The Importance of Protecting Substations Against Electromagnetic Threats

What is happening in the field of EMP for power utilities and the U.S. grid?

There has been quite a bit of movement in the U.S. regarding EMP since the studies that were done by EPRI, the Electric Power Research Institute. They started an EMP study that lasted three years to try to determine the effects of EMP on the utility grid. As part of that, at Roxtec, we are also doing our own investigations to figure out how we would be able to mitigate such effects. At the same time, legislation was being introduced at both the state level in Texas and the federal level. Roxtec has also had a presidential executive order that requires us to do some study regarding EMP. NERC, which is the regulatory body, has formed a task for us to investigate EMP in the utility business as well.

What third party research efforts related to EMP mitigation has CenterPoint Energy participated in? What is the general knowledge about hardening and shielding in the industry?

The industry is still working to develop mitigation techniques. The EPRI research, which CenterPoint Energy was a part of, has helped to increase awareness and inform the industry on what we need to do to protect against EMP. We have worked with third party vendors to do testing of the devices that we use on our system, but we have also participated in the more general testing that EPRI has done. We think this will help us transition to a more resilient grid in terms of EMP protection.

What electromagnetic threats require protection?

There are three main threats that we are working to protect against: The first one is a high-altitude electromagnetic pulse, which is a weapon that is detonated above 19 miles and produces an electromagnetic pulse over a wide area. The second is intentional electromagnetic interference, which is a more localized event that might affect one station or two. That typically is at a higher frequency, so the challenges are differently addressed. Lastly, we have geomagnetic disturbances, a result of naturally occurring events on the sun that can also affect large transformers on our system.

What are the challenges when hardening a power substation?

There is several major challenges associated with hardening a substation. Most of the standards that exist today are for fixed installations, which do not change much over time. What we have in the substation is a living environment where we must expand the substation or do retrofits. Therefore, we need a more dynamic solution that allows us to modify the protections over time without any degradation in performance.

What happens if you do not have proper shielding?

Without proper shielding, there are two types of threats: The conducted and the radiated. They will affect our equipment in different ways, but the result could be that either the equipment is upset, which means it needs to be reset or restarted, or it is damaged which means we may need to replace or repair it. Without going through the measures to protect the conducted energy from directly entering the equipment or the radiated energy from propagating through the building, we could have a case where the equipment no longer functions, and the substation becomes inoperable. That could either be mitigated by long construction cycles, which may take months or up to a year, or we may be able to quickly reset the equipment and get it back in service.

How did CenterPoint Energy’s EMP mitigation efforts develop?

CenterPoint Energy started on our journey to EMP resiliency in the substation by looking at building an entire control house, typically a 20-foot by 30-foot enclosure. As we studied the problem more, we found that we would rather have a modular-based solution. We wanted to build in overall resiliency, with resiliency based on our ability to adapt. We also wanted our solution to address other threats such as fires and floods. We set out on a modular-based approach, which decreased the footprint and accordingly decreased the cost. This allows us to deploy the solution in multiple substations or even out of our warehouse in a real emergency in an isolated part of the system.

Who are the key stakeholders for advancing EMP mitigation?

Several stakeholders need to participate in EMP mitigation efforts. Of course, we start with the utilities because they understand our challenges best and what we are typically building for. Then we have the third-party researchers that can help us better understand the challenges associated specifically with EMP. It is something that is new for the power industry. However, we have seen similar challenges that we needed to overcome, and we can overcome this one as well. Lastly, we have our regulators, because we must figure out how we are going to pay for and having a cost recovery for the assets that we would add to the system to make us more resilient.