SOLORMAX project - a real-time digital twin demonstrator for renewable curtailment optimization in low voltage networks based on grid state estimation

High residential photovoltaic (PV) penetration in Belgium has led to increasing overvoltage issues in low-voltage distribution networks. The SOLORMAX project addresses these challenges through the use of a digital grid twin, enabling automated voltage regulation based on state estimation (SE) and active power curtailment. The digital twin is validated in a real-world field trial, incorporating actual household behavior, consumption profiles, and customer responses to voluntary grid-supportive control. A key innovation of the project is the implementation of an alternative control approach not relying on smart meter gateways (SMGWs). Instead, control signals are transmitted via Nexxtlab’s Smartmaster and dongle devices, enabling direct communication with PV systems by a digital twin without the involvement of metering point operators. This architecture offers a streamlined and interoperable solution suited for deployment across different regulatory environments in the EU. Complementing the field demonstration, a theoretical analysis is performed to determine the minimum number of sensors required for accurate state estimation across the network—without depending on transformer or substation measurements. The study shows that random sensor deployment at grid connection points achieves robust estimation results, with approximately 10% coverage being sufficient for reliable operation for rural branch networks. The results demonstrate that the digital grid twin, combined with a lightweight and secure communication architecture, provides an effective and scalable strategy for voltage management in distribution networks with high PV penetration. Additionally, the sensor placement analysis delivers practical guidance for distribution system operators (DSOs) seeking to implement advanced grid monitoring and control without costly infrastructure upgrades.