Potential induced degradation (PID) of a solar module — you know it, and you hate it. We met with string inverter manufacturer OMRON at Solar Power International, which claimed its inverter can actually prevent PV degradation from PID.
They explained it like this: Grounding module frames causes a voltage difference between the frames and the cells, which causes mobile ions to migrate to and from cells. Positive sodium ions contained in the module glass can then migrate toward the cells and crystalline defects known as stacking faults permit the ingression of these sodium atoms in the PV cells. This results in short circuits that are symptomatic of PID. There are PID reduction boxes that can reverse this effect, but OMRON wants to simplify that and eliminate problems caused by module duds.
The answer is in its ZCC inverter topology, which introduces a DC virtual link that allows transformerless string inverters to connect the negative pole to the AC neutral. Ta-da.
— Solar Builder magazine