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Measured Data Analysis (Measured - Simulated Values)


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Dear Andrew,

I am currently trying to run a Measured data analysis using PVsyst V6.31. I am feeding measured SCADA data for a typical day (24 hr data) which is in 1 minute intervals using the post processing method. The Issue that I am facing is once the simulation is performed the EGRID value that I get is much lower than what the plant has produced measured on the meter for the day. There are some values on the CSV file generated after the post processed simulation that simply show a zero value, when I know there is a production during that hour.

Not sure if PVsyst accounts zero for any clipping hours. The plant is a 10 MWac plant and does experience clipping for some time in the day.

Please let me know if you can provide any feedback.


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First please check that your imported values are correct within PVsyst (using "Data Tables and Graphs").

And after that you should check that your simulation parameters are correct.

If you have intermediate measured values (like the PV voltage and currents), check that they correspond to the simulated equivalent values.

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Dear Andre',

I typically always check the imported values and ensure they match with SCADA values. There is no issue with that. Values such as Irradiance, ambient temperature and wind speed are fine. Also, the Eout Inv and Egrid values when verified using graphs and tables appear good. It's only that once the simulation is performed, I see a significant amount of Egrid data is lost and is shown as "Inverter loss over nominal inv power". However, I am not sure why that would happen and we are modelling the inverter correctly.

Also, I am not importing any PV voltage or current values or any other values

Is there a particular reason why PVsyst would show zero values for particular hours of the day in the CSV file that we review once the simulation is done.

Please find attached loss diagram where you will find a significant amount of data is lost over nominal inverter power.

Thank you for your help,



Sample result file of measured data analysis

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The problem is here in the inverter's definitions.

Please carefully check these definitions, namely for the nominal power and the operating voltage.

Please have a look on our FAQ Why sometimes the overload losses increase without reason ?

You can directly analyze the evolution of the different variables in hourly values, using "Hourly Graphs" in the Results dialog.

NB: I see that you have drawn this "Loss diagram" for a very short time (probably one only day). This may explain that the losses have not the same magnitude than on usual yearly simulations (for example for the temperature loss).

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  • 2 years later...

Dear Andrew,

I am currently trying to run a Measured data analysis using PVsyst V6.30. I am feeding measured data for one year (24 hr data) which is at 5-minute intervals using the sensor box of SMA inverter(there are some missing data). The Issue that I have a big difference between the simulation and measured data (current array, voltage array, the effective energy output of array, the effective energy output of inverter ), I check the data in using( "Data Tables and Graphs"), it give me an acceptable message.

Please let me know if you can provide any feedback.

thank you very much





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  • 1 month later...

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