How does the relay switching work on EMS

The relay switch function on the EMS is primarily designed to control based on the grid connection measurements. This means that the measured grid connection is used to determine whether a relay should be turned on or off.

Export to the grid

It is possible to connect relay-controlled devices that only respond when there is export to the grid. The EMS controller detects the presence of surplus energy and, depending on priority and nominal power, will switch these relays on.

This example is given with devices 1 through 3.

Grid consumption limit

It is possible to connect relay-controlled devices that respond when the grid consumption approaches or exceeds the connection limit. For example, if there is a 10 kW limit and the grid consumption approaches 10 kW, the EMS will check which low-priority devices can be switched off first to stay below the limit. Once the consumption returns to a safe level within the connection limit, these devices are switched back on.

This example is shown with devices 3 through 5.

Device priority

Relays are switched on according to priority. Devices with the highest priority are turned on first. For switching off, the order is reversed: devices with the highest priority are turned off last.

When devices have the same priority, the EMS controller considers the nominal power to determine which device is best suited to be switched on or off at that moment.