Impacts of New Suggested Ferroresonance Limiter on the Stability Domain of Ferroresonance Modes in Power Transformers Considering Metal Oxide Surge Arrester Effect

This paper studies effect of new suggested ferroresonance limiter on controlling ferroresonance oscillation in the power transformer including metal oxide surge arrester (MOSA). A simple case of ferroresonance circuit in a three phase transformer is used to show this phenomenon and three-phase transformer core structures including nonlinear core losses are discussed. The effect of MOSA and ferroresonance limiter on the onset of chaotic ferroresonance and controlling chaotic transient in a power transformer including nonlinear core losses has been studied. It is expected that these ferroresonance Limiter generally cause into ferroresonance control. Simulation is done on a power transformer rated 50 MVA, 635.1 kV with one open phase. The magnetization characteristic of the transformer is modelled by a single-value two-term polynomial with q=7, 11. The core losses are modelled by third order in terms of voltage. The simulation results reveal that connecting the MOSA and ferroresonance limiter to the transformer, exhibits a great impact on ferroresonance overvoltages. Significant effect on occurring chaotic ferroresonance, the range of parameter values that may lead to overvoltage and magnitude of ferroresonance overvoltage is obtained and showed.