Voltage source type multi-level converter, direct current power transmission system, fault processing method and apparatus

The invention discloses a voltage source type multi-level converter which comprises a phase unit. The phase unit comprises a first bridge arm and a second bridge arm. A first end point of the first bridge arm is a first direct current end point of the phase unit. A first end point of the second bridge arm is a second direct current end point of the phase unit. The second end points of the first bridge arm and the second bridge arm are connected in a short way and serve as the alternating current end point of the phase unit. The first bridge arm comprises a first module and a first reactor which are serially connected. A first end point of the first reactor is connected with the alternating current end point. A second end point is connected with a first end point of the first module. A second end point of the first module is connected with the first direct current end point. The second bridge arm comprises a second module and a second reactor which are serially connected. A first end point of the second reactor is connected with the alternating current end point. A second end point is connected with a first end point of the second module. A second end point of the second module is connected with the second direct current end point. A parallel fault shunting circuit is connected between the second end points of the first reactor and the second reactor. The invention further discloses a direct current power transmission system, a fault processing method and apparatus.