IEC 61850-5:2013 applies to power utility automation systems with the core part of substation automation systems (SAS); it standardizes the communication between intelligent electronic devices (IEDs) and defines the related system requirements to be supported. The major technical changes with regard to the previous edition are as follows: - extension from substation automation systems to utility automation systems; - inclusion of interfaces for communication between substations; - requirements from communication beyond the boundary of the substation.