PVSyst Japanese Translation Summary: Basic Settings Guide for Design Beginners

Introduction

PVsyst, an indispensable PV power generation system design tool, is a power production simulation software used worldwide. However, for first-time users it can be difficult to understand because many technical terms are displayed in English. This article carefully explains the basic terms and settings when using PVsyst with a Japanese interface. Aimed at those searching for "PVSyst Japanese translation," it summarizes the initial setup points beginners should grasp—from creating a project and entering meteorological data to selecting modules and inverters, setting tilt and azimuth, configuring shading, and adjusting loss parameters. Reading this article will help you understand PVsyst’s basic operations based on Japanese display and enable you to perform designs with higher simulation accuracy.

What is PVsyst

PVsyst (pronounced “Pee-Vee-Sist”) is a solar power generation simulation software developed in Switzerland. By inputting meteorological data such as irradiance, specifications of solar panels (modules) and power conditioners (inverters), and installation conditions, it can calculate annual energy production, losses, performance ratio (PR), and other detailed metrics. It is so reliable that it is considered a world standard, and it is used widely from large-scale mega-solar projects to small residential systems. A notable feature is its ability to analyze the effects of shading caused by surrounding terrain, buildings, and trees in 3D, enabling simulations that faithfully reflect on-site conditions. PVsyst supports multiple languages and can be switched to Japanese display (change the language to Japanese in the menu settings). However, some translations are incomplete, so it is important to cross-check with the English notation as needed. In the following chapters, we will look at the meanings and usage of the basic settings items on the Japanese interface one by one.

PVsyst Main Screen and Japanese Terminology

When you start PVsyst, a menu to select the project type and buttons to access various databases are displayed. If you have selected the Japanese interface, the main menus and buttons are shown in Japanese. Below are the basic terms beginners will first encounter, presented with their Japanese translations.

• Project Design (プロジェクト設計): The mode for creating new projects and managing existing projects. Normally, select a "Grid Connected" (系統連系) system.

• Site and Meteo (サイト情報と気象データ): The screen for entering the site’s latitude, longitude, time zone, and selecting meteorological data.

• Orientation (方位・傾斜設定): The settings screen for the panel installation azimuth and tilt angle.

• System (システム): The screen to configure the system, including selecting PV modules and inverters, number of strings, and wiring.

• Simulation (シミュレーション): The screen to run generation simulations with the entered conditions. You can also output result reports from here.

• Near Shadings (近接影): A function to set nearby objects (buildings, trees, other panel rows, etc.) that cast shadows on the panels using 3D models.

• Horizon (地平線): A function to set the horizon profile to account for irradiance blocking by distant terrain.

These are the main menu items and their Japanese translations. Next, let’s go through each item in detail following the flow of the initial setup.

Creating a Project and Setting Meteorological Data

First create a project and set the design site and meteorological data. From the main PVsyst menu select "Project Design (プロジェクト設計)" and start a "New Project." Next, choose the system type—typically the grid-connected (Grid Connected) option.

After entering the project name and notes, go to the "Site and Meteo" screen. Here you will configure the following:

• Enter geographic information: Set the installation site’s latitude, longitude, and time zone. For locations within Japan you can often select existing nearby data by prefecture or city name. In the Japanese UI choose “Country” and select “Japan,” then specify the prefecture or region. If your area is not in the list you can register a new site.

• Select meteorological data: Choose the meteorological data for the site (annual irradiance, temperature data, etc.). PVsyst includes typical meteorological year data for many locations worldwide, but for Japanese sites users often import their own data. For example, official domestic observation data can be imported into PVsyst from CSV or Excel. The Japanese display has a button like “Import Meteorological Data,” so if you have data on hand you can load it from there. Setting appropriate meteorological data is a critical step that directly affects the accuracy of energy yield forecasts.

• Altitude and ground albedo: If necessary, set the site elevation (altitude above sea level) and the ground reflectance (albedo). Elevation affects air density, and albedo is used to calculate additional irradiance from reflection off snow or the ground. For typical grassland, an albedo of 0.2 (20%) is a reasonable guideline.

With the site and meteorological conditions set, next enter information for the equipment that composes the system.

Module (Panel) Selection

PVsyst provides an extensive database of PV modules from many manufacturers, and this can be used even in the Japanese interface. In the System settings screen, first select the module(s) to be used. In the “PV modules” field choose the manufacturer and model. In the Japanese display the manufacturer and model lists are also alphabetical, and the major manufacturers distributed in Japan are generally registered.

