Six-phase turbine generators are used in constructing high-power units of power plants. Issues of operation conditions of a six-phase turbine generator could be studied by analogy with three-phase machines based on the equations of state of two mutually perpendicular axes of the Park-Gorev form given for an idealized machine. Compared with traditional three-phase machines, this approach is different by its representation of the stator’s leakage reactance as consisting of two components: self and mutual leakage reactance of three-phase winding systems. Th proposed analytical estimate of the parts of stator leakage reactance has a short working time, is physically clear and its accuracy is satisfactory for practical issues, which is confirmed by the results of numerical calculations and experiments. In an effort to provide experimental estimation of the components of stator leakage reactance, a few methods based on well-known methods of three-phase machines were proposed.