Towards a constraint based approach for Self-Healing Smart Grids

One of the most important functional requirements of an electrical grid is the balance between consumption and production of power and due to the centralized structure of grids, this balance is currently achieved through central power generation. However, the increased usage of decentralized renewable energy sources in combination with the Information and Communication Technology (ICT) applied to the grid tends to result in a global reformation of the current electrical grid. During this reformation new features will occur such as the handling of bidirectional energy flows, automatic fault detection, self-healing of the network, demand-side management, load adjustment, smart sensing and measurement to name only a few. Due to the increased complexity associated with the requirements of this features there is a high need for capturing, modeling, specifying and formalizing them. Thus, predicate logic plays a significant role for the logical specification of system behavior. This paper provides an insight into the current- and future grid. A 3-tier architecture is introduced specialized on the aspects of a smart grid. A show case demonstrates how this architecture assist us by understanding the reformation process of the basic electrical grid to a cellular smart grid. Thus, we introduce the concept of cellular composition and decomposition. For the formalization of the above concepts we propose a constraint based engineering method based on FOCUS [1] theory which also aims to assist engineers from multiple disciplines during the entire phase of reformation. Finally we apply the method to describe Self-Healing Smart Grids and present a model for fault-detection and restoration.