The visual specification method — Making specifying IEC 61850 based system easier

IEC 61850 supports the use of functional designs for specifying substation automation systems. However, specifying such systems is not standardized within IEC 61850. This means that utilities are somehow left in the dark regarding the use of the engineering process defined in IEC 61850–6 and therefore often revert to using traditional and proprietary ways to specify their requirements. To overcome this hurdle UTInnovation has invented a visual specification method (VSM) that graphically specifies functions, the interconnections needed and all the associated performance classes. The result of this method is a set of so called ‘function layers’ that together describe that total functionality of a substation. This abstract specification can be used as part of the overall functional specification and serves as the basis for the .ssd file that should be constructed for every IEC 61850 based system. Based on this process, the utility can much easier select the IEDs that implement the required functions and create reusable modules that make the specification process much more efficient. The main benefit of the presented method is that it combines several specifications in one document that can be processed by computers because the specification is defined using as much graphical representation as possible making it also easier to understand for humans. The paper explains the use of the method based on a real project in which the method is applied to define the functionality of six (6) different medium voltage substations with the objective to significantly reduce the time necessary to specify IEC 61850 based systems, remove ambiguities, standardize substation functions, create reusable specifications and create a common specification platform