The influence of protection system failures and preventive maintenance on protection systems in distribution systems

Protection systems in power networks can fail either by not responding when they should (failure to operate) or by operating when they should not (false tripping). The former type of failure is particularly serious since it may result in the isolation of large sections of the power network. However, the probability of a failure to operate can be reduced by carrying out preventive maintenance on protection systems. This paper describes an approach to determine the impact of preventive maintenance on distribution network protection systems on the reliability of the power supply to customers. The proposed approach is based on Markov models.