Worked on the e2nIEE/pandapower repository to address a critical bug affecting low-voltage short-circuit calculation accuracy in compliance with IEC 60909 standards. The solution involved tuning the cmin and cmax tolerance parameters to ensure correct behavior under low-voltage conditions, directly improving the reliability of protection coordination for grid analysis users. Expanded unit and integration tests were implemented to validate the fix and prevent future regressions. The work was carried out using Python, with a focus on backend development, data analysis, and rigorous testing practices to enhance model trust and maintain traceability through detailed commit documentation.