Infeed: Line Supply Undervoltage

What does A06105 mean?

The filtered (steady-state) value of the line supply voltage at the infeed unit has dropped below the configured alarm threshold (p0282 multiplied by p0210). This indicates a potential issue with the incoming power supply, which could lead to operational instability or trigger more severe faults if not resolved promptly.

• Utility grid voltage sag or brownout condition, resulting in input voltage dropping below the P0282 * P0210 threshold.
• Overloaded upstream transformer or distribution circuit causing excessive voltage drop during heavy load transients.
• Loose connection or high resistance in the main incoming power circuit (e.g., main contactor, fuses, input terminals L1/L2/L3).
• Incorrect setting of parameter P0210 (Voltage factor for line phase monitoring) or P0282 (Undervoltage threshold) for the actual line voltage.
• Faulty voltage measurement circuitry within the infeed unit providing an inaccurate or falsely low reading.

Click steps to track your progress.

1. 1

   Monitor the actual line supply voltage at the infeed unit's input terminals (e.g., L1, L2, L3) using a true RMS multimeter and compare it to the nominal voltage (e.g., 400V).

2. 2

   Check parameter P0210 (Voltage factor for line phase monitoring) and P0282 (Undervoltage threshold) to ensure they are set appropriately for the nominal grid voltage and desired alarm sensitivity.

3. 3

   Inspect the main incoming power circuit, including main contactor contacts, fuses, and terminal connections, for signs of overheating, corrosion, or looseness.

4. 4

   Verify that other heavy-load equipment on the same supply circuit is not drawing excessive current, causing a voltage sag on the common bus.

5. 5

   Consult utility power quality logs, if available, to identify external grid disturbances or voltage fluctuations.