Aurora features an interactive stringing mode that can be entered by clicking String Modules in the right toolbar (or pressing S) in Designs → System Design. Once you are in stringing mode, click on any panel to start the string and drag the mouse across adjacent panels to add them to the string. Release the mouse when you are done to finish the string.
While you are stringing, Aurora will highlight the panels of your string for you in one of three colors:
- Red means that your string is too short or too long
- Yellow means that your string is still valid, but is about to exceed the maximum string length
- Green means your string length is valid
To determine whether a string is valid, too short or too long, Aurora uses the appropriate string sizing rules for the components you are using. If you are doing a string inverter or DC optimizer design and you have already placed an inverter, Aurora will string the modules/optimizers for this inverter. If you have not yet placed an inverter, Aurora will prompt you to specify which inverter model you would like to string for. Learn more about stringing and connecting modules here!
String Inverter Designs
In the case of a string inverter design, it will check that the temperature-adjusted string voltage is within the input voltage window of the inverter.
$$ n_\mathrm{modules} \times ( V_{oc} - T_{Voc} \times (25 ° C - T_{min}) \times V_{oc} ) \ge V_\mathrm{input, min} $$ $$ n_\mathrm{modules} \times ( V_{oc} - T_{Voc} \times (25 ° C - T\_{max}) \times V_{oc} ) \le V_\mathrm{input, max} $$
For string sizing, Aurora uses the minimum temperature (\( T_\mathrm{min} \)) and maximum temperature (\( T_\mathrm{max} \)) defined in System Design → Settings
DC Optimizer Designs
For DC Optimizer Designs, Aurora implements the string sizing rules provided by the manufacturers. Currently SolarEdge and Tigo are supported.
Microinverter Designs
While technically microinverters do not operate in strings, Aurora's stringing tool can be used to connect microinverters to their trunk cable. In this case, Aurora will ensure that the current does not exceed the trunk cable's maximum ampacity rating (20A).
$$ \sum_1^n ( I_\mathrm{microinverter} \times 1.25 ) \lt 20\mathrm{A} $$