High voltage bypass device, voltage source converter and operating method

An operating method for a high voltage bypass device, comprising:

• triggering a trigger element connected to two terminals of the bypass device in case of an overvoltage condition, in particular by creating heat through a spark or ohmic heating;
• at least partially destroying, in particular by melting, evaporating or combusting, a shutter of the bypass device in response to triggering the trigger element, thereby releasing a conductive, flowable material;
• and
• at least partially filling a cavity of the bypass device with the conductive, flowable material, thereby creating a permanent electrical path between a first terminal and a second terminal of the bypass device,
• wherein the trigger element comprises at least one of the following:
• a first electrode connected to the first terminal, and a second electrode connected to the second terminal, each of the first electrode and the second electrode protruding into the cavity to form a spark gap, between the first electrode and the second electrode, underneath the shutter, such that a spark is generated in the spark gap in case of an overvoltage condition;
• and/or
• a varistor connected between the first terminal and the second terminal.