Investigation Of Current Transformer Saturation And Assessment Of Its Impact On Differential Protection

Current transformer saturation will cause the secondary current distortion.The error of the current transformer increases sharply with saturation,because the magnetization current increases disproportionately to the primary current.In thesis the effect of DC current component and the residual magnetization on the current transformer saturation is investigated.The influence of residual induction is more affected when the direction of the external magnetic field coincides with the sign of residual induction.The Jiles-Atherton method of ferromagnetic hysteresis is widely used approach for electromagnetics transient simulation.In thesis different models and implements of Jiles-Atherton model were summarized in both MATLAB and Simulink.Saturated current transformer influence on the operation of differential relaying protection and can lead to its non-selective operation,especially in the mode of external short circuit.Thus,for correct operation of the differential relaying protective is necessary to correct detect the saturation process and take appropriate measures.In thesis on the example of the part of power systems various short circuit modes were simulated and analyzed in Simulink.Obtained research results could be a strong background for further development of radical new methods of detecting the CT saturation.