Symptom
Grid synchronization failure
- ID
symptom:grid-sync-failure- IRI
https://solarlattice.org/kb/symptom/grid-sync-failure- Status
- active
- Also known as
- Grid failure, Grid Abnormal, Grid Uncompliant, Grid incident
The inverter does not connect to the utility grid, or drops off it, and shows a message such as waiting for grid voltage, grid failure, grid abnormal or grid incident. In monitoring data, AC output stays at zero even though production conditions are good, often because the inverter did not restart after a grid fault; the display or the data log shows the fault code. If the grid itself is the cause, the measured voltage or frequency is outside the trip limits, a zero-sequence overvoltage is present, or the frequency changes very sharply. Usually the inverter reconnects by itself once the grid is back to normal; if the fault keeps coming back, measure the actual grid and contact the utility if its values are outside the set range. Check on site first: is the AC circuit breaker closed, is the AC cable firmly connected to the correct terminals, and does the grid supply power reliably. If the grid is within limits and the wiring is sound, suspect the configuration: a wrong country data set can also prevent connection. If a restart does not clear the fault, or the fault keeps recurring, a service team usually has to find the cause; software issues may be fixed by a firmware update.
<!-- review notes
- sentence 2: support check: partial - The passage supports good conditions, lack of restart after grid faults and fault codes in display or data log, but not explicitly 'AC output stays at zero' or 'often'.
- sentence 6: support check: partial - A wrongly configured country data set is mentioned as a cause, but the ordering ('if grid within limits and wiring sound') is not stated.
-->
Claims
observed_as
c1 drafted · lead
Zero AC grid voltage
The inverter reports that it is waiting for grid voltage, or reports a grid power outage. Causes named in the sources: the AC breaker is open, the AC cable is miswired or loose, or the grid itself is out.
review note: support check: partial - Waiting for grid voltage, grid power outage, breaker and cable causes are stated, but zero AC voltage as a measurement is not explicit and the passages don't say the AC breaker is open.
c2 drafted · lead
Grid voltage outside limits
Over- or undervoltage measured beyond the protection trip thresholds blocks connection.
c3 verified · fact
Grid frequency outside limits
Over- or underfrequency, or a very large change in frequency, causes a disconnect.
verified by: review-workflowverified on: 2026-10-20
c4 verified · fact
Zero-sequence imbalance
The Grid Uncompliant point includes zero-sequence overvoltage beyond the hardware trip thresholds.
verified by: review-workflowverified on: 2026-10-20
c5 drafted · lead
Zero inverter AC output
The inverter does not restart after a grid fault, even though production conditions are good.
review note: support check: partial - Passages say the inverter not working despite good production conditions often reflects no restart after grid faults, but the specific zero-power and irradiance signal values are not stated.
Referenced by
Data