  Electric grid faults are increasingly the source of ignition for major
wildfires. To reduce the likelihood of such ignitions in high risk situations,
utilities use pre-emptive deenergization of power lines, commonly referred to
as Public Safety Power Shut-offs (PSPS). Besides raising challenging trade-offs
between power outages and wildfire safety, PSPS removes redundancy from the
network just at a time when component faults are likely to happen. This may
leave the network particularly vulnerable to unexpected line faults that may
occur while the PSPS is in place. Previous works have not explicitly considered
the impacts of such outages. To address this gap, we propose the
Security-Constrained Optimal Power Shutoff (SC-OPS) problem which uses
post-contingency security constraints to model the impact of unexpected line
faults when planning a PSPS. This SC-OPS model enables, for the first time, the
exploration of a wide range of trade-offs between both wildfire risk and pre-
and post-contingency load shedding while designing PSPS plans, providing useful
insights for utilities and policy makers considering different approaches to
PSPS.We demonstrate the efficacy of our model using the EPRI 39-bus test system
as a case study. The results highlight the potential risks of not considering
security constraints when planning PSPS and show that incorporating security
constraints into the PSPS design process improves the resilience of current
PSPS plans.
