An efficient method for investigating the ferroresonance of single-phase iron core devices

The paper presents a fast and efficient method for determining the solutions of the ferroresonant circuits generated at the switching of different single-phase low-voltage iron-core devices. These are widely encountered in modern electric installations as no-loaded power transformers, magnetic choke or shunt reactors. The here suggested procedure basically relies on the solutions of the nonlinear and non-autonomous differential equations systems that model the commutation (dynamic) process. Starting from the devices manufacturer data, the energy supply installation specification and adopting an adequate description of their magnetic characteristics, the time evolution of the major electrical parameters is numerically predicted and critically analyzed. The power spectrum, phase portraits and Poincaré map of some relevant electrical quantities variation complete the analysis of the ferroresonance phenomenon. Additionally, mitigations strategies for the common undesirable power quality issues associated with the ferroresonace occurrence are proposed and discussed.