A switchgear system includes an enclosure made of dielectric material and containing atmospheric air and a plurality of switch assemblies within the enclosure arranged in a plurality of rows. Each switch assembly is electrically connected to at least one other switch assembly in another row and includes a loadbreak module, a bushing, and a disconnect switch. The loadbreak module includes a fixed contact, a movable contact, and a pair of opposed line terminals electrically coupled to the movable contact. The bushing includes a load terminal, and the disconnect switch is positioned between the load terminal and the fixed contact to selectively break or establish an electrical pathway therebetween. Each disconnect switch of each switch assembly and each movable contact of each switch assembly is coupled with each other disconnect switch and each other movable contact, respectively, of the switch assemblies in the same row to be operable in unison.

Devices, methods and techniques are disclosed to interrupt a fault current in a high-voltage direct-current circuit. In one example aspect, a device includes a mechanical switch including a pair of contacts configured to be positioned apart upon activation of the circuit breaker, and a photoconductive component connected in parallel with the mechanical switch. The photoconductive component is configured to establish a current upon activation of the circuit breaker. The photoconductive component comprises a crystalline material positioned to receive a pulsed light signal from a laser light source, and a pair of electrodes coupled to the crystalline material and configured to allow an electric field to be established across the crystalline material to generate the current.