André Mermoud

Which version of PVsyst are you using ?

Getting data for sub-systems or sub-arrays individually is not possible in PVsyst. You should perform a separate simulation for each sub-system you want to study.

Please see our FAQ What is the shading loss "according to module strings" ?

There is a limit value for discriminating when 2 arrays have the same orientation. This is in the Project's definitions, button "Albedo & Settings", page "Other limitations" > item "Discriminating orient. differences between shading planes". This is normally fixed at 1°, but you have perhaps increased it by accident.

Thank you for the suggestion. We will indeed think about periodical saves during the calculation. For the slowing of the full system by heavy shading scenes, this is not normal. In the menu of the 3D editor, please check the item "Ignore field interpenetration check" which should become "Enable field interpenetration check". This option is usually very time-consuming.

As you say, there are many models proposed for different technologies. These models usually require meteorological information (like precipitable water contents, or humidity), which are not yet implemented in the import and treatment of meteo data of PVsyst in the present time. We intend to do so in a rather near future, but we have still other priorities in the present time. NB: The instantaneous shifts may be important in some situations, but the annual balances are usually rather low. Except perhaps for specific technologies like CdTe.

When defining the Power factor, you can also define the corresponding Tan(Phi). You can simply define a negative Tan(phi). By the way in terms of Apparent energy, the result is exactly the same.

There is probably a problem in your system's definition, that I don't identify. Which version of PVsyst are you using ? Please send your whole project (using "Files > Export projects" in the main menu) to support@pvsyst.com

OK, I was not aware of this limitation of 400 trackers, and I have increased this limit to 1000 sheds or trackers. However such a number of trackers doesn't make much sense: if you have, say, 6m between trackers, this represent a width of the PV plant of 6 km. If you want to increase it you can simply define different arrays. Now if you have backtracking, it is quite normal that you don't have any electrical losses, as you don't have shading losses on the beam component (by definition of the backtracking strategy).

The format .h2p has been developed in collaboratioon with the Helios3D team, specifically for the import of helios3D files. It has not been published, and we don't intend to completely document it in a near future as it is still evolving, nor to support its use. Skelion has used it for their plugin, but without any contacts with us. PVsyst doesn't support the Skelion files.

Yes. The management of the grid limitation is indeed performed by the inverter's control circuits (the Power information at the injection level should be an input information for the inverter). The limitation itself is done by the inverter, and is considered equivalent to a limitation of the nominal power. We didn't define a special loss variable for that.

The diffuse shading loss is supposed to be "uniformly" distributed: you don't see any "shades" on the array due to the diffuse componrent. Now the elctrical losses are due to a mismatch when some cells only are shaded within a string (or an array). This cannot occur with the diffuse.

Please check that your inverter is correctly defined. This usually arises when the efficiency curve is not well defined.

As explained in the help, in PVsyst you should import the file "Obstruction Elevation" for import in the Horizon tool. However the "Far shading" loss is of course closely related to the horizon line you have imported. You can check that this horizon line as imported by your SunEye is correct, by measuring the altitude angle of some points of your profile (on site). NB: The Solmetric horizon profile will also include the near shading objects. The shades of near objects should not be evaluated by the "Far shadings", but by the "Near shadings" part of the software. Therefore you have to remove their contribution in the Solmetric profile if any (i.e draw a line of the "Far" horizon only).

This is not a problem of import, but just of display on the tables. The values in the program are not truncated. However decribing hourly values of irradiance with 0.1 W/m2 resolution doesn't make sense, as the measurements have a much higher uncertainty. The same holds for ambient temperatures specified with 0.01°C. Did you ever try to measure an ambient temperature with a thermometer ? Even with 1°C resolution the value will not be stable over one hour ! NB: The rounding errors of measurements are always randomly distributed: the variance on several measurements goes with 1/sqrt(n) (n = number of measurements). For one year (8700 values), this becomes 0.01 times your uncertainty interval.

The "Module Layout" part is not suited for such big systems. It should no be used for systems greater than 500 kW or 1 MW at most. See our FAQ With my big power plant, the calculation time is prohibitive.

The Ohmic loss is quatdratic (R * I**2). Please see our FAQ How to determine the wiring loss parameter?

Yes of course, PVsyst is able to perform simulations with arrays specified for 1500V or more (without limitation). However up to now, most of the devices were limited to 1000V. The limitations are at 2 levels: - The inverter definition: few inverters are specified for a Maximum voltage greater than 1000V. - PVsyst will forbid using a system voltage greater than the maximum voltage specified for the PV module. Almost all PV modules are specified for running in Arrays which don't overcome 1000 V (IEC specification). However you have more and more PV modules certified for 1500V in the PVsyst database. This limitation is in the PV module's definition, page "Size and technology", item "Maximum voltage IEC". If you want to modify this value, it is under your own responsibility on the field. The choice of IEC or UL limit during the sizing process is in the project's definitions "Albedo and Settings".

In both module, you have the same parameters (namely Rserie and Rshunt) and therefore the muVco calculated by the model is identical. NB: The muVco value slightly varies with these parameters, especially Rserie. But in your export to EXCEL, the column muVco corresponds to the value specified by the manufacturer. This value may have been specified differently. See our FAQ How to adjust the Voc temperature coefficient ?

I'm afraid that you have completely misunderstood this little visual tool. The blue line represents the PV module plane (as seen from the prolongation of the axis). The green branches are the normals to this plane. As anywhere in PVsyst, red dots are for dragging with the mouse. You can play with the red dots for setting the stroke limits, and then orientate the PV modules between these limits as you like.

Does the program crash or hang ? If it crashes, please send a screenshot of the error to support@pvsyst.com. If it hangs up, it is probably being computing. Please see our FAQ With my big power plant, the calculation time becomes prohibitive

C:\Program Files (x86) is the space reserved by Windows for the installation of programs. You cannot write anything here. By default when using PVsyst for the first time, the workspace of PVsyst (named \PVsyst6_Data\) is located in your personal working area, usually named "My documents" (or something like this). Now if you have really worked with this workspace up to now (perhaps it was allowed by Windows formerly), Windows has displaced your data, and you will retrieve them in your personal working area, in a directory named "c:\ Users \ User \ AppData \ Local \ Virtual Store \ ProgramFiles \ PVsyst6.0.6 \ PVsyst6_Data" (see our FAQ I don't find my files in the Data structure) You should create a new data structure \PVsyst6_Data\ in your personal area (using button "New" in the Workspace dialog), and displace your \VirtualStore\ data here.

The time of your data are probably not matching the time of PVsyst. And you have probably not followed the advice of PVsyst for checking the data quality when importing your data. Please analyze your meteo file in "Databases > Meteo Tables and graphs", page "Check data quality". Here you have performant tools for the analysis of your imported data, and you can press F1 for a complete explanation in the help.

For the angle's definitions, see our FAQ How is defined the plane orientation ?. The azimuth angle is your choice according to the environment of your installation. Now if you want to identify the best angle - or the loss you will have if you are not at the optimal angle - you can use: - either the little tool in the orientation dialog (button "Show optimization") for a quick but rough estimation. - or the dedicated tool "Tools > Transposition factor", where you can get better estimation, taking eventual Horizon or periods for optimization into account.

For comparing differences bvetween equivalent simulations, you should compare the "Loss diagrams", which will show exactly what is different in the behavior of your systems. In your case I can see 2-3 possible causes: - If the ambient temperatures are not the same, the Temperature losses will be different. - If the Diffuse component is different, the result of the transposition may be different. - If the Irradiance distributions are very different, the Irradiance losses may be different.