Analysis of the Properties of HTS 2G SCS and SF Windings During Failure States of Superconducting Transformers

The article presents a PSpice software-based numerical model of a superconducting transformer with HTS 2G SCS and SF windings for the analysis of electrical circuits, developed using PSpice version 24.1 (Cadence, 2024),which allows for the determination of equivalent parameters and properties of such a transformer in the steady state and in emergency states. The model has user-defined ABM (Analogue Behavioural Modelling) computational blocks and avails itself of the level 2 Jiles-Atherton magnetic hysteresis model and Rhyner’s power law describing the E-J relationship of the HTS superconducting tape. This model was experimentally verified by measurements of a real 10 kVA HTS transformer. On this basis, an extensive numerical model of a superconducting transformer with a more complicated winding structure and a higher power of 21 MVA was developed. For such a transformer, power losses were analysed and the time courses of resistance, current and temperature of superconducting windings made of HTS 2G tapes of the SCS type with a copper stabiliser and SF without a stabiliser were examined during emergency states, such as connecting the transformer to the network and operational short circuit. A discussion was carried out on the effectiveness of using both types of HTS tapes to limit the current in emergency situations posing a risk of loss of superconductivity and destruction of superconducting windings.