Worked on the PyPSA/pypsa-eur repository to address a critical geographic modeling issue affecting the Ultranet HVDC link endpoint. By correcting the endpoint from Philippsbourg, France to Philippsburg, Germany, the update improved the accuracy of cross-border power flow modeling and ensured compliance with TYNDP 254 requirements. The solution involved careful analysis of clustering logic to respect country borders, preventing misattribution of flows in downstream dispatch results. Leveraging skills in documentation and technical writing, the work enhanced model fidelity for policy and investment analysis. All changes were thoroughly documented and linked to reproducible tests, supporting transparent and auditable development practices.