Residual currents

Autarco inverters are equipped with sensitive residual current monitoring to ensure safety. When this protection mechanism detects excessive leakage current, it triggers a shutdown, interrupting solar energy production. Addressing this issue promptly is crucial to restore the system's functionality and ensure continuous energy generation.

Possible causes of residual current issues:

• High leakage currents from the PV array: This is a common issue that can be caused by damaged or worn-out DC cables, poor insulation, or an improperly grounded system. If the insulation resistance decreases, leakage current can increase, potentially leading to the inverter shutting down. In such cases, it is essential to thoroughly inspect the wiring and grounding connections and repair them if necessary to ensure the stable operation of the solar energy system.
• Issues with the Residual Current Device (RCD): RCDs, especially those with low tripping values (300mA or less), can be sensitive and trip in wet or humid weather, leading to inverter shutdown.
• Environmental factors: Wet weather conditions can contribute to increased leakage current, potentially triggering RCD trips and inverter shutdowns.

Before you begin:

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 the number of strings).

Troubleshooting Steps:

1. Check the Inverter Error Code: Autarco inverters display specific error codes related to residual current detection. Common error codes include:
   • ILeak-PRO01: 30mA
   • ILeak-PRO02: 60mA
   • ILeak-PRO03: 150mA
   • ILeak-PRO04: 300mA
2. Restart the inverter: Try restarting the inverter through the display menu or by briefly disconnecting it from the power source. This can sometimes clear temporary faults.
3. Inspect Environmental Conditions: Consider whether current weather conditions could be a factor, especially if you are experiencing wet or humid weather. For large commercial projects, RCD tripping values of 300mA or less might be more susceptible to tripping in such conditions.
4. Contact Autarco support: If you are using RCDs with low tripping values, you can lower the threshold in the inverter to prevent it from tripping the external RCD. Contact Autarco support for assistance with this adjustment.

Validating Solution

After completing these steps, monitor the inverter for at least 24 hours. The inverter's display should indicate normal operation, and there should be no active alarms. If the issue is resolved, you will observe a steady power output from the inverter without any leakage current alarms.

If the problem is not resolved:

• As a system owner: 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.

Remember, while Autarco inverters have residual current suppression technology to reduce internal residual currents and slightly mitigate those from the PV array, they cannot eliminate high residual currents originating from the array itself. If the issue persists, further investigation and diagnosis of the PV array may be required.