AI L2 Over Voltage

What does F28 mean?

This fault indicates an L2 over-voltage condition (135 VAC) detected by the anti-islanding protection, triggering a fast disconnect. This mechanism ensures the inverter disconnects from an unstable grid, protecting both the inverter and grid from potential damage due to excessive voltage.

• Grid L2-Neutral voltage exceeding 135 VAC due to a grid transient, voltage surge, or utility grid instability.
• High reactive power compensation or sudden load shedding on the grid causing a momentary voltage swell on phase L2.
• Inverter's L2 voltage sensing circuit experiencing calibration drift or hardware failure, leading to an inaccurate over-voltage detection.
• Anti-islanding parameter P_AI_L2_Volt_Max_Fast set too low or configured incorrectly for the operating grid conditions.

Click steps to track your progress.

1. 1

   Using a true RMS multimeter, measure and record the L2-Neutral voltage at the inverter's AC input terminal L2 over several minutes, looking for spikes.

2. 2

   Compare measured L2-Neutral voltage values to the specified 135 VAC trip threshold and the inverter's P_AI_L2_Volt_Fast parameter.

3. 3

   Inspect the wiring connection for the L2 phase and neutral conductor at the inverter's input terminals for looseness or damage.

4. 4

   Review the inverter's event log for occurrences of high L2 voltage readings that correlate with fault triggers.

5. 5

   If grid conditions appear stable and parameters are correct, perform a diagnostic check on the inverter's internal L2 voltage sensing circuit or contact service.