A distribution network solid-state DC circuit breaker with current limiting function

Abstract

The Solid-State direct current (DC) circuit breaker (SSCB) is a key equipment to ensure the safe and reliable operation of medium-voltage DC (MVDC) distribution networks. A distribution network solid-state DC circuit breaker with current-limiting function (CLSSCB) topology is proposed in this paper. The CLSSCB adds current-limiting circuit and continuous current branch on the basis of traditional SSCB. The current limiting circuit can significantly reduce the rise rate and peak value of the fault current by using auxiliary current limiting reactance and current limiting impedance. The continuous current branch uses the freewheeling diode to reduce the energy absorption of the non-fault side arrester and effectively shorten the fault clearing time through the input of the freewheeling resistance. In this paper, the working principle of CLSSCB is analyzed in detail and theoretically deduced, and the selection method of key device parameters of CLSSCB is given. The CLSSCB simulation experimental model based on the PSCAD/ EMTDC software is built, and the feasibility and effectiveness of the proposed scheme are verified in the single-end and two-end DC distribution network scenarios, respectively.