Re: Voltage Stabilizers/Regulators
There are lots of transformer systems for stabilizing line voltage. I don't know, but I would think that most would work with GT inverters. The problem with adding a voltage stabilizing transformer is that they will add losses and can cost you a fair amount of lost power (check idling and operational losses before buying).
Back to the basic problem... Is the Line voltage high when the GT inverter(s) are not operating? If so, then see if the utility will adjust the line voltage back down to "normal".
If the line voltage is only high when the GT inverters are operating, then it sounds like your wire resistance is too high for the distance of the run. Run larger diameter wire from the GT inverter back to the main panel--You may need to review the resistance of the drop from the utility transformer to the main panel too (rural area, long utility drop run).
If you are mounting the solar array a long distance from the main panel--I would suggest using a Central GT inverter near the main panel and run long DC cabling back to the Solar Array (where voltage drop is much less of a problem and you can design for optimum drop in your installation). A long AC run back to Enphase/micro inverter type installations again puts the voltage drop back on the AC mains side--which is not in your control (if you have utility issues).
20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.