Transient Electromagnetic Analysis of the Turbine Generator Flux Decay Test

The turbine-generator flux decay test is modelled using transient field analysis. The field in the cross-section of the machine is calculated on a step by step basis using a two-dimensional, non-linear finite element approach, with a conductivity matrix to represent the effects of eddy currents in the solid iron and field winding. Various practical aspects in the implementation of the method are described. Computed and test results of a 500MW machine compare well, and not only enable machine parameters to be calculated at the design stage, but give a better understanding of the machine transient behaviour.