In Germany, energy grid providers are concerned about grid stability. In many towns and municipalities, for example, the electrical connection of the town is not sufficient to transport the corresponding quantities of electricity to the sub-distributors (districts) or streets. As a result, even new buildings can rarely be fully equipped with charging points for electric cars because there is simply not enough electricity to be transported. While a household socket transports 3.6kW, there are wallboxes with 11kW and 22kW, which transport correspondingly higher amounts of electricity. If you multiply this by the number of parking spaces, large amounts of electricity can theoretically be demanded at the same time.
Due to the theoretical maximum load, load management systems are prescribed for the installation of multiple wallboxes in order to prevent blackouts. These communicate with each other via a data cable in order to distribute the total amount of calculated electricity provided between all charging points accordingly. If there is only one wallbox, this is usually not necessary as there is enough electricity available. If there are 2 or 3 wallboxes, there could be peaks, so that instead of e.g. 4x 22kW = 88kW, only 50kW may be drawn as the maximum quantity. Each charging point would accordingly receive a maximum of 12.5 kW. If a charging point draws less, the released quantity is distributed to the other points.
The information required for this is shared via a data cable, i.e. via a network. This can be implemented using a LAN or WLAN-based solution. The control unit must be accessible online, i.e. externally, so that the energy supplier can dynamically adjust the maximum amount of electricity for charging electric cars in the event of bottlenecks in a street, district, town or municipality.
The suppliers do this via load management systems that they can access. The city of Dreieich, for example, has opted for the manufacturer ABL so that they can control all charging infrastructures via ABL software. This means they do not have to keep track of heterogeneous landscapes and their specifics, which reduces complexity in terms of management.
In addition to the actual power connection via the respective meter, the load management system requires Internet access and a data connection to the respective charging points. The electricity meters for this are often located in the basement, so that load management is also installed there when the electrical wiring is laid.
If electrical cables already exist, a different solution can be found for data connections. For example, there are WLAN and LAN solutions that can be integrated into existing networks. This requires good planning in terms of WLAN coverage to ensure a stable connection. For my scenario, I have therefore identified the eMC2, for example, as load management, including 2 charging points, which is accessible online via WLAN for the network provider. Additional charging points (ABL Pulsar or ABL eM4) can be integrated via the same network in order to interact with the load management system and implement the load management in accordance with the specifications.
Please see my post EV-Charging in Dreieich, Hessen for a deep dive for charging points.
