Effect of capacitance variation on physical characteristics of ferroresonance severity and jump phenomenon based on Rudenberg graphical method

This paper performed the ferroresonance generation experiment with variation of capacitance based on Rudenberg graphical method. The voltage and current measurements were conducted on the transformer primary windings, source voltage, and capacitor. The trend of transformer voltage waveform was then analyzed by using bifurcation diagram. Moreover, the fast Fourier transform (FFT) was applied on the transformer primary voltage. The harmonics spectrum would show the ferroresonance mode. Then, its total harmonics distortion (THD) was calculated. The level of ferroresonance severity involving the values of transformer voltage and overvoltage level as well as THD was mapped based on the quadrant system. The results showed that the appearances of jump phenomenon and different ferroresonance severities could be explained more clearly by using Rudenberg graphical method. In addition, the proposed mapping of ferroresonance responses based on the quadrant system was successful not only to highlight the impact of given variables on ferroresonance but also to categorize more easily its danger level.