방사상 LVDC 배전계통에서 고장전류의 극성을 이용한 보호 방법

Abstract

The low-voltage DC (LVDC) distribution system is attracting attention due to the increase in DC-based distributed generation and the development of power conversion technology. This technology has various advantages by reducing power consumption through high-efficiency conversion that reduces the number of AC/DC power conversions. In this paper, a new protection method for the stable operation of LVDC distribution system is proposed. The change of fault current according to fault location in LVDC distribution system is analyzed. Based on this, a new protection method using the polarity of the fault current is proposed. The proposed method determines the fault location and transmits a trip signal of circuit breaker (CB) accordingly. For verification of the proposed method, the LVDC distribution system and the proposed method are modeled using Electro Magnetic Transient Program (EMTP). Simulations are performed according to the fault location and fault resistance, and the results are analyzed. The simulation results show that the fault location is accurately determined and the trip signal of CB is transmitted according to the proposed method.