Ferroresonance in power systems: A structured technical review and mitigation strategies

Ferroresonance is a complex and potentially destructive phenomenon that poses significant risks to the reliability and stability of power distribution systems. Although incidents have been documented for more than a century, the underlying mechanisms and effective countermeasures remain only partially understood. This paper presents a structured technical review of ferroresonance in power distribution networks, integrating historical developments, classical analytical modelling, documented damage mechanisms, and mitigation strategies within a unified analytical framework. A classical analytical approach is employed to examine system behaviour, providing a consistent foundation for interpreting previously reported case studies and simulation results. Rather than proposing a new nonlinear model, the study consolidates and critically synthesizes existing theoretical and practical knowledge to offer a comparative perspective on the fundamental physical mechanisms of ferroresonance and the associated engineering mitigation strategies. Particular emphasis is placed on the systematic evaluation of mitigation approaches, including transformer core design modifications, capacitance management practices, deliberate damping techniques, and surge arrester applications, assessed in terms of effectiveness, practicality, and operational impact. The key finding is that there is an engineering trade-off between costly design-stage modifications that improve inherent ferroresonance immunity and retrofit suppression measures, such as lightning arresters, that effectively mitigate ferroresonance in existing installations without reducing normal operating efficiency.