Jump to content

Lazare Fesnien

Administrators
 View Profile  See their activity

  • Posts

    238

  • Joined

  • Last visited

 Content Type 

Posts posted by Lazare Fesnien

    Minimum parameters for energy injection to the grid

    in Simulations

    Posted

    Hi,

    You can limit the power injected into the grid by indicating a limit from the "energy management" tab then "Grid power limitation".

    If this doesn't suit you, you can restrict the AC output power of your inverter by modifying the "Pnom" and "Pmax" values from the OND file.

    The production begins as soon as the MPP power is over the power threshold Pthresh of the inverter. The MPP power below this threshold is accounted as IL_Pmin loss. It is usually less that 0.1% over the year.
    PVsyst doesn't manage a Voltage threshold, as the Array voltage is not very dependent on the irradiance. Even with a very low irradiance, the array MPP voltage becomes significant.
    The Pthresh power may be understood as the power required for the Inverter internal circuits consumption.
    Some manufacturers claim for a very low threshold. We can observe that 0.5% of PNom would correspond to an irradiance of 5 W/m²  (with respect to 1000 W/m²). Please remember that by very covered weather we have already 30 to 50 W/m² !

    Please read our FAQ :https://www.pvsyst.com/help/inverter_inputmodel.htm?zoom_highlight=power+threshold

    Thermal Loss Factors - Uc & Uv to be considered in PVSyst for Floating PV Plants

    in Simulations

    Posted

    Hi, 

    In PVsyst there is no specific parameter for simulating floating PV installations. You might consider using a modified ambient temperature to account for the fact, that close to the water surface the temperature is generally lower during the day. So far I have not seen systematic studies on this, and there is no published model to account for this effect, so the best you can do, is to perform a direct measurement yourself.

    In PVsyst the relative humidity is only used to estimate precipitable water, in order to perform a spectral correction. This should be the humidity in the atmosphere above the PV installation and not the local humidity close to the PV modules. Therefore it should not change whether you have a floating system or a ground-mounted one.

    The albedo of water is generally lower than the one of land, so you might adapt this in the project parameters.

    PVsyst has no model to simulate the waving effects of water.

    How to set the active power setpoint in the PVsyst?

    in Simulations

    Posted

    Dear YajMarc,

    In PVsyst, the Power factor may be specified by pressing the "Energy management" button, either as Cos(phi) or as Tan(phi). It may also be specified in monthly values.

    This will act on the inverter Pnom limitation if specified as Apparent power limit, and the apparent "energy" is mentioned on the loss diagram.

    Please read our FAQ : https://www.pvsyst.com/help/power_factor.htm?zoom_highlightsub=active+power

    Detailed losses Ohmin Losses Tab

    in Simulations

    Posted

    Hi,

    For the DC part: there is indeed a tool for a quick evaluation of the array's resistance in rather simple cases.

     This may involve combiner boxes. Please see "Detailed losses > Ohmic losses > Detailed computation".

    But if this is a complex layout, you can also calculate the wires resistance by yourself, see the help  "Project design > Array and system losses > Array ohmic wiring loss".

     For the AC losses after the inverters, you have to define wire lengths and sections between inverter, transformers and injection points. You can do approximations if you have more complex circuits with combiner boxes.

     NB: we are preparing a tool for drawing the shema of the installation, which should be available soon.  

    Different string configuration with solar inverters in stand alone

    in How-to

    Posted

    Hi,

    With stand-alone systems, PVsyst doesn't define an inverter yet.

    The user's needs are handled as an energy at the output of the system (DC).

    If you want to include an inverter, you should do that externally (in your EXCEL for example), by taking the efficiency into account.

     

    Sorry,  with stand-alone systems, only one sub-array is possible. Therefore one only orientation.

    This is a limitation of PVsyst, that we should improve in the next months.

    How can I solve this System Output Power Distribution problem?

    in Simulations

    Posted

    Hi,

    If the message "The inverter power is silightly undersized" is in orange, this will not block the simulatio. 
    This just indicates that the wiring isn't optimal. Otherwise, you can increase this value from the advanced settings.

    When editing the plot in  « Detailed  results > Predef. Graphs”, you have an up/down button for adjusting the scale:

    In this graph, the las bin contains the whole energy delivered when in overload conditions. It my be very high.

    Battery Performance

    in How-to

    Posted

    Hi,

    PVsyst performs the simulation taking into account that the battery is full on the first day.

    Two parameters can be configured : 

    • Initial State of Wear (nb. of cycles)
    • Initial State of Wear (Static)

    You can export variables as a time file from the "output file" window (advanced simulation"

    Data not yet defined

    in How-to

    Posted

    The required format for the importing of hourly parameters in PVsyst  is the following:

    • Text file (CSV format with commas or semicolons) written in ANSI  (not UTF8)
    • All lines beginning with the hash symbol '#' are assumed to be comments, and will be ignored
    • Blank lines are ignored
    • The first line that does not start with #, holds the column titles. The first two columns should be "Date", and "P Load", further columns are ignored
    • The following line contains the units of the data in the columns. The date should have no units, the units for the load can be power ([W], [kW] or [MW]) or energy ([Wh], [kWh] or [MWh])
    • Then there follow the lines with the values, one line per data entry
    • The date and time in the first column can be given either in European format (DD/MM/YY hh:mm) or in US format (MM/DD/YY hh:mm)
    • The file should contain all hours of a generic year (from  01/01 at 00:00 up to 31/12 at 23:00). Only day and month will be retained, the year will be ignored
    • These dates/hours do not need to be related to the dates of your input meteo file: they are for each hour of a generic year

    If you are blocked, you can send us your excel file to support@pvsyst.com in order to look at it and help you.

    Simulation for a multi-orientation PV arrays in a hilly terrain

    in How-to

    Posted

    Hi,

    1st option :
    You ignore your land and you define in the "orientation" window then "several orientation" the Tilts and Azimuth characteristics of your sub-fields.

    2nd option :
    Design your project and go to the 3D scene:

    • Import your terrain with topology via a CSV file
    • Draw your areas to fill with PV module.
    • Use "Automatic Tilt" options
    • Fill your areas according to your needs and projects

    With this technique, PVsyst will automatically detect the Titls and Azimuth characteristics of your sub-arrays and will propose to automatically update the information in the "orientation" window.

×
×
  • Create New...