Influence of DC Power System Parameters on Fault Interruption Characteristics of Electronically Assisted Circuit Breaker (EACB)

This paper investigates the influence of DC power system parameters such as L/R time constant and available fault current on the fault interruption time of a newly developed Electronically Assisted Circuit Breaker (EACB). Unlike other HCB concepts in the literature, the EACB uses a conventional thermal-magnetic MCCB baseline design with minimal modification of its actuation mechanism, and an electronic commutation circuit which is activated at a reduced fault current for a very short time duration, both contributing to significant cost savings. The fault interruption time of EACB mainly depends on the fault current limiting process of the MCCB which is related to the DC power system parameters. In this paper, fault interruption time of EACB in PV systems with different system parameters is studied. The interruption time is mapped out based on arc modeling analysis. Finally, prototypes are designed and demonstrated, experimentally showing the influence of system parameters on the fault interruption time of EACB.