André Mermoud

You have obviously some limitations in voltage and power when using an inverter. And also some reasonable conditions. Your array of one string of 8 modules represents 1.16 kWp. This is obviously not suited for an inverter of 4.6 kW. PVsyst puts some reasonable limits. Now when increasing the number of modules is series, you overcome the voltage limit. You should put several strings in parallel instead.

This depends on the Manufacturer's conditions of course. To my opinion, if the inverter is correctly designed, there is no reason for limiting the nominal power of the connected PV array, because the power limitation is ensured by the inverter itself, by displacing the operating point on the I/V curve. Now if this condition is marked as contractual in the datasheets, you have to observe it of course. You have a checkbox in the PVsyst definition of the inverter, indicating whether the condition is contractual or not. If checked, PVsyst will not allow to design a system overcoming this condition.

Sorry, this error message is erroneous. Probably your import has not been successful, the MET file doesn't hold any data, and result in this error message. We have worked a lot for improving this importing tool in the next version 6.71. In order to help us understanding this problem, please send us your source file, the *.SIT file used for the import, and your *.MEF formatting file. Send them to support@pvsyst.com.

GlobInc is the irradiance on the plane, calculated by the transposition model. GlobEff is the irradiance effectively falling on the PV modules, after optical losses like shadings, IAM or Soiling. You should compare with GlobInc of course.

Probably your Meteo file is not complete. The optimization of the transposition factor can only be performed on a complete year of data. Now be aware: there is a bug in the version 6.70: the transposition factors plot (optimization) crashes. You should revert to a previous version for getting this plot, sorry.

You can get a lot of solar geometry results, for any location, in "Tools > Tables/Graphs of solar parameters".

We don't know this problem, we have never observed such a strange behavior. The problems with CSV files produced by PVsyst are usually due to bad settings in your EXCEL (decimal character, separator, date format, see "Internationalization" in EXCEL and Windows). This case seems really strange. Please send us your full project, using "Files > Export projects" in the main menu. Address it to support@pvsyst.com.

Some people will perhaps like to have an average.

If this was the last error in PVsyst, we would be very happy. Would you be more rich when you get one Euro when your fortune is 449'000 euros ?

The only gains of yield in tracking systems are due to the plane orientation of course. These are correctly evaluated in the different tracking options of PVsyst. There isn't any reason that your PV module behaves differently in Tracking systems. This doesn't make sense to modify the PAN file parameters for such applications (nor for any other application).

Please read my previous post ! Here you have an inverter with VmppMin = 280V and VmppMax = 550V. And defined efficiency curves for 280, 480 and 600V !

This is not a bug. For normal sizing, PVsyst has opted for an hypothesis of limiting the overpower losses at 3%. However when you want to oversize the PV array, this limit is adjustable in the project's settings. See our FAQ Can I define a system with highly undersized inverter ?

In PVsyst you can define up to 8 different orientations. Some of your roofs with a same (or very simular) orientation may perhaps be grouped. Otherwise you should define several different variants, and add the results at the end.

In your first plot you have a "line of points" indicating that a string is not working. You should remove these points for the statistical evaluation. Now the scattering of the data may be due to a lot of different causes. The first one being the Measurement's quality (and especially the meteo).. You have several tools in the "Measured Data Analysis" for analyzing the discrepancies as function of different parameters, in relative or absolute values, as function of time, etc. This should allow to identify the phenomenons (or simulation parameters) causing these discrepancies.

This depends on the system you have defined of course. With tracking systems you will see the involved parameters. If you see "profile angle", you are probably in a sheds system.

Your explanations are correct. However the mismatch between the performances of each modules have nothing to do with the sahdings. For the mismatch due to modules: in the "Detailed parameters" dialog, please see the tool "Mismatch > Detailed computation". For the mismatch due to shadings, please see the graph in the "Module Layout" tool, page "Shading3D": press "calculate" and have a look on the I/V curves.

There may be several situations: - PVsyst doesn't treat hours with GlobInc < 10 W/m2 (remember that a very covered weather corresponds to 40-50 W/m2). - The inverter may be under its operating conditions. Please have a look on the inverter losses (IL_PMin, IL_VMin) for these particular hours.

The separators are not recognized. In EXCEL, you have a tool "Data > Convert" for importing data which are not recognized (select the whole column before using this tool).

You should choose the part which gives the higher losses in your system. By the way you can specify (add) an equivalent part corresponding to the other side if necessary.

This is not possible, and really not very common. We won't implement such a possibility in PVsyst. You should find another way of comparing your data (the total price instead of a specific one for example).

The help gives the list (and properties) of almost 20 popular data sources that you can directly import in PVsyst: See the help "Meteo Database > Notes on Meteo > Meteonote2_Meteorological data sources".

You can simply reinstall PVsyst. You should not "work" in the C:\program files\ area, which is pror^tected by Windows.

This percentage concerns the I/V curve calculation for one sub-module. It means that when 1 corner is shaded, 10% of the cells are shaded, 33% of the cells when 2 corners are shaded, etc. This affect the I/V shape of each shaded submodule. By the way this real shape has almost no impact on the full sub-array shaded I/V characteristics. Only the number of shaded sub-modules - whatever the number of cells shaded - is significant.

The calculation of the IAM loss on diffuse is based on the hypothesis that the Diffuse is isotropic. This means that the diffuse irradiance contribution is the same whatever the direction of the sky. Therefore we can calculate an integral of the IAM loss (function) over all the sky directions "seen" by the collector plane. This integral is independent on the sun position, as well as the goegraphic location. This is a constant value, only dependent on the system geometry.

There are 2 input current limitations in PVsyst: - At the sizing time: some manufacturers specify a maximum ISC current (or sometimes a maximum PV power) for the array to be connected on the inverter. To my understanding, this doesn't make much sense as the inverter is normally able to limit the input current (or power) by itself. The only cases where this should be respected are when this is a contractual condition, which affects the warranty. This will provide an error message, and the prohect cannot be created as such. - During operation, up to now there was a input parameter of the inverter "Minimum Voltage for getting Pnom". This corresponds indeed to an input current limiting, managed by the inverter. Since recent versions of PVsyst, this current limit may also be explicitly defined, alternatively to VminPnom. These 2 varialbes are closely related: Imax * VminPnom = Pnom !