An Approach to Designing the Stator Windings of High-Capacity Wind Generators

Abstract

The capacity of a single offshore windfarm turbine has by now reached 10 MW, and its further growth is possible by making a shift for using superconducting synchronous generators. The article considers the factors that determine the choice of classical distributed and concentrated stator windings in designing high capacity superconducting wind generators. A 10 MW, 3300 V, 10 rpm superconducting wind generator with an excitation winding made of high temperature superconducting material Bi-2223 with ferromagnetic stator and rotor is studied. The stator volume and superconducting wire length were adopted as design selection criteria. It is shown that in the range of pole pair numbers 2p = 32-40, the use of a distributed two-layer winding has limitations in regard of the generator operation stability (the short-circuit current is less than the nominal value), and the use of concentrated windings has limitations due to a significant value of the differential leakage component. It has been found that for a distributed winding in the specified range of pole pair numbers, almost equivalent versions can be obtained with the stator volume equal to 78 m3 and superconductor wire length equal to 16 km. For a concentrated winding, it is preferable to choose a single-layer winding with the embodiment conditions Z = 12 + 6k, 2p = Z – 2, k = 0, l, 2,...; however, the obtained indicators are inferior to those in the case of using a classical distributed two-layer winding.