1699   dbRef should not be mandatory for APC and BAC

Created: 17 Jun 2020

Status: In Force (green)

Part: Part 7-3 (2020; Edition 2.1)


Page: 74

Clause: 7.5.9

Paragraph: 7.5.9


Data attribute dbRef has a presence condition of mandatory for APC and BAC.
It is not coherent with the presence condition of data attribute db which is optional for this CDC. Data attribute dbRef used in CDC MV and CMV has presence condition MO(db).
In addition, new DA dbRef for APC and BAC are not mentioned for Use case 3 'Add elements of existing types, existing FC' in annex F.2 'List of the modifications to consider for backward / forward compatibility '


Use presence condition MO(db) for DA dbRef of APC and BAC.
Update Annex F.2 use case 3, to consider dbRef for APC and BAC.

Discussion Created Status
Tissue in Force 11 Oct 22 In Force (green)
TISSUE has been batched - see 57/2445/INF 09 Feb 22 Must Implement
Ballot expired - no disagreeing comment received. Moved to solution accepted 03 Jun 21 Solution Accepted
Move to ballot 15 Feb 21 Ballot Period
Progress to conformance test verification 13 Nov 20 Conformance Test Verification
Agree that nsd update will be needed. This will be sent out with the proposal once it is released. 11 Nov 20 Conformance Test Preparation
NSD update is needed and should be added to proposal.

No additional tests are needed if NSD is updated. Existing sMdl2 is:
Verify presence of conditional presence true data objects for each LN type and data attributes for each DO type. Passed when all objects/attributes are present
11 Nov 20 Conformance Test Preparation
Move to next step 11 Nov 20 Conformance Test Preparation
Analysis of compatibility:
The change corresponds to use case 12a - a DA has now a weaker presence condition: If db is not in the model, dbRef becomes optional.
As described in Annex K of IEC 61850-7-1, table K16,
(1) client forward compatibility is achievable based on the general rule that the client shall tolerate missing elements,
(2) system tool forward compatibility is achievable, if the system tool is tolerant, when an expected CF attribute is not present, and
(3) all other cases are guaranteed.
The case (2) related to the system tool seems to be very theoretic anyway, as we would not expect a system tool to configure a value for dbRef, if no db is supported.
Conclusion: no compatibility issues!
06 Nov 20 Analysis Of Compatibility
Implementation of the TISSUE requires the following changes:

1. In table 46, change in the row where the attribute name is dbRef the value in the last column from M to MO(db)

2. In table 47, change in the row where the attribute name is dbRef the value in the last column from M to MO(db)

3. In chapter F.2, table for Use case 3, in the table section for use case 3a, add for the namespace 61850-7-3:2007B a new paragraph with the following text:
CDC APC, BAC – DA “dbRef” has been added as conditional: MO(db).
03 Nov 20 Verify Draft Implementation
set to drafting implementation 24 Sep 20 Drafting Implementation
As the solution is clear, we can move to discussion 19 Jun 20 Discussion (red)
set to accepted 19 Jun 20 Accepted


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