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Bill Yingling reports that 


The electric power industry has known for decades that a nuclear detonation in the atmosphere above the United States could disrupt the nation’s electric grid. Now the industry’s research arm, the Electric Power Research Institute (EPRI), working with the U.S. Department of Energy, is performing a study that will help predict the extent of the damage. That, in turn, will help determine the steps utilities can take in advance to prevent, or at least mitigate, the consequences. A panel of experts discussed the topic Sunday at the National Association of Regulatory Utility Commissioners’ Winter Policy Summit in Washington D.C.


EPRI is in the middle of a three-year study on the impacts on the bulk power system of an electromagnetic pulse (EMP). The focus on the nation’s high-voltage transmission system, not necessarily the lower-voltage distribution system that delivers power directly to homes and businesses. Research started in April 2016. The organization expects to release findings late this year or early next year, said Mike Howard, president and CEO of EPRI.


The EMP threat has gained visibility in recent months as North Korea claims to have developed nuclear ballistic missile technology that could threaten the U.S. mainland. “This three-year study is to get into the technical details, and really understand the technical facts and the truths around this important topic,” Howard said.


The study has broad support among 63 utilities. These companies are interested because it will fall on their shoulders to buy and install the equipment necessary to protect the grid and to restore service in the aftermath. While the study will focus on electric utilities, Howard said, the findings should be helpful for other industries as well.


Howard opened Sunday’s discussion explaining the difference between a geomagnetic disturbance, or GMD, and electromagnetic pulse, or EMP, because often there is confusion regarding the two. A GMD can occur when the sun emits a burst of charged particles that can disrupt the earth’s magnetic fields.


This low-frequency energy can couple with transmission system creating a current that can cause transformers to overheat, can cause a loss of reactive power — which supports the flow of electricity — and, in extreme cases, can cause voltage instability and possibly a collapse of the electric system. A geomagnetic storm hit North America in March 1989, causing a widespread outage on Hydro-Quebec’s electric transmission system that affected 6 million Canadians.


“Fortunately it doesn’t happen very often,” Howard said. An electromagnetic pulse, in contrast, is man-made, caused by the detonation of a nuclear warhead about 150 miles above the earth’s surface. The blast showers a wave of energy on the surface below and can disrupt electronic equipment.


An EMP, he said, is actually a series of three pulses: E1, E2 and E3:


E1 is extremely fast, lasting only about 5 nanoseconds, which is 5 billionths of a second. It delivers a high amount of energy. “It’s a very short, intense pulse,” Howard said.


E2 is longer, lasting about 1 microsecond, a millionth of a second. Its energy also couples with the transmission system, but it’s not a big threat, Howard said. “We’re not really overly concerned about it because it doesn’t have the potential to really cause a lot of damage.”


E3 is longer, lasting for tens of seconds and up to several minutes. EPRI released a study on the effects of E3 last February.


“What we found is that very, very few transformers — these are your bigger transformers, your substation transformers — would be impacted,” Howard said. Some transformers would overheat, their internal windings would short out and cause units to fail. But the study found that only about a dozen would be affected. “We have spare transformers around and we can recover from that,” Howard noted.


E3 would likely cause voltage stability issues at the regional level. “Voltage stability issues could result in a voltage collapse. And, while a voltage collapse is never good, one of the things we found is that it would be on a regional basis, not a national basis, so you could recover from that,” he said. “You’re going to have to start back the system again and then slowly bring it up, which could take a few days, but it’s at the regional level.”


EPRI is now studying the E1 pulse and its effects on the electrical system. “We want to do this right because getting to the truth of what will occur and the damage that it could cause is extremely important. So then we can start turning our attention to cost effective solutions,” Howard said.


“We are looking to see what are the cost effective solutions to mitigate the disruption to the electric system. And we are finding some very inexpensive solutions. We’re going to test those,” Howard said. Devices, such as circuit breakers and relays, can be tested in field trials with a small number of utilities, said Randy Horton, EMP program manager for EPRI. “The field trials and the lessons learned are a very important aspect of this,” Horton said. “The last thing you want to do as an industry is fix the EMP problem and then cause other reliability issues due to the fix.”


There’s still a lot of work to be done, including examining E1, E2 and E3 together, Horton added. EPRI has looked at E1 by itself and E3 by itself. But he said researchers need to assess the impact of all three types of pulses combined. EPRI is not working on EMP in a vacuum. Other parties in government and industry have a stake.


Devon Streit, deputy assistant secretary of Infrastructure Security and Energy Restoration in the Department of Energy, said her agency is close to releasing an unclassified document intended to give all stakeholders a common understanding of EMP and its potential impacts to help facilitate future discussion. As a result of research, the Federal Energy Regulatory Commission, has established standards for utilities to protect against GMD, said FERC Commissioner Cheryl LaFleur.


“In the case of EMP we have not up till now felt that we know precisely what the companies should be directed to do to their systems,” she said. That’s why EPRI’s research is critical. It will help in deciding how to direct utilities making changes to the grid. E3 is like GMD, just a lot more of it, LaFleur said. So that issue is being addressed. And E2 is like lightning, for which utilities already have protection equipment. “But E1 is its own beast and companies have not been required to do something about it,” LaFleur said. “And when they find out how to start, that’s going to be pretty critical.”


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