Power Quality Analysis and Improvement of Power-to-X Plants Using Digital Twins: A Practical Application in Denmark

This paper presents an analysis of a Power-to-X (PtX) system with a specific focus on the integration of Solid Oxide electrolyzers Cell (SOC) for renewable hydrogen production within the practical Power-to-Hydrogen (PtH) platform located in Denmark. The investigation spans the physical PtX system and includes the design of its energy conversion system's Digital Twin (DT), which models the energy conversion process from renewable energy to various types of SOC electrolyzers through different layers of power converters, referred to as the Digital Power Twin (DPT). The proposed DPT framework fed by real-time data from the physical system over short and long-term durations establishes a bidirectional relationship through a measurement layer and a LoT-based cloud. This framework proves essential for optimizing operations that harness real-time insights and ensure continuous improvement in PtX system efficiency. This research examines the energy conversion system of the PtH platform and emphasizes the pivotal role of DPT in enabling advanced predictive capabilities, real-time analysis and simulation. The experimental and simulation results first demonstrate the accuracy of the designed DPT and then address the power quality challenges, particularly harmonic distortions and voltage regulation. The study also presents a compensation approach utilizing multi-level Shunt Active Power Filters (SAPFs) and their adaptive control strategy. This paper discusses the potential effect of large-scale PtH systems on future power grids. The findings contribute to a comprehensive understanding of the complexities regarding the PtH system integration and provide solutions to boost scalability and enhance power quality.