EPRI: Sandy exposes smart grid limits, and maturity
- Nov 19, 2012 12:00 am GMT
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If you want to talk about how smart grid fared during Hurricane Sandy, Arshad Mansoor, a senior executive at the Electric Power Research Institute (EPRI) has two lines of thought:
First, with recovery still ongoing, any post-mortem on the role of sensors and controls on the grid is premature. (Although we may find that smart meters played a role in outage management.) Second, the full value of smart grid systems in such an event has yet to be fully realized and years of systems integration, analytics development and significant expense still lie ahead.
Mansoor, who has studied and written extensively on the subject, described for me how EPRI frames the related issues of grid resiliency that includes hardening, recovery and survivability as a three-pronged approach and what steps might be taken to improve them and the process of integration and data analytics that must be completed to fairly ask whether smart grid can play a role in a scenario presented by Hurricane Sandy.
(A variety of my own theses, and robust reader responses, may be found in yesterday's column, "Sandy Versus Smart Grid: Who Won?")
The starting point is to acknowledge the role of physical damage to the grid and the laws of cost/benefit analysis.
It's simply not possible to harden the sprawling electric transmission and distribution grid against all eventualities, Mansoor told me, echoing a widely held view. "All eventualities" cannot be predicted, hardening can never be 100 percent and the cost of even attempting this is prohibitive and ill-advised.
But the experience gained in dealing with Hurricane Sandy raises several issues that require attention, he said. Utilities have work to do, regulators have prudent costs to consider and end-use customers need tools and strategies to cope, as well.
"We see a three-pronged approach to resiliency," Mansoor said of EPRI's approach. "First is hardening. This could involve things such as undergrounding, vegetation management, hydrophobic coating for lines, substation storm surge and seismic design criteria. The second aspect is recovery: identifying the location of damage, isolating the damaged portion and restoring power. The third prong is survivability—how can we equip consumers with technologies beyond a candle to better cope with a prolonged outage?—which is the least-resourced area.
"We must assume that infrastructure can never be technically or cost effectively feasible to withstand everything that Mother Nature or a human act can throw at it. We must accept that we must plan for failures."
I suggested that generalizations were difficult to make, as steps toward hardening and resiliency would be different, say, for coastal utilities versus inland utilities during the recent hurricane. Likewise, utilities across the country assessing their grid's survivability are dealing with different risks and, thus, need different strategies and tools. Further, on any single utility's grid, a variety of tools might be applied in different places based on cost effectiveness.
"Generalization is difficult," Mansoor agreed. "But a few are possible, such as selective undergrounding. Every utility has unique circumstances and they'll take a look at where undergrounding makes sense, where more aggressive vegetation management makes sense, where seismic hardening makes sense."
Selective undergrounding will always remain one of the key hardening options, but EPRI wants to highlight that 100 percent undergrounding doesn't make sense, Mansoor added. The biggest challenge in selective undergrounding is applying it intuitively. Undergrounding main lines with the most customers would seem to make sense. But, according to Mansoor, undergrounding at the extremities could be a better approach if reducing storm restoration time is the main objective. A circuit cannot be re-energized until the circuit is completed to the end-use customer. Sometimes a cost/benefit analysis that uses traditional reliability metrics like SAIFI/SAIDI as its guide may not provide the best options for selective undergrounding to reduce restoration time.
Back to different tools for different folks. For ConEd (serving New York City), for instance, flooding was a major impact, Mansoor noted.
"No amount of SG technology will dry out a substation quickly," he pointed out.
"If you look at the unique circumstances of a storm surge beyond the substation design criteria, that's very different from what we're seeing in Connecticut, which is more typical of storm damage we've seen before," Mansoor said.
Smart grid systems will help, if fully integrated, Mansoor added, but that's a multi-year effort requiring substantial investments—perhaps hundreds of millions of dollars for a large utility.
Mansoor then described the systems integration and analytics work ahead for utilities, the cost considerations for regulators and the role of customers in coping with outages in the face of overwhelming natural assaults such as Hurricane Sandy. "Big Data" is also an opportunity for electric utilities to innovate and we are at the early stages of leveraging the enormous amount data from smart meters, sensors and other devices we will be getting from the grid.
That will be the subject of tomorrow's column.
Intelligent Utility Daily