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WG10 Future Work #3102

https://iec61850.tissue-db.com/tissue/1744 Clarification of Start Times in StrTm.setCal

Added by Henry Dawidczak over 3 years ago. Updated 10 months ago.

Status:
New
Priority:
Normal
Assignee:
-
Start date:
08/10/2021
Due date:
02/10/2022 (over 2 years late)
% Done:

0%

Estimated time:
Source:
TissueDB
TF Unique ID:
4 # TissueDB
WG10 Proposal:
Discuss in Upcoming Meeting:
No
Short Proposal:

Include in edition 3 - not very urgent

Standard(s):

IEC 61850-7-4

Needs More Information:
No
Assigned TF:
61850-7-4
Target edition:
Next

Description

Part 7-4, page 481, clause K.2.4
Applying the standard’s schedule definitions to practical use cases caused some discussion on how to interpret part 7-4.
IEC 61850-7-4 annex K.2.4 states: “In case, for whatever reason, the schedule cannot start at the time given by the occurrence of a start time setting, but afterwards, then the schedule will run sharply as if it has started at the time given by the start time setting. Said in other words, the schedule won’t shift the scheduled values based on the real-time start.”

German users group, VDE FNN Project Group Steuerbox, concluded that an enabled periodic schedule would run as if enabled with its most recent (periodic) start time, if it were still running from this start. Because it affects interoperability of the specified devices, we decided to discuss the issue with the community.

The attachment shows the issue with examples.


Files

cyclic schedules tissue.pdf View cyclic schedules tissue.pdf 133 KB Henry Dawidczak, 08/10/2021 05:06 AM

Proposal descriptions

Chapter K.2.4 of part 7-4 (2020) shall be amended:

A schedule assumes status 'running' from 'not ready', if the following conditions are true:
1) the schedule is well-formed (has starting times, output values etc.)
2) if a UTC Start time (setTm) is present, it lies in the past
3) if the schedule is cyclic, there exists a cyclic start time (last cyclic start Time from setCal, lcst), for which is
lcst <= now <= lcst + (SchdIntv * NumEntr).

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