Experimental establishment of ferroresonance and nonlinear dynamic analysis of line capacitance effects on system stability

Ferroresonance is an oscillation in a power network having a capacitor and a saturable transformer linked to a light load or no load. Stability of the ferroresonance circuit and its dependency on the different circuit parameters are the key concerns to understand its behaviour. As the internal structure of a transformer is non-homogeneous and the system equation is also nonlinear, the nonlinear dynamic method is considered the best method to solve the problem. A nonlinear equation is used to describe the nonlinear behaviour of the transformer's core material when there is no load. The power network's capacitive effects are regarded as a capacitor connected in series with the equivalent circuit of the transformer. To validate the model, ferroresonance was first established in a laboratory experiment. The parameters thus obtained from the experiment are used in the simulation. The line capacitance is taken as the variable parameter in the simulation. The stability of the ferroresonance circuit was examined with the variation of capacitor values. The Poincaré map is used to understand the change in the stability behaviour of the system. Although many analytical methods have been attempted to explain the ferroresonance oscillation, the change in stability of the system dynamics with the line capacitance has not been demonstrated in any previous literature.