Simulation of PV Array installed on wavy terrain

[arossi77]

Hello,

I'm facing the situation where the PV Arrays are installed in a wavy terrain (refer to attached picture). Azimuth is constant. I'd like to run simulation to evaluate the benefit of the multi-MPPT operation against the single-MPPT operation in order to select the proper DC-side inverter configuration. I guess I should consider the same installation conditions (same azimuth and tilt) with different IAM values, but how to evaluate the bo factor? To compare the multi-MPPT operation with the single-MPPT operation, I could set up the simulation defining multiple subsystems each one with its own bo factor (how to calculate it basing on the mechanical positioning of the modules?) and another simulation defining a single subsystem with a different (higher) bo factor (how to "average" the bo factors to define the single-MPPT simulation value for bo?).

Any help will be highly appreciated!!!

Best regards, AR

[André Mermoud]

The IAM performance and bo factor are not dependent on the module positioning in any way: this is an intrinsic characteristics on the PV module cover (glass with or without antireflective coating).

Now in your situation the orientation of each table will be different due to the base slope (see the FAQ about tilted base slope).

In the present time, only the terrain representations provided by the Helios3D software can treat the case of spread orientations, and in an approximate way: PVsyst assumes an average orientation for performing the simulation. We are preparing our own possibility of terrain representation and PV modules covering with adapted baseslopes. This will be available very soon.

However this will not give any answer to your question about the performance of centralized or decentralized MPPT. I don't see how to do that with PVsyst.

[jammyc]

We are preparing our own possibility of terrain representation and PV modules covering with adapted baseslopes. This will be available very soon.

 

Slightly off-topic, but can you elaborate further? We are very interested in this topic and have looked at a number of plugins for PVsyst - such as Helios3D - but perhaps your extensions will do what we need?

[arossi77]

Thank you for the answer.

I understand the IAM is an intrinsic characteristic of the module, my intention was just to take in account (through this parameter) the different quantity of energy which is "captured" by the panels due to the different exposition.

However, from your answer it seems there are no chances to compare - using the PVsyst - the performance of multi-MPPT inverter respect the single-MPPT inverter. I run some simulations considering two different orientations and in the first simulation "connecting" one MPPT on the array with one orientation and the second MPPT on the array with other orientation; in the second simulation I considered the inverter as monolithic (single-MPPT) and I configured the array as "mixed". It is not surprising for me the PR in case of monolithic is lower than the multi-MPPT but from the report the difference is related to the efficiency of the inverter (probably because the inverter works at lower voltage where the efficiency is lower?) and not to the panel mismatch. The two orientations were set to 10° and 25°. Attached the PVsyst report.

Thank you.