Is there a limit to the system size ?

[André Mermoud]

There is no formal limit to the system size in PVsyst.

However for very big systems (dozens of MW), the calculation time may be prohibitive, and even the management dialog of the system may become unworkable.

There are several bottlenecks:

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

Therefore you should define "tables" (areas for receiving a set of modules) as big as possible in order to limit their number.

In the version 6 there is an optimization which may gain a factor of ten. Please check that for your simulation, this optimization is effectively active (in the 3D editor, menu "Tools" / "Optimized shading calculation" checked).

- This calculation time for the shading factor is especially penalizing when establishing the shading factor table (prior the simulation) , which involves a calculation for 190 positions, and may spend several hours.

- 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.

- When using "Module layout" for electrical mismatch effects, defining more than 1000-1500 modules becomes impraticable. And this results in very long simulation time.

For very big systems, you should perform a simulation with Module Layout on a reasonable subsystem, which will give you an electrical loss value.

Then you can use the simulation on the full system with the option "According to strings of modules", and adjust the "Fraction for electrical effect" in such a way that you get the same electrical loss.

- With string inverters, the simulation is performed for each inverter input, which significantly increases the simulation time.

We are working on the improvement of the calculation performances, by optimizing the algorithms.

We will also develop a parallel calculation for a better use of multicore processors, which should be available soon.