DCInj-FAULT: DC injection protection fault

This guide explains how to troubleshoot a "DC Injection Protection" error, which can also be displayed as "DCinj-FAULT", on an Autarco inverter. This error occurs when the inverter detects direct current (DC) flowing into the alternating current (AC) grid.

Why it's problematic

DC injection into the AC grid is a safety hazard that can disrupt grid operations and potentially damage grid equipment.

Possible causes

Grounding issues: Incorrect grounding of the PV system can lead to DC current leakage into the grid.
Faulty inverter components: A malfunctioning component within the inverter might cause DC to leak into the AC output.
Wiring problems: Damaged or incorrectly connected wiring can create pathways for DC current to flow into the grid.

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 AC and DC connections: Ensure all AC and DC connections are tight and secure. Look for signs of damage, such as melted insulation or loose terminals.

Verifying the solution

After performing the troubleshooting steps, power on the inverter. If the "DC Injection Protection" error disappears and the inverter functions normally, the problem is likely resolved.

If the problem is not resolved

If the error persists, there might be a more complex problem, like a faulty inverter component or undetected grounding issues.

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.