Inverter Clipping on certain period

[Aidenn]

Hi PVSyst team,

Can someone explain how do PVSyst determine the clipping loss on these periods? I attached also the setting for the MPPT sharing applied for the system. Please let me know for any other files needed to identify these losses below. Thank you!

Edited August 5 by Aidenn

[Linda Thoren]

Hello Aidenn,

I first notice that the power sharing has not been equalized in your print screen. All sub-arrays has the same Pnom/MPPT, though different installed PV power in each sub-array. This results in unequal Pnom ratios across the sub-arrays. You can toggle the "Auto-equal. Pnom option", or clicking on the weight icon for the specific configurations concerned. This will distribute the Pnom/MPPT values proportionally according to the installed PV power in each sub-array, thus equalizing the Pnom ratios.

The production begins as soon as the MPP power is over the power threshold Pthresh of the inverter. The MPP power below this threshold is accounted as IL_Pmin loss. The Pthresh power may be understood as the power required for the Inverter internal circuits consumption. These losses might be reduced if activating the power sharing, since certain sub-arrays have rather low Pnom ratios. 

You can read further about in the following help pages:

https://www.pvsyst.com/help/project-design/grid-connected-system-definition/inverter-array-sizing.html#difference-with-the-hourly-simulation
https://www.pvsyst.com/help/physical-models-used/grid-inverter/inverter-operating-limits.html

[Aidenn]

Hi Linda,

Thanks for the reply!

May I ask if its always the case for MPPT sharing, to use Auto-equal. Pnom option?

Thanks,

Aidenn

[Linda Thoren]

Hello,

Yes if you are defining the MPPTs you have an interest to use the Auto-equal Pnom option, to avoid overload losses in some sub-arrays while other underperform. If you have multiple orientations, you can use the multi-orientation daily sharing option.

Kind regards,