Flexible low-frequency power transmission system and overvoltage suppression method thereof

Abstract

The invention discloses a flexible low-frequency power transmission system and an overvoltage suppression method thereof. The flexible low-frequency power transmission system comprises a plurality of sea low-frequency fans, a low-frequency transformer, a shore frequency conversion device and a low-frequency energy consumption device, a plurality of sea low-frequency fans are gathered and then connected with at least one low-frequency transformer, the low-frequency transformer is connected with at least one shore frequency conversion device through a low-frequency submarine cable, and low-frequency voltage is converted into power-frequency voltage through the shore frequency conversion device. The low-frequency side of at least one ashore frequency conversion device is connected in parallel with the low-frequency energy consumption device; and a direct current side Chopper device is arranged in the offshore low-frequency fan. According to the invