Is the Power factor sign convention Chart wrong in PM800 user manual

[sesa207393_brid]

Hello everyone,

In the Power factor sign convention chart for PM800, it shows that in quadrant 2, the load is capacitive and the load in quadrant 3 is inductive. But I think it's wrong, because there are different explain in the user manual of PM5350 and IEEE1459. Can anybody help to confirm whether it's right? Thank you!

The PQS Coordinate System chart in PM5350 user guide: in Quad2 the load is inductive and in Quad3 it's capacitive load.

Four quadrant power flow directions chart is IEEE1459-2000:

[DanL]

In general there is consensus on how to describe a system with net positive real (active) power flow.

It is less clear how to describe a system in which the "load" current exceeds 90 degrees from the supply voltage (such as power generation).

https://www.msl.irl.cri.nz/sites/all/files/training-manuals/TG28%20Mar%202013.pdf

IEEE 1459 (both 2000 and 2010) has no direct discussion on the description nor definition of the terms Lead, Lag, Inductive Load, Capacitive Load - especially in regards to quadrants 2 and 3. However, a primary contributer to IEEE 1459 has indicated that some of his underlying assumptions about negative power were incorrect and that another revision is needed to correct this.

http://powerstandards.com/Shymanski/draft.pdf

The PM800 documentation agrees with other standards and references in the designation of capacitive/inductive and lead/lag:

see IEC62053-23, IEC62053-24, IEC61557-12, IEC61268,

and

Page 243 of Handbook For Electricity Metering 10th Ed.

The simple validation test that makes sense to me is where a power meter is monitoring an inductive motor load:

Wired correctly to measure power delivered to the load as positive, the load will be in Q1 (lagging/inductive).

Wired with the current sensor backwards, to measure power delivered to the load as negative, the same "load" will be in Q3 (lagging/inductive).

The PM800 supports two conventions for PF sign: "IEEE" and "IEC"

The convention called "IEEE" appears a little misleading to me in that the current IEEE definitions for signing PF all agree with the IEC definitions - the sign of PF is the same as the sign of the active power flow. In any case, the intent of this configuration is to use the sign of the PF register to directly indicate lead (capacitive) vs. lag (inductive) to the user.

The PM5350 manual appears to be derived from the superset of the IEC diagram and the (uncorrected) IEEE1459 diagram.

From some quick testing done here, the PM5350 device does not appear to have indicators or registers for neither
Leading/Lagging nor Inductive/Capacitive.

The plan is to revise the PM5350 documentation.

Dan Loewen

[Anonymous user · Accepted solution]

The information in the PM800 series user guide is correct.  Some information in the PM5350 user guide is a bit confusing, so we tried to improve the description in the PM5000 series tech docs.

PM5500 series user manual has a section that describes power factor and how it is stored in the meter's Modbus register (Chapter 16: Power, energy and power factor).