Synchrophasors and containing blackouts
- Posted on May 1, 2012
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Smarter grids are on the way.
In one case, however, the smarts hadn't arrived soon enough to have prevented the regional blackout of last Sept. 8, which led to power losses for 2.7 million people in Arizona and Southern California.
The causes of that event and the lessons learned were presented yesterday in a conference call with the Federal Energy Regulatory Commission (FERC) and the North American Electric Reliability Corporation (NERC), charged with analyzing the causes and making recommendations. While the blackout's myriad causes—inadequate system design, operations scenarios that didn't recognize the potentially disruptive role of low-voltage lines in the bulk power transmission system, poor communication between grid players, other technical and human failures—were complex, the role of phasor measurement units (PMUs) jumped out at me.
In this event, PMUs successfully recorded the origin and spread of the blackout on a split-second timeline. But they have not yet been adequately integrated and their data communicated to all players in a manner that would have limited the September blackout. The good news is that, at least in the Western Interconnection, that work is proceeding apace and due for completion next spring.
Looking back, we've done a fair amount of reporting on PMUs and their promise of situational awareness and the role that both can play in limiting blackouts. These three links provide solid background in the subject.
"Situational Awareness Requires Data Visualization Tools," by Intelligent Utility magazine editor Kate Rowland ran in March/April 2011.
"The Wide Area View: Synchrophasors," remains a webcast available on demand. (Click on "View This Resource Now" at the bottom of the linked Web page.)
"Invisible Smarts: Let's Talk Synchrophasors," by yours truly.
Strategically placed PMUs can record and transmit aspects of system vulnerability up to 30 times per second (about 120 times previous capabilities) to grid operators, theoretically in time for operators to contain or mitigate a blackout. An effort is underway to integrate this capability into the nation's grid interconnections by the North American Synchrophasor Initiative (NASPI) and, here in the West, by the Western Electricity Coordinating Council's Western Interconnection Synchrophasor Program, or WECC's WISP.
The role that situational awareness could play in limiting blackouts was established in the analysis that followed the massive 2003 blackout in the Northeast. That analysis took years. By 2009, the WECC WISP was underway but this advancement in situational awareness will take time (four years) and money ($108 million) and integration (ongoing) and we're on schedule but we're not quite there yet. (More on the WECC WISP below.)
So I asked NERC Senior Vice President Dave Nevius, one of the two participants on yesterday's call, whether the intended outcome of the WECC WISP, for instance, would have provided the situational awareness to not just piece together what happened after the fact, but also alerted grid operators in time to prevent the blackout from spreading as it did.
The real answer, obviously, is technical and, possibly, unknown. But Nevius gamely took a crack at it.
A "substantial number" of PMUs already have been installed and "additional PMUs would have helped," Nevius said. You can "never have enough PMUs," he added. (The gentleman said the same for transmission capacity.) The goal for the NASPI (and, no doubt, the WECC WISP) is just that: situational awareness that allows real-time intervention to keep blackouts from spreading. Left unspoken: we're not there yet.
So, for readers who want to know about when we'll be "there," here's the latest update from the WECC WISP website:
"WECC is meeting the project's key milestones. It has completed data center construction in Vancouver, Wash., and in Loveland, Colo.
"In addition to detecting electric system disruptions, synchrophasor technology can help companies see and manage intermittent renewable resources—and to deploy the ancillary services when necessary.
"In December 2011, the team began testing phasor data communications, system integration and software application functionality; and some partners have started transmitting synchrophasor data. WISP's full implementation phase will take place beginning summer 2012, with training, business readiness and system cutover planning. The implementation phase is scheduled to end with the completion of the system cutover by March 2013."
(Editor: An alert reader at the Bonneville Power Administration pointed out that the WISP's substation PMUs will be installed by summer 2013. The system per se is not expected to go live until two years later.)
Keep in mind that the WECC WISP has eight original utility participants and another 10 have joined the effort, all of whom pour matching funds into a project half paid by federal taxpayers through the stimulus program. Here, potentially, is one of the best uses of our tax dollars in grid modernization. Of course, the proof is in the pudding.
To return to our point of departure, the FERC/NERC analysis of last September's blackout was in the nature of an enquiry, rather than an investigation. (An investigation that assigns responsibility, spokespersons said in response to repeated questioning by reporters, is confidential unless or until responsibility is assigned and fines are levied.)
Meanwhile, it occurred to me that one of the smart grid technologies furthest away from the customer—yet critical to reliability, one of the customer's two top concerns (the other: cost)—is expensive, time-consuming and (thankfully) in the process of implementation. Here in the West, the real test comes after next spring, when the full potential of coordinated PMUs will be brought to bear on future events. Big stuff, coming soon. Can't wait.
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