Ferroresonance Detection in Voltage Transformers Through Vibration Monitoring

Ferroresonance is a very studied phenomenon by the distribution electrical companies since it can cause damage to transformers and other line elements. This problem is generated by the association in series or in parallel of capacities (overhead and underground power lines) and saturable inductances (voltage transformers). During the ferroresonance, the Voltage Transformer (VT) becomes saturated and the magnetic field varies in a high way; all this produces that the ferromagnetic material dimensions of the transformer change due to the phenomenon of magnetostriction. Thus, magnetostriction generates a vibration on the transformer. The main effects produced by ferroresonance are as follow: core saturation, voltage and current distortion, overvoltages and overcurrents, temperature increase, vibration and noise. The aim of this paper is to detect the ferroresonance by analyzing the vibration on the VT.