Extending the Substation LAN Beyond Substation Boundaries: Current Capabilities and Potential New Protection Applications of Wide-Area Ethernet

Ethernet-based local area networks (LANs) have become an indispensable tool that promises to revolutionize power system communications. Recent advances in Ethernet-based technology have taken this industry from shared 10 Mbps LAN segments to switched 100 Mbps LANs followed by 1 Gbps backbones for metropolitan area networks (MANs) and more recently 10 Gbps Ethernet technology for use in wide-area networks (WANs). Up until now, intersubstation communications typically have been provided by a SONET/SDH communication infrastructure. Although well understood and widely deployed, this legacy approach is not optimized for data traffic and requires protocol mapping and/or translation at both ends of the interface. The more recent trend of migrating towards voice over IP services combined with the advent of low-cost gigabit Ethernet switches and low-cost long-haul fiber optics has made it possible to deploy native Ethernet networks in wide-area applications. This paper looks at the new capabilities in substation automation, protection, and control made possible by native intersubstation Ethernet. Analysis is made of the current capabilities of this technology and state of the art tools available for Ethernet network management. The paper also examines application examples such as: Ethernet-based POTT protection schemes and synchrophasor data collection infrastructure. It concludes with a short overview of future application trends, including Ethernet-based line differential example