...means the capability of two or more intelligent electronic devices (IEDs) from one or several vendors to exchange information and to use it in the performance of their functions and for correct co-operation. Providing data transfer is normally a one-way procedure with data flowing from a simple sender to a highly sophisticated receiver, which interprets complex data. This is very often a human being that can read and understand the data with the help of its comprehensive background. An example is the master-slave communication commonly used in the past, as for the information interface of protection devices according to IEC 60870-5-103. Interoperability as provided by IEC 61850 is much more than simple data transfer, but provides for information exchange between two or more devices of similar intelligence. The receiver has to understand not only the structure of the data (syntax), but also its meaning, i.e. the semantics based on the data attributes received in a communication. Interoperability does not mean interchangeability, but it is a pre-requisite for it. Interchangeability without impacts on the system behavior would require devices of identical functionality. This would imply the standardization of functions, which is outside the scope of IEC 61850, as it would hinder further development of functions for substation automation. --> back to IEC 61850 start page