Characteristics of a Superconducting DC Circuit Breaker According to L and C Elements of LC Divergent Oscillation Circuit

Abstract

Currently, we are developing an AC/DC conversion technology with the development of power semiconductors. Accordingly, DC is attracting attention because it is advantageous in the current transmission system. However, it has a problem that the cut-off technology required for DC system operation has not been secured yet. We are researching and developing a DC cut-off technology in several ways. We proposed a model that combines a superconducting fault current limiter and a DC circuit breaker. This is a configuration which a superconducting fault current limiter and a mechanical DC circuit breaker are connected in series. The superconducting fault current limiter limits the initial fault current and the mechanical DC circuit breaker cuts off the fault current. The mechanical DC circuit breaker consists of a high-speed DC switch, a LC divergent oscillation circuit and a surge arrester. This creates an artificial zero-point by affecting the blocking of the DC fault current according to the LC diverging oscillation circuit. In this paper, we analyzed the effect of the LC divergent oscillation circuit on the superconducting DC circuit breaker according to Reactor (L) and Capacitor (C). As a result, we analyzed the operating characteristics of the superconducting DC circuit breaker according to the application of the LC divergent oscillation circuit using the PSCAD/EMTDC program. Also, we confirmed the characteristics of the initial fault current limit rate of the superconducting fault current limiter and the possibility of controlling how the LC divergent oscillation circuit affects the DC arc generated at the opening of the mechanical DC contacts.