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Everything posted by dtarin

  1. Either is correct, you can enter 3 and average the no-load and full-load loss, or add them into one. Since you have combined the MV ohmic losses into a single loss, I suggested to do the same with the transformer, perhaps a bit more accurate instead of averaging them, since pvsyst is using the total power into the transformer
  2. Your total power loss is 0.106%. The first segment carries 1/3 of the total power. The second segment carries 2/3s. The final segment carries 100%. That is total loss for the entire plant. Enter that for the MV ohmic loss %.
  3. Calculate the weighted average and enter 1 transformer. If you have the no load and full load losses for the transformer add them together when entering 1 transformer
  4. If the user selected a backtracking pair under the backtracking management menu prior to computing the initial shading table, is there still a possibility for this to occur? Typically I do not generate the shading table from the shading menu, and instead have it compute during the simulation process. Is there any difference? One last question, what is the approximate error in % you are seeing?
  5. The the auto button in power-sharing screen to balance Pnom ratios.
  6. What I have found helpful for custom PAN files is to rename the manufacturer to something else in the PAN file, such as my company name or custom or "[manufacturer] custom", so they don't show up mixed with the regular 3rd party or manufacturer PAN files.
  7. Thank you for the link, haven't needed to use this in a few years.
  8. There are a number of ways to import your own data if you just want to look at terrain arbitrarily. Here is one. https://portal.opentopography.org/datasets
  9. Add "dummy" mppt inputs by modifying the OND file of the inverter. You can add for example two (2) mppt inputs if it is a 50-50 split, add one subarray with (1) mppt and the second subarray with (1) mppt, which will be equivalent to one inverter. Go into power sharing and allocate it evenly. If it is a non equal split, for example module A is 70% and module B is 30%, then add ten (10) mppt inputs to the OND file, and allocate seven (7) to subarray A and three (3) to subarray B. There looks like a bug though, I am not seeing the information being generated in latest version. Should there be something displayed @Michele Oliosi? I have an unequal number of strings for each subarray and different ratios, but when I click enable power sharing, nothing really happens.
  10. Mismatch loss is not calculated, it is entered by the user under detailed losses menu. Mismatch due to differences in IV characteristics is relatively low, but it is one contribution to mismatch losses; temperature and irradiance differences also contribute to mismatch losses.
  11. These are not equivalent models, so the comparison with GHI is not a valid comparison. The locations are very different, as Michele noted, the site by the equator has an optimal tilt around 6-7 degrees which means you are limited in your POA transposition gain. The Santa Catarina site is further from the equator and realizes a higher transposition gain from the 27 degree tilt, which makes up for the lower GHI by comparison. It also has a lower temperature loss compared to Ceara.
  12. Is there any documentation available detailing the capabilities and restrictions for the PVsyst trial?
  13. They are in different locations, and you have different tilts. Without knowing these and overall orientation details, no.
  14. These are not equivalent models. The global incident in collector plane shows a 7% gain for sim#1, whereas it is a loss in sim#2. Something is off with the orientation or shade scene. Additionally, there is a large difference in ambient temperature, and sim#1 has a lower temperature loss compared to sim#2. The latter you can do nothing about.
  15. It does not update DC/AC ratio. In order to check, look at the 8760 at the inverter output. Ensure that PF is being applied such that it matches the PNOM definition in the OND file.
  16. If it is a P90 weather file, then you are correct, do not include interannual variability or any additional uncertainty for the weather resource. You will just need to include the additional sources of uncertainty in the simulation (soiling, mismatch, etc). The P90 weather file already includes in its construction the interannual variability and the solar radiation model uncertainty.
  17. If your shade scene has independent trackers (importing from .PVC or using zone creation), you always need to select the pair. Since you have specified the same pair for each variant, now your elec. effect losses are equal. However, be sure to select a representative pair of trackers. Calculate the weighted average tilt for all trackers, then select a pair at that tilt. The phi limits might be a display bug. I have a model with no terrain and it is showing the same phi limits (+/- 79.9) on the backtracking strategy for a +/-60 phi range. However, if you check your 8760, you will see the trackers do not exceed the input phi min/max, in your case, +/- 55.
  18. In the shading scene, which trackers are selected under backtracking management? Have you selected the same trackers in both instances? This can have an impact shading calculations.
  19. You can only have one module in one sub-array, but you can have multiple sub-arrays and multiple modules into a single inverter. The inverter will need mppt inputs defined, and then allocated per each sub-array. See previous threads:
  20. It depends on the weather file you are using. What is your weather resource? If it is a standard TMY file, it is a P50 estimate. Whether it is gross or net depends on if you have included all loss factors for your system, i.e. AC losses, transformer losses, night and auxiliary loss, degradation, etc.
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