Physically Consistent Overload Scenario Generation for Transmission Networks

Any study of corrective congestion management—benchmarking of optimisation solvers, operator training, security assessment, or data-driven control—requires a base of operating points in which one or more branches are actually overloaded. Such cases are scarce in historical records and are rarely obtained by random perturbation of a base case, which mostly yields non-convergent or operationally meaningless configurations. This paper presents a generator that builds reproducible corpora of physically consistent overloaded states from a full AC continuation power flow, with Newton–Raphson correctors, adaptive step control, a PTDF-based stress-direction library and Sherman–Morrison–Woodbury updates for the contingency sweep. Each scenario is stored as a compact genotype from which the complete operating point is reconstructed exactly, so a corpus can be distributed as parameter vectors instead of solved cases. A linearised variant based on Power Transfer and Line Outage Distribution Factors is described as a higher-throughput baseline for studies in which only thermal limits bind. Applied to the IEEE 118-bus system extended with a VSC-HVDC link, the AC generator produced 253,378 overloaded states covering 101% to 199.82% branch loading and 60 distinct overloaded branches, split evenly between intact-grid and single-outage topologies, with exact reconstruction verified for every stored scenario.