The text below is the transcript from the Smart Charging Connections: Centrally Managed Constraint Scheme video.
Video Title: Centrally Managed Constraint Scheme
A centrally managed constraint scheme is required when chargepoint demand could potentially overload the network at multiple locations.
To ensure that network capacity is not exceeded, a central DNO system sends instructions to the chargepoint operator’s chargepoint management system.
In this example, power demand from the chargepoints at a fuel court could potentially overload sub-stations A & B and jeopardise the town’s electricity supply.
Initially, vehicles are able to charge at maximum power.
The load increases at both sub-stations, but marginally more at sub-station B.
As more vehicles begin to charge, the demand at both sub-stations increases, with sub-station B nearing its threshold. However, the chargepoints are still able to operate at maximum power.
As the surrounding area’s electricity demand increases, the DNO’s central system detects that sub-station B is about to reach its maximum load.
To prevent this, the system automatically instructs the fuel court’s chargepoint management system to reduce demand by constraining the chargepoints’ power output.
With chargepoint demand reduced, the load at sub-station B reduces to an acceptable level.
As network demand reduces and the load at both sub-stations returns to acceptable levels, the constraint at the chargepoints is automatically lifted.
Charging can now resume at maximum power.
This scheme would work equally well if a potential overload had occurred at sub-station A.