Revitalization of the power grid: Improvement, renovation and increase of short-circuit capacity in substations

The rapid growth in electrical energy demand, driven by industrial development, urbanization, and the large-scale integration of renewable energy sources, is placing increasing pressure on existing power grid infrastructure. Many substations currently in service were designed and built decades ago based on load levels and operational assumptions that no longer reflect present or future grid conditions. Consequently, these substations face significant challenges when accommodating repowering initiatives aimed at increasing transmission capacity, as well as higher short-circuit currents that exceed their original design limits. Aging substation infrastructure poses a critical risk to system reliability and operational safety. Legacy equipment such as circuit breakers, power transformers, busbars, and protection systems often exhibit technological obsolescence, limited interrupting capability, and reduced resilience to fault conditions. In particular, insufficient short-circuit withstand capacity has become a major constraint, impacting equipment integrity, network expansion, and interconnection of new generation sources. Without adequate modernization, these limitations may result in increased failure risk, unplanned outages, and non-compliance with current technical and regulatory requirements. This paper addresses the technical and operational challenges of substation modernization with a focus on repowering and short-circuit capacity management. It proposes a structured approach starting with a comprehensive assessment of existing assets, considering equipment age, electrical performance, and remaining service life as the basis for informed modernization strategies. Special consideration is given to long-serving substations, where upgrades must be implemented while respecting space constraints, operational continuity, and safety requirements. The study also examines the role of SF₆-based equipment, highlighting its historical importance and the growing environmental and regulatory pressures that drive the transition toward alternative technologies or optimized designs. Furthermore, the paper emphasizes the use of point cloud technology based on