Analysis on IEC 61850 Interoperability Support

The three goals of IEC 61850 are interoperability, function free distribution and allocation (FFDA) support, and Function Extension (FE) support. Interoperability is the most important one but it would be weakened by the other two if they are not handled adequately. Interoperability is guaranteed by real-time communication and the consistency of object's semantic. FFDA can cause large delay on data transfer, and FE can introduce new semantic. Both of them can impair the interoperability of substation automation system (SAS). A principle of Minimum Traffic (MT) based on Piece of Information for COMmunication (PICOM) calculation is brought forward. The principle can be used to select the best FFDA manner that will result in the least impact on interoperability. An interoperability impact evaluation is given as well.