Patent ID: 8812256

Claim:
An intelligent electronic device for use within a power protection system comprising: a first port for accepting a primary time signal over a first network, the primary time signal remote from the intelligent electronic device; an internal clock, wherein the internal clock is initially synchronized according to the primary time signal; a second port for accepting a backup time signal over a second network from a time server disposed remote from the intelligent electronic device, the backup time signal not synchronized with the primary time signal and having an error relative to the primary time signal; an error estimating module for generating an error signal approximating the error of the backup time signal relative to the primary time signal when both the primary and backup time signals are available to the intelligent electronic device, and adjusting the backup time signal using the error signal to synchronize the backup time signal with the primary time signal; and a switching component for switching synchronization of the internal clock from the primary time signal to the adjusted backup time signal when the primary time signal is not available, wherein the internal clock is synchronized according to the backup time signal taking into account the error signal.