Linda Thoren

The inverter efficiency depend on a certain extent on the DC power. In the .OND file, in the Efficiency curve tab you can see the relation between the inverter efficiency and the Power in the DC circuit. The efficiency is then calculated in hourly time steps in the simulation and monthly averages of the total production is shown in the report. The PR is also calculated in hourly timesteps and monthly and yearly averages are shown in the report.

Dear Rajesh saha, Your understanding is correct! At the moment the temperature and the losses due to high temperatures are not being considered at the transformer level, these are parameters we might include in future versions. So if your transformer will operate at 50°C, you should use the values for these conditions. Kind regards

Hello, In the current version of PVsyst it is not possible to use multiple orientations in a standalone project, this will be possible in the coming version 8. For now you can simulate your project as a grid connected system with multiple orientation and in the storage parameters, not allow injection to the grid. In case your result includes energy from the grid to fulfill the users need, that should be considered equivalent to missing energy in a standalone project. Kind regards

Hello, The yearly production from your system is much larger than the consumption. If you do not allow injection to the grid there will be a lot of losses even with battery storage. In your calculation you say you need a storage system of 20kWh but in your picture you have defined a storage of almost 20000 kWh. With such a large storage and low charging and discharging power PVsyst gives you this error message. You can also see in the system information for instance that you have defined your system so that discharging under maximum load will take 20359.5 hours.

Hello Mohamed Abdelkader, Thank you for your question. It is not directly clear why this number change, it is likely linked to the Global capacity (C10) used to calculate the stored energy at 80% DOD in the definition of the storage pack and that some definition or values might be different when this value is estimated for the characteristics in the report. The possible difference in capacity depend on for instance the discharge rate, see the graph below. Thank you for highlighting this, we will look into it.

Hello, PVsyst does not have any default numbers or recommendations and regarding the temperature shift. The temperature shift can depend on various factors such as characteristics of the inverter, your installation method and site.

Dear Solaranger, Indeed the values here looks a bit strange. Please send your project file to support@pvsyst.com and we can have a closer look at it. Kind regards

Dear Joaquina, The warning message indicates that the Max. charging power is too high and that you should consider increasing the battery capacity or reduce the charging power (by reducing the charging power you are increasing the c-rate). This is a limit that you can change in the advanced parameters. If you have a Lead-acid storage the minimum charging/discharging rate is set to 2.5 hours. you find these parameters in the category Verification on Grid systems (#815 and #816 for Lead-acid Storage) Kind regards

Dear Madela, The Global incident in collector plane (GlobInc) measures the solar radiation received on a surface that is inclined or tilted in [kWh/m2] (compared to the Global horizontal irradiation (GlobHor) that measures the total solar radiation received on a horizontal surface, such as the ground). The GlobInc is the result of the transposition from the GlobHor from the meteo data. Thus changing the tilt or the azimuth will change the GlobInc, but it will not be affected by the size of your system given that the value is normalized (given in energy per unit area) In the Orientation window, you can see a quick optimization of which plane tilt and azimuth that results in the highest Global on collector plane at your site. Kind regards

Hi Auxi Madero, Very true! In the Pan file, in the Additional Data, Degradation you can change the Global degradation factor on Pmpp. Normally this value is indicated per year in the panels data sheet, and should for 10 years be a value of something in the order of magnitude of 3.8%. By modifying the PAN file and saving it with a new name, you can create your project with the two variants of panels. In the Detailed losses window, in the Module quality - LID - Mismatch tab you can also increase the Module mismatch losses for the sub-arrays with the degraded modules. Kind regards

Dear Main AlBataineh, I assume you are using the aging tool in the advanced simulation. If the production year 1 in the results in the aging tool is slightly lower than in the results summery, it could be because the aging has not been defined in the detailed losses. If you in the detailed losses window, in the Aging tab have not ticked the box "Uses in simulation" (see screen shot below), the simulation will not take the aging into account. If you in the detailed losses window under the aging tab have defined the aging parameters, the produced energy that defined year, should correspond to the value that same year in the aging tool in the advanced simulation. Kind regards

Dear Auxi Madero, In detailed losses, in the Aging tab you can simulate the degradation of your system after 10 years, though only for your entire system. To get around this you can divide your project and run one simulation for the already existing system and a second for the new additional part. Kind regards

Dear hvf, The grid limitation is reflects a scenario where the grid manager impose a limit to the injected power to the grid. If your system at certain moment produce higher then this limit, it will be managed by the inverter as a clipping loss. There is a help page here explaining this further: https://www.pvsyst.com/help/grid_power_limitation.htm The power factor is the ratio between active and apparent power, i.e. Cos(phi) and does not limit the power to the grid at a certain threshold. The active power is the power obtained along one sinus period, when we integrate the product of the instantaneous Voltage by the Instantaneous Current at each time step. This results in a multiplication by the cosine of the phase shift: Pactive = Ueff * Ieff * Cos(phi) expressed in [kW]. The reactive power is the vectorial difference of these contributions: Preactive = Ueff * Ieff * Sin(phi) expressed in [kVAr]. Following help page explain the Power factor further: https://www.pvsyst.com/help/power_factor.htm Indeed, if the Nominal AC Power is defined in Apparent power in the inverter file, the two variants should give similar results. To assist you further please provide us with the loss diagrams for the two variants, or send your project to support@pvsyst.com Kind regards

Hello Sascha, By using the mixed orientation option, all the strings are the same lengths and by increasing the numbers of strings, you then increase with 16 panels every time. You have more liberty if you define sub-arrays, you then assign each sub-array to an orientation/inverter/MPPT. In the Sub-array name and Orientation dialog you can define a name of your sub-array and the orientation, in the generic example below I have 2 orientations, 3 subarrays in the first orientation and 1 subarray in the second orientation, see the list of subarrays to the right. You can create a new subarray, or copy a subarray by using the first two icons under the list of subarrays. I also activate the use multi-MPPT feature for this example and I activate the power sharing. Using these features I have defines a global system with 2868 modules and 9 inverters (1588 panels and 5 inverter in orientation 1 and 1280 panels and 4 inverter in orientation 2). I hope this example helps you to define your system. If not please send your project to support@pvsyst.com Kind regards

Dear Sascha N. By creating subarrays you can define different amount of panels per string, different amount of strings per MPPT, orientation etc. This gives you a large liberty to define exactly the amount of modules required. You find the list of subarrays to the right in the system window. I hope this helps, if you wish for more precise assistance, please provide us with more information of your system. Kind regards

Hi, Make sure you have ticked the alternative "Show P50-Pxx values on main results page" in the "Display on report" box in the P50 P90 window, see below. By generating a report, your main result will include also the specific production for the defined Pxx. See below the report of the DEMO Residential system at Geneva. Kind regards

Dear Andel, If you have defined the P50, P75 and P90, the specific production in kWh/kWp/year for the given probabilities is printed under System Production in the Main results page. Kind regards

Dear Cleyson, Thank you for your question. In the simulation, the inverter derating will depend on the inverter temperature. By default, the inverter temperature is the same as the ambient temperature, but this behavior can be changed in the Energy management tab. 1. In the OND file in the Output parameters, it is the Inverter's temperature that is indicated. With an increase of temperature, the Maximum Power is often limited. These values are defined by the manufacturer in the datasheet. In the case the temperature exceeds the threshold of where the power is limited this will be taken into account in the PVsyst simulation as an (extra) overload loss 2. Energy management a) External ambient temperature thus assumes that the inverter has the same temperature as the outside. b) External ambient temperature with shift allows to define that the inverter temperature will follow the ambient temperature, plus or minus a constant value in degrees that is defined as the "Temperature increase". For example if you define a temperature increase of 5°C, and at a given time the ambient temperature is 38°C, then at that time in the simulation the inverter temperature will be 43°C. c) Fixed temperature, correspond to the case the inverter is placed somewhere with a fixed ambient temperature (for instance inside with cooling) with a possibility to increase the temperature according (proportionally to) to the irradiance on your field, i.e. the power generated. In the meteo file for your site, the ambient temperature and irradiance are available and according to your definitions in the energy management tab, the inverter's temperature is estimated. The simulation will consider the limiting effects on the inverter at high temperature according the the output parameters in the OND-file.

Dear Michalis Angeli, You can change the template or create a new file with hourly timesteps as long as the csv file follows the required format. The date should be in the first column and the time format must contain the day the month, the year as well as hours and minutes. The load should be in the second column with the unit of the load specified in in the second row of the second column. Kind regards

Dear Arnon, In the detailed losses tab you can define the size of the DC wires, the losses due to the DC wiring is printed in the report but not the size of the wire. One option could be to add a Variant or Project note where you indicate the size and tick the box to include the notes in the final report. Kind regards

Hello, In the case of your first 5 inverters where all strings are the same, there is not necessarily a need to use the multi-MPPT feature and the power sharing, you can simply define the entire inverter. But of course you can also define it the way you have explained it. For the last inverter with different number of modules in series you should activate the Use multi-MPPT feature and define two sub-arrays, one with 1 MPPT input 4 strings and 28 modules in series, and the second one with 5 MPPT inputs 20 strings and 27 modules in series. By using the Power sharing, you will be sharing of Nominal Power between MPPT inputs of the same inverter. In the following links you can read more about the MPPT feature, and an example of a configuration using the MPPT feature and the power sharing: https://www.pvsyst.com/help/multi_mppt_use.htm https://www.pvsyst.com/help/powersharing.htm https://www.pvsyst.com/help/multi-mppt_more-examples.htm Regards

Dear Sheriif, The CSV file must follow a certain required format, you can see how they are supposed to be formatted in the templates. The date should be in the first column, it must contain day, month, year as well as hours and minutes. The load should be in the second column, with “Load” written in the first row and with the unit of the load specified in the second row. You can see find a tutorial for the self-consumption in the link below: https://www.youtube.com/watch?v=-PGRnnF1VuA

Dear Tormi Teedemaa, This is a PV module that you have defined yourself or imported from manufacturer. It is possible that some parameters are not well defined. Moreover, the choice of inverter should be based not only on the power but also for instance the operating voltage. In your print shot you you have only 1 module in series and 666 strings that is resulting in operating condition for your system of 31 V at Vmpp (60°C) when the inverter you have chosen has an operating voltage between 180-1000V, thus the error message in your print screen. By clicking the Sizing button, you can more clearly see the different limitations in your system. Kind regards

By clicking on the Sizing button you will see a graphic with the Array Voltage Sizing, showing the different limitations to consider when choosing inverter and sizing your system. You can consider choosing another inverter with another voltage range. An orange message is a warning, but you can still run your simulation.

Dear Michalis Angeli The error message indicates that the inverter power is strongly oversized, with a Pnom ratio of 0.5. The Pnom ratio is the ratio between installed Nominal PV Power (125 kWp) and the inverter (250 kW). Normally the Pnom ratio is around 1.25. You correctly use the subarrays, MPPTs and Power sharing, though the installed Nominal PV Power is too small compared to the inverter. Regards