Fragility-based system performance assessment of critical power infrastructure

Climate change and population growth require the development and operations of critical power infrastructure systems to meet the energy demand. Performance assessment of the power infrastructure usually focuses primarily on the thermodynamic analysis calculating the energy output and system efficiency. However, the energy output from the thermodynamic analysis under normal operation could not fully represent the infrastructure behavior due to the neglect of the component reliability in the energy generation system. There is a lack of consideration of the energy delivery system and its fragility with respect to external meteorological parameters (e.g., wind). In this study, the fragility of the energy-delivery system concerning wind speed is modeled and integrated to assess critical power infrastructure performance. The reliability consideration of the energy generation system is included based on the state space diagram and the frequency-balance method. The fragility of the energy-delivery system is used to derive a system reliability index for the system which is the probability that end-users will receive the energy. Besides, sensitivity analysis is conducted to investigate the influence of the important decision variables on the system performance. The study employs a small-scale power infrastructure system at the University of Connecticut as an example to demonstrate the feasibility of the performance assessment framework. The system is composed of a cogeneration plant and energy distribution systems. The results from the case study prove that the decision variables have considerable nonlinear impacts on the system performance. With the integration of fragility, the proposed approach could estimate the energy received by consumers from the generation site.