Sensitivity studies on power transformer ferroresonance of a 400 kV double circuit

The ability to predict ferroresonance significantly relies on the accuracy of the transformer model and the power system´s parameters. The accomplishment of a suitable simulation model allows the sensitivity studies to be performed to determine the degree of influence of various components and parameters of the ferroresonance phenomenon such as line length, point-on-wave switching and transformer core loss. The modelling work carried out in ATP (commercially available software) on a 1000 MVA 400/275/13 kV power transformer model is described and the simulation with field ferroresonance test recordings is verified. The maps that define the boundaries between safe and ferroresonant (fundamental, subharmonic, chaotic) regions as a function of system parameters are created through the sensitivity studies performed.