Unlike most communication protocols, IEC 61850 Standard is based on the principle of object orientation, so that it works with information-oriented modeling and not device- or protocol-oriented. These models define data formats, identifiers, behavior, and controls.

The Standard adopted a Logic Node, which is the smallest part of a function to exchange information, used as core of models. Logical Nodes are functional groups of information to exchange data among them and they carry information that must be transmitted. The location of Nodes is not linked to a single IED, when considering that a function is composed by several Nodes, that is, there is a free allocation of functions, which admit centralization or decentralization.

Inserted in LNs, which follow the structured data model, there are sets of data belonging to the function and reference to a physical element of the network, which by its turn contains a set of attributes expressing an information to retrieve or send to the current object model. These sets of data are grouped in Logical Devices inserted in IEDs. The next figure presents the relationship between these elements.

Elements from IEC 61850 Standard

The IEC 61850 Standard established a standardization of names for all these elements, by using a sequence of non-ambiguous mnemonic characters, that is, users can identify through names which tasks these elements are performing. For LNs, this identification is given by four characters.

The next figure contains a detailed example of a data structure of IEC 61850 Standard in a generic device. In this tree structure, users can notice that the first level contains a physical device called IEDElipse, then a logical device MET (Measurement), a Logical Device MMXU (Measurements of voltage, current, and power), a Data Class PhV (Voltage), an Attribute phsA (Voltage of Phase A), and then data cVal (Complex Value), whose dead band is a variation step of data.

Data Structure

After modeling a device, users get a syntax used to reference a function to monitor or control, represented in the format IEDElipse.MET.MMXU.PhV.phsA.cVal.