The monograph is devoted to the evaluation of the structural reliability of complex electric power systems (EPSs). The general approaches applied to the calculation of reliability of complex technical systems are also discussed, special features of EPS are determined and basic methods for determining structural reliability indices are examined. The procedures of probabilistic simplifi cation of the failure processes are considered in detail for the power supply systems of the consumers’ nodes. The mathematical models of these simplifications are developed characterizing two types of failures. The proposed simplification procedures are used in computer calculations and modeling. The monograph can be used as a textbook by the students of “Electrical and Power Engineering” programs of higher education institutions within the course “Reliability of EPS”. It may also be of interest to researchers and engineers working in this field.