IEC 61850 is an international standard defining communication protocols for intelligent electronic devices at electrical substations. It is a part of the International Electrotechnical Commission's (IEC) Technical Committee 57 reference architecture for electric power systems.^[1] The abstract data models defined in IEC 61850 can be mapped to a number of protocols. Current mappings in the standard are to MMS (Manufacturing Message Specification), GOOSE (Generic Object Oriented System Event) [see section 3, Terms and definitions, term 3.65 on page 14^[2]], SV (Sampled Values) or SMV (Sampled Measure Values),^[3] and soon to Web Services. In the previous version of the standard, GOOSE stood for "Generic Object Oriented Substation Event",^[4][5] but this old definition is still very common in IEC 61850 documentation.^[6] These protocols can run over TCP/IP networks or substation LANs using high speed switched Ethernet to obtain the necessary response times below four milliseconds for protective relaying.