An Annual Quasi-Static Time-Series Simulation Framework for Enhanced Transmission System Expansion Planning

Traditional transmission system expansion planning (TSEP) relies on snapshot-based and deterministic approaches that fail to capture the temporal dynamics of modern grids with high distributed energy resources (DERs) and variable renewables. Hussein Suprême and colleagues at Hydro-Québec and partner institutions propose an annual quasi-static time-series simulation (AQSTSS) framework that models system performance hour-by-hour across all seasons and operating conditions. This high-resolution approach incorporates detailed equipment behavior, control strategies, and DER interactions, bridging the gap between long-term planning and real-time operational needs.

Applied to Hydro-Québec's projected 2035/2036 grid under high wind and electric vehicle penetration, the framework reveals critical insights: it identifies flexibility opportunities and operational constraints overlooked by static methods, integrates an energy storage control strategy specifically designed to mitigate wind variability, and enables resilience assessment under extreme weather and load variability. The results demonstrate that aligning planning with operational realities is essential for secure, efficient, and future-ready grid development. The paper (arXiv:2605.00231) is a significant step toward more robust TSEP.