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Abstract

A circuit breaker for high voltage direct current (HVDC) power transmission includes a module with a pair of terminals for connection to an electrical network, and four of conduction paths. Each first conduction path includes a mechanical switch connected in series with at least one first semiconductor switch to selectively allow current to flow between the first and second terminals through the first conduction path in a first mode of operation or commutate current from the first conduction path to the second conduction path in a second mode of operation. The second conduction path also has a semiconductor switch to selectively allow current to flow between the terminals through the second conduction path or commutate current from the second conduction path to the third conduction path in the second mode of operation. The third conduction path has a snubber circuit with an energy storage device to control a rate of change of voltage across the mechanical switch and oppose current flowing between the first and second terminals in the second mode of operation. The fourth conduction path has a resistive element to absorb and dissipate energy in the second mode of operation and divert charging current from the first and second terminals away from the energy storage device to limit a maximum voltage across the pair of terminals.

First Claim