Study on AC Loss Characteristics in HTS Windings of a HTS Controllable Reactor With Orthogonally Configured Core

The controllable reactor is one of the most effective methods for compensating reactive power, which can smoothly and fleetly adjust its output reactance with the change of transmitted power. A high temperature superconducting (HTS) controllable reactor with an orthogonally configured core has been proposed and developed. The HTS windings with direct current (DC) are adopted as the control windings to improve the excitation efficiency. However, under high level excitation condition, especially in the case of fast adjusting process, ac losses will occur and lead to reduction of thermal stability in the HTS windings. The E-J characteristics of HTS windings, magnetization characteristics of iron-core, and 3-D asymmetric structure of the reactor make it difficult to estimate ac loss of the HTS windings based on traditional finite-element methods. This paper proposes a new method to estimate ac loss for the HTS controllable reactor with orthogonally configured core. The ac losses and the critical current of the HTS windings in the reactor are presented and discussed, which has great guiding significance for prototype design.