Analysis of Electromechanical Transient Propagation and Cascading Failure in Auxiliary Systems: A Deterministic Resilience Framework for Voltage-Dip Mitigation at Hwange Thermal Power Station

Under-voltage transients represent a critical power quality disturbance that compromises the operational reliability of thermal generation assets, particularly those with aging auxiliary electrical infrastructures. Moreso, the recurrent voltage dip-induces forced outages resulting in reduced constant power production at Hwange Power Station Zimbabwe’s principal coal-fired baseload plant. This research establishes a deterministic resilience framework for the station’s auxiliary systems through an integrated engineering methodology, combining historical disturbance analytics from SCADA and operational records with high-fidelity dynamic electromechanical simulation in DIgSILENT PowerFactory, standards-based benchmarking per IEEE guidelines, and a structured risk assessment via Failure Mode and Effects Analysis. Focusing on critical auxiliary subsystems including automatic changeover schemes and protection, control circuits, the study identifies vulnerable equipment, elucidates root-cause failure mechanisms, and evaluates practical mitigation strategies. The resulting technical framework is designed to enhance baseload reliability at Hwange and provide a translatable reference for voltage-dip resilience in analogous regional thermal power stations.