Virtual energy meters and meter aggregation

The term virtual meter is used for several different configurations. Choose the option based on the electrical question you need to answer.

Aggregate several physical energy meters

Use this topology when several measured feeders together form one common control boundary. Typical examples are two transformer feeders behind one shared site limit, or several departures whose powers must be summed for curtailment.

Meter A  ──┐
           ├──  Shared switchboard total = Meter A + Meter B
Meter B  ──┘

Configure the aggregate

1. Add every physical energy meter and verify that each one reports plausible power and energy values.
2. Open Groups and enable Advanced groups.
3. Create a Switchboard that represents the shared electrical boundary.
4. Add the physical meters as members of that switchboard.
5. Organise the controlled devices and any lower-level switchboards according to the single-line diagram.
6. Confirm that the calculated switchboard power equals the sum after applying the configured direction of each physical meter.
7. Test import, export, and the intended control action before commissioning the site.

An energy meter that is assigned to a device or group has a different meaning: it measures that entire child branch. Do not also add the same electrical flow elsewhere in the group tree, because it will be counted twice.

Transformer and connection limits

Keep the hierarchy faithful to the electrical installation:

• use a common parent switchboard only for a limit that applies to the sum;
• keep a switchboard per transformer or feeder when it has its own current or power limit;
• configure both the shared site limit and the lower-level equipment limits when both apply;
• use separate EMS configurations when grid connections must operate independently.

For complex multi-transformer sites, validate the proposed single-line diagram and failure behaviour during commissioning before enabling automatic curtailment.

Calculate an unmetered remainder

A virtual energy submeter estimates the part below one real meter that is not covered by its other measured children.

Virtual remainder = Real parent meter - all other known child branches

For example, a main meter measures a complete switchboard and a branch meter measures the EV chargers. The virtual submeter can represent everything else on that switchboard.

Create the virtual submeter

1. Open Groups and use Advanced groups.
2. Choose Assign an energy meter to a device or a group.
3. Select the real energy meter and the branch it measures.
4. Select the checkbox Add a virtual energy submeter.
5. Assign the meter.
6. Verify the calculated power and imported/exported energy with a known site state.

The controller creates a meter named after the measured branch with remaining energy (virtual meter) appended.

Boundaries of a controller virtual submeter

• It is a fixed residual calculation, not an arbitrary formula editor.
• Only one virtual submeter is supported below a real meter.
• A virtual submeter cannot be selected as the grid energy meter.
• It is intended for remaining-energy measurements below its real parent meter.
• Removing the parent-meter assignment also removes its automatically created virtual submeter.
• Import and export are netted correctly when the subtraction crosses from one direction to the other.

Create an analysis-only virtual meter

For arbitrary sums, differences, and scale factors in charts, use Virtual meters in SmartgridX Monitoring.

That function is well suited to questions such as:

• Transformer total = Meter A + Meter B;
• Unmetered load = Main meter - Submeter A - Submeter B;
• comparing a calculated total with an existing physical reference.

It does not change the controller configuration and cannot be used as a setpoint or grid-control meter.

Commissioning checklist

See Grouping devices for the advanced group editor and Supported energy meters for device-specific wiring and setup.