI offer? First, AMI can provide a utility a real-time connection to all its customers, providing actionable information to consumers and utility staff. Second, a utility can have a better understanding of the quality and distribution of its product, allowing for improvements in the utility’s reliability and efficiency. This can lead to improved financial benefits for the utility and improved satisfaction for customers.
Upon completion of Lake Country Power’s AMI rollout, general manager Rick Lemonds said, “Our AMI system has already made positive service impacts by providing the right employees with the right information when requested. This provides our members with data to support answers to their questions.”
Although AMR had its run, the more one looks at AMI, the more it seems its uses are limited only by imagination.
Roche is the senior marketing manager for AMI solutions for Cooper Power Systems/Cannon Technologies. He received his bachelor of science degree in electrical engineering from Iowa State University in 1998 and has worked in various engineering, customer service and product-management positions at Cooper/Cannon for 11 years. For more information e-mail him at [email protected].