Hybrid circuit breaker for HVDC grids with controllable pulse current shape

In this paper, two new hCB concepts for DC-grids are presented, which use a pulse current to extinguish the arc in the mechanical switch after opening. Both concepts are capable to adjust the pulse current amplitude/waveform to the fault current amplitude and so generate a slow current slope
^di/
d
_t
directly before the zero current crossing without large passive components for a fast and reliable fault clearing. By improving the controllability of the hCB and with a new control concept the capacitor volume of the first concept could be reduced by 60% and the inductor volume by 88% compared to the existing solution. At the cost of more active components, the capacitor volume could be even more reduced by 98.4% compared to the first concept (99.4% compared to the existing solution).