Analysis of stator leakage reactance computation with finite element methods

The leakage reactance of large turbogenerators is an important electrical parameter. Standard IEC 60034-4 gives measurements on the stator only which can be translated straightforwardly in computational electromagnetics. Several previous studies on this subject can be found in literature. In our opinion, they do not take into account accurately enough the actual leakage flux. Indeed a part of the flux in the machine without the rotor is also a part of the main flux. So we propose here another way to compute leakage reactance based on 2D and 3D electromagnetic computations. Results comply well with manufacturer's measurements. Several calculations with different tools are used to validate our approach.