Determination of Waterwheel Alternator Steady-State Reactances from Flux Plots

In the steady-state analysis of salient pole alternators the reactances Xd and Xq are generally assumed to be constant. This is not the case in saturated machines. The reactances are functions of the operational regime of the alternators, and for an exact analysis of the alternator´s behavior the appropriate values of Xd and Xq have to be used. The magnetic induction is found in the cross section of the alternator by difference methods established at the Universityl and then saturated Xd and Xq are determined from flux plots. The results confirm that Xd and Xq are load dependent. The analysis is applied to a General Electric alternator with nameplate data 82.5 MVA, 16.5 kV, wye-connected, 40 poles and 60 Hz.