Reliability Assessment of a Cyber Physical Microgrid System in Island Mode

As cyber physical systems, microgrids (MGs), with distributed generations and energy management systems, can improve the reliability of power supply for customers in MGs. To quantify the reliability of isolated MGs, a cyber-physical assessment model is proposed. In this model, the circuit breakers and distributed energy resources are treated as the coupling elements between the cyber system and physical system, where the circuit breakers are uniquely modelled by using the Markov process theory based on the indirect interdependencies between cyber physical elements. For the cyber system, the reliability model of communication networks is formulated based on the link connectivity evaluation method. For the physical system, a system state generating method is presented to account for the optimal operation strategy, which considers the influence of the optimization strategy on the failure consequence analysis. With the proposed cyber and physical reliability models, the sequential Monte Carlo (SMC) simulation method is adopted to assess the reliability of islanded MGs. Simulations are carried out on a test system, and results verify the feasibility and effectiveness of proposed assessment method. Furthermore, one application of the proposed method is on the parameter setting of the cyber system, in terms of enhancing MGs reliability.