A Multiport DC Circuit Breaker for High-Voltage DC Grids

A Low-Loss Integrated Circuit Breaker for HVDC Applications

“…Isolation of dc bus faults and backup protection are desirable capabilities of any DCCB. For instance, both features are achievable with a multiport DCCB using bidirectional thyristor units in its main breaker, as shown in [43]. The presented ICB in this paper may also offer these capabilities if its unidirectional main breaker is replaced by a BMB.…”

“…The device presented in this paper arguably offers an extra advantage compared to the DCCB in [43] following a fault. In the presented ICB, the post-fault currents cause small power losses similar to those of the LCSs of HCBs as they flow through MFBs containing only a few IGBTs.…”

“…In the presented ICB, the post-fault currents cause small power losses similar to those of the LCSs of HCBs as they flow through MFBs containing only a few IGBTs. Instead, post-fault currents flowing through the DCCB in [43] do so through a string of series-connected thyristors. Given that the string is rated at system voltage level, as a result, larger power losses are produced, which could be comparable to those of a SSCB.…”

“…Currents at the healthy nodes will keep flowing. A comparison between the ICB and the DCCB in [43] is given in Table I. Notice that the design in Section III considers a unidirectional main breaker with a single string of IGBTs.…”

“…Although the DCCB contains fewer mechanical switches than the ICB, and a thyristor has a lower unit price compared to an IGBT, the total number of required thyristors in [43] is much higher than the number of IGBTs in the ICB-even following inclusion of the BMB. This facilitates device maintenance for the ICB as mechanical switches are easier to maintain compared to semiconductor devices.…”