Line noise

[ggunn]

I deal with PV microinverters that rely on power line data transmission over AC lines for monitoring production, and the manufacturer is telling us that the reason the monitoring is not operating correctly at one of our installations is because of interference from X dB of line noise at the site. What tool would we use to measure it ourselves to verify what they are telling us?

 

[wwhitney]

So is it important to know the frequency of the power line communications and just measure the noise in that part of the spectrum? For example, Enphase says their North American products do their power line communications at 144 kHz.

Cheers, Wayne

 

[zbang]

I get suspicious whenever people blame problems on "line noise", "ground loops", no "dedicated ground", etc. Does the mfg provide any further info about the spectra of the "line noise" and signal levels?

Also, are the leads in conduit? If they are, it'd hard to get noise induced into them; it would have to come from connected equipment, maybe from the incoming line.

A spectrum analyzer should give you all the info you need about any noise.

 

[LarryFine]

Noise-suppression equipment can also absorb intentional power-line signals.