The paper describes the phenomenon of ferroresonance, types of ferroresonant steady‐states, and typical cases of ferroresonance in electrical power network. Ferroresonance can occur under normal operational conditions leading to overvoltages several times the normal equipment ratings with subsequent catastrophic damage to electrical equipment affecting the reliability of power networks. Most important properties of ferroresonance and usual methods for its analysis are presented, as well as the most important modeling options and issues.