Using software-defined networking to build modern, secure IEC 61850-based substation automation systems

Substation automation systems (SASs) are an essential part of smart grid systems. They consist of intelligent electronic devices (IEDs) communicating using digital communications protocols over a secure local-area network. Today, SASs can support multiple protection, monitoring, and control applications over the same network, allowing real-time decision making by various devices and fast reactions to ever-changing power system states, within a few milliseconds. Additionally, large amounts of data exchanged by devices in an SAS enable smart decision making by stakeholders and improve overall system performance and efficiency. To ensure reliable operation of SASs, a highly secure and resilient communications network backbone is a must. Traditional Ethernet technology was not designed to meet the performance and reliability requirements that are essential for SASs. Moreover, an electric power system is an attractive target for cyber attacks, so modern operational technology (OT) Ethernet networks must be designed with security in mind to protect against cyber threats. In this paper, we discuss an application of software-defined networking (SDN) to meet stringent network performance and cybersecurity requirements. We compare this application to traditional spanning-tree-based networks to show SDN's ability to meet and exceed those requirements.