  Hidden failures present a noticeable impact to the reliability of the United
States electrical grid. These hazards are responsible for protective device
misoperations and can cause multiple-element contingencies across nearby
components, greatly increasing the likelihood of cascading events. This paper
provides an in-depth overview of the causes and risks of hidden failures and
discusses methods for identifying critical locations where hidden failures
could pose a risk of cascading failure, with the ultimate goal being to
identify efficient mitigation methods that can prevent their occurrence in
protective relays.
