Ferroresonance Phenomena in Medium Voltage Systems

The paper deals with the analysis of the formation of ferroresonance in MV systems. The analysis is focused on ferroresonance caused by instrument voltage transformer (IVT) connected to the outlet of the tertiary winding 10,5 kV autotransformer 400/110 kV. A non-linear element in this case is the magnetic circuit of IVT Ferro-resonance, in this case exhibits similar to the imperfect ground connection. The two phases may arise overvoltages in two phases and undervoltage in one phase. The rate of these adverse events is given by the initial conditions and load of switched circuits when circuit is switched on. Similarly, other exhibit nonlinear chaotic circuits. The main adverse effects include overvoltage that can damage the power system components well as a significant harmonic distortion.…