Identification of ferroresonance phenomena using wavelet transforms

With the inclusion of advanced technologies in the power systems, the issues which are not considered in those days are in need to be investigated. One of the issues that captured the consideration in both transmission and distribution system is Ferroresonance (FR). Though the FR mitigation was done in earlier days, the utility's failure reports indicated its presence in higher magnitudes. This paper studied the mitigations for potential transformer suggested by various papers using wavelet transforms. The energy values proved the presence of FR created by energy exchange between a grading capacitor and a voltage transformer in a 500kV Gas Insulated Substation (GIS). The focus was given to primary voltage and flux of the voltage transformer which may damage the equipment insulation. The study results like to suggest that the addition of a nonlinear inductor provides good damping to FR oscillations as well as reduces core saturation effects.