According to recent reports by NPR and the Wall Street Journal, last year’s attack on the Metcalf substation in California was not random. Rather, the attackers targeted equipment to disable it after cutting communications lines. Whether or not the result of terrorism, the event demonstrates the vulnerability of electric grid assets to physical attack, as observed by former FERC Chairman Jon Wellinghoff.
Fortunately, the attack occurred at an off-peak time, when demand was significantly below capacity. As a result, the effect on electricity consumers was minimal. A coordinated attack on assets at peak times, however, could result in cascading outages and blackouts. Dealing with such an attack would require major repairs and replacement of devices such as large transformers, which would result in many months of lost electricity services.
To prevent such a catastrophic scenario, Pacific Gas & Electric says it is planning to install walls and enhanced security at various substations. And it’s these preventive investments that my colleagues at the Naval Postgraduate School and I are in the midst of studying. So far, our research is focused on how to identify which facilities are most significant in the context of vulnerabilities. Approaching the challenge as a large-scale, bi-level optimization problem, we developed algorithms and software that help utilities in just such situations to systematically identify their greatest vulnerabilities. We are now developing further enhancements to select the best preventive investments.
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