Can you go into more detail on what happens when a solar cell is partially shaded? At what point does the bypass diode trigger?
That is a good tough question and there are many variables.
What it comes down to in an interactive (grid-tied) system, the inverter will MPPT the PV. If the array will be more efficient using the group of PV cells that include the partially shaded cell, then that bypass diode will not kick in, because the inverter will be working at the voltage that includes those cells.
If the inverter can make more power bypassing the group of cells that include the partially shaded cell, then the inverter will work at a lesser voltage that would bypass the group of cells that include the partially shaded cell.
Some inverters will MPPT differently than other inverters, but one thing for sure, any inverter manufacturer will tell you that they have the best MPPT algorithm.
To sum it up, the inverter should work at the voltage that makes the most power. If the inverter can make more power at a lower voltage by letting the bypass diodes skip shaded cells, then the inverter will work at that voltage.
They call it sweeping the array when the inverter tries different voltages to see where the opportunity for maximum power lies.
Thanks for the good question!