Stability analysis of air-core superconducting power transformer

The air-core superconducting power transformer is being investigated as a transformer having the function of a shunt reactor. From the results of the authors´ previous analysis, the magnetic field acting on the superconducting wires of an air-core transformer under load includes the rotating component besides the alternating component. Since this rotating component has a possibility of affecting the wire stability, the influence should be clarified. In this paper, a method of stability limit analysis based on the instantaneous magnetic field calculation is proposed. Quench tests of an experimental air-core superconducting transformer are carried out, and the stability limit of the air-core superconducting transformer is analyzed by using the proposed method. From the results of the analysis, it is seen that the load factor of the superconducting wire, which is defined in this paper, is almost the same regardless of the superconducting power transformer load.