How Many and Which Information Models are defined in IEC 61850?

I guess you have heard that IEC 61850 defines a lot of Information Models. Yes, You are right.

The models are managed exclusively by the corresponding working groups with the Enterprise Architect UML Tool (the UML data base is for internal use only). The model version:

UML model of 61850 (wg10built6-wg18built3-wg17built5-jwg25built2-tc17built1-tc38built1.eap)

comprises the following number of Logical Node Classes, Data Objects (Attributes), Enumerations and Abbreviations:



An excerpt from the UML modes looks like this:



The UML Model is the single source data base that is used for the extensions and maintenance of the model, as well as the generation of Word or PDF documents ... The PDF documents are sold by IEC and other organizations.

You may complain that the standards are not for free ... hmm ... BUT look: You can download the various Code Components for free.

Click HERE for the Code Component for IEC_61850-7-4.NSD.2007A2.light.zip (IEC 61850-7-4 2007A2 NSD light, see the IEC 61850-7-4:2010 for full legal notices). The full version has additionally the semantic descriptions of the models.

Example of Enumeration:


Example of excerpt of LN Class MMU:



Click HERE to see the list of all Code Components as per today ... more to come soon.

To my understanding you can model many required information generated and consumed by a huge number of applications in almost all application domains of automation in the electrical system and beyond.

As the above example of MMXU shows, you can use this LN Class wherever you have 3 phase AC system!! In a building heating system for the electrical values of a compressor or a fan or a pump or ... the blue sky is the limit for the applications.

Click HERE to learn about crucial details discussing the LN Class MMXU and how it can be applied ... you may have never expected this comprehensiveness of the MMXU.

Note that the 3 phase system was first (more than 100 years ago) - then we have put a facade in front of the measurement function which exposes the measurements as data objects of the class MMXU. The application has driven the class - not vice versa.

The current edition 2.1 models defined in IEC 61850-7-3 and 7-3 are listed in the contents tables of the preview documents. The following Preview documents (free access) for models of the edition 2.1 consolidated versions are available:

Preview IEC 61850-7-3 Edition 2.1
Preview IEC 61850-7-4 Edition 2.1

Example of 7-4 from the preview:



In case you find any error in the standards, please visit the Tissue Database:
https://iec61850.tissue-db.com/parts.mspx

The History Of The IEC 61850 Modelling

The standardization of IEC 61850 started in 1995 when the IEC TC 57 Working Groups 10, 11, and 12 had been setup. Later all projects have been moved to the Working Group 10 - that is still (very!) active today.
Prior to the new project proposal for IEC 61850 the EPRI UCA project developed core models for many signals and communication services. UCA used a simple table notation for defining "models".
The experts involved have discussed several options how to model the signals. In December 1998 the editors of the core documents (including myself) met in Ann Arbor (MI, USA).


We discussed modelling with ASN.1 or our own notation:



we were not quite happy ... then we discussed trying UML … walked across the street to the University bookshop to purchase some 10 Books about UML Modelling. I purchased several books, too:





… a senior development manager of protection relays was strictly against UML … he said, it will never be used for protection and automation. Some weeks later I met his engineers in their office … and saw that they used UML for developments …

Later I tried OWL with some success:



Experts involved in CIM (Common Information Models) used UML - with the SPARX tool Enterprise Architect (EA). It took several years before UML (and EA) was used to define all models of IEC 61850. Today (end of 2019) almost all models and other definitions are managed with the EA - it is a big success! The latest version comprises the following parts:


There are tools available to export parts of the model from EA as Word documents, html pages, pdf ...

Example of a model:



With the application of the SPARX EA we have a single source of all crucial definitions.

Note: The EA package "IEC61850Domain" is only available for the experts writing, publishing and maintaining the various standard parts.

Some exported documents (the so-called code components) are available for free access:
Click HERE for accessing these documents.

Thanks to the experts that have continuously pushed for using UML and EA. It took several years ... and it was not easy for engineers to use a formal language and tool to get where we are today.

These days the EA is used also for many other tasks: use cases, design state machines like for IEC 61850-90-16 (System management), ... IEC TC 57 has done a good job in using UML for CIM and IEC 61850. But another generation of engineers is needed to understand the full benefit of using UML.