Analysis of communication networks for smart substations using a virtualized execution platform

The current development of the power grid towards a Smart Grid advances the complexity of the system, involving active control, new software components and large amounts of data. This, in turn, requires new approaches for the ICT infrastructure to guarantee real-time capability and reliability. In this work, we present our design of a novel infrastructure for smart substations in the transmission grid, applying the concept of virtualization to substation devices. Since virtualization has already been successfully applied for fault-tolerant and dependable computer systems, it promises to be a valuable concept for substation automation. However, virtualization poses additional challenges to the real-time capability of the substation infrastructure in terms of additional traffic and resource allocation. For analysing the impact on substation communication, we apply simulations and the analytical technique Network Calculus to provide guarantees on the performance of the proposed communication infrastructure. In addition, the performance of the execution platform is studied empirically, measuring occurring delays in a test-bed set-up. Finally, we combine the results from both evaluations to derive an end-to-end delay bound for a power grid related example. Our results show that, other than Fast Ethernet, Gigabit Ethernet networks can guarantee the secure operation of virtualized, fault-tolerant substation infrastructures.