Wind power soft straight system with automatic fault ride-through capability and control method thereof

Abstract

The invention discloses a wind power soft straight system with an automatic fault ride-through capability and a control method thereof. The system comprises a wind power plant, a wind field side converter station, a power grid side converter station and a dissipative module. The wind field side converter station and the power grid side converter station include a direct current basic controller and a fault ride-through controller and are used for realizing automatic current limiting control of alternating current and direct current faults. The dissipation module is used to protect an overvoltage of each converter station submodule from being lower than a rated value during a fault period. The method comprises the following steps of detecting voltage signals of alternating current and direct current ends and automatically identifying the alternating current and direct current faults; realizing the automatic current limiting control of the alternating current and direct current faults bycomparing the direct current basic controller and the fault ride-through controller; connecting a dissipative resistor in parallel to alternating current sides of the wind field side converter station and the power grid side converter station, and realizing dissipation through a switching criterion. Under the coordination effect of the automatic current limiting control and the dissipative resistor, a fault current, a voltage and MMC energy during an alternating current and direct current fault period is in a safe range so as to ensure the transient safe operation of the alternating current and direct current faults of the whole system.

Description

technical field [0001] The present invention relates to the technical field of electric power transmission and distribution, and more specifically, relates to a wind power flexible DC system and a control method with fault automatic ride-through capability. Background technique [0002] As a clean alternative to coal power, wind power is an important direction of my country's power production reform. In 2017, the accumulative grid-connected installed capacity of wind power in my country reached 164 million kilowatts, accounting for 9.2% of the total installed capacity of power generation. However, the wind curtailment rate in Gansu, Xinjiang, Inner Mongolia and other regions is still high. In order to solve the problems of wind curtailment and wind power consumption, the use of flexible DC transmission technology for wind power grid integration is an important means to solve cross-regional power interconnection and increase wind power penetration. one. Most of the existing...

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Problems solved by technology

[0006] Aiming at the defects of the prior art, the purpose of the present invention is to solve the problem that the overvoltage of the sub-module exceeds the rated value when the wind power flexible straight-to-grid system fails

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