Hvdc breaker and control apparatus for controlling an hvdc breaker

An HVDC breaker comprising a parallel connection of a non-linear resistor and at least one interrupter, where the resistance of a non-linear resistor decreases with increasing voltage, wherein

• the HVDC breaker is sectionalized in that the HVDC breaker further comprises at least one further parallel connection of a non-linear and at least one interrupter, the first and further parallel connections being connected in series;
• at least one of said parallel connections and/or at least one group of said parallel connections is arranged to be controlled individually from the other said parallel connections;
• and
• the HVDC breaker is arranged in a manner so that the number of parallel connections in which the at least one interrupter is tripped upon tripping of the HVDC breaker depends on the operational event in response to which the tripping occurs.

A method of interrupting a DC current in an HVDC system, the method comprising:

• receiving, in a control apparatus for controlling an HVDC breaker, a system status signal the type of which is indicative of an operational event requiring the interruption of the DC current, wherein the control apparatus is arranged to control an HVDC breaker being sectionalized in that the HVDC breaker comprises at least two series-connected parallel connections of a non-linear resistor and at least one interrupter, where the resistance of a non-linear resistor decreases with increasing voltage;
• and where at least one of said parallel connections and/or at least one group of said parallel connections is arranged to be controlled individually from the other said parallel connections;
• the method further comprising:
• determining, in dependence on the type of the system status signal received, the number of said parallel connections and/or groups of said parallel connections to be used for interrupting the DC current;
• and
• sending, to the HVDC breaker, a corresponding section actuating signal or signals to trip said number of parallel connections and/or groups of parallel connections.