Ferroresonance in low-loss distribution transformers

Field experience indicates that ferroresonance events occur more readily with low-loss distribution transformers, compared to distribution transformers with conventional loss levels. Extensive testing of a large number of transformers has shown a very strong and direct correlation between transformer core loss and the amount of capacitance needed to sustain a ferroresonant condition. A heuristic explanation is provided to show the important role of core loss in the ferroresonant circuit.