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Fixed-tilt - stringing

Updated

Learn to define, apply, and optimize stringing patterns on fixed-tilt PV layouts in PVcase, including automated methods, custom presets, and terminal orientation management.

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Stringing types

Select the stringing option in PVcase that best fits your site layout and electrical design requirements:

  • Single-row stringing - This stringing type connects every panel in the row in series into a singular string spanning the whole row.

  • U-stringing - This involves connecting all panels in the frame in series, with the positive and negative terminals on the same side. Note that this setup requires an even number of rows.

  • Leap frog - This stringing type connects every second module on one side and returns via the remaining modules, with the positive and negative end terminals on one side.

  • Smart Stringing - This automated method groups solar modules into strings based on a user-defined module range and the "Row End Exception," which determines how leftover modules are handled. If the exception is "Leave unstrung," any modules that can't be connected are left unstrung.

  • S/U string: Leftover modules are arranged into an S- or U-shaped string to fill the row.

  • Jump row: Leftover modules jump to the next row to complete the string.

  • Manual Stringing - an interactive electrical design feature that lets you manually define stringing paths by drawing a path directly across solar modules in your drawing workspace.

  • Custom stringing - This option enables you to manually create custom patterns of one or more strings within one or more PV frames.

Workflow Example: Creating a custom preset 

  1. Select Custom Stringing and name your new preset (e.g., 2C20).
  2. Click Select frames and pick the frame you want to string. In this example, we will select a single frame.

  1. With the frame selected, press Space or Enter to open the unstrung frame in the workspace.

  2. Select a module and click it to make it our positive terminal, shown by '+'.

5. Left-click the module next to your positive terminal to assign the Negative (-) Terminal. The previously seen dashed lines become intertwined. This is how we can create a leapfrog string in PVcase.
6. Repeat the steps for the unused modules: Click the module directly below your first positive terminal, click the far-opposite module on that row, and return to click the adjacent starting module to complete the second string.
6. To delete the string, right-click the entire string - this will remove the string you drew.
 

Note: You can mirror this preset if you need to quickly reorient it so the terminals are on the opposite side of the frame.

 

Applying or Removing Strings

To string our frames, we have two options:

  • String area - using this function, we can select a PV area that we want to fully string with this preset on supported frames;

  • String frames - use this function to select individual frames to which we would apply these features.

To remove some or all of the stringing, click Destring Frames, select the frames you want to destring, then press Space or Enter.

 

String Orientation

It's important to consider where to place DC combiners/string inverters and adjust string directions accordingly. This is a recommendation, as directions can be changed later. For example, in the below, we plan to place electrical devices along the yellow line.

 

With that in mind, you can plan to have the strings on either side of the line, facing the line (West frames facing east & East frames facing West). This can help reduce the DC cable run length:

To accommodate that, you may use the mirror function. The mirror function will automatically invert the position of the strings, as can be seen below:

Reversing Strings

Once you finish the electrical design and add all labels and devices, you might notice one or more strings with incorrect polarity. You can correct this by selecting the string, right-clicking, going to PVcase, and selecting Reverse string polarity.

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