한류기 보호 MTDC시스템에 과전류 계전기적용을 위한 전압기울기 방향 보정 연구

Abstract

In the DC system, the fault current is quite fast and rises significantly due to capacitor discharge. Due to this, DC fault conditions must be cut off more quickly and accurately than AC. However, DCCB is more complicated to operate and more expensive than AC system circuit breaker. Therefore, it is necessary to introduce a superconducting fault current limiter, and the trip delay may occur in the overcurrent relay due to the introduction of the superconducting fault current limiter. To prevent this, a correction algorithm is needed. In this paper, an algorithm that considers the voltage slope and the direction of the current is applied to effectively limit the fault current through a superconducting fault current limiter, and a method to prevent the malfunction of the circuit breaker.