[RFI] Solar Panel RFI in Kings Park, NY - Update

[Tony]

All:

It's interesting to see how similar the RFI characteristics are from one 
Solar Edge system to the next. Dave Cole's website has a few screenshots 
including one of my own that are nearly identical:
See: https://www.nk7z.net/solar-2/ shows

Dave (NK7Z) should be commended for gathering this type of information: 
this is clearly one of those rare cases where the similarities in 
spectral noise can help identify the source of the problem.

Tony -K2MO


On 9/14/2018 5:48 PM, Randy Standke wrote:
> A new SolarEdge system 190 feet from my house spread very strong RFI all
> over the 20 meter band the day the roof panels went up.  These signals had a
> "squiggly" sound and look on a SDR waterfall.  This was well before the
> system was completed and operational.  It was just from the power the
> optimizers receive from the panels.  The system was not making power at that
> time.  The "every 200 kHz" signals came on strong once the system was making
> power, and all the "squiggly" signals remained strong.  Some good examples
> can be seen on Dave Cole's NK7Z at https://www.nk7z.net/solar-2/  My three
> examples are just under the "More Solar Edge Systems." line.  As Tony
> Brock-Fisher describes, it takes lots of ferrites and twisted wires to quiet
> these systems down.  In addition, if they do rework the system and miss even
> one optimizer you will still have strong RFI.  One (of the seven and
> counting) reworked SolarEdge systems in my neighborhood took four visits
> from the installer until they finally got it right.
>
> 73,
>
> Randy KQ6RS
>
>
>
> -----Original Message-----
> From: RFI <rfi-bounces at contesting.com> On Behalf Of Tony Brock-Fisher via
> RFI
> Sent: Friday, September 14, 2018 2:15 PM
> To: Edward Mccann <edwmccann at yahoo.com>
> Cc: rfi at contesting.com
> Subject: Re: [RFI] Solar Panel RFI in Kings Park, NY - Update
>
> Fair Rite 2631626202 core, mix 31.
>
>
> On 9/14/2018 4:43 PM, Edward Mccann wrote:
>> Tony-
>> What type ferrite toroid did you use in your three-turn choke?
>> AG6CX
>>
>> Sent from my iPhone
>>
>>> On Sep 14, 2018, at 1:00 PM, Tony Brock-Fisher via RFI
> <rfi at contesting.com> wrote:
>>>   From my testing, the optimizers internal switchers continue to run (at
> 200kHz) anytime the optimizer gets power from the panel - therefore during
> daylight hours. This noise exits the optimizers on both the panel leads as
> well as the DC output leads. This was the reason I retrofitted my system
> with the 3-turn bifilar chokes, in between each optimizer and it's panel.
>>> During power generation, the optimizers emit higher levels of noise, from
> both the panel leads and the output leads, at the 200khZ switching frequency
> and harmonics, up through 10 meters or higher.
>>> If the DC output leads have already been properly retrofitted with
> reduced loop area, twisted pair wiring, and chokes, it may now be beneficial
> to add the 3-turn biifilar chokes to the optimizer input leads. I noticed a
> significant improvement in noise when I completed this step on my system.
>>> Disconnecting every panel from every optimizer is very labor intensive.
> While this experiment might provide conclusive information about the cause
> of the noise, it won't buy you anything in actual remediation. For the same
> amount of labor, and a moderate additional materials cost, you can add the
> 3-turn bifilar chokes to the optimizers, with the likely result of
> permanently lower noise when the work is completed. This would actually be
> less labor, as the panels can be lifted one at a time, not requiring they be
> removed from the roof, as the chokes are added underneath them. Note that
> this technique has been applied to multiple systems with good results each
> time.
>>> This is like 'peeling the layers of the onion', and you may need to
> address several 'layers' before you get the noise down to an acceptable
> level (which may never get to 'zero noise').
>>> -Tony, K1KP
>>>
>>>
>>>> On 9/14/2018 3:40 PM, Tony wrote:
>>>> All:
>>>>
>>>> Solar Edge shut down my neighbors solar panel system to test for RFI
> this week. The strength of the noise dropped, but it's still detectable. I'm
> told that the inverter and optimizers are inactive which my neighbor
> confirmed.
>>>> The problem with this test is that the power supplies within the
> optimizers remain active since they receive their power from the solar
> panels. The noise is also typical of the type generated by switching power
> supplies.
>>>> The next logical step would be to disconnect the power supplies from
> each solar panel to see if the noise goes away. It's something I've asked
> Solar Edge to do for some time now.
>>>> Before I make that request, does anyone have any thoughts on what else
> could be generating noise with the system turned off?
>>>> Tony -K2MO
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