Flexible and Robust Status Dissemination Middleware for the Electronic Power Grid

Electric power grids are complex interconnected systems that in North America can span more than a thousand miles. They must be operated such that the dynamic balance between supply and demand is maintained. Grids exhibit many power dynamics that are global over the entire grid, yet their control mechanisms and almost all of their operational data on the current dynamics and configuration of the grid–status data–are local in nature, typically limited to a single substation. In this paper we describe the limitations of the current communications infrastructure of the North American electric power grid and how they restrict its efficiency and its ability to respond to accidental failures and deliberate physical or cyber-attacks. We then describe status dissemination middleware, a new specialization of the publish-subscribe model that takes advantage of the semantics of status data. Next we describe the design and implementation of GridStat, a middleware framework for status dissemination across wide areas in the electric power grid and other critical infrastructures. It takes advantage of the semantics of status data to optimize delivery and to manage its subscriptions for quality of service. In doing so, GridStat allows status information, control decisions and commands to be disseminated over a wide-area.