Mains Harmonics measuring instruments operate unusually?

[ocset]

Hello
Why do  instruments which measure mains harmonics of SMPS’s , measure the harmonics by considering that the fundamental current sinusoid is the fundamental of the actual mains input current waveform?
As you can see in the attached waveform showing mains input current and voltage to a PFC’d SMPS, the fundamental of the actual  current is not quite in phase with the voltage in this case. 
As such,  the fundamental  current  sinusoid should be that 50Hz sinusoid  component that is in phase with the voltage, do you agree?
Then, for example, for Class C equipment, the 9th Harmonic maximum should be 5% of that fundamental, and so forth.
 

[Phoenix]

As such,  the fundamental  current  sinusoid should be that 50Hz sinusoid  component that is in phase with the voltage, do you agree?

What? No!

The fundamental component is the entire 50Hz component, regardless of phase. It is then broken down into real and reactive components based on phase.

[ocset]

Thanks, i was forgetting that mains harmonics pertain to core losses (ie heating) in mains power system transformers, and so the phase of the current is not relevant in  the restriction of the harmonics levels.   

[Berni]

Harmonics and power factor are not the same thing!

Power factor is just a ratio between the apparent power and real power. Both harmonics or phase shift cause this ratio to get worse. The worse the ratio becomes the more Amps are flowing trough the wires to bring the same amount of usable power to the load.

[ocset]

Thanks, the point about Mains Harmonics though,  is that they are  limited not only as part of improving power factor, but for the fact that  too-high harmonics levels cause heating due to core losses in the mains power system transformers, do you agree?

I mean, as you know,  its possible to have a power factor which is a pass in the regulations, but you can still fail on mains harmonics.

[dmills]

Different regs for different reasons...

The power factor stuff is mainly an efficiency thing, the harmonics stuff is about limiting flat topping of the voltage waveform due to the interaction of the harmonic load and the supply impedance.

The fact that triplen harmonics sum in the neutral and end up heating up delta/star transformers is a fairly minor consideration for most loads (There are exceptions).

Regards, Dan.