Victron Grid Codes and Loss of Mains Detection: Configuration and Safety

Key Takeaways

• Loss of Mains (LOM) detection is a critical safety feature that prevents back-feeding into the grid.
• Disabling LOM detection requires a password and may necessitate external anti-islanding safety devices.
• Grid codes are country-specific regulations ensuring safe and compliant operation with the utility.
• Always contact your Victron dealer for password-protected settings or if you intend to disable LOM detection.

What are Victron Grid Codes and Loss of Mains Detection?

Victron Energy inverter/chargers, including Multis, Quattros, and MultiCompacts, are designed to operate safely and compliantly with utility grids. A key aspect of this compliance is Loss of Mains (LOM) detection. LOM detection is an automatic process that identifies when the main utility grid supply is lost. This feature is essential for preventing dangerous conditions during a grid outage.

Grid codes are country-specific regulations that define the requirements for grid-connected equipment. These requirements cover aspects such as the speed of LOM detection, acceptable under and over voltages, and allowed ramp times for power changes. Victron devices with VE.Bus firmware 419 and later are designed to adhere to these various grid codes. For example, the MultiPlus-II is certified for installation in Germany without requiring additional external anti-islanding safety devices.

Understanding Loss of Mains Detection

The primary purpose of LOM detection is safety. When a power outage occurs, the inverter/charger must immediately disconnect from the grid to prevent back-feeding electricity onto the utility lines. This is crucial for the safety of utility workers who might be working to restore power.

After detecting a loss of mains, the inverter/charger will open its back-feed relay. This action ensures there is no live AC voltage on its AC inputs, and consequently, on anything connected to these inputs that would otherwise be connected to the grid. Not performing this disconnection would be unsafe, as it could energize lines that utility personnel believe to be de-energized.

Configuring Loss of Mains Detection in VEConfigure

Configuring LOM detection settings is done using the VEConfigure software. This software allows you to adjust various parameters of your Victron inverter/charger.

Steps to adjust LOM detection:

1. Access VEConfigure: Connect to your Victron inverter/charger using the VEConfigure software.
2. Navigate to the Grid Tab: Once in VEConfigure, locate and open the "Grid" tab.
3. Change LOM Detection Setting: Within the Grid tab, you will find the LOM detection setting. You can change this setting to "None" if required.
4. Password Requirement: Be aware that changing the LOM detection setting to "None" requires a password. You must contact your Victron dealer to obtain this password and for guidance on disabling this critical safety feature.

Disabling LOM detection should only be done under specific circumstances and with appropriate safety measures in place.

Safety: The Importance of Anti-Islanding

Loss of Mains detection is a form of anti-islanding protection. Anti-islanding refers to the ability of a grid-tied inverter to detect when the grid has failed and to cease supplying power to the grid. This prevents the formation of an "island" of energized circuits that are disconnected from the main utility grid but are still being powered by local generation, such as your solar system.

If you disable LOM detection on your Victron inverter/charger, you create a potential safety hazard. In such cases, external anti-islanding safety devices, such as those from Ziehl or other brands, are required to maintain safety and compliance with local regulations. These external devices provide the necessary protection to prevent back-feeding into a de-energized grid. Always ensure that your system complies with all local grid codes and safety standards, especially when modifying critical safety settings.

When to call a technician instead

While some settings can be adjusted by users, critical safety features like Loss of Mains detection often require specialized knowledge and access. If you are unsure about any setting in VEConfigure, especially those related to grid interaction or safety, it is always best to consult a qualified Victron installer or your dealer.

Disabling LOM detection without understanding the full implications and without installing appropriate external anti-islanding devices can create a dangerous situation and may void your warranty or violate local electrical codes. Your dealer can provide the necessary password for protected settings and advise on the correct external safety measures required for your specific installation.