• Check module specifications: The selected module's rated power (W), conversion efficiency (%), nominal operating cell temperature (NOCT), temperature coefficients, and other specs are displayed. Verify these as needed.

• If not registered: If the module you want is not found in the database, you can add it by entering the panel specifications yourself. In the Japanese UI use “Edit Database” or “Create New Module” to input new module parameters such as open-circuit voltage Voc, short-circuit current Isc, and maximum power Pm. For beginners, it’s often practical to choose an existing model with similar specs to run initial simulations.

After selecting modules, proceed to set the power conditioner (inverter).

Inverter (Power Conditioner) Selection

Next, choose the system inverter. This is also selectable from PVsyst’s database. In the system settings screen specify the inverter manufacturer and model in the “Inverter” field. The list is alphabetical even in Japanese, and using the “filter by model” feature makes it easier to find your target device.

• Inverter rated capacity: The selected inverter’s rated output, input voltage range, maximum input current, and other data are displayed. Check whether the inverter capacity is appropriate relative to the total panel capacity (verify the overloading ratio). For example, a total panel power up to about 1.2 times the inverter’s rated capacity is commonly considered acceptable.

• Number of units and string connections: Enter the number of inverters to be used and the number of strings (series-connected panel groups) connected to each. PVsyst displays fields like “Number of strings” and “Number of panels in series.” In the Japanese UI these correspond to the number of strings and the number of panels in series respectively. The number of panels in series indicates how many panels are connected in series per string, and the number of strings indicates how many strings are connected in parallel.

• If the model is not registered: As with modules, inverter models not present in the list can be added manually. In the Japanese screen use “Create New Inverter” or similar to input rated capacity and efficiency curves. If you are a beginner and do not know the detailed specs, substituting a model with similar specifications is acceptable.

Once module and inverter selection and connection settings are complete, the overall system capacity and configuration will be determined. The screen displays the current total capacity and the expected operating voltage range, so verify there are no errors.

Panel Tilt and Azimuth Settings

Next set the panel installation angles. These greatly affect energy production, specifying the direction and tilt at which PV panels are installed. In PVsyst’s Orientation screen enter the following:

• Tilt angle (Tilt): Specify the panel surface tilt relative to the horizontal plane. In many regions of Japan, approximately 30° tilt facing south is near-optimal for annual energy maximization, but optimal tilt varies with latitude and the project goal. In the Japanese UI enter the angle in the “Tilt” field.

• Azimuth (Azimuth): Specify the panel azimuth in degrees. In PVsyst, for projects in the Northern Hemisphere the azimuth is defined with true south = 0°. Angles toward the west are positive (e.g., west = +90°) and angles toward the east are negative (e.g., east = -90°). Thus, a south-facing installation in Japan is azimuth 0°, southwest by 30° is +30°, and southeast by 30° is -30°.

• Layout options: PVsyst has layout calculation options for multiple rows (sheds), and modes like “Unlimited sheds” can be selected. For beginners, assuming flat land with parallel rows all at the same tilt, Unlimited sheds is convenient. In this mode, setting the row spacing automatically calculates shading between front and back rows and displays the Shading limit angle. If row spacing is too narrow and neighboring rows cast shadows on the panels during winter, this limit angle is shown as a warning so you can adjust appropriately.

Save the settings after deciding tilt and azimuth. Proper south-facing orientation and suitable tilt generally maximize annual generation, though site constraints may require compromises. For rooftop installations, measure the roof pitch and orientation and enter the actual tilt and azimuth.

Considering Shading (Horizon Profile and Near Objects)

Appropriately considering shading effects is indispensable for accurate PV system simulation. PVsyst allows you to set both horizon effects caused by distant mountains or tall buildings and near shading from trees, buildings, or other nearby objects.

• Setting the horizon profile: If there are obstructions (mountain ranges or hills) around the site, input their elevation angles by direction. The Japanese UI provides a screen to define the horizon, plotting obstruction heights by azimuth. For example, if a mountain of 5° elevation exists in a certain direction, set 5° for that azimuth. You can obtain horizon data from simple commercial apps or on-site surveying and import it as text data. Correctly setting the horizon profile allows the simulation to reflect irradiance blocking by mountain shadows in mornings and evenings in winter.

• Setting shadows from near objects: Objects that may cast shadows on panels at close range—buildings, trees, utility poles, other panel rows—can be modeled with PVsyst’s 3D shading feature. In the Japanese interface, the Near Shadings settings let you add objects and specify their heights and positions. For example, if there is a tree 10 m (32.8 ft) tall on the south side of the site, add an object with height 10 m (32.8 ft) and position it at the appropriate distance on the scale. Register multiple objects to run time-of-day shadow simulations over the year. Note that highly detailed 3D modeling can increase computation load, so beginners may choose to include only the major shading objects or consider using separate analysis tools as mentioned later.

By setting shading, you obtain generation forecasts closer to reality than calculations using only irradiance. This is particularly useful for understanding how much generation drops in mornings, evenings, or winter, aiding in system design risk assessment.

System Loss Parameters

Finally, set the system-specific loss items. PVsyst includes several default loss factors, and these can be customized per project. In the Japanese interface the parameters are shown with terms like “losses,” so let’s review them.

• Soiling loss: Losses due to dirt and dust on the panel surface. In the Japanese UI this appears as “Soiling loss (%)” and an annual average of a few percent is typical. Set a larger value in areas prone to bird droppings or dust storms.

• Wiring losses (cable losses): Resistive losses in DC and AC cables. These are set as percentages for “DC wiring loss” and “AC wiring loss.” For typical wiring, about 1–3% each is a guideline; using thicker and shorter cables reduces losses. PVsyst also allows separate settings for losses between inverter and transformer.

• Temperature losses (output reduction due to temperature): PV panels’ output decreases with rising temperature. PVsyst automatically calculates losses from module temperature coefficients and ventilation conditions, but you can review the overview under items like “Temperature effect.” Panel temperature varies depending on whether the installation is on a roof with poor ventilation or on open ground with good airflow, so adjust NOCT values as needed.

• Mismatch losses: Losses from performance variation between panels (individual rated power differences) and differences in aging. PVsyst lets you set mismatch losses as a few percent—typically 1–2% by default.

• Other losses: Conversion losses (calculated automatically from inverter efficiency), transformer losses (for large systems), downtime due to night self-consumption or maintenance, and other factors can also be considered. PVsyst provides detailed settings for items like “Transformer loss” and “System downtime.” For beginners, leaving these at default values is acceptable, but adjusting them to reflect actual conditions improves accuracy.

These loss settings determine how much is subtracted from the ideal energy production in the simulation. The result report also shows the breakdown of losses so you can identify which items contribute most to generation reduction.

Improving Design Accuracy Using LRTK Terrain and Obstruction Data

So far we explained PVsyst’s basic initial settings using the Japanese interface. Finally, as a method to further improve simulation accuracy, here is how to incorporate detailed site terrain and obstruction information. Recently, it has become common for beginners to obtain 3D site data using simple surveying tools and reflect that in PVsyst. A representative approach is using a solution called LRTK.

With LRTK you can perform easy measurements with a smartphone to capture site boundaries, terrain elevation differences, and the positions and heights of surrounding structures and trees with high precision—centimeter-level (half-inch accuracy). Using the coordinates and point cloud data obtained, you can enhance PVsyst settings as follows:

• Apply to horizon profile: Calculate elevation angles of distant mountains or high ground from LRTK-measured terrain data and input them directly into the horizon definition, ensuring on-site terrain shading is fully reflected.

• 3D modeling of near objects: LRTK point cloud data includes detailed information on surrounding trees, poles, and buildings. From these data determine object heights and positions and place equivalent-height and distance objects in PVsyst’s near shading settings. Alternatively, import 3D models created from the point cloud into PVsyst to analyze detailed shading on a per-panel basis.

• Reflecting terrain undulations: For large sites with elevation differences, generate a surface model from LRTK survey data and reflect it in PVsyst panel placement. For example, adjust racking heights along slopes or compare generation impacts before and after land grading—such advanced analyses are possible when you have measured data.

Utilizing simple survey data from LRTK dramatically improves the input accuracy for PVsyst simulations. Terrain and shading information that previously required specialized surveying equipment or complex methods can now be obtained easily by beginners with LRTK. As a result, you can minimize the gap between simulation and reality and achieve more reliable energy forecasts and optimized designs. Even those just starting solar design can plan with professional-level accuracy by combining PVsyst’s basic settings with technologies like LRTK. Using this PVsyst Japanese interface basic settings guide, try performing high-accuracy simulations.