抄録
This paper presents field current calculations of synchronous machines with revised dq-axes equations and two-dimensional numerical magnetic field analysis. The dq-axes equations are modified by considering reactance time variations due to magnetic saturation of core and saliency of poles. The revised dq-axes equations and magnetic field analysis are used to calculate on-load field currents and steady-state reactances of a 592MVA turbine generator. The findings are as follows.
(1) Results from the revised equations indicate a mutual reactance between d-axis and q-axis xdq and a mutual reactance between field and q-axis xfq are theoretically not negligible in saturated synchronous machines.
(2) Numerical values of the mutual reactances xdq, xfq grow with increasing load.
(3) Differences between field currents calculated by conventional equations and by the revised equations widen with numerically increasing load.
(4) Field currents calculated using the revised equations show good agreement with measured ones.
