Stringing and Connecting

When should I string my design?

After placing modules in your Aurora project, pressing the Simulate button will give an accurate estimate of the power that system will produce. If modules are properly strung and connected to inverters, production will be estimated using the "Aurora simulation engine," by default. If no inverters are present in the design, Aurora will default to the PVWatts simulation engine instead. Feel free to experiment with both types of simulations.

If you are using microinverters for all the modules in your design, modules do not need to be strung or connected to run the Aurora simulation engine. You may, however, string these modules for visual and planning purposes if you choose. If you are using string inverters in your design, all modules must be properly connected and strung to run the Aurora simulation engine. 

Generally, the Aurora simulation engine will give more conservative production estimates than the PVWatts simulation engine, so keep this in mind as you are working on your projects.

What type of inverters should I use in my design?

The use of string inverters in your design, as opposed to microinverters, has its advantages and disadvantages:

• String inverters are an older technology, so they are usually less expensive than other options.
• String inverters do not handle shade well - if a single panel within a string is shaded, it can significantly impact system production.
• String inverters require all panels on a given string are similar pitch & azimuth.

If your site is heavily shaded, or you plan to design one system over many varied pitches and azimuths, microinverters may be your best choice. If you are using relatively fewer mounting planes, with relatively fewer shade threats, then string inverters are a great option. 

AutoDesigner

Aurora's AutoDesigner allows you to create and string your PV design with just a few clicks. Click System from within Design Mode and you will see the AutoDesigner option.

The System menu.

1. Click AutoDesigner
2. In the right-side menu, select your Target Mode: Energy or Max Fit. Energy target mode allows you to select a desired energy production number for your design, while Max Fit will place as many PV panels onto your site model as can fit.
3. In the right-side menu under Panels, select a type of module from the drop down menu. You may also select a desired Panel Orientation from this menu, and can click Advanced Settings if you would like to configure details like row spacing
4. In the right-side menu under Components, choose either a String Inverter or Microinverter option. Some String Inverters also require you to select a compatible DC Optimizer, but most do not require a DC optimizer.
5. Click Run AutoDesigner after you have selecting your desired options.

In a few moments, Aurora will create a PV design based on your specifications. If you have selected the String Inverter option, then panels will already be connected to strings. Click the Simulation button in the upper right corner to see how much power this system should produce.

Manually String Panels

1. Click Add Components in the System menu in the left toolbar.
2. Click Inverter (or press the V key as a shortcut for steps 1 and 2).
3. Select the appropriate inverter and place it in the desired location. Exact location of the inverter in your model will not affect production simulation results.
4. Click String/Connect in the System menu in the left toolbar (or keyboard shortcut C ).
5. Left click and hold to drag the string across modules. Red means the string length is too short or too long (outside the inverter's acceptable voltage input range). Green means the string length is valid (within the acceptable input range).
6. Release left click to complete the string.

If the string length needs to be adjusted, left click on the string node and drag to the desired length.  

To connect the inverter, left click the inverter once, then left click again on either end of the string you have created.

Auto-String

1. Left click and hold to outline the panels you would like to string.
2. Click the Auto-String button at the bottom of the right toolbar.
3. Select the inverter you would like to string and click Auto-String.