Interruption Characteristics of Transformer-Type Superconducting DC Circuit Breaker According to Transformer Turn-Ratio

Series and parallel connection of each superconducting element is required to solve the capacitance problem of the superconducting element. However, unbalanced quench of the superconducting element may occur due to the difference in critical current of a single element. We intended to add a neutral line to the secondary of the transformer of the transformer-type superconducting DC circuit breaker among the interruption technologies proposed. This way has the advantage that the transformer-type superconducting element reduces the fault current through the quenching, and the DC circuit breaker interrupts the fault current by creating an artificial zero-point. In addition, the neutral line solves the unbalanced quench of the superconducting element. In this paper, we compared and analyzed the operating characteristics of the transformer-type superconducting DC circuit breaker by changing the turn-ratio of the transformer from 1:1. As a result, we confirmed that the efficiency of the transformer-type superconducting DC circuit breaker was the best when the turn-ratio of the transformer was 1.1:1.