Starting from the initial targets - 70% reduction of time to outage diagnosis, 10% reduction of LV grid losses, 60% reduction of voltage quality issues, 30% reduction of grid reinforcement costs - the Net2DG project developed a set of novel observability applications for Grid Monitoring and Analysis, Loss Calculation, Outage Detection & Diagnosis. These applications are running on top of a Net2DG developed ICT-Gateway that enables a digital twin of the low voltage distribution grid from the fusion of heterogeneous data sources for grid topology and measurements in the grid. Based on the available integrated and normalized data, calculations of not-measured relevant electrical parameters are performed through an integrated observability grid model which supports a smooth execution of the aforementioned applications and enables a fully digital process for operation and planning of the low voltage grid. In addition, coordinated control of reactive power behaviour of inverters in the low-voltage grid has been addressed via the Automatic Voltage Regulation application, which also is executed on top of the ICT-Gateway.
The integrated Net2DG system has been deployed in two field environments, one at Stadtwerke Landau a.d.Isar in Germany, and the second at Thy Mors Energi in Denmark. In addition, the technical benefits of the system have been assessed through a real-time Hardware-in-the-Loop laboratory setup at Aalborg University and through extensive offline simulations.
The results from the assessment through the combination of field trial analysis, laboratory setup, and offline analysis showed the following benefits in the scenarios of the German and Danish low-voltage field trial grids: (1) Outage detection and diagnosis time in the low-voltage grid could be reduced to few minutes; (2) Grid losses could be reduced by 11% via voltage management applied in combination with continuous voltage monitoring; when applying a variant of the reactive power coordination of inverters, a reduction by even 20% was possible. (3) The hosting capacity of the field trial example grid was increased by 30% through an enhanced planning process using the digital grid status, and an additional 50% increase was achievable through the coordinated reactive power management of the inverters.
Figure 3 shows the result visualized by the Net2DG solution for an outage scenario. Figure 4 shows the corresponding physical grid scenario, namely that a short circuit fault has been caused in the marked place on one cable, which in this scenario caused a fuse in a junction box to burn. Due to the Net2DG solution, the DSO can immediately send repair staff to the identified locations.
Therefore, the results clearly show the benefits of the developed Net2DG solution for the future digital operation and planning of the low-voltage grids and that such digitalization will be a critical contributor to the realization of the energy transition. The project in addition quantified the resulting financial benefit of low-voltage grid observability using a Cost Benefit analysis based on data and input from the two DSOs in the Net2DG consortium. The developed integrated prototype system has been shown to in total more than 100 DSO participants on a series of three workshops and a demonstrator has been shown at European Utility Week 2019 and E-World 2020. Finally, the Net2DG approach and individual solutions have been disseminated in the scientific community via, e.g. three organized workshops in connection to high-reputation international conferences, and 18 published peer-reviewed publications.
