Anyone know the specification for generation of a good enough grid signal from an inverter to trick a GTI to function when grid is down? I assume in the US the inverter would need to produce 240v@60hz. But is there any other documented requirements like impedance needed from the inverters "grid" signal?
Specification of an inverters Grid Signal
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RCinFLA
Solar Wizard
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Spec;
Frequency, 59.3 Hz to 60.5 Hz for GTI. Source should be better, typically within 0.1 Hz of 60 Hz.
AC voltage, 211 to 264 vrms , nominal 240 vrms.
Total Harmonic Distortion, <3%. Source should be better.
You have to have some place to put PV generated power, reduce generation or shut it down if not using all PV power generated. An AC coupling hybrid inverter handles this by moving frequency out of range tolerance for GTI.
The source impedance necessary depends on power of GTI. GTI inverter tries to 'wiggle' phase to ensure grid is still present. This causes some extra current to be drawn and source inverter must be strong enough to resist 'wiggle'. Generally okay if hybrid inverter power capability is greater than half the capacity of PV GTI power output although there are other reasons, like momentary battery charge pushing, that suggest the source inverter should be closer to PV power levels. It is as important that battery capacity and battery impedance is appropriate. A large hybrid inverter with small battery capacity may not be good enough since the effective output impedance of hybrid inverter will depend to some extent on battery impedance.
Frequency, 59.3 Hz to 60.5 Hz for GTI. Source should be better, typically within 0.1 Hz of 60 Hz.
AC voltage, 211 to 264 vrms , nominal 240 vrms.
Total Harmonic Distortion, <3%. Source should be better.
You have to have some place to put PV generated power, reduce generation or shut it down if not using all PV power generated. An AC coupling hybrid inverter handles this by moving frequency out of range tolerance for GTI.
The source impedance necessary depends on power of GTI. GTI inverter tries to 'wiggle' phase to ensure grid is still present. This causes some extra current to be drawn and source inverter must be strong enough to resist 'wiggle'. Generally okay if hybrid inverter power capability is greater than half the capacity of PV GTI power output although there are other reasons, like momentary battery charge pushing, that suggest the source inverter should be closer to PV power levels. It is as important that battery capacity and battery impedance is appropriate. A large hybrid inverter with small battery capacity may not be good enough since the effective output impedance of hybrid inverter will depend to some extent on battery impedance.
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