Analysis of large turbogenerator´s asynchronous operation during loss of field

The author studies the impedance of eddy current circuits for the solid rotor of a turbogenerator by Canay´s formulation. The mathematical model of variable parameters, which change with slip, is obtained by applying Canay´s calculating formulas. Simulation of field failure for the 125/900 MW turbogenerator set on infinite system, inclusively of governor, automatic voltage regulator, transformer and transmission line, is respectively analyzed. The calculated variables, such as the changing amplitude, period, and waveforms of power and reactive power, are relatively close to oscillograms and data measured at site. The conclusion of this article can be used as a reference for the operation of a power system