Study of Petersen Coil Grounding System Inductance Variation on Ferroresonance in 150 kV Transformer

This study dealt with the effect of inductance variation of Petersen coil grounding system on ferroresonance overvoltage in a power transformer transmission. The study was simulated by using ATPDraw. The switching operations with opened one-phase, two-phase, and three-phases were given as a transient that initiated ferroresonance. The output of ATPDraw performed the voltage responses of transformer on primary and secondary side. The results showed that the given inductance variation of Petersen coil on power transformer resulted in different ferroresonance voltage response on the transformer. Using 5 mH inductance would make the higher overvoltage, while using 95 mH inductance would make the lowest voltage peak response. When one-phase open fault occurred, using inductance in range 20 - 100 mH would make Fundamental mode of ferroresonance in phase R on the primary and secondary side of the power transformer. When two-phase open fault occurred, using inductance 95 mH would make Subharmonic mode of ferroresonance in phase R and Fundamental mode in phase S on primary and secondary side of the power transformer. When three-phase open fault occurred, using inductance in range 15 - 100 mH would make Chaotic mode of ferroresonance in phase R, S, and T on the primary and secondary side of the power transformer.