Distribution substation

A smart secondary substation gives grid operators continuous condition data such as voltages, currents and temperatures, recorded by its sensors and sent to an IoT platform. This gives the grid operator a real-time view of the load on its low-voltage network. At Regionetz, the data flows via MQTT and Kafka into the IoTnova platform and into a digital twin of the low-voltage grid, which grows with every additional substation that is equipped.

Monitoring distribution substations provides the data a German grid operator needs for load management under Section 14a of the Energy Industry Act (EnWG). Regionetz wanted to see grid loads in real time and be able to intervene early in the event of overloads. The sensor data from the substations is therefore passed to downstream systems that implement the Section 14a functions. According to the project report, the architecture is scalable and compliant with Section 14a EnWG.

OT security continuously monitors the communication of the grid control system for anomalies and suspicious activity. At MEGA Monheim, the Rhebo Industrial Protector system also analyses communication from and between several hundred substations. The aim was an alarm system that detects successful unauthorised access, for example via stolen credentials, at an early stage. Every week, the team reviews the alerts with Rhebo specialists and builds up its own OT security expertise in the process.

Monitoring data reaches the grid operator's systems via a messaging protocol such as MQTT and a central data hub. At Regionetz, the sensors send their data to a HiveMQ broker, and a Kafka instance distributes it to the business systems. New systems can be connected this way without fixed interfaces. Certificate management from ECOS secures the communication channels, and a second HiveMQ instance with geo-redundancy is planned to increase resilience.