Managing Ferroresonance Overvoltages in Distribution Systems

Overvoltages resulting from ferroresonance have been a hurdle to utilities for several decades. Ferroresonance is frequently difficult to diagnose as its development and effects are often surprising. This paper presents qualitative and quantitative approaches, and a theoretical background on how ferroresonance develops, as well as a guideline on how to manage the extent of its effect. The paper also presents a case study experienced by a Canadian electric utility company. The goal is to aid utility staff by presenting its experience on how to understand and diagnose the phenomenon.