Self shading

I want to model 2 rows with 7 modules each, facing south with 30° tilt. The inverter has 2 MPPT's.

If I define 2 subarrays of 7 modules, each on a MPPT,  I get only 1 row in the Shading Page. Self-shading doesn't work with 1 row.

If I put 14 modules in 1 subarray with 2 strings, I get 2 rows in the Shading Page, can do the self-shading analysis, but cannot use 2 MPPT's.

Is there a way to use 2 MPPT's and simulate self-shading?

Best regards,
John

Hi John,

SAM only models self shading within a subarray. The self shading model does not work to determine shading between subarrays.

If the two rows have the same orientation and number of modules per string, you could model them as a single subarray connected to the same MPPT input on the inverter. The separate MPPT inputs are really only required when you expect each row to operate at a different voltage because they have different orientations or have different numbers of modules per string. (If you are using the 3D shading calculator, you could use separate MPPT inputs if the two rows are exposed to different shadows.)

If the arrays are fixed (no tracking) and have different orientations and/or numbers of modules per string, you could use the 3d shade calculator to calculate shading between the subarrays.

Best regards,
Paul.