The inverter raises a grid underfrequency fault when the grid frequency it measures drops below its configured lower limit. Look at the logged grid frequency reading and see if it fell below the underfrequency trip threshold before the event. First measure the actual grid frequency on site. If it is outside the set range, the cause is on the grid side, so contact the local utility. If the grid frequency looks normal, check in the app or on the LCD that the protection parameters are set correctly. Trip and reconnection thresholds can be changed, and default values differ by product, for example 58.5 Hz or 59.3 Hz. The inverter reconnects only after the frequency rises back above a separate underfrequency reconnection threshold. On some storage systems this condition shows up as a general Grid Uncompliant alert that covers both voltage and frequency excursions. If grid and settings causes are ruled out and the fault keeps coming back, contact the manufacturer's service.
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- sentence 2: support check: partial - Passages give a grid frequency reading and underfrequency trip thresholds, but nothing states this diagnostic step of comparing the logged reading to the threshold before the event.
- sentence 5: support check: partial - A separate underfrequency reconnection threshold exists, but the passages do not explicitly state the inverter reconnects only after frequency rises back above it.
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c1 drafted · lead
Grid frequency outside limits
Inverter reports grid underfrequency (e.g. fault code 9/009) when measured grid frequency is below its lower limit; storage systems may flag a Grid Uncompliant alert for over/underfrequency beyond hardware trip thresholds.
review note: support check: partial - Fault 9 and Grid Uncompliant alert are supported, but the passages don't state the inverter output drops while below a reconnection threshold or the specific 'configured trip threshold' wording; the frequency reading is documented but not the pattern.