Bedda, Zekri SadMekkaoui, TarekBoutora, S. (Supervisor)2022-06-162022-06-162016https://dspace.univ-boumerdes.dz/handle/123456789/947245 p.Ferroresonance is a phenomenon usually initiated by transients in power networks resulting from switching operations or ground faults or others. Nonlinear behavior of the core of a power transformer results in magnetic saturation. Long-lasting ferroresonant state is dangerous to the equipment due to prolonged overvoltage and large overcurrents in MV windings. In this thesis, a ferroresonance solution using Alternating Transient Program, was attempted. The ferroresonant oscillations analyzed result from interaction between the power transformer and a grading capacitance of a circuit breaker. Some practical solutions are suggested and introduced after creating a ferroresonance situation, they had a considerable effect on damping and eliminating the risk of ferroresonance.enFerroresonancePower transformerThesis