Besarab O. Analysis of stability zones ferroresonance processes in switchgears high voltage electric networks

The thesis is devoted to improvement of models and development of new methods with the purpose of determination of ferroresonance processes stability domain edges in order to prevent switchgear failures in high voltage power networks with effectively grounded neutral. The refined mathematical models of switchgear have been developed in this thesis. Great attention has been paid to representation accuracy of electromagnetic voltage transformer nonlinear model by application of hysteresis model in which the influence of magnetization reversal rate is taken into account. Three-phase switchgear model has been offered for the consideration of interphase coupling. Quantitative relations between boundary conditions of ferroresonance processes stability domain and switchgear parameters have been investigated. The results have been systematized and presented in the form of neuro-fuzzy network on the basis of Suheno fuzzy inference systems which made it possible to develop software for the ferroresonance processes analysis.