Simulation of ferroresonance in low-loss grounded wye-wye transformers using a new multi-legged transformer model in EMTP

Ferroresonance in five-legged, grounded wye-wye transformers is investigated through computer simulation. The transformer model is based on a novel approach and is able to simulate transient and steady-state behaviors of modern low-loss transformers with severely nonlinear cores. Published waveforms from field tests of transformer ferroresonance are successfully reproduced. Simulations suggest a simple method for suppressing ferroresonance overvoltages. The physics of grounded wye-wye transformer ferroresonance is explained and verified by simulation