Author:Christoph Brunner, it4power, Switzerland

(Technical Issues)

When you develop a standard that has multiple parts and more than 1000 pages, there is always a risk that inconsistencies are introduced between the different parts, or that what the Editor believes is pretty clear is interpreted differently by the developer. As a consequence, not only the standard needs to be fixed, but the developers also need to get an answer as to what the right interpretation is.
To address this, since the first publication of IEC 61850, a process was established that was somehow unique for IEC standards – the TISSUE process. TISSUE stands for “Technical ISSUE” and through this process we collect technical feedback on IEC 61850.
You may already be familiar with the TISSUE process, but while we are now in preparation of Edition 2.1 for the core documents of IEC 61850, we had to refine both the TISSUE process as well as the versioning of the standard. We now differentiate between Version and Revision of a standard. The version refers to the year of publication. For Edition 2 this has been defined as 2007. The Revision is a character; Ed. 2.0 is Revision A. Edition 2.1 will be Revision B.

TISSUES shall be limited to technical issues with the current standard documents that require an urgent solution or clarification. For new extensions to the standard, the new work item process of IEC shall be used. TISSUES are identified per part of the standard. TISSUES are categorized to indicate the impact of the TISSUE resolution on standard documents and implementations.

The stage of a TISSUE in the process of handling it is typically indicated with colors:

  • In order to categorize the TISSUE, an initial evaluation by the experts takes place. When the impact is a clarification of editorial nature without technical change or impact on implementations, the clarification will be done in the current revision of the standard (category CurRev) and the TISSUE changes to the final stage “blue” without a need to vote on the TISSUE. It may as well be that the TISSUE resolution has no impact on this part of the standard; in that case the category would be Ntp
  • If a TISSUE has a technical impact but there is no immediate requirement to solve the TISSUE as it addresses long term improvements or extensions with new capabilities that typically have a larger impact and need a careful evaluation of the solution, the TISSUE will only be addressed with the next Version of the standard (category NxtVer); e.g. Edition 3, and the stage of the TISSUE will be set to “on hold”
  • All the other TISSUES will go through a voting process, where the Editors will make a proposal. A vote is considered as approval, if within 4 weeks no negative comment is raised. Voting starts with the stage “final proposal” and terminates either in the stage “green” (approved) or “yellow” (not approved). If the TISSUE ends in the stage yellow, it gets the category NxtVer and a solution has to be found through the normal standardization process

For these other TISSUES, we have again various categories depending on the nature of a TISSUE. It can be a clarification, but may require editorial changes in a specific product if the standard was misinterpreted before. Such a TISSUE has the category CurRev. If it is a correction, requires technical change of the standard and may affect interoperability, the category is IntOp. TISSUES of category IntOp and CurRev are applicable immediately following approval. That means, the conformance test specifications should be updated within three months. The Test Procedure Change List (TPCL) will identify which TISSUES are considered within a specific version of the test specification.

If a TISSUE is an improvement with a technical change and may be required by other parts of the standard, the TISSUE resolution will be applied in the next revision, e.g. Edition 2.1 (category NxtRev). That means, it is only valid once the next revision has been published and it shall only be implemented in products that conform to that next revision.
I hope this clarifies our process.

The last question you may have is: Who can participate in the TISSUE process and how? The answer is: everybody. Currently, the TISSUE process is supported by a website (tissue.iec61850.com). To avoid SPAM, you need to register in order to be able to raise a TISSUE. For the future, it is foreseen to embed the process within IEC.
Before I close, I would like to mention that in Fall 2015, we will again conduct interoperability tests. The tests will be managed by the UCA International Usersgroup, and will be supported with Use Cases provided by ENTSO-E. If you are interested to participate - either with products or as a witness - you should contact the UCA International Usersgroup.  


Christoph Brunner is the President of his own independent consulting company it4power LLC based in Switzerland. He has over 25 years of experience with knowledge across several areas within the Utility Industry and of technologies from the Automation Industry. He has worked as a project manager at ABB Switzerland Ltd in the area of Power Technology Products in Zurich / Switzerland where he was responsible for the process close communication architecture of the automation system. He is Convener of WG 10 of the IEC TC57 and is a member of WG 17, 18 and 19 of IEC TC57. He is senior member of IEEE-PES and IEEE-SA. He is an IEEE Fellow and he is active in several working groups of the IEEE-PSRC and a member of the PSRC main committee and the subcommittee H. He is international advisor to the board of the UCA international users group. 

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