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
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi