dtarin
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Posts posted by dtarin
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Try changing the discriminating angle, set to 1 degree. See image.
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Hello,
I have a system with multiple orientations but only one sensor mounted for one orientation collecting POA irradiance at a one minute interval. Is it possible to use this POA irradiance to calculate GHI, and then use this GHI to calculate POA for other orientations? Or can I convert directly from one POA to another?
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It would be helpful to add a timer to the hourly simulation progress, or include it in the output file(s). For long simulations, it would help budget time and plan work accordingly.
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Hello,
I just upgraded to 6.6.2, and I am missing the options to add variables to my simulation output and also in batch simulation mode.
Thank you.
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Hello,
I am running a simulation with an OND file that had a night loss parameter. I set this value to zero and saved the OND file, variant, and project. When I run a batch calculation though, the runs are all done with night loss still there. When I run a single simulation, the night loss is not there in the 8760 data.
Thank you.
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There is no straight answer. Dimensions for a table depends on different factors like cost, the conditions of the ground, type of racking, type of modules, size of system, etc. Sheds will give you a more accurate estimate when partitioning into strings and calculating electrical loss due to electrical effect; the table method will slightly underestimate this. Tables give more flexibility in being able to position on top of ground objects, you can use them in zones, etc.
If you zone is very large, it could be why it is crashing. Break it up into N zones, get one section into position, then work on another. Once created, you can copy all the modules and paste and position. Also if you provide images it can help to provide an answer.
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I am referring to other parameters of a PV table/shed, like the inactive band size or module spacing.
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Hello,
In the new shade scene construction, it gives an option to select the module for that shading object. I have a project with two different modules, and the shade scene seems to pick which module is attributed to which array by default, and does not change. If I select the module it is not defaulted to, it reverts back. Is this a bug, or is there something I am not doing or understanding correctly?
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abdulrahman95 ,
Is this what you mean by curved suface?
You can create a ground object which matches the terrain, then create a zone of tables/modules on top of the ground object, and then select position tables on scene. This doesnt work for every PV field (ie tracker).
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The measuring tool was modified in the newest release, and I think it is now missing one of the most useful features. It does not lock onto objects in the same manner as before, such that when you snap it to two corners and move one of the objects, it does not stay locked and show you the distance as it changes. Placing objects around the array or setting the pitch for PV sheds/tables make use of this now missing feature.
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Hello,
Is it possible to modify the module type for more than one PV table at a time? Selecting multiple and pressing ctrl+m to modify does not work for me. For complex array layouts with many independent sheds, this is a very tedious task. Using 6.6.1.
Thank you.
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I have also had an error in 6.61 importing ground images. The image covers up the array, but does not cover objects like trees or buildings.
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There is an error with the units display. Although the label reads MWh, the values are in GJ. There is a factor of 3.6 between the two (1MWh = 1MJ/s * 3600s = 1GJ * 3.6).
I will fix the error and post from which version on the fix applies.
A comment on the work-around proposed by nickSHIFT:
You can also retrieve the results from the Optimization tool in Excel. They are stored as CSV files in the PVsyst workspace in the subdirectory 'UserOptimization'. The file names are constructed from Project name, Variant Id, Scan Name and a counter. In those files, the energies are given correctly in kWh.
It would be nice if the units were included in the column header.
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A fraction of these 4-5 % might result from a change in the transposition model from Hay to Perez.
btw: how is it possible that an "identical simulation" delivers a non-constant result like "4-5 %" is...every run should deliver the same result.
I have seen older versions of PVsyst project higher losses compared to newer versions when running the same project.
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Hi Andre,
The PVsyst help section states, "...you should be aware that the resulting simulation will not be valid for the first production year..."
Could provide some additional information or explanation on why the light-soak gain is not valid for first year energy? I was thinking it might have to do with the time it takes to stabilize, but would like to hear from you on the matter.
Thank you.
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Hello,
According to this page, http://forum.pvsyst.com/viewtopic.php?f=20&t=1594, it states, "...Now it is often believed that when the bottom cell row is shaded, the by-pass diodes will limit the electrical loss to the sub-module row, i.e. the string electrical production will remain 2/3 of the normal production. This is only true (about) if you have one only string per MPPT (violet curve)..."
With microinverters, we have one module/string each with its own MPPT. Is it correct then to create the partition size in the shade scene based on the submodule size, as in for a single module, creating three strings in height x 1 in length?
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Thank you for the reply. The help does not provide much guidance in determining this weight factor. I am more concerned with how and when to utilize the according to module method for calculating shading losses. I cant seem to get an answer on if it is the most accurate method to estimate shading losses, or if it is something else. If the according to strings method is the upper limit, is the according to module layout the lower limit, and the best estimate somewhere in between?
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Is using the method you described above a reliable or accurate method to generate global incident energy for multiple orientations? I have sites with multiple orientations but only 1 weather station, so I am curious to know if this can be used to create a simulated POA for system performance testing for multiple orientations.
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Thank you for the reply, that was my guess for approaching the implementation (hadnt gotten to trying it out).
As for your comment on overproduction, I cant think of a way to test or benchmark this. Perhaps Andre or someone at PVsyst with a better understanding of what is happening could comment on this.
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SAT Layout
in How-to
Hi Andre,When I try to model near shadings for a utility scale system (100MW+, tracker with backtracking)....
There is a setting in hidden parameters you can set to get rid of this error, so your 1MW block can be used for a 100MW plant. See attached.
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How accurate is this method - creating a dummy multi MPPT device? I have a PE inverter which is being spec'd with two different modules, but does not have the multi mppt capacity. How do you size the number of MPPT inputs when doing so, is it just arbitrary?
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Andre,
Do you have any comment on why there is at times a large difference between the according to module layout and according to strings method, and which is the most accurate method of approximating shading losses? I have rooftop systems where the according to strings method projects shading losses 1.5% to 2.0% higher or more compared to according to module layout. For an entire portfolio, this is significant.
I have read elsewhere about running both methods: 100% elec. effect according to strings and module layout, finding the ratio between the two, and using that as the new electrical effect. Is this the proper method for utilizing the according to module layout method? Am I misunderstanding the use of the according to module layout method as a standalone method for calculating shading losses?
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Inside the ZIP file is the MEF file. You will need to extract that into the meteo directory. You will need to have a site created first for your location. Then you will go to Import ASCII meteo file, under ASCII source, select your PSM weather file, change your names if necessary under "Hourly file to be created", and under conversion, select the MEF file (I have named it NREL PSM 5, but you can rename it to anything), click start conversion.
You will want to see 1990 grayed out in reference year. After you convert, view the meteo file and check the quality. You will most often need to implement a time shift. Re-run the conversion by adding the time shift by opening the conversion template and entering the shift under the date tab. Sorry if this was very brief or repetitive.
Saving simulation output 6.6.1
in Problems / Bugs
Posted
Hello,
From the simulation menu, I press output file, and then I select to change file. The file type that is shown is a MET File, and I cannot see other csv files in the directory. See attached image.