Voltage Stabilizers/Regulators

lazza
lazza Solar Expert Posts: 336 ✭✭✭
in Grid Tie and Grid Interactive Systems #1
Hi Forum

Does anyone know anything about voltage stabilizers?

We have installed some small grid-connected pv systems. However the normal grid voltage here should be around 230V, but in some places we have noted that at times it's above 247V! This has caused problems with the parameter limits of the grid-tie inverters, and one model has been having real problems with such high voltages, switching on and off so many times that a permanent fault occurred.

Is there any product that will limit or stabilize grid voltages that could be placed either just before the inverter, or alternatively at the main house panel?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,639 admin
    #2
    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).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,023 ✭✭✭✭
    #3
    Re: Voltage Stabilizers/Regulators

    My situation exactly with Enphase inverters. 180 foot run from inverters to transformer, voltage rise putting the voltage at the inverters over 255vac. Enphase has an extended window for input voltage, up to 260vac, once re-programmed the inverters stopped dropping out/re-connecting endlessly. (line was undersized from transformer to array/inverters).
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