André Mermoud

The format has changed with the version 6.80. You cannot read files created with versions greater than 6.80 in versions lower then V6.79.

It depends on which version of PVsyst you are using. For the first question: Defining 1 kW for the grid injection limit is not really the right way, as the process for handling the losses after the inverter is not simple, and may lead to uncertainties if the difference between produced and limited power is too high (because it involves quadratic ohmic losses). For this situation, the best way is to let the energy be delivered to the grid, and consider that the injected energy is indeed unused energy. In the latest versions, you have the option "Allow solar injection into the grid". For the second question: This depends on the version you are using. There was probably a bug concerning this in an previous version, I don't remember well.

I don't know. When you calculate the average efficiency (from the hourly CSV file?), don't forget to weight each houtly point by the EOutInv value.

Thank you for this information, we will check this for the next version.

Please send us the corresponding *.DAM file. We will check what arises with this file. (support@pvsyst.com).

We will check this. I think it is already corrected. In the meanwhile please modify anything else and PVsyst will ask for saving.

Sorry, I did not know the existance of this norm. However, I don't know the effective difference between the bifaciality factor of ISC with respect to the bifaciality factor of Pmpp. No manufacturer has never mentioned this difference, they only specify the factor for the Pmpp (when they specify it... which is not always the case). NB: several datasheets mention a table of power increase for the bi-facial yield, but without mentioning the corresponding irradiance conditions. Therefore these data are completely useless. However they usually give a stable Vmpp voltage for all powers, which indicates that the bifaciality of Pmpp is identical than the bifaciality of Isc. I don't have any information about the LID effect on the bifaciality factor. Please ask the manufacturers.

This tool shows the evolution of the yearly production, as a function of a fixed array voltage kept constant all over the year. It is very specific, when you have some converter with a fixed input voltage, to adjust for using a PV array.

Please check that you have not defined "Unavailability losses" in your project.

Please chack that you have not defined "Unavailability Losses".

The problem with the PVGIS API change has been solved in the latest version 6.87. This version is available for any user who has upgrade rights up to December 17th, 2019.

I don't know. Please send us your whole project, using "Files > Export project" in the main menu. Send it to support@pvsyst.com.

I don't know. It is strange ideed. Perhaps the simulation has been reexecuted between both outputs ?

You cannot define curved surfaces in PVsyst. You have to create a set of planar surfaces, and use the option "Orientation > Several orientations". However be aware that each orientation should be treated independently (on a different inverter MPP input). You can eventually mix 2 orientations (the orientations #1 and #2) on one MPP input. In you case you have to do some approximations.

Yes you cam import CSV files of XYZ points. Please see the help "Project design > Shadings > Near Shadings: Import > CSV Ground data"

During the installation, the program should have defined a suited workspace C:\ Users \ YourSession \ PVsyst680_Data \ If this workspace is not present, please uninstall PVsyst and reinstall it.

After defining the data you want to get in the CSV file, please don't forget to check "Datafile output / Output on filename" top left. The file will be available at the end of the next simulation. The simulation will notify you where it is located (i.e. in your workspace \Userdata\). NB: You have to re-check the option "Output on filename" at each executions when you want an output file. NB2: This is fully explained in the help "Project design > Simulation > Simulation: export ASCII file", available by F1 in the importing tool. You have access to the Help by F1 (or little questionmark buttons for mor specific information) from everywhere in the software. Please use it.

These are not significant. You can let all these values to 0. See the help "Project design > P50 - P90 evaluations"

Sorry, this is not possible in PVsyst in the present time. You have to define 2 different variants (i.e. perform two different simulations).

Please explain where you found this functionnality. I don't see any place in PVsyst giving directly an energy production as function of the ground area. This information would require to define a GCR, as well as a plane orientation.

This is normal. The values mentioned (and modifiable) in the bi-facial tool are intended to analyze your Bi-facial system in diverse conditions. This is a pedagogic tool. If you have specified a 3D scene (with sheds or trackers), the simulation will take the parameters corresponding at best to these definitions in the 3D construction. This is mentioned on the dialog: The only parameter which is really defined here and not specified in the 3D scene is the "Height above the Ground".

This is quite normal. If you have overpower conditions, all the production hours for which the Power is limited will fall in this last bin (corresponding to PNom).

You cannot mix different PV modules in a single sub-array. The only way to do that is to redefine your inverter as a Multi-MPPT inverter, and attribute different sub-arrays to different MPPT inputs.

By which amount ? The shading calculation principles are very different between the 3D and the Unlimited sheds models. However if you correctly define the 3D scene (i.e. by observing the hypothesis of the "unlimited sheds", i.e. very long sheds or rows), both simulations usually give close values. Now the optimum tilt angles have a very broad maximum: large interval in tilt may lead to very little yield differences. So that the maximum tilt may be significantly different even with little simulation differences.

No this is not yet possible. Please see our FAQ How can I include an inverter in a Stand-alone system?