Reliability of the smart grids has always been an important factor considered by power system planners. Cyber network failures have significant impacts on the reliability of the smart grids as a cyber-physical system. The complexity of the reliability assessment of cyber-physical systems is significantly higher than traditional power systems due to interdependency between cyber and power network elements. A mapping step is applied to system states to address this interdependency in the reliability assessment task. This paper aims to lower the complexity and computational cost of reliability assessment in cyber-physical systems by proposing a simplified mapping step. The simplification steps are applied to various connection types between cyber components using a defined interconnection matrix based on the cyber network topology. The two-state reliability model probabilities are updated for each cyber element. The proposed method lowers the number of possible system states and computational cost significantly since the effects of some cyber networks are considered in the probability updating step. The proposed approach is applied to different cyber network topologies such as bus, ring, and redundant star in a microgrid. Loss of load probability and expected energy not supplied are calculated as the reliability indices of the system. The results reveal the efficiency of proposed method in reliability assessment of the cyber-physical system using remarkably decreased numbers of system states.

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