| 摘要 |
A primary conduction path 722 for use in a DC circuit breaker comprises a first semiconductor 704 connected in parallel with a first energy absorber such as varistor 708 that limits the voltage across the semiconductor to less than or equal to its turn off capacity. A mechanical member 706 is connected in series with the semiconductor and the energy absorber and provides a low impedance path in a first configuration and withstands a transient recovery voltage in a second configuration. The first semiconductor 704 can be turned off to generate a commutation voltage across the primary conduction path to commute line current away from it, whereupon the mechanical member is commanded to the second configuration. First semiconductor 704 can be one or more semiconductor switches, connected in series and/or in parallel, such as a gate turn-off thyristor, an integrated gate commutated thyristor or an insulated gate bipolar transistor. The mechanical member can be one or more fast acting switches or breakers. In parallel with the primary conduction path there can be a secondary conduction path 724, comprising a second semiconductor 724 and a passive component such as capacitor 712, and an energy absorbing path 720 having a second varistor 716. The circuit breaker can be used in a high voltage DC grid connecting offshore wind farms.
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