Methods of Determining the Parameters Representing the Cross-Magnetizing Effect in Saturated Synchronous Machines
MetadataShow full item record
In recent studies of the saturation effect in saturated synchronous machines, it has been recognized that the magnetic coupling between the direct and quadrature axes of these synchronous machines (the cross- magnetizing phenomenon) plays an important role in their analysis using the two-axis frame models. To determine the parameters that represent this cross-magnetizing effect, the saturation characteristic curves in the various intermediate axes of the synchronous machines are needed. If a synchronous machine has both direct- and quadrature-axis excitation windings, its saturation characteristic curves in the various intermediate axes can be measured by exciting the machine from both these two windings simultaneously under open-circuited condition. However, for the industrial synchronous machines, which have no excitation winding in their quadrature axis, there has been till now no technique for measuring these saturation characteristic curves experimentally. Wu, in his Master's thesis , has proposed an "Analytical" method for the determination of these saturation characteristic curves. In the present thesis, an experimental method for the measurement of the saturation characteristic curves in the various intermediate axes of synchronous machines, which will be called the "Back-to-Back" method, is proposed. Applying this method, the saturation characteristic curves and the parameters representing the cross-magnetizing effect of a synchronous machine are experimentally obtained. By comparing these results with those obtained from Wu's "Analytical" method, the accuracy and the validity of the assumptions of this analytical method are thus verified. Moreover, the importance of the inclusion of the cross-magnetizing effect in the two-axis frame model is demonstrated by comparing the measured and the calculated active and reactive power/load angle curves of the synchronous machine used in the investigations reported in this thesis.