1691   Contradictory statement for Mod.stVal

Created: 28 Apr 2020

Status: Future Improvement

Part: Part 7-4 (2020; Edition 2.1)

Links:

Page: 454

Clause: Annex A

Paragraph: first

Issue: The below statement is contradictory. in the first sentence we say value can be changed only from the operator and in the next sentence we say it can be changed from operator or IED Local actions

"Switching between the modes (Mod.stVal) should only happen as a result of an operator command to the data object Mod. This can be a remote command as well as result of an IED local action. Mod and Beh are always accessible by the services."

Proposal: Rephrase the sentence as

"Switching between the modes (Mod.stVal) can happen as a result of an operator command to the data object Mod. This can be a remote command as well as a result of an IED local action (User & Process). Mod and Beh are always accessible by the services."

Note: The IED local action can be a binary input to the IED that can be activated when the operator inserts the test plug. So the local actions can be also derived using logics/ binary inputs.

Discussion Created Status
Accepted Future improvement 17 Jun 20 Future Improvement
Change to WGApproval state. 03 Jun 20 WGApprovalFutureImprovement
Summarizing the discussion, the tissue and the discussion describes a proposal for future improvement. Final text will be agreed within Ed.3 work. 20 May 20 Discussion (red)
The Note (Bruce) with the test plug example shows that we should report this event "Insertion of test plug". For Ed3 we should screen if we have not much more of such local (Henry) issues. For safe system operations we should state mandatory rules what local issue actions/reactions should be reported. 08 May 20 Discussion (red)
This was a functional change from 61850-7-4:2010 added to Am1 as a result of TISSUE 1273.
However, the agreed text on 29-July-2014 was not adopted in Am1 "Switching between the modes (Mod.stVal) should happen as a result of an operator action to the data object Mod. This can be a remote command as well as an IED local action." to replace the first sentence. Note that the word "only" is not present in the agreed text.

TISSUE 1273 made it clear that Mod.stVal can change under vendor-dependent rules without any visible control operations. Because this change to the 61850-7-4:2010 text has been in force for almost 6 years, it may be too late to now claim Mod.stVal can only change by explicit control or by the GrRef hierarchy and introduce another incompatbility with devices implementing Ed2+TISSUEs.

Consider for Ed3 "Should Mod.stVal only be changed upon a control operation or the LD hierarchy and Beh.stVal may be affected by proprietary local functions.

Also note that approval of TISSUE 1273 included "It should be clear that internal automatic functions (like fuse failure) should not change Mod." which does not seem to be part of 61850-7-x.
29 Apr 20 Discussion (red)
Request to discuss the tissue were send to me. So changed back. 29 Apr 20 Discussion (red)
Text will be improved with next edition.
In my opinion, a change of Beh by a binary inputs (e.g. test plug) should be characterized as a local issue (internal function).
28 Apr 20 WGApprovalEditorial

 

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