Performance of Differential Protection under the influence of Ferroresonance
This paper presents a scenario of the possible mis-operation associated with transformer differential relaying during a ferroresonance condition. Ferroresonance is a non-linear resonance involving the exchange of energy between capacitance and nonlinear inductance (energy exchange between magnetic and electric circuit). Ferroresonance behavior can be analyzed using a nonlinear dynamic tool - Bifurcation analysis. This paper discusses the application of this tool to understand the possible mis-operation of the differential relay. A rudimentary model for the transformer differential relay is modeled in ATP and different harmonic restraint strategies are shown under ferroresonance.