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Problem with generating Meteo file from ASCII file


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Hello dear forum members,

I have mesured data for one day with a time step of 10 minutes. I am trying to generate the Meteo file from this data using "Import ASCII meteo file" in "Tools". I have already defined site parameters and the format protocol file. The conversion is successful but with a warning message:


"The clearness index of the best clear days is very low by respect to the clear day model"


Can this be because of the reason that measured data is only for one day??

The generated file is XYZ.MET that is stored in the PVsyst directory structure that is copied to D: drive.

When I try to add this meteo file using

Site and Meteo
, as soon as this dialog box opens, the XYZ.MET is automatically deleted from
directory. Every time, I try to open the dialog box of
Site and Meteo
, the meteo file is deleted and I have to create it again and again.

Could someone please suggest some solution for this?

Best Regards

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  • 4 months later...
I'm a new user, in the U.S. midwest. I have found that the simulation results are significantly different (ie. 13%) between Lat/Long generated NASA-SSE (synthetic) and TMY3, which i believe uses NREL data. Two questions: is this kind of variance to be expected between simulations using these different data sets? And is there a generally accepted viewpoint of which of these sets of data are considered to be more accurate?
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  • 3 weeks later...

Yes of course, the sample is not sufficient.

This test is meant for a one-year dataset, it compares the best days in the data with the clear day model for getting an estimation of the quality of the data (namely the solarimeter calibration).

For the discrepance between data, please see the help of PVsyst: "Geographical and Meteorological data > Import from Meteorological data sources: Meteorological data comparisons".

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