Latency considerations in IEC 61850-enabled Substation Automation Systems

Substation Automation Systems (SAS) offer powerful, fast, and viable ways to design, automate, and implement substation protection, control, and monitoring functions in modern transmission and distribution grids. Today's SAS - ore than ever - rely on the adoption of IEC61850 as a worldwide standard for interoperability and dependable peer-to-peer and substation communications. Being based on the Ethernet computer networking technology, the reliability issues associated with latency in 61850-enabled SAS is of a design consideration. Unpredictability is the most important challenge for latency assessment. This paper discusses the background framework for latency evaluations in SAS by considering the delay elements in nodes and links. The methodology adopted for Local Area Networks has been applied to a real SAS case study and verified from engineering point of view.