cesmith

I am simulating string inverters (SMA STP) which have 2 MPPTS. It turns out that many times these have odd numbers of strings (5 or 7) so the MPPTs have different numbers of strings attached. I noticed that I was getting significant (>2%) "Inverter Loss over nominal inv. power" even though the Pnom ratio is 1.2 or less. There is no loss when the multiple MPPT box is not selected. It appears that PVsyst is treating the inverter as two separate halves, for example a 15kW inverter with 5 strings is being treated as two 7.5kW inverters, one with 2 strings (Pnom <1) and one with 3 strings (Pnom>1.3). This is not how the inverter works. Each MPPT input can take enough current to comfortably handle 3 strings, and then all the current goes to a single inverter core which can comfortably handle 5 strings without clipping. Perhaps other inverters do work this way? I am therefore not using the multi-MPPT feature to avoid getting hit with what I believe is an invalid additional loss.

I created a new variant with double (heterogeneous) array orientations (-6 and -24). I then created these two arrays (as rectangular PV planes) in the global scene view with the same orientations. When I return to the Near Shading Definition screen, it shows “Warning: you defined heterogeneous fields in the Orientation parameters but not in the shading scene!”. How do I create heterogeneous fields in the shading scene? I tried putting a single azimuth in the Orientation, which gets rid of the above message, but then the simulation just uses the single azimuth specified in the Orientation for both arrays, and ignores the second azimuth specified in the global scene. I thought maybe the global scene would override the orientation setting (which would be really useful for simulating multiple array tilt/azimuth angles in a single PVsyst run) but this does not appear to be the case. Can anyone offer any insight on this? Thanks. I am using string inverters (SMA STP) so each array will have multiple inverters.

When exporting a project with near shadings specified (.SHD files for example), these files are not exported. If I copy the missing files explicitly to the export location and then import, the shading files are again not transferred.