Estudo comparativo de técnicas de detecção e correção das distorções de corrente secundária de TC para serviço de proteção.

Abstract

The nonlinear character of the magnetization in the current transformer causes distortions in the waveform of a secondary current, directly altering the operation of measuring devices or protection connected to it, regardless of its use. The phenomenon of saturation, sharp during the occurrence of faults, reduces the accuracy of protective relays connected to the power system, affecting its operation in permanent regime. This dissertation is an analysis of the main methods of detection and correction of distorted currents in the secondary winding of CT for protection service. It is also proposed a correction technique such distortions, based on quasi-Newton method of Levenberg- Marquardt, with part of the current signal samples secondary being used to estimate portions of the distorted portion of the original waveform, upon the occurrence transient events.