This document serves as a guide for the application of protective relays used for load shedding and restoration during electric power system abnormal frequency conditions. It presents background information, a bibliography, and recommendations. It discusses abnormal frequency power system behavior, existing load shedding and restoration practices, the abnormal frequency function of typical protective relays, and possible new methods for improved load shedding and restoration. This guide is limited to electric power system applications and does not include abnormal frequency protection for power generating plants.