Structural Design and Electromagnetic Performance of 50 Mvar HTS Synchronous Condenser

Superconducting synchronous condensers have the capability of quick reactive power regulation and play an important role in maintaining the stability of renewable energy grid. In this paper, the structural and electromagnetic parameters of a 50 Mvar, 10.5 kV high temperature superconducting (HTS) synchronous condenser are designed. For the rotor, only the yoke is retained, forming an air-core superconducting rotor. The field windings are made of rare earth barium copper oxide (REBCO), cooled by helium gas and operate at the temperature of 30 K. The rated no-load field current is in consideration of the maximum magnetic field at the end of the field windings, so that quench can be suppressed. As for the stator, non-magnetic stator teeth are adopted, and the armature windings are supported by epoxy resin, which can effectively restrain the ferromagnetic teeth from saturation. The armature windings are distributed at two layers and composed of thin Litz copper wires. The internal magnetic field distribution of the superconducting synchronous condenser is preliminarily obtained by constructing a two-dimensional (2D) finite element model. It is found that the maximum magnetic flux density in the air gap is 1.6 T, and the no-load electromotive force (EMF) varies linearly with the field current. The simulation results validate the design scheme and provide a theoretical basis for manufacturing a prototype in the future.