Uncertainties about smart metering goals are hindering efforts to standardize communications protocols and feature sets. While vendors battle over standards, utilities and policy makers are moving...
Smart-Grid Strategy: Why Wireless?
Radio waves deliver flexibility and security.
also to get the wireless network back on,” he says. “This can take a fairly long time—hours beyond the restoration of power. If we are using a public cellular carrier, and if their network goes down, they will fix it, and they are just as incented as we are to get it back up quickly.”
For Duke’s architecture, Mohler sees fertile ground for development from the central communications collection point—which, for Duke, is located on distribution transformers—into customer premises. The collection point has memory processing, backup power supply, USB ports, a modem, and a number of communications cards. These allow the utility to transmit information from a multitude of devices in the neighborhood area network— i.e., meters and sub-meter devices, reclosers, street lights, capacitor banks, transformers, weather monitoring equipment, and security equipment—to the communications box. For this piece of the smart grid, Mohler says public networks can serve the company’s needs. Toward that end, Duke plans to deploy a SmartSynch product called the Universal Communications Module (UCM) to serve some of its commercial, industrial and residential customer sites. The UCM transmits and receives data over public wireless networks using Internet-based or other open standards, which Mohler says will allow Duke to spot-deploy smart-grid applications, such as load profile and control, power quality monitoring, distribution automation, and stand-by generator control; and to support retail demand response , conservation and real-time pricing programs.
“Ultimately, a portfolio of communications technologies will be required to achieve the kind of communication reliability we want,” Mohler says. “We don’t think any one communication technology will be the solution. In fact, we’ve developed an architecture at Duke that anticipates and is designed to accommodate this kind of portfolio communication.”
Whether public or private, over time, the smart grid might become more wireless than wired—if only because wireless is becoming ubiquitous for all types of connectivity, supplanting copper in many situations.
For example, in comparing wireless to power-line carrier (PLC) technology, Trilliant’s Miller points out that with the exception of a few industrial applications, PLC doesn’t have a lot of application outside of the utility industry. “In addition, the quality of the wire can have an impact on the capacity and data quality you can get from PLC technology,” he adds. “In fact, as we see it, PLC technologies are probably below the minimum thresholds of what are required for true smart grid.”
In addition, wireless connectivity provides an easy upgrade path, compared to hard-wired technologies that can be limited by the bandwidth constraints of the wire. Accordingly, the wireless smart grid will continue to develop and evolve, as companies explore various approaches to addressing their particular needs.
“There won’t be many solutions that will be in a shrink-wrapped box that can be shipped as-is,” says Pitstick of Cooper Power Systems. “Every utility network is different and will require a custom solution.”