Modelagem de transformadores de corrente e correção distorcidas no enrolamento secundário.

Abstract

In this dissertation work is presented a new technique for the correction of distorted currents in the secondary winding of current transformers (CTs) used for the protection service. Unlike conventional methods in which the current is integrated numerically to calculate the flow loop, this technique is based on integrating the voltage across a tertiary winding. Thus, the magnetizing current is determined by the saturation curve of the core and added to the secondary current distorted so as to obtain a faithful reproduction of the primary current waveform. Another innovative aspect is the fact that the residual flux in the core is determined by detecting the level of secondary current and integration of the analog voltage at the tertiary winding, since the system prefault to about 1/6 cycle voltage of 60 Hz after occurrence of the fault.