Analysis of saturated synchronous reactances of large turbine generator byconsidering cross-magnetizing reactances using finite elements

This paper describes a method to calculate saturated reactances of synchron ous machines at various loads under steady-state operation by considering i nfluence of cross-magnetizing phenomenon between d- and q-axis circuits. In the method, mutual reactances x(dq) due to the cross-magnetizing phenomeno n can be calculated on the basis of two-dimensional magnetic field analysis . The validity of analysis is shown by good agreement between measured and calculated field current values. of a 592MVA turbine generator at various l oads. it is clear that quantitative accuracy requires the magnetic coupling between d- and q-axis circuits be considered. Subsequently, steady-state reactances at various loads are analyzed by cons idering mutual reactances x(dq) due to cross-magnetizing phenomenon. The re lation between the load angle delta and mutual reactance x(dq) is clarified , and the difference between equivalent synchronous reactances that are obt ained by considering x(dq) and conventional defined synchronous reactances that do not consider x(dq) is shown numerically.