Ed Hare Wrote: I am going to see if they can send us a panel
Ed:
I believe SolarEdge removed the defective panels from a few
installations so they should be able to accommodate you. The ones that
were found to emit RFI were manufactured by Hanwha.
Hanwha also manufactures solar panels under different names and I'm told
that the manufacturing process is essentially the same.
I'll send you the contact information for the engineer I spoke with - he
has first-hand knowledge about this issue.
Tony -K2MO
There are a number of possibilities here.
Yes, the panels themselves could be generating noise by any of a few different
mechanisms. What is not really known is whether this is an extreme near-field
phenomenon, heard only very close to the panel, or radiated more effectively.
Any panel noise could also conduct onto electrical wiring connected to the
panel. A common-mode choke is only going to be effective if it includes hot,
neutral and ground for ac wiring and +, - and ground for dc.
If the ground lead is not choked off, common mode noise from any source could
be conducted to the panels and radiated from both the conducting wiring and the
panels.
Other noises could be present, confounding any findings.
And, of course, the panels could be creating and radiating noise.
I am going to see if they can send us a panel and microinverter that we can set
up here for testing purposes.
Ed, W1RFI
-----Original Message-----
From: Tony <dxdx@optonline.net>
Sent: Sunday, June 2, 2019 4:28 PM
To: Tony Brock-Fisher <barockteer@aol.com>; Rfi List <rfi@contesting.com>; Hare, Ed W1RFI
<w1rfi@arrl.org>; Cianciolo, Paul, W1VLF <pcianciolo@arrl.org>
Subject: Re: SolarEdge Finds New Source of Solar System RFI
Tony:
I asked if they were sure about their findings and the answer I got was that
they were still seeing RFI with the system turned off and the array
disconnected and disassembled. I'm assuming disassembled means they removed the
optimizers from the panels.
They found that the noise dropped significantly after they applied ferrites to
the panels, but I'm not sure if they tested a stand-alone panel with and
without chokes or if they ran the test with the system completely reassembled
and turned on. I'll asked that question the next time I speak with them.
The engineer mentioned the diode theory as well. If there is ambient RF
exciting the panel diodes, is it possible that it would come from the inverter?
Tony -K2MO
On 6/2/2019 8:51 AM, Tony Brock-Fisher wrote:
Tony et al-
This sounds pretty hard to believe to me. The panels normally contain
no active circuitry, so it's hard to see how they could be generating
RFI.
The panels may have a series diode. Additionally, the cells themselves
are really, really large diodes. The only thing I can think of is that
they could be getting excited by high ambient RF, and then rectifying
that RF to produce harmonics or possibly cross modulation products.
I have an AM BC station that is less than a mile, line of sight, from
my QTH. During the day they transmit at 44kW. I have tons of RF all
over the place, and it does cause lots of products with other BC
stations and AC line modulated direct-diode supplies.
Just my opinion here...
-Tony, K1KP
On 6/1/2019 5:59 PM, Tony wrote:
All:
I recently spoke with an engineer from SolarEdge who said that they
discovered a previously unknown source of RFI which turned out to be
the solar panels themselves. They found that the panels were
producing noise while physically disconnected from the system at a
few installations.
They are now working with the panel manufacturers Hanwha and Trina to
determine why a certain batch of their panels are producing RFI. The
goal is to locate installations with the defective panels and replace
them.
Cumulative RFI from multiple panels is apparently enough to cause
serious RFI and may be the reason why my neighbors installation still
makes noise during?? the day while the system is turned off. It could
also be the reason why the choking the Optimizers had little effect.
Tony -K2MO
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