1721   Power factor related data objects in LN MMXU

Created: 22 Sep 2020

Status: Solution Accepted

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

Links:

Page: 215 (consolidated version)

Clause: 6.10.14

Paragraph: table 101

Issue

For smart grid application (operational functions) a signed power factor is needed.
The DO PFSign explains "Sign convention for power factor 'PF' (and reactive power 'VAr')", but no signed power factor is available.
DO PF explains "...The power factor is defined as P (active power) / S (apparent power), so the value range is 0...1" (only positive range, like it is defined in the IEV 131-11-46).
An additional DO for signed power factor is needed (like in IEC 61557-12).

Proposal

Correct the description of PFSign: Sign convention for signed power factor (and reactive power 'VAr').
Correct the description of PF: The power factor is defined as the |P| (absolute active power) / S (apparent power), so the value range is 0...1.
Add in LN MMXU an DO (CDC WYE) SignPF Power factor, signed acc. enumeration of DO PFSign (Power Factor Sign convention).
Do we need also a DO SignTotPF (average between 3 phases) ?

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Discussion Created Status
Solution is accepted. 02 Aug 21 Solution Accepted
Starting ballot period 30 Jun 21 Ballot Period
No change to test procedures needed except reference to new NSD file during batching process 30 Jun 21 Conformance Test Verification
Next step is to prepare/change conformance tests if necessary. 07 Jun 21 Conformance Test Preparation
Added the complete solution, as described on 18th Dec, in file Solution_tissue1721_2.zip.
No change of compatibility.
04 Jun 21 Analysis Of Compatibility
Correction of semantic, description improved. Cooresponds with usage in part 7-420.

Conclusion: no compatibility issues!
04 Jun 21 Analysis Of Compatibility
Change to Verify Draft Implementation 13 Apr 21 Verify Draft Implementation
Change to next stage- drafting implementation. 28 Jan 21 Drafting Implementation
Proposal:
TotPF - change of the description to "Signed power factor in a three-phase circuit. The power factor is defined as ratio of the absolute active power to the apparent power (acc. IEV 131-11-46). Sign is added and determinded by the PF sign convention (DO PFSign). Calculation method of apparaent power is defined by the data object ClcTotVA.”

PF – change of the description to "Phase to ground/phase to neutral signed power factors. The power factor is defined as the ratio of absolute active power to apparent power (acc.IEV 131-11-46). Sign is added and determinded by the PF sign convention (DO PFSign).
If current (I) and voltage (U) are sinusoidal and displaced by the angle phi, then the power factor is cos phi. Therefore, for the power factor per phase, value is contained in 'mag' and 'ang' is not used.”

Add the following description to section 7.2.27 (enumeration of PFSign, before the figure 45):
"According to the IEC convention, the power flow direction is determined by the sign of the power factor (Export/Import). Devices, which are both producers and consumers of power, are treated as consumers for the IEC sign definition.
According to the IEEE convention, the type of load (inductive/capacitive) is determined by the sign of the power factor (lagging/leading)."
18 Dec 20 Discussion (red)
I agree, description of TotPF seems wrong. Shall be corrected as well.
TotPF has CDC MV, PF has WYE.
25 Sep 20 Discussion (red)
TotPF definition seems wrong. Should be TotW/TotVA with sign as per PFSign. with current definition, TotPF=1.0 if one phase is +0.9 and other is -0.9 which makes no sense. When re-defined, SignTotPF will not be needed 24 Sep 20 Discussion (red)
Accepted and open for discussion. 22 Sep 20 Accepted

 

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