How to optimize simulation time

[Lazare Fesnien]

The speed of the simulation mainly depends on the complexity of the system and the complexity of the 3D scene you are trying to simulate.

Here are a couple of ideas:

• In the 3D scene:

When near shadings are used, the calculation of the shading factor basically requires to compare each elementary surface to each PV table (goes with the square of the number of elements)

1. You can simplify the calculation by using arrays of tables instead of single PV tables if your tables are well aligned;
    
2.  The shading calculation with trees is very slow, as each face of each tree has to be calculated independently. For tree arrays, you are advised  to use a single parallelepiped;
    
3. A significant time may also be due to the pre-calculations for the optimization of the shading factor calculation, or the check that each table should not interpenetrate any other table or objects. Try to avoid interpenetrating objects;
    
4.  Too much detail in the topography will lead to long import and simulation durations and possibly slows down the user interface.

There is a limit of 500’000 unique points when importing topography data through a CSV file, and a maximum of 1’000’000 triangles when the triangulation is performed. In the ground data details, you can use the simplification tool to reduce the number of points.

 

• System definition:
   

1. You can simplify the definition of the system if you have defined many sub-arrays with a single inverter. This will make the simulation very slow, and it is best to group identical inverters in the same sub-arrays;
    
2. Using the multi-MPPT feature will slow down the calculation. If possible, you can disable it, which means considering inverters as a whole;
    
3. With string inverters, the simulation is performed for each inverter input, which significantly increases the simulation time.

 

• Shadings calculation:
   

1. When using the “Module Layout” for electrical mismatch effects, defining more than 1’000 - 1’500 modules leads to extremely long calculation times;
    
2. You can simplify the shadings calculation by using "According to module strings", and if necessary the "Fast (table)" option, instead of "Detailed electrical calculation (acc. to module layout)". The shadings calculation will be less accurate but it should be much faster.
    

Here is the link to the help page that explains how to set up partitioning:
https://www.pvsyst.com/help/index.html?shadings_partitioninstrings.htm

In the slow case, at each simulation step the shading factor is recomputed.