Contingency analysis in power Systems: A Comprehensive review of Methods, Challenges, and applications

Contingency analysis is essential to the reliability and resilience of modern power systems, especially as grids face rising demand, broader interconnections and increasing renewable penetration. This review presents a global synthesis of N-1 and N-2 contingency studies performed on real transmission networks (2015–2025). By examining outage behaviors and operational vulnerabilities in emerging grids, the study highlights recurrent weaknesses and convergence issues under stressed conditions. The review provides a structured overview of contingency analysis methods, covering classical power-flow techniques and sensitivity-based indices. It also documents the major simulation platforms for modeling line outages, tracking overload propagation, and assessing voltage-regulation. By mapping these constraints to the mitigation strategies commonly applied, this review proposes a unified constraint-to-mitigation framework for planners and operators. The synthesis of results from diverse regional grids offers the largest cross-country comparative reference, supporting enhanced grid security, reduced cascading-failure risks, and the development of reliable and future-ready transmission networks.