Victron Grid Codes and Loss of Mains Detection Troubleshooting

Key Takeaways

• Overload shutdowns or feed-in issues can stem from unstable Loss of Mains (LOM) detection, especially with weak grid connections or generators.
• Always check your Victron inverter's firmware version (VE.Bus firmware 419 or later) using VEConfigure before adjusting grid code settings.
• Disabling LOM detection on a utility-connected input requires external anti-islanding safety devices for critical safety.
• Contact your Victron dealer for the necessary password to change LOM detection settings in VEConfigure.

Why is my Victron inverter shutting down or having feed-in issues related to the grid?

Overload shutdowns or temporary disabling of feed-in on Victron inverters can occur if the Loss of Mains (LOM) detection algorithm becomes unstable. This instability is often triggered by a high impedance grid connection, such as a generator or a long extension cable. This can cause a safety mechanism to activate, temporarily disabling feed-in or causing the unit to switch itself off in overload.

Diagnosis

Follow these steps to diagnose issues related to Victron grid codes and Loss of Mains detection:

1. Check for overload shutdowns: Observe if your inverter/charger is frequently switching itself off due to overload. This can indicate that the LOM detection algorithm is becoming unstable.
2. Monitor feed-in status: Note if your system experiences temporary disabling of feed-in. This can be caused by continuous increases and decreases in frequency due to a too weak connection to the utility.
3. Identify grid connection type: Determine if your system is connected to a stable utility grid, a generator, or a high impedance connection (e.g., long extension cable). High impedance connections can destabilize the LOM detection algorithm.
4. Verify firmware version: Use VEConfigure to check the firmware version of your VE.Bus inverter. This document's information applies to VE.Bus firmware 419 and later.

Cause/fix table

Configuring Victron Grid Codes and LOM Detection

Victron VE.Bus inverters, including Multis, Quattros, and MultiCompacts, are designed to comply with local grid regulations through configurable grid codes and Loss of Mains (LOM) detection. The MultiPlus-II is certified for installation without requiring additional external anti-islanding safety devices (ENS) in Germany.

To configure these settings, you will use the VEConfigure software. Ensure your system is running VE.Bus firmware 419 or later.

Understanding Grid Codes

Grid codes are essential settings that ensure your installation complies with local regulations. These regulations dictate various parameters, including LOM detection speed, under/over voltages, and ramp times. Selecting the correct grid code is necessary for regulatory compliance.

Even if LOM detection is disabled on an AC input, the inverter/charger will still use the acceptance limits required by the selected grid code. To make the inverter less restrictive on that input, you can set the grid code to "None", "Other", or "Germany: VDE-AT-N 4105:2018-11 external NS protection" when external anti-islanding safety equipment is in place.

LOM Detection Types

Victron offers different LOM detection types to suit various grid conditions:

• Type A: This is the strongest form of LOM detection, resulting in the quickest detection time. It requires a low impedance connection to the grid, meaning short, well-sized cables. LOM Type A will not work with generators.
• Type B: This type has a more soft approach and a slightly longer detection time. LOM Type B has been type tested and approved for most Multi/gridcode combinations and works better with generators or high impedance mains connections.

Disabling LOM Detection

There are situations where you might need to disable LOM detection. This is done through VEConfigure, on the Grid tab.

• Temporary Disabling: To temporarily disable LOM detection for troubleshooting overload issues, you can change the LOM detection setting to "None". This requires a password, which you can obtain from your dealer.
• Permanent Disabling: To permanently disable LOM detection for certain generators or when LOM causes issues with the utility connection, you can choose "Disabled" in the LOM options. This also requires a password from your dealer.

Safety: Critical Considerations for LOM Detection

Loss of Mains (LOM) detection is an automatic process designed to detect a loss of the mains/network/grid supply. After detection, the inverter/charger opens its back-feed relay, ensuring there is no live AC voltage on its AC-inputs and anything connected to these inputs. This is a critical safety feature.

Safety with Disabled LOM (Utility Connection)

Disabling LOM detection on an input connected to the grid is only allowed when other external safety equipment is installed, specifically an anti-islanding safety device. Victron does not manufacture such products; a common brand is Ziehl. It is crucial to comply with local rules and regulations, as this is a critical safety issue.

Safety with Disabled LOM (Generator Connection)

There is no regulatory need to install external anti-islanding equipment when disabling LOM in combination with a generator. However, you must ensure clear signage and other means to make it very clear to any installer working on the generator that they must also switch off, or otherwise disconnect, the inverter/charger system. For less stable generators, if LOM must be disabled entirely, the installation must be made safe. This includes avoiding simple extension cords, using enclosed wiring cabinets with warnings on the outside, and/or installing an external anti-islanding safety device (ENS).

ESS in Vehicle/Boat Safety

Using an Energy Storage System (ESS) in a vehicle or boat with LOM detection can pose a safety risk. After unplugging the shore cord, it can take up to a few seconds for the system to detect the loss of mains and open the back-feed relay. During those seconds, the shore power plug will be live, meaning there is 230 Volts AC on the terminals. This is not recommended due to the potential for a live shore cord after unplugging.

When to call a technician instead

You should contact a qualified technician or your Victron dealer if:

• You require the password to change LOM detection settings in VEConfigure.
• You need to install external anti-islanding safety devices (ENS) for a utility-connected system where LOM detection is disabled.
• You are unsure about selecting the correct grid code for your specific region and installation type.
• Overload shutdowns or feed-in issues persist after attempting basic troubleshooting steps.
• You need assistance with complex system configurations or compliance with local regulations.