Convertor station having direct current fault clearance capacity and control method of convertor station

Abstract

The invention discloses a convertor station having direct current fault clearance capacity and a control method of the convertor station. The convertor station comprises a modularized multi-level convertor, a smoothing reactor, a fast shunt isolating switch, a fast on-off switch, a current transfer switch and a line discharge leading circuit. According to the convertor station, direct current faults can be cleared away quickly and effectively. Compared with a sub-module replacement scheme, the convertor station has the advantages that manufacturing cost is approximate or slightly high, and running loss is low and identical with that of the modularized multi-level convertor with a half-bridge sub-module; compared with a scheme that a direct current breaker is adopted, the convertor station has the advantage that manufacturing cost is greatly reduced, particularly in a multi-terminal direct current transmission system.

Description

technical field [0001] The invention belongs to the technical field of power system control, and in particular relates to a converter station capable of clearing DC faults and a control method thereof. Background technique [0002] The modular multilevel converter has the advantages of low harmonic distortion rate of the AC output voltage, easy packaging of the modular structure, small electrical stress on the switching devices, and low switching loss. Since it was proposed in 2002, it has been widely recognized by the industry after more than ten years of development. Modular multilevel converters composed of half-bridge sub-modules are the most commonly used structural solutions in high-voltage DC projects today, but because they do not have the ability to self-clear DC faults, the existing modular multilevel converters based on The high-voltage DC projects of the inverters all use low-failure rate DC cable lines to reduce the probability of DC faults, but the cost is exp...

AI Technical Summary

Problems solved by technology

For the second option, high-voltage DC circuit breakers have not yet been commercialized and are expensive

In addition, in order to effectively cut off the fault current, DC circuit breakers need to be installed at both ends of each DC line. In the future multi-terminal DC transmission system and DC grid, in order to ensure the redundancy of power transmission, the number of DC lines will be significantly more than The number of converter stations and the number of installed DC circuit breakers will also be greatly increased, and the resulting grid cost will increase several times

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