Time-Dependent Unavailability Exploration of Interconnected Urban Power Grid and Communications Network

This paper presents a time-dependent reliability analysis created for a critical energy infrastructure use case, which consists of interconnected urban power grid and communication network. By utilising expert knowledge from the energy and communication sectors and integrating the renewal theory of multi-component systems, a representative reliability model of this interconnected energy infrastructure, based on real network located in the Czech Republic, has been established. This model assumes reparable and non-reparable components and captures the topology of the interconnected infrastructure and reliability characteristics of both power grid and communication network. Moreover, a time-dependent reliability assessment of the interconnected system is provided. One of the significant outputs of this research is the identification of the critical components of the interconnected network and their interdependencies by the directed acyclic graph. Numerical results indicate that the original design has an unacceptable large unavailability. Thus, to improve the reliability of the interconnected system, a slightly modified design, in which only a limited number of components in the system were modified to keep the additional costs of the improved design limited is proposed. Consequently, numerical results indicate reducing the unavailability of the improved interconnected system, in comparison with the initial reliability design. The proposed unavailability exploration strategy is general and can bring a valuable reliability improvement in the power and communication sectors.