Author: Gerd vom Bögel, Fraunhofer IMS
This article shows a use case of the Energy ECS project [1], in which the development and realization of suitable components for condition monitoring of electrical distribution grids is carried out. By means of suitable sensor systems, communication and IT infrastructure components, relevant information on network infrastructure elements at neuralgic points is collected, aggregated and communicated. This information can be used directly for a highly dynamic grid-serving control of grid components to ensure a robust and efficient use of the distribution grid also for the wide-range charging of EVs. The main objective is the development and realization of energy-autonomous sensor systems for recording the status of relevant components of the distribution network. The work to be carried out includes sensor principles as well as the field of energy harvesting or the field of sensor signal processing [2].
Fig. 1. Monitoring points in the electrical distribution grid
Critical points in the distribution network were identified in discussions with distribution grid operators. Overloads can occur due to increased power draw, e.g. by EV charging, and due to decentralized feed-in by renewable sources, e.g. photovoltaic power favoured by weather conditions. The two most important spots are transformer stations and distribution cabinets. Fig. 2 shows a typical distribution cabinet as used in residential areas to distribute electrical power to the streets.
The main parameters to be measured are current and phase between voltage and current in each conductor. Further values can be derived from these basic parameters by calculation and signal processing.
Fig. 2. Typical distribution cabinet (left) and cable connection (right). The intended position of the sensor inside the distribution cabinet is marked with a green circle in the right photograph. Each connected cable will be equipped with a sensor module.
The concept for the sensor systems uses inductive energy harvesting and avoids so contacts to the three phases. According to the developed concept, the outgoing conductors will be equipped with energy-autonomous wireless sensor systems primarily for current and phase measurements. Fig. 3 shows the principle with a harvester for energy harvesting and current measurement and with a phase detector for each wire.
Fig. 3. Sensor module attached to a cable with harvester/current sensor and phase detector.
The data is transmitted via LoRaWAN radio interface to the microgrid controller (Fig. 1) and from there to the network operator’s control center for further evaluation and grid control.
Reference
- Energy ECS Project, Smart and secure energy solutions for future mobility | Energy ECS Project | Fact Sheet | H2020 | CORDIS | European Commission (europa.eu)
- WIKIPEDIA, “U.S. Department of Energy: “What Is the Smart Grid”,” (Online) Available: https://upload.wikimedia.org/wikipedia/commons/6/6a/What_Is_the_Smart_Grid-.webm (last accessed 21st March 2023)
- L. Cousin, P. Gembaczka, A. Grabmaier and A. Hennig, “Smart Self-Sufficient Wireless Current Sensor,” in Fraunhofer-Institut für Mikroelektronische Schaltungen und Systeme, Duisburg, 2018.
