Patent ID: 8611113

Claim:
A Voltage Source Converter having at least one phase leg connecting to opposite poles of a direct voltage side of the converter and comprising a series connection of switching assemblies, each switching assembly having an electrically conducting plate member carrying a plurality of semiconductor chips each having at least a semiconductor device of turn-off type and a free-wheeling diode connected in parallel therewith, said chips being connected in parallel with each other by each being connected by at least one individual conductor member to a said plate member of an adjacent switching assembly of said series connection of switching assemblies, a midpoint of said series connection forming a phase output being configured to be connected to an alternating voltage side of the converter and to divide the phase leg into an upper valve branch and a lower valve branch, wherein each said switching assembly has a mechanical switch configured to be open under normal operation of said switching assembly and configured to enable connection of said plate member of this switching assembly to the plate member of an adjacent switching assembly for bypassing said semiconductor chips of the switching assembly to which the mechanical switch belongs, a release mechanism is associated with each said mechanical switch and configured to, when triggered, move a movable contact of said mechanical switch for transferring the switch from an open to a closed state, at least one said conductor member of each switching assembly is designed to burn through upon occurrence of a short circuit current through the semiconductor chip to which this conductor member is connected while creating an arc, and each switching assembly comprises a fuse member associated with said at least one said conductor member, configured to be ignited by a said arc and extending to said release mechanism for triggering thereof upon ignition of said fuse member for establishing a current path between said two adjacent plate members bypassing said semiconductor chips of said switching assembly.