The paper reviews the options to reduce the impact of failure effects in medium voltage distribution grids in terms of the frequency and duration (short, long, very long and catastrophic) of outages of end-consumers’ supply. As the method to reduce the failure effects, the placement in the grid structure of remotely controlled circuit breakers and/or reclosers was adopted, which in the event of a failure allows disconnecting only part of the grid in the failure area. An important element of this method is the selection of the optimal number of these circuit breakers and their optimal location in the grid structure. The paper proposes a method of solving these issues by applying distribution grid reliability models and evolutionary algorithms that allow for optimizing the location of circuit breakers. As the optimization criteria, the ENS, SAIDI and SAIFI indicators were adopted. The analysis was based on an example model of a real distribution grid structure. The model includes the reliability parameters of individual grid sections, distribution nodes, MV/LV switching substations, and the number of recipients connected to a specific substation.