This article explains what zero-curtailment protection is, how it prevents EVs from being curtailed to zero during load management, and how to activate and configure it.

Zero-curtailment protection ensures that all connected EVs receive at least a minimum charging power during load curtailment, rather than being cut to zero.

Without the feature activated, when grid capacity is constrained, the EMS can curtail non-prioritized EVs down to zero power. With zero-curtailment protection enabled, each charger on the site is assigned a minimum power floor. The EMS respects this floor before distributing any remaining capacity, so lower-priority EVs continue charging at a baseline level rather than stopping entirely.

When zero-curtailment protection is active, the EMS reserves the minimum power floor for each connected charger before distributing remaining capacity. This means non-prioritized EVs are no longer curtailed to zero before prioritized EVs begin to be curtailed.

The minimum power floor is determined as follows:

Important: the minimum power floor applies on a best-effort basis. If total available capacity is so constrained that the site cannot cover every active charger at its minimum level, chargers are still curtailed to zero. The floor only holds when there is enough power to cover all active chargers.

Step 1: Enable the feature

In XENON, open the site's Energy Management Configuration and edit Zero-curtailment protection. Toggle Zero-curtailment protection on. By default, Use EVCS default minimum power is also on, so the charger driver's own minimum power value is used automatically — no further configuration is required.

Step 2: Set a minimum power value (optional)

If the hardware driver default is not appropriate for your site, toggle off Use EVCS default minimum power and enter a Custom minimum charging power value in kW. If this value is lower than the driver's minimum, the driver's value is used instead.