P50 and P90 userhourly CSV

[Thet]

It can be possibel to create  both P50 and P90 userhourly CSV  seperately?.If yes,how to create it.Thank you for your support .

[dtarin]

Two ways. One, you can use a weather file which corresponds to each, or two, using a standard TMY weather file, calculate your P90 factor, and multiply your P50 8760 data with it to get a P90 dataset. 

Edited September 30, 2022 by dtarin

[Ishan31]

@dtarinDoes P90 factor mean Annual generation P90 / Annual generation P50 ? 

[André Mermoud]

Yes, in this case, this is the ratio of the annual values. 

In fact, the P50/P90 statistical evaluation only make sense when you compare yearly results. These notions  don't apply to hourly or daily values,  and hardly on monthly values.

For example for evaluating the P90 of the results of, say, January, you should avail of a list of January values from many years, and calculate the standard deviation of this sample. This will obviously be far larger than the yearly variability. This doesn't make sense. 

Now applying the P90 factor to each hour of a  climatic data file is not correct. This would mean that each hour of a clear day would be diminished by this factor, which is obviously not the case. The P90 factor will induce a difference in the distribution of the bad and good days, not the absolute values of irradiances.  

The only way to get P90 hourly values is to use a TMY weather datafile specifically constructed in this way. I.e. choose periods for the TMY construction which result in a P90 predefined yearly sum. This file may be completely different than the original P50 weather file.