A circuit breaker comprising: a superconducting fault current limiter ; and a circuit breaker module connected in series with the superconducting fault current limiter , characterised in that the circuit breaker module comprises: a first branch comprising a disconnector and a first semiconductor switch unit connected in series, the disconnector being connected in series to the superconducting fault current limiter , a second branch connected in parallel with the first branch, the second branch comprising a second semiconductor switch unit , a third branch connected in parallel with the first and second branches, the third branch comprising an LC resonant unit and a third semiconductor switch unit connected in series, a plurality of diodes , the diodes being connected in parallel with the second semiconductor switch unit and the third semiconductor switch unit respectively, and wherein conducting directions of the diodes are respectively opposite to conducting directions of the second semiconductor switch unit and the third semiconductor switch unit , and a nonlinear resistor , the nonlinear resistor being connected in parallel with the LC resonant unit and the third semiconductor switch unit . a superconducting fault current limiter ; and a circuit breaker module connected in series with the superconducting fault current limiter , characterised in that the circuit breaker module comprises: a first branch comprising a disconnector and a first semiconductor switch unit connected in series, the disconnector being connected in series to the superconducting fault current limiter , a second branch connected in parallel with the first branch, the second branch comprising a second semiconductor switch unit , a third branch connected in parallel with the first and second branches, the third branch comprising an LC resonant unit and a third semiconductor switch unit connected in series, a plurality of diodes , the diodes being connected in parallel with the second semiconductor switch unit and the third semiconductor switch unit respectively, and wherein conducting directions of the diodes are respectively opposite to conducting directions of the second semiconductor switch unit and the third semiconductor switch unit , and a nonlinear resistor , the nonlinear resistor being connected in parallel with the LC resonant unit and the third semiconductor switch unit . a first branch comprising a disconnector and a first semiconductor switch unit connected in series, the disconnector being connected in series to the superconducting fault current limiter , a second branch connected in parallel with the first branch, the second branch comprising a second semiconductor switch unit , a third branch connected in parallel with the first and second branches, the third branch comprising an LC resonant unit and a third semiconductor switch unit connected in series, a plurality of diodes , the diodes being connected in parallel with the second semiconductor switch unit and the third semiconductor switch unit respectively, and wherein conducting directions of the diodes are respectively opposite to conducting directions of the second semiconductor switch unit and the third semiconductor switch unit , and a nonlinear resistor , the nonlinear resistor being connected in parallel with the LC resonant unit and the third semiconductor switch unit . <EOS>