Frequency dependent eddy current models for nonlinear iron cores

Frequency dependent representations of eddy currents in laminated cores of power transformers are developed. One representation is based on a continued fraction expansion for the frequency dependent magnetizing impedance while the other is based on a discretization of flux distribution within the lamination. Both models are low order and reproduce the frequency characteristics of the transformer magnetizing branch up to 200 kHz with less than 5% error. The importance of modeling the frequency dependence of eddy currents for the calculation of the transient recovery voltage across a low voltage transformer breaker interrupting a nearby fault is demonstrated. >

[1]  E.P. Dick,et al.  Transformer Models for Transient Studies Based on Field Measurements , 1981, IEEE Transactions on Power Apparatus and Systems.

[2]  Jaime Avila-Rosales,et al.  Nonlinear Frequency Dependent Transformer Model for Electromagnetic Transient Studies in Power Systems , 1982, IEEE Transactions on Power Apparatus and Systems.

[3]  G. Slemon.  Magnetoelectric Devices: Transducers, Transformers and Machines , 1966 .

[4]  Irene A. Stegun,et al.  Handbook of Mathematical Functions. , 1966 .

[5]  A. Semlyen,et al.  Iron Core Modeling For Electrical Transients , 1985, IEEE Transactions on Power Apparatus and Systems.

[6]  S. Ihara,et al.  Chopping of Transformer Magnetizing Currents Part II: Three-Phase Transformers , 1983, IEEE Transactions on Power Apparatus and Systems.