Protection schemes are modelled through Petri Nets, in order to carry out performance evaluation. Marked Petri Nets are suitable for qualitative evaluation, while Time Petri Nets and Timed Petri Nets are convenient for cycle time evaluations, and for deriving relationships between the time parameters of the primary and the secondary protection. Stochastic Petri nets are used for the modelling of the stochastic nature of protection; they enable the evaluation of probabilistic performance measures, and have advantages over simulation techniques.