Radio frequency interference with recently installed solar panels

[Timmyscott]

I recently had panels installed in 2 series on either side of my ridge line and now have rfi when trying to listen to fm radio. A SolarEdge tech remotely turned off
each series and found that one array, on the western side of my home, caused the rfi. He said the pv panels themselves are producing a “shield” blocking the fm signals.
i don’t speak this stuff very well, but im hoping I can install an fm antenna on the roof, run wire into my attic, and reamplify the radio signals there, to allow 3 radios in different rooms, to capture a clean signal.
is this a viable solution?
does anyone have experience doing this?
are there others ways of accomplishing my goal?

i have 26 LG 335 panels with SolarEdge optimizers and inverters.

as I mentioned, I’m very uneducated with all this stuff. any device w/b very appreciated.

[Mike90250]

PV panels make a poor shield. RFI blocking the FM radio band is unusual.

That's my 2 cents

[bcroe]

It is a bit strange that only half of your setup generates noise, could be a partially failed
component. I would start with a portable radio (AM and FM if possible) and move it around
the equipment looking for the source of the noise. Look for bad connections or a specific
part. Swapping some around might identify which is/are the noise source. Straight string
converters are the easiest to clean up, with active components off the roof.

Yes even a simple roof mount FM antenna will help, again move it away from the noise
source. Best is to use an antenna mount amplifier to get the signal well above the noise
before the transmission line. Bruce Roe

[bob-n]

Mike and Bruce are right. Your SolarEdge is producing RF noise.

If they can change the interference by turning on and off a piece of equipment, then it isn't shielding. It is that piece of equipment spewing noise. It could be that the EMI filter on one string is worse than the EMI filter on the other string, but those filters are inside the SolarEdge box, so it strongly suggests that the SolarEdge box is your problem.

Bruce is also right that a better FM antenna and placing it far from the SolarEdge and far from the panels will help. Getting a new SolarEdge might or might not help, but I'd be tempted to demand that they do that first.

[peakbagger]

Any chance that application of ferrite core inductors on the lines might quiet things down? I do not claim to be RFI expert but I picked up military lighting system last year used on military vehicles that use HID ballasts and IR sources, at every lightbar has a HID ballast and some sort of IR LED control board with large ferrites cores attached around the cables before they exit the lighting housings. My assumption is they are there to cut down the RFI profile of the vehicle and prevent interference to the electronics in use in the vehicle. The cores are readily available and cheap plus the split core versions are easy to install, just clamp them over the lines and use a UV resistant Tie wrap.

As a side note this lighting system appears to be designed to day light up a couple of blocks around a vehicle. One fixed lightbar with multiple heads on all four sides of the vehicle plus two motorized spotlights. Flip a switch and the HIDs go black and LED IR lamps take over for black out mode. No such thing as common wiring, every lightbar has its own dedicated wiring to a terminal box mounted inside the vehicle. I dont plan to simulate a war but the components are worth far more than I paid for the system that was new in boxes. I will use what I need and sell the rest piece by piece on Ebay. Unfortunately I have not found a wiring diagram so I had to point to point the entire system and create one. To make it interesting at some of the connectors they change wire colors from one side to the other

[SunEagle]

Any chance that application of ferrite core inductors on the lines might quiet things down? I do not claim to be RFI expert but I picked up military lighting system last year used on military vehicles that use HID ballasts and IR sources, at every lightbar has a HID ballast and some sort of IR LED control board with large ferrites cores attached around the cables before they exit the lighting housings. My assumption is they are there to cut down the RFI profile of the vehicle and prevent interference to the electronics in use in the vehicle. The cores are readily available and cheap plus the split core versions are easy to install, just clamp them over the lines and use a UV resistant Tie wrap.

As a side note this lighting system appears to be designed to day light up a couple of blocks around a vehicle. One fixed lightbar with multiple heads on all four sides of the vehicle plus two motorized spotlights. Flip a switch and the HIDs go black and LED IR lamps take over for black out mode. No such thing as common wiring, every lightbar has its own dedicated wiring to a terminal box mounted inside the vehicle. I dont plan to simulate a war but the components are worth far more than I paid for the system that was new in boxes. I will use what I need and sell the rest piece by piece on Ebay. Unfortunately I have not found a wiring diagram so I had to point to point the entire system and create one. To make it interesting at some of the connectors they change wire colors from one side to the other

More than likely the rfi is coming from the inverter and not the panel string. The issue is usually the "load" and not the solar panel that creates rf.

[Timmyscott]

My wife and I thank all of you for your suggestions and advice. Really gave us something to think about. Now we think the SolarEdge tech sort of sold us a bill of goods and that the rfi is caused by SE equipment.
Followup question - how would one ID which optimizer could be making rfi?

[sdold]

My wife and I thank all of you for your suggestions and advice. Really gave us something to think about. Now we think the SolarEdge tech sort of sold us a bill of goods and that the rfi is caused by SE equipment.
Followup question - how would one ID which optimizer could be making rfi?

Have you shut the system down to confirm that it's the Solaredge system? I wouldn't think you'd need to tell them which optimizer it is or if its the inverter, or a particular string, just turning the system on and off should confirm it. But an AM radio moved along the array might narrow it down.

[bob-n]

sdold has a great suggestion. It might take an FM radio, but a portable radio would be a great debug tool.

Walk around with it and see where the interference is better and worse. Turn things on and off.

Your system will have a DC disconnect and also an AC disconnect. It's always safe to turn off the AC disconnect but leave the DC disconnect alone. There are safe sequences required for turning off the DC disconnect without arcing.

It wouldn't hurt to also experiment with turning off other things in the house, just to make sure that you've isolated it. An easy way to do this is with one person holding the radio where interference is worst and another throwing circuit breakers in your main service panel.

[bcroe]

More than likely the rfi is coming from the inverter and not the panel string. The issue is usually the "load" and not the solar panel that creates rf.

An optimizer at a panel is another possibility. Bruce Roe

[SunEagle]

An optimizer at a panel is another possibility. Bruce Roe

Yes. Technically that is a load and an inverter. Still the OP needs to disconnect his system and then trace where the rfi is coming from. Remember it may be more than one place

[Mike90250]

I think the testing has to happen mid day, with the system live. if it's disconnected, it's off and not doing anything. Walk along the array and use a portable radio on a stick over each panel, to find the one causing the RFI.

[J.P.M.]

I think the testing has to happen mid day, with the system live. if it's disconnected, it's off and not doing anything. Walk along the array and use a portable radio on a stick over each panel, to find the one causing the RFI.

I wonder if the shade a radio creates might change the output of the panel. Maybe there's room under the array ? Just wondering.

[sdold]

Since the interference is noticed mostly in the FM band, an FM radio might work, but I bet an AM radio tuned to an open channel might work better because FM radios aren't good at responding to noisy signals which more resemble AM than FM. Funny this came up, I just spent all day tracking down switching noise from power supplies using a spectrum analyzer. Here's what a highway patrol radio sees when the officer turns on his dash camera, and I bet inverters can look pretty similar. This is from a switching power supply in in the camera system running at about 200 KHz, black is before turning on the camera, red is after. It shows how evenly-spaced harmonics can be. Luckily it's a prototype system not yet in service.

150-170 LPR and cameras only - and all off baseline.JPG

[bcroe]

Hopefully the designer learned something about real world designs from this.
Bruce Roe