Direct-current transmission protection apparatus, current converter, and protection method

摘要

A direct-current transmission protection apparatus, a current converter provided with the protection apparatus, and a protection method, which are used in flexible direct-current transmission. The protection apparatus comprises a resistor unit (R) and a bidirectional circulation current switch unit (D, T). The protection apparatus is formed by connecting the resistor unit and the bidirectional circulation current switch unit in parallel. The resistor unit is formed by at least one resistor in a cascade connection manner. The bidirectional circulation current switch unit is formed by at least one bidirectional circulation current switch in a cascade connection manner. The current converter is serially connected to at least one protection apparatus in each phase unit. The apparatus can rapidly and effectively suppress vibrations of a direct-current short-circuit current and a damping current, better protect the safety of a device, and greatly shorten a fault current attenuation time, thereby shortening a direct-current outage time, and reducing economic loss and system instability risk caused by the outage to a maximum extent. In addition, the apparatus has a simple structure, requires low cost, and has good realizability and economy.