[Elecraft] OT: RF noise in solar photovoltaic system

[Alan Bloom]

In case anyone's interested, I decided not to go with Solar City.  I 
think they would have done a fine job of installing a standard, 
off-the-shelf solar system with a 20-year warranty that would have 
worked fine as far as providing solar power.  I was planning to buy it 
outright rather than lease and I'm convinced that the investment would 
have paid for itself in reduced electricity costs.

But I was worried about RF interference from the inverter, basically a 
3000-watt switching power supply attached to the side of my house.  So 
instead I have decided to go with a local company that is willing to 
work with me on RFI issues, even though their price is higher.  Rather 
than one big inverter, their system uses "micro-inverters" mounted on 
each solar panel.  They did some research and found that it is possible 
to get extension cables to go between each micro-inverter and its panel 
and between each micro-inverter and the power bus.  The extra length can 
accommodate a common-mode choke by wrapping several turns of the cable 
through a ferrite core.

So the plan is to install the system without chokes and see if there is 
any interference.  If so, then I will buy the extra cables and ferrite 
cores and install the chokes.  For testing purposes I can just 
temporarily disconnect all the panels but one and then apply whatever 
works with one to them all.

Alan N1AL


On 07/18/2016 07:32 PM, Alan Bloom wrote:
> I am now leaning on going with a local company rather than Solar City.
> They quoted a higher price for a lower-power system, but because of some
> convoluted accounting it will actually end up costing me less.  And they
> are at least willing to talk about adding some common-mode chokes. Their
> system uses micro-inverters on each panel, which potentially should
> cause less interference because all the switching  electronics is
> localized with short connections.  Only 240 VAC 60 Hz comes out of the
> panels.
>
> Alan N1AL
>
>
> On 07/18/2016 06:49 PM, John Kaufmann wrote:
>> My advice on Solar City is to avoid them at all costs.  Their systems,
>> manufactured by SolarEdge, generate horrendous broadband RF noise....