This article was published in the World Generation Magazine Nov/Dec Issue 2016
Do you remember the late 1990s, when Apple was very much an underdog fighting for its share of the computer-market bone? IBM’s slogan was “Think,” so Apple ran with “Think Different.”
Today, twenty years later, the company that never did manage to elbow windows computers off the shelf still prevailed by following its own slogan. Consider this: Some 40 percent of U.S. smartphone users are walking around with an iPhone in their pockets.
I recall this marketing success because I want utilities to take a cue from Apple: Think different. If you’re not already doing so, now would be a good time to start. Many utility professionals have already begun to think differently, and I have the honor of working with some of them in the Grid Management Working Group hosted by SGIP. What are they thinking about? Take a look.
GRID-EDGE MONITORING AND CONTROL TECHNOLOGY
We must move monitoring and control technology farther out toward the grid edge. My discussions with utility professionals tell me we’re already behind on this evolution. As examples showing why this is so important, consider these experiences from a West Coast utility.
In one case, the utility had grid-scale solar generating at full output as well as a 400 MW pump storage station that was pushing water behind the dam. When the pump station tripped off, voltage jumped and capacitor banks tripped off.
While this didn’t result in outages, it could have. If a bunch of capacitor banks go down and voltage goes too low, lines will trip off due to instability.
In another case, outages did occur. The utility had an under-frequency scheme in place, and it had to respond within six cycles to be effective. All looked well when low voltage kicked this protective scheme into operation, and a 7 kV line was tripped off. But, there was so much solar on the line, it remained energized beyond the six-cycle time limit, and six more feeders tripped off as a result. In both of these cases, one problem looms: lack of control. Much of that problem stems from centralized control that takes too long to really react to rapidly-changing conditions from intermittent generation.
THE OPEN FIELD MESSAGE BUS APPROACH
A few years ago, engineers at Duke Energy were trying to coordinate solar and storage installations. To that end, they clocked the round trip from sensors on an inverter to the head-end system, through the computation cycle and then back to the inverter. It took some 40 seconds. This is what got Duke started down the path of OpenFMBTM, a reference architecture that provides a framework for distributed intelligence.
Working with Duke and other industry players, SGIP’s OpenFMBTM working group shepherded this architecture through the standards process. It was ratified as a standard by the North American Energy Standards Board (NAESB) in March of 2016 and, at SGIP’s 2016 Grid Modernization Summit held in Washington, DC November, we launched a collaborative website where people can access the OpenFMBTM code itself.
OpenFMBTM supports grid-edge coordination of distributed energy resources and the grid itself because it facilitates local data exchange on a circuit segment, which enables decision making without centralized system control. That’s crucial because Supervisory Control and Data Acquisition (SCADA) systems typically collect grid status data every four or five seconds, and that’s just not fast enough when you have a protective scheme that must operate in six cycles.