Resonance overvoltages in electric power networks

Resonance exists in circuits composed of inductance and capacitance, possibly resistance. Resonance can cause big overvoltages in power systems. Many resonance circuits, that are present in practice, include induction coils with iron core which that induction is nonlinear. These resonance events are called ferroresonance. In this paper are included measured curves of various variables in case of ferroresonance in auxiliary's circuits of power plant.