Priority Differentiation for Low-latency Smart Grid Communications in Wide Area Control

Wide area control (WAC) in smart grid requires low-latency communications across the grid to transfer various control commands and Phasor Measurement Unit (PMU) measurements. \textcolor{red}{Smart grid communications are generally implemented between multiple control centers, between transformer substations and control centers, and between power plants and control centers}. While there have been a number of international standards for smart grid communications, detailed methods have not been specified in existing standards for low-latency transmission of different types of application data, particularly high-priority control commands, between control centers.  To fulfill this requirement, a priority differentiation approach is presented in this paper for low-latency communications between control centers. With two application-layer queues, it incorporates a cross-layer design between the application layer and data-link layer to keep the delay of high-priority packets to the possible minimum. Simulation results in typical scenarios show  a reduced communication latency of about 45\% for high-priority packets when our approach is incorporated with existing communication technologies.