Offshore wind power flexible HVDC system and method capable of realizing AC short circuit fault ride through

Abstract

This invention relates to the field of flexible DC transmission, aiming to provide an offshore wind power flexible DC transmission system and method capable of overcoming AC short-circuit faults. The method includes: when an AC short-circuit fault occurs in the onshore AC grid at the receiving end, calculating the difference between the output power of the sending-end converter station and the output power of the receiving-end converter station to obtain the required surplus power; calculating the number of energy-consuming sub-modules to be deployed based on the surplus power and the resistance value of a single energy-consuming unit in the converter; realizing the consumption of surplus power by controlling the number of energy-consuming units deployed in each bridge arm branch; and controlling the first and second switching units to disconnect all energy-consuming units after the fault is recovered. This invention integrates distributed modular energy-consuming devices within the converter, offering advantages in equipment purchase and maintenance costs and saving land. The energy-consuming sub-modules are bypassed through power electronic devices, thus not affecting the converter's control strategy under normal operating conditions.

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