Central inverters

Soulbringer

Hello everybody,

I wanna ask you guys did anyone have an experience with Central inverters 250 kW or higher? Because when we have 1MW PV power plant for example it`s better to use 4 Central inverters than 125 Mini central 8 kW.
But in this case the cross section of DC cables from the modules to DC side of the Central inverter is very big.How do you thing what is better?
More cabling with Cental inverters but less price or less cabling with Mini central 8 kW but higher price of the inverter.

Best Regards

Roderick

Re: Central inverters

I believe the system on the roof of Cypress Semiconductor ("Sunpower") uses lots of small inverters, the second choice that you describe. I don't know why.

A guess would be that it's easy to assemble, and it avoids long runs at low voltages. Also, if one inverter fails, the system doesn't go down. One could turn off any number of them at a given time for servicing of panels or wiring.

Try looking at the design of the Google rooftop system, which is also in the 1 MW range. That might give some ideas. They might even be willing to answer your questions directly, if you have a serious project.

niel

Re: Central inverters

with a single large inverter of that magnitude, the wiring wouldn't be wiring as it would be huge bars of copper and very difficult to handle and connect. large wires are bad enough, but are doable for many smaller inverters as the dc wire size would be workable for an 8kw inverter. these wires would have to be as short as possible and still be able to connect 125 inverters so to accomodate them and the lengths of wire would ultimately be slightly larger for the I^2R losses. large bars of copper would still be on order to make for large terminal blocks making connections easier.