Linda Thoren

Indeed, the second screenshot indicates a Voc(-15°C) of 50.0 V, though the Internal model result tool at TOper of -15°C results in Voc of 49.6 V. On the "Basic data" page of the PV module's definition, the frame "Internal Model result tool" allows to display the main electrical characteristics under chosen operating conditions. This tool is only informative. It doesn't hold any parameter for the definition of the PV module. We will investigate the reasons behind the discrepancy and apologize for the inconvenience and confusion this is causing

Dear Dotun Tokun, This can be due to a variety of reasons, and it is difficult to give a precise answer without more detailed information about your system. As a first approach, make sure that you indeed have activated the use of the bifacial model for the simulation (by clicking on “Bifacial system” button in the selection of PV module section in your system. The led should be activated if all parameters are well defined). See following link to the PVsyst help describing the bifacial system procedure: https://www.pvsyst.com/help/index.html?bifacial_procedure.htm Also verify that your input parameters are accurate, including the solar module characteristics, that the albedo values are realistic and that the spacing between the panels are sufficient for sun to reach the ground between the panels which is essential for bifacial panels to harness reflected light effectively. Regards.

Dear chudy14, In the Meteo database tab you have a button “Compare meteo data”, allowing you to compare datasets. Also keep in mind that the origin of the data might vary between being a typical meteorological year (TMY), synthetic data or measured data for a specific year, this might affect the year-to-year variability. You can also find an extensive amount of help-pages with information on meteorological data sources (see link below), as well pages on the constructions of meteo-files, sources of uncertainty etc https://www.pvsyst.com/help/index.html?meteo_datasources.htm Regards.

Dear rangsarit, Importing a CSV file with a 15min timestep is possible as long as you follow the required format, PVsyst will automatically convert this into hourly values for the simulation. In the case of a warning message of “Incomplete data”, it means that data is missing or cannot be read at certain time periods, but you can still run your simulation for the dates available. In the screenshot provided, it seems like your file has not been read correctly given the “Hourly User’s needs” table and the "No data" in the Preview. Please send your CSV file to support@pvsyst.com and we can try to find the problem. Regards.

Dear Michalis, The strategy for Peak Shaving storage management is designed to precisely control the flow of energy injected into the grid. If your goal is to not injecting energy into the grid, you should choose another strategy such as the "self-consumption", and untick the option to "Allow solar injection into the grid". If you aim to create a system entirely independent of the grid, you should consider designing a "standalone" project.

Dear Michalis Angeli, Battery OUT, inverter loss represents the losses in the inverter that is converting the energy from the battery to AC. It is probably a combination of parameters leading up to this large loss. Without more detailed information about your system, it is hard to pinpoint the exact causes. Please send your project to support@pvsyst.com if you'd like us to take a closer look. E_solar is in fact the part of the energy that is used internally, such as battery charge/discharge inefficiency, DC-AC and AC-DC conversion devices. EUnused is the energy produced that is wasted because the system does not inject energy to the grid, batteries are already fully charged and there is no self-consumption at that moment when there is production. EFrGrid is the energy from the grid needed to fulfill the users need. Regards,

Dear Michalis Angeli, In a grid-connected system with self-consumption, some of the energy need will be met by energy from the systems own production, that is the “to user from solar” (the purpose of self-consumption). When the user's energy need cannot be met solar production, energy is distributed from the grid, referred to as "grid consumption" and "to user from grid" in the diagram. Conversely, when the system generates surplus energy beyond the user's needs, it is fed to the grid, referred to as "to grid" in the diagram. Consequently, the total energy output of the system combines the energy supplied to the user from solar and the energy injected into the grid. Regards,

Hello Michalis, Yes that is correct, you should consider the average length of the (DC) cables in the string. The Ohmic Losses tab is divided in one section for the DC circuit (in the box with light green background colour) followed by AC losses after the inverter (in the box with a grey background colour)

Dear Michalis, You can configure your array in the way that is the most optimum for your scenario. PVsyst is a simulation software that will simulate the parameters you provide and the system's dimensions and setup are ultimately your responsibility. You can see how many strings, inverters and MPPT you have in your array in the summary to the right. By default, PVsyst will suggest one string per MPPT in your case. Since you now have two strings, you correctly see in the orient distrib that you have an equally distribution of Inverter inputs in each orientation. In other words, the Inverter is evenly distributing power from both the east-facing and west-facing solar panels. This balance ensures that, for example, in the morning when only the east-facing panel is producing power, this string generates electricity while the west-facing one does not. Conversely, in the evening. However, if you were to combine these two orientations into a single string, the overall production would always be limited by the orientation with the lower power output. This would result in a suboptimal performance because the combined string's production would never reach its full potential due to the constraint imposed by the least productive orientation.

Dear Shashank Sharma, P50-P90 estimations rely on yearly data. Calculating P90 for monthly values is not advised. Yearly weather data has variation (around 3-4% RMS), while monthly data can vary significantly year-to-year, leading to unreliable probability profiles for each month. You can read more about the P50-P90 evaluations in the Help in the link below: https://www.pvsyst.com/help/index.html?p50_p90evaluations.htm Regards

Yes you can run your simulation.

This is not an error, but the result of having only one string. Installing modules in two complete opposite orientations on the same string would result in a very suboptimal energy production, so therefor it is not implemented in PVsyst to preform such a simulation. To use the solution of power sharing with one inverter and two orientations you need to have two strings, or simulate an average of the two orientation.

Panels in different orientations will produce varying amounts of electricity at different times, reducing the overall output and efficiency of the solar array. Thus, in PVsyst you cannot simulate two orientations in one string. By defining only 1 string with 12 modules, PVsyst will simulate all the modules in one direction, leaving the other direction empty, see screenshot below. This is why you have 24m2 in one direction (Fields azimuth 90) and 0m2 in the other (Fields azimuth -90). You can define the average between the two orientations or apply the configuration suggested earlier.

Dear Michalis, I am not completely sure what it is that you want to do. Though, by creating two subarrays, one for each orientation, you can use the inverter you mention, by putting one string with for instance 4 panels in one sub-array/orientation and 5 panels in the second array/orientation, a total of 9 panels with a total Nominal PV Power of ~4kWp, using one MPPT for each string and activate the Power sharing. See example below. With an inverter of 5kW and an installation of 4kW, the inverter will be slightly oversized. Regards

What I understand from your screen-shot, is that you have 2 orientations, one string in each orientation, both with 6 modules in series. The total Nominal PV power is 5kWp. In your configuration you have 2 inverters of 5kW, one for each orientation and thus it is strongly oversized. By mixing the two orientation (In the “Sub-array name and Orientation” box) and keep your entire PV Array as one sub-array with 6 modules in series in 2 strings, PVsyst allows you to use only one inverter for the two strings, see screen-shot below. You are though obliged to have one string per orientation.

According to your attached picture, the average length of one string (including 23 modules) is 33m and no distance from the main box to the inverter. We've identified a bug that will be addressed in the next version. It is marked here that you have 8 inverters, even though you've indicated in your message that you only have one (I assume with 8 MPPT inputs, causing PVsyst to incorrectly register 8 inverters). If you want to be sure to take all the losses into account, it is always possible to slightly increase the Loss fraction at STC from the calculated values, as suggested earlier.

Dear Michalis Angeli, Power optimizers are electronic devices, which aim to draw the maximum energy possible from the PV modules within an array (i.e. they try to ensure that each module is working at its MPP at any time). The benefit we can expect from Optimizers is the recovery of electrical mismatch losses. Your choice comes down to what kind of configuration your system have and what level of detail you will construct in the 3D scene. By choosing According to module strings, you will in the construction of the 3D scene, define a partition in module strings. This option will calculate a shading factor "According to strings", representing a higher limit for electrical effects. The partition model for electrical shadings is an approximation that allows to compute electrical shading losses faster than with the detailed "Module Layout" mode. This approach works best in regular row-based systems. By choosing Detailed electrical calculation (acc. To module layout) you have to start by specifying a detailed "Module layout" configuration, you can ask to compute the shadings according to detailed electrical losses. The Module Layout tool is aimed at the detailed calculation of the Electrical shadings mismatch loss. It requires a description of the position of each PV module in the 3D scene, and the module interconnection as strings according to the inverters defined in the "System" part. Regards

Dear Mohamed, You can find a template for the PVsyst format for the Horizon file in the folder “templates” in your workspace. The format Horizon file should contain one line per defined point. Each point defined as an Azimuth and a Height value, expressed in degrees. You would either have to completely restructure your TMY hourly data, going from -180 to 180 degrees with corresponding height values, or import the horizon from web sources. If you wish to use the meteorological data from your site, you can do so by importing your file as a Custom file. You do this by opening Databases, Custom file, choose your Source file and go through the necessary step to do the conversion to import your site. Once saved in your workspace you can use this your created site in your projects. Regards

Dear Angel Mlga, Indeed it seems to be a problem here that I do not have a direct answer to. To address this, I recommend exporting your project as a zip file and sending it to support@pvsyst.com. This way, we can examine your system and provide the assistance you need. Regards

Dear Dominik Damberger In most cases, the open-circuit voltage (Voc) of a PV module will increase as the temperature decreases. This phenomenon is known as the temperature coefficient of voltage, and it's a fundamental characteristic of solar panels. However, at very cold temperatures, such as those below -20°C, will have adverse effects on the performance of a PV module because of mechanical stress on the components etc. The Temperature coefficient is defined by the manufacturer. So, while the temperature coefficient generally causes an increase in Voc, at temperatures below -20°C, other factors related to extreme cold can impact the overall performance and efficiency of a PV module.

Dear Michalis Angeli, In the Wiring layout you should define the average length for one string (blue) and the distance to the main box to the inverter (green). If you have multiple strings and/or inverters this will be reflected in the Global array and the Field global wiring resistance. See example below. It is this number that will be used in the simulation. If you wish to simulate a more pessimistic scenario, to be on the safe side, you can artificially increase the Loss fraction at STC to, for instance 0.8%, compared to the calculated values of 0.65 from the example.

Hello, Adding transformers results in a reduced current load for each individual transformer. The Loss fraction at STC thus decrease at each transformer, but to evaluate the entire system you have to run a simulation and look at the loss diagram.

Dear Michalis Angeli, There are no default values for the output parameters of an inverter, as these values are contingent on the specifications of your inverter model. Consult the inverter’s data sheet to see its specification.