UN-G-V: Grid under voltage

The inverter is reporting that the utility grid's voltage is lower than the allowed limit. This safety feature can trigger the inverter to shut down.

Possible causes

Utility Grid Issue: The utility grid might be experiencing voltage drops or fluctuations that are causing the voltage to fall below the acceptable range for the inverter.
Connection Issues: There might be loose connections or a faulty grid switch, leading to a voltage drop between the grid and the inverter.

Before you begin

Safety First: Working with electrical equipment always involves risks. Ensure you are qualified and follow appropriate safety precautions. Disconnect the inverter from both AC and DC sources before performing any physical inspection or adjustments.

Gather Information: Before starting troubleshooting, have the inverter manual on hand. You should also gather information about the inverter model and serial number, the installation date, and the PV array configuration (number of panels, capacity, and number of strings).

Troubleshooting steps

Check Grid Switch and Connections: Inspect the connections at the grid switch and ensure they are secure and free from corrosion.
Measure Grid Voltage: Use a multimeter to measure the voltage at the inverter's AC input terminals to confirm that the voltage is indeed below the acceptable limit.
Contact Your Utility Company: If you confirm the grid voltage is low, contact your utility company to report the issue. They can investigate and address potential problems with the grid voltage in your area.

Validating the solution

Once the utility company has resolved the grid voltage issue, the inverter should function normally. Monitor the inverter's display to confirm that the grid voltage is within the acceptable range, and the “UN-G-V” error should disappear.

If the problem is not resolved

If the “UN-G-V” error persists despite a stable grid voltage, there might be an internal fault within the inverter.

As a system owner: In this case, contact the inverter installer or distributor for further assistance. You can find the details of your installer in the MyAutarco app.
As a certified installer: Contact Autarco Support, you can submit a support case via Helios.