6.78: Wrong report numbers when simulating mixed orientations

[AKE]

In 6.78 I encountered a bug in the PVsyst Report when simulating a system with mixed orientationes (e.g east/west). After a little testing, the bug seems to appear only when there are multiple inverters.

The losses for

- PV loss due to temperature

- Module quality loss

- LID

- Mismatch

- Ohmic wiring (DC)

are all divided by 2 in the loss diagram, so e.g. Ohmic wiring -0,2%, instead of -0,4%.

Another example: LID loss on page 1 (PV array loss factors): -1.0%

But LID loss in the loss diagram: -0.5%

The resulting energy in MWh however seems to be still correct, so I assume only the displayed numbers for these losses are bugged.

[André Mermoud]

You are right.

The "Array nominal energy" is indeed a new intermediate calculation (introduced in V 6.77) , which was not correctly calculated for Mixed Orientation in the versions 6.77 and 6.78. This will be corrected in the version 6.79, to be released within about 2 weeks.

This only affects the losses expressed as a percentage in the loss diagram (up to EArray at MPP). The simulation results are quite correct.

NB: In the meantime If you need a correct report, the can download the version 6.76 from our web site www.pvsyst.com, and install it in parallel with your exiting version. Both versions may by used without interaction.