Analysis of ferroresonance phenomena in power transformers including neutral resistance effect

This Paper studies the effect of a neutral resistance on the ferroresonance oscillations of the power transformer. It is expected that this resistance generally cause ferroresonance ´dropout´. Time-domain simulation has been carried out using MATLAB SIMULINK to study this effect. Simulation has been done on a three phase power transformer with one open phase. Effect of varying input voltage has been studied. The simulation results reveal that connecting the neutral resistance to the transformer, exhibits a great mitigating effect on ferroresonant over voltages. Phase plane along with bifurcation diagrams are also presented. Significant effect on the onset of chaos, the range of parameter values that may lead to chaos and magnitude of ferroresonant voltages has been obtained, showed and tabulated.