With the improvement of digital technologies, digital I&C systems have included more
various fault tolerant techniques than conventional analog I&C systems have, in order to
increase fault detection and to help the system safely perform the required functions in
spite of the presence of faults. So, in the reliability evaluation of digital systems, the fault
tolerant techniques (FTTs) and their fault coverage must be considered. To consider the
effects of FTTs in a digital system, there have been several studies on the reliability of
digital model. Therefore, this research based on literature survey attempts to develop a
model to evaluate the plant reliability of the digital plant protection system (DPPS) with
fault tolerant techniques considering detection and process characteristics and human
errors. Sensitivity analysis is performed to ascertain important variables from the fault
management coverage and unavailability based on the proposed model.