Multiple PV Inverters

[sampenfold]

Hi all,

I have a situation where I have been given one 17kW 3 phase inverter and one 3.5kW single phase inverter to install.

Usually when installing multiple inverters, I would install a dedicated DB for the inverters and have a generation meter for that DB. However I am unsure on how this will work as there is a mixture of single and 3 phase inverters.

Should I just install a 3 phase DB as normal, and supply the single phase inverter and 3 phase inverter from that DB with a one 3 phase meters for that DB?

 

[Leesparkykent]

Ideally the smaller inverter would be 3 phase to balance it out, both connected to your new 3phase board and the feed for the new board taken through the generation meter.

 

[sampenfold]

Ideally yes.

I have spoken to Elecsa today, who said it is an 'unusual' configuration. I am waiting on a response from Solar Edge, who's design software churned out the kit.

The office said I may need to fit two generation meters. But this would result in the DB having effectively a triple supply to it... Not sure about that!

 

[Gavin A]

Should be fine with a 3 phase meter, I think it should be compliant as it's less than 16 amps imbalance between phases.

 

[sampenfold]

I read about the 16A limit. Have you ever installed inverters in this configuration? I'm concerned that the meter readings may be strange, although a 3 phase meter averages out each line I guess.

 

[whinmoor]

Is the 3.5 inverter needed at all? You can "tweak" the DC/AC sizing up to 138% (sic) within the SE Designer software. If the job's in Leicestershire, the peaks will be lower than farther south. The default is set at 120% but if it's on several different roofs with different orientations and pitches, you might find a higher sizing tolerance would work better?

Have a read of SE's advice on this subject:

http://www.solaredge.com/files/pdfs/inverter_dc_oversizing_guide.pdf