For WYE CDC, it is stated that:
With regard to data attributes of the CDC CMV, the following additional specifications apply:
- The values of phsA.t, phsB.t, phsC.t, neut.t, net.t and res.t are identical.They specify the time at which the values for phsA, phsB, phsC and neut have been simultaneously acquired or determined.
But for CMV, "t" changes when "cVal", "range" or "q" changes.
What happends if "phsA.cVal" changes due to db, but not the rest of the CMV (phsB, phsC...) in the WYE? Is it mandatory to change the "t" attribute of all the other CMVs in the WYE simultaneously when one of them changes? It seems unnatural...
Remove the paragraph if it does not apply.
a). you are right - I mean WYE....
b). option 1 is the normative one. As in your example the value of phsA does change (even if triggered by phsB.db), a dchg report event should be created with the appropriate t value.
10 Jan 18
Just to clarify:
a) When you say "The purpose of CMV is to supply all phase values at the same point in time", I think that you wanted to say "The purpose of the WYE...", as CMV is just complex measurement.
b) When you say "If the db or some other condition triggers an update of one of the values, then naturally all other values also need to be updated", when you refer to "update", do you mean refreshing the "cVal" value of the CMV? Let's illustrate it with an example: - "MMXU1.A": All the three phases have the same value (starting in 2A, "rangeC" goes from 0 to 7A, "cVal.mag" updated to 2A, "t"=21/12/2017 14:00:00.000). - "MMXU1.A.phsA.db" = 10000 (0.7A). - "MMXU1.A.phsB.db" = 100 (7mA). If "instCVal.mag" raises to 2.008A for phase A and B at 21/12/2017 14:00:10.123, "phsB.cVal.mag" is updated to 2.008A and "phsB.t"=21/12/2017 14:00:10.123. As stated, "phsA.t"=21/12/2017 14:00:10.123, but which of the next options is normative? 1) "phsA.cVal.mag" updates its value to 2.008A. 2) "phsA.cVal.mag" remains in value 2.000A as "db" has not been exceeded.
If option 1) is the normative one and only "phsA" data has been added to a dataset and configured in a RCB, when reporting 2.008A, "dupd" reason should be used or is it valid to use "dchg" ("db" has not been exceeded and therefore "dchg" has not officially ocurred)? If option 2) is the normative one, updating just "t" attribute seems to violate standard, because "cVal", "q" and "range" do not change...
Thanks in advance.
21 Dec 17
The purpose of CMV is to supply all phase values at the same point in time. Therefore, the time stamp values must be identical. If the db or some other condition triggers an update of one of the values, then naturally all other values also need to be updated, else the goal of CMV is not reached.