A Practical Approach to Inclusion of Electromagnetic Field Nonlinearities in Dynamic Modeling of Large Turbogenerators-Part (I): Basic Principles for Inclusion of Instantaneous Magnetic Saturation

This paper details the salient features of an approach to include the influence of magnetic field saturation, on an instantaneous basis in large turbogenerators, on the values of machine inductances. This is done by means of numerical analysis of two dimentional magnetic fields coupled with a concept of ampere turn drop functions. This method is applied to the determinationof dynamic characteristics of an existing 659 MVA 4-pole turbogenerator, including the instantaneous saturation effect on the inductances, and the effects of instantaneous rotor speed variation coupled with saturation on equivalent damping resistances. Details of this development are given in a set of three companion papers, of which this is Part (I)