Redundant Relay Protection Devices for Power Systems Reliability Model

The study's purpose was to develop a mathematical model for the redundant RP systems functioning under health poll and to study the influence of RP failures on the RP reliability indicators. The study result was to find the dependence on the initial characteristics of such indicators as the unavailability factor, average time between failures in standby mode, the RP failure probability in external short circuit modes and in damage to the securable unit, the RP mean time effect on the reliability and operation indicators. The model of the RP system operation cycle based on semi-Markov processes theory has been developed. The model allows calculating and forecasting operation and reliability indicators, such as RP system's unavailability factor, recovery frequency, and technical position checks frequency. The above model allowed minding three different types of failures, which allows obtaining the frequencies of these failures.