How does one HALF CUT solar module affect the other modules in the string when it is partially shaded?

[JackPV123]

Hello everyone,

I have a fairly technical question. I wonder what will happen to the efficiency of the PV system when we shade the bottom of one solar module (HCC) connected in series? Will the performance of the entire string decrease by half because only the top works in this module? Isn't it that the performance of the modules in the chain depends on the weakest module (which is that one half-working module)? How does this process look from the electrical side?
Thank you for every reply

 

[dogbob]

Some PV systems use microinverters, one per panel. If you have one of these systems, then shading one panel will not affect power produced by another panel.

Some system simply put all panels in series and feed a large inverter. If one panel gets shaded, all panels lose output.

Some systems use a large inverter, but add optimizers on each panel. With optimizers, shading one panel won't affect the output of the others.

Note that a typical solar panel contains many solar cells in series, so shading a small part of the panel affects the output of the whole panel.

 

[energyd]

No, when you shade half of your module then the bypass diodes will kick into action and the current will bypass the module. In other words, the one shaded panel will give you 0% power and the un-shaded modules will give you 100% power. With microinverters or power optimisers you will get 50% from the (partially) shaded module and 100% power from the others. The idea that the entire sting will stop working because one module is shaded is a myth that was probably cooked up to sell more optimisers.

 

[btelis]

The current output for a circuit of dissimilar devices in series is limited to the current of the lowest performing device in the entire string.
This white paper from REC "Managing mismatches when replacing panels and using panels with different power ratings in a string " maybe will help you