Emerging cyber-physical systems (CPSs) incorporate intelligence into power distribution networks. These CPSs provide the capabilities required for handling the challenges of increasing complexity in the bulk power grid, responding to growing demand, supporting renewable energy sources, and satisfying the requirements for enhanced, adaptive service quality. Achieving these goals requires a framework for cohesively integrating communication and information technologies using complex, real-time control networks for both energy and information. This framework must support the principal properties of smart grids, including self-healing, availability, and responsiveness to variability in demand and supply. CPSs pose new challenges for security and privacy because of the increased exchange of information.