Tony,
Regarding your statement below:
"We found high levels of RFI on the A/C lines throughout my neighbor's home and
that's likely the case with all Solar Edge installations .............since
there are no chokes between the mains and inverter."
It is the last part that I take issue with. See the attached photo. This is
the EMI filter on the SE inverter on my house. Also see the attached PDF, look
under page 3 COMPLIANCES you will find part 15B
They could not legally connect these to a residential AC line if it were not
part 15b compliant. In addition I have a Corcom 25fc10 installed at my home.
See the data sheet and response curves here.
http://www.farnell.com/datasheets/1430489.pdf
The filter makes a barely detectable change in the any received RFI I have from
the SE system.
What needs to happen here is to determine, the source of the RFI first, not
the radiating elements. In the past you have mentioned that even with the
inverter off, not producing power, you still had the interference. In fact you
had covered the panels and the RFI went away.
With that in mind here are a couple of sources, or generators, and not he
radiating element that I cab confirm in my testing.
1) The inverter itself. The original inverters SE used had an internal
switching frequency of roughly 18 KHz and thus harmonics were found every 18
KHz
2) The HD wave inverters operate at roughly 50 KHz and thus you can see
harmonic energy at 50 KHZ intervals Other manufacturers that I have worked
with use 39 KHZ .
It is difficult to switch, in my case 6.5 Kilowatts of power in a box 12" x 12"
by 8"
3) The original optimizers as we all know had a serious 200 KHz problem. In
the next version, as I have in my installation that problem has been rectified.
4) This leaves the fact that the current optimizers, the SP350? I believe? may
still generate some noise in the non-power generating state. I am pretty sure
you sent me a video or photo comparison that Randy, sorry I forget his call at
the moment, but he did bench test on a non-power generating optimizer.
In that video, you showed the spectral waveforms looking similar I believe?
I don't think the inverter is the cause of your issues at that this point. The
exact radiation mechanism of the RFI from your neighbors SE system is still
unknown.
I also do not see the noise issue you have, as you previously described at my
house. The again I only have a 275' open wire fed dipole that I tune on all HF
bands 200 feet away from house. I don not have a multielement beam design for
20 meters.
To me it would make the most sense to concentrate on the specific device
generating your noise based on the RF signature.
73,
Paul Cianciolo, W1VLF
ARRL EMC Engineer
ARRL - The national association for Amateur RadioT
225 Main Street, Newington, CT 06111-1400 USA
Telephone: (860) 594-0392
FAX: (860) 594-0259
Email: w1vlf@arrl.org
World Wide Web: www.arrl.org
-----Original Message-----
From: RFI <rfi-bounces+pcianciolo=arrl.org@contesting.com> On Behalf Of Tony
Sent: Friday, September 25, 2020 6:23 PM
To: Rfi List <rfi@contesting.com>
Subject: [RFI] Question Regarding Variations In Solar Panel RFI?
All:
The reports I've read suggest that the strength of interference caused by solar
panel systems can vary from one installation to the next EVEN when the distance
to the source is similar. That variation could be attributed to radiating
conductors tied to the system such as the house wiring.
We found high levels of RFI on the A/C lines throughout my neighbors home and
that's likely the case with all Solar Edge installations since there are no
chokes between the mains and inverter.
Given those facts, would a large home with long runs of un-shielded Romex
produce higher levels of interference compared to a smaller home with shorter
runs? Or does the resonance of the wiring play more of a role than length and
number of runs?
It's an oversimplification, but it seems logical to consider what's connected
to system and not just the system itself.
Tony -K2MO
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