Abstract
This work calculates the reliability of protective systems of industrial facilities, such as nuclear, to analyze the case of equipment subject to aging, important in the extension of the qualified life of the facilities. By means of the method of supplementary variables, a system of partial and ordinary integral-differential equations was developed for the probabilities of a protective system of an aging channel. The system of equations was solved by finite differences. The method was validated by comparison with channel results with exponential failure times. The method of supplementary variables exhibits reasonable results for values of reliability attributes typical of industrial facilities.
Highlights
The reliability analysis of protective system components is of paramount importance and widely studied
This relevance is related to the fact that the protection function in an industrial installation is fundamental for its integrity, because it monitors process parameters, such as pressures and temperatures and, if necessary, commands the shutdown of the facility. This problem has been addressed by considering its behavior when the plant it should protect is subject to high demand rates [6] and, later, the influence of the channel repair rate was addressed [9] and by considering a two redundant channel protective system [10]
Pi(x) represents the probability that the channel is in the i − th state, x is the channel age; λ (x) stands for the age-dependent failure rate; μ is the channel repair rate; ν is the channel demand rate; and γ is the probability of a human error during the channel maintenance
Summary
The reliability analysis of protective system components is of paramount importance and widely studied This relevance is related to the fact that the protection function in an industrial installation is fundamental for its integrity, because it monitors process parameters, such as pressures and temperatures and, if necessary, commands the shutdown of the facility. The reliability parameter of interest is its average unavailability, U, which depends on the failure, λ , and repair rates, μ, on the number of channels constituting it, in addition to the demand rate, ν, and on the test and maintenance policies and their actuation logic. The distinction between covered and uncovered faults is important in this context, since channel failure detection only occurs in two situations: when the system is called for (a real situation), or when the system is tested
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
