<p>The prominent objective of the present study is to explore the applicability of fuzzy set theory in reliability evaluation of turbogenerators in thermal power plants. For this purpose, reliability function of turbogenerator is derived the minimal path set method under the concept of Weibull distributed random variables. The turbogenerator is a very complex structure in series–parallel type redundancy framework and its reliability function is evaluated using the membership functions like triangular fuzzy numbers, triangular institutionstic fuzzy number and triangular dual hesitant fuzzy numbers. Failure rates of the subsystem considered to be time dependent triangular intuitionistic fuzzy numbers. By using alpha and beta cuts, membership and non-membership functions are derived as a type of fuzzy number that helps in evaluation of certain and uncertain dependability factors for more precise evaluation of reliability of turbogenerator. The results highlight the minimal variations in the fuzzy reliability over time with respect to various fuzzy numbers.</p>