effect of configuration (voltage window & panel combination) on output AC kWh

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Ben Lovell
Topic Author

16 Jul 2014 05:50 #2427 by Ben Lovell

effect of configuration (voltage window & panel combination) on output AC kWh was created by Ben Lovell

Hi!
How come when we ask SAM what the kWh production outputs for 2 panels per string versus 10 panels per string on an array (eg using an SMA SB 5000TL 240) SAM is only showing a variance in kWh output of 3%?

We would expect the output to be drastically reduced because 1 panel on this inverter will give Voltage in daylight of approx only 37V, but the inverter minimum MPPT DC Voltage is 175V (voltage window 175V-600V or thereabouts).

Is there a setting to factor this reality in SAM so that the output hourly ac kWh reflects the inverter voltage window, min MMPT V etc and panel characteristics?

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Paul Gilman

16 Jul 2014 20:39 #2428 by Paul Gilman

Replied by Paul Gilman on topic effect of configuration (voltage window & panel combination) on output AC kWh

Dear Ben,
SAM assumes that the photovoltaic array is sized to operate within the inverter voltage limits. That is why it displays messages about potential sizing problems on the Array page, and why it displays messages about operating outside the limits in the post-simulation messages.
The simulation model is not detailed enough to model the actual behavior of an inverter operating outside of its limits, but it does check the limits and give you feedback when the limits are exceeded.
See the description in SAM Help -- Sizing the Flat Plate PV System topic under "Post Simulation Warning Messages" for more details.
Best regards,

Paul.

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