How ro model a project with two rooftops and converted by separate inverters?

Hi, I'm trying to model a solar PV installation that contains panels installed on top of two different buildings: each of them has sifferent array configurations, plus one building contains one inverter while the other uses two.  After the voltage is converted into AC they are then exported with two separate MCBs controlling the same busbar like this:

Do I have to simulate the two solar configurations in two separate cases, or would I be able to set both up under one case?  Especially the combined generation will be used for offsetting a single installation consumption, and I only have the half-hourly pure consumption values for the entire site and it does not make sense to divide the consumption up into half.

Thanks all.,

 

Hi Joel,

That configuration requires modeling each building as a separate case.

You could model the combined system using the Generic System model, which allows you to provide a generation profile (hourly or subhourly) as input. To do that, start with a .sam file with the two Detailed PV cases and set up the system design for each building (don't worry about the financial model inputs yet. Next, add a third case using the Generic System performance model with a financial model appropriate for your project. Then, on the Power Plant page, choose Calculate generation profiles and nameplate capacity from open cases, and click Select Cases and follow the prompts. This will create a generation profile by adding the profiles of the two PV cases that you can use to model the two buildings as a single system. After SAM creates the combined generation profile, you can set up the inputs for the financial model (load, electricity rates, financial parameters, etc.) for the project.

Let me know if you need help getting that to work.

Best regards,
Paul.

Hi Paul, thank for your assistance, that worked for me.

I have another question: if I modelled each of the three inverter strings with their own DC and AC losses etc, am I correct in assuming the total power plant losses would have been 0%, as the losses are already accounted for in the individual cases already.

 

Thanks again.


Joel

Hi Joel,

Yes. If you account for losses in each individual case, then you do not need to account for them in the case that represents the combined system.

You can check the generation profile in the results (system power generated) to make sure it is what you expect for the combined system.

Best regards,
Paul.