Ferroresonance in subharmonic 3rd mode in an inductive voltage transformer, a real case analysis

This paper focuses on a ferroresonance incident in subharmonic 3rd mode captured in the electrical substation Rio Escondido (REC), in the northeast of Mexico. Bearing in mind that this kind of ferroresonance phenomenon is a sporadic event and difficult to record, the contribution of this paper consists of the analysis of this real-life ferroresonance phenomenon and to propose a practical solution that prevents these kinds of incidents. An analytical calculation to obtain the electrical parameters of a damping reactor used to damp out the ferroresonance phenomenon registered in the REC substation is reported.