Theoretical Evaluation on the Response of Superconducting Transformers to Lightning Surge

II. Current Oscillation Characteristics and Ac Loss in Superconducting Windings

Abstract

Current and magnetic-field oscillation forms induced by lightning surge in superconducting transfomers were examined in detail by the numerical simulation method proposed in the previous paper for ordinary circular disk type, high-series-capacitance type and multi-layer type windings. Ac losses of the superconducting cable due to the major components of magnetic-field oscillation were evaluated quantitatively for each type of winding and compared with proposed theoretical expressions. Reduction method of the ac loss was also discussed by comparing the current responses to lightning surge of several kinds of winding structures for ordinary circular disk and high-series-capacitance type windings with each other.