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@contesting.com> On Behalf Of Tony Brock-Fisher via
RFI
Sent: Friday, September 14, 2018 2:15 PM
To: Edward Mccann <edwmccann@yahoo.com>
Cc: rfi@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@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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