An Electromagnetic–Thermal Coupling Numerical Study of the Synchronous Generator with Second-Generation High-Temperature Superconducting Armatures

Abstract

Generators with high-temperature superconducting armatures have an advantage in the fact that they can carry high currents. However, the AC loss of high-temperature superconducting (HTS) armatures is difficult to calculate precisely because HTS coils exist in a complex and time-varying electromagnetic environment. In addition, when the HTS coil is carrying a short circuit fault overcurrent, an electromagnetic–thermal simulation study of this process is required to ensure that the HTS coil is not damaged. In this paper, first, a fully coupled T-A formulation model is used to calculate the AC loss of HTS armatures. Then, the current and temperature distributions are simulated, considering the intrinsic characteristic of superconducting coated conductors, when the generator suffers the worst short circuit fault accidently. It is found that the turn with the lowest critical current quenches after 0.01 s, but the temperature rise cannot damage the coil if the circuit breaker can clear the fault quickly. The effects of the copper stabilizer thickness on the thermal stability of the HTS coil during the worst short circuit fault are also investigated. A thicker copper stabilizer improves the thermal stability of the HTS coil in the event of a short circuit fault, but the use of a simulation model is needed to make trade-offs between the engineering current density and the thermal stability of the HTS tapes. The work in this paper is necessary and can provide an important reference for manufacturing superconducting generators.