Transformadores de corrente para relés de proteção: modelagem e análise do comportamento transitório.

Abstract

This research aims to study the transient behavior of transformers due to the protection of electrical systems. In this work the distortions presented by the secondary currents, in 60 Hz, caused by the operation of the nucleus in a saturated regime, on the occasion of defects that produce high primary currents, with high degrees of asymmetry are analyzed. Four models are presented for digital simulation, where, in order of presentation, the ferromagnetic core is represented with saturation; saturation and hysteresis; saturation, hysteresis and parasitic currents, as well as saturation, hysteresis and between iron. Such models are used to simulate TC performance without different operating conditions in primary and secondary, respectively. For the purpose of validation of the analyzed models, some results obtained through digital simulation are compared with those obtained by using an actual CT and assemblies with elements of concentrated parameters, intended to reproduce the parameters of a real power system.