Optimising a Substation's Own Requirements

Thanks to battery storage with emergency power capability, the substation's requirements are also supplied in the event of a power failure

The substation houses communication nodes of the fibre optic network and equipment for the secure grid management of the power grid, such as protective devices and remote-controlled switchgear. These devices are supplied via an uninterruptible power supply system (UPS). The UPS system consists of rectifiers that feed lead-acid batteries. These lead batteries guarantee a certain degree of self-sufficiency. Thanks to the ecoBatterySystem, with a capacity of 45.5 kWh and a charging and discharging capacity of 22 kW, the bridging time can be extended considerably, thus avoiding the use of emergency diesel generators. Without energy production from the PV system, the battery storage system can ensure the operation of the UPS system for up to 17 hours via emergency power capability. With the energy production of the PV system, there is the opportunity to extend operation even further, as the ecoBatterySystem from ecocoach AG enables the battery to be charged with the PV system during daylight hours in the stand-alone grid.

Optimising self-consumption for the operation of the substation

As much of the energy produced by the 110 kWp PV system should be used to operate the substation. Thanks to the installed battery storage and the monitoring system, self-consumption can be optimised accordingly.

Normally, PV systems of this size are difficult to combine with battery storage systems in the stand-alone grid, as they deliver more power than the battery storage system can absorb. However, as we can measure and control the PV inverter directly with our energy management system, the ecoEnergyCoach, the combination is possible. The battery storage system absorbs as much energy as possible. Once the maximum has been reached, the residual energy from the PV system is regulated back so that the stand-alone grid does not collapse.

The ecocoach cloud solution meets high-security standards

The security requirements for cloud solutions and network connections are very high in a substation. We, with our software developers, had to clarify whether ecocoach's software and cloud solution met the necessary security standards. For example, no external connections are permitted. Even so-called VPN tunnels are not sufficient to guarantee security. With such a connection, it is unclear to the customer precisely what data is being transmitted. In our case, however, we work with a TLS-encrypted TCP connection that fulfils the security requirements. In addition, we can manually configure the control system's IP settings on-site, allowing us to store the customer's DNS servers. This project in Kaiseraugst, therefore, demonstrated that the encrypted connection method from the controller to the cloud can still be used for the specific customer customisations on the controller and is thus very well monitored. TLS encryption ensures uniquely defined and controlled connections from the controller to the cloud, not least through customer-specific DNS resolutions.

This project is interesting for ecocoach AG due to various aspects: It demonstrates a new and promising application area for the battery storage system, the ecoBatterySystem. Following a test phase, further AEW Energie AG substations will be equipped with a PV system and a battery storage system in the future.