Maturity status | Stable |
This article explains what phase allocation is, why it matters for load management, and how to configure it in the XENON Dashboard. For sites with AC or single-phase chargers, correct phase allocation is important for load management to optimize per-phase power distribution.
What is phase allocation?
Phase allocation defines which electrical phases each EV charging station (EVCS) is physically connected to. The Energy Management System (EMS) uses this information to optimize charging on individual phases — not just at the overall Grid Connection Point (GCP).
Incorrect phase allocation can lead to suboptimal power distribution or, in the worst case, damage to electrical components.
Why does phase allocation matter for load management?
Load management controls charging power per phase to avoid phase asymmetry and respect per-phase import limits. To do this correctly, the EMS needs to know the exact phase wiring of each EVCS.
How does the EMS use phase allocation?
The EMS uses two inputs to make per-phase decisions:
Phase arrangement — determines which EVCS is connected to an overloaded phase and should be curtailed first
EV characterization — any newly plugged-in EV is initially assumed to be three-phase and given brief charging priority to determine its actual phase behavior. This is necessary because the phase information is initially unknown to the charger.
Once the phase arrangement is known, the EMS enforces the configured import limit on each individual phase — ensuring that no single phase is overloaded, even when the total GCP limit is not yet reached.
What are the requirements for phase allocation?
All EVCS must be installed with symmetrical phase rotation
A physical wiring connection document must be available at commissioning
When phase mapping is essential:
Sites with single-phase or AC chargers — the EMS must know which phase each charger is connected to in order to balance load correctly across phases
When phase mapping is not required:
Sites with DC-only chargers — DC chargers convert power internally and do not impose phase imbalance on the grid
How do I configure phase mapping in XENON?
In XENON, go to the Assets tab at the site level
Click the action button for the EVCS and select Phase mapping
Assign each phase of the charging station to the corresponding network phase according to the physical wiring document
For clarity, a schematic wiring diagram with the corresponding settings is shown below.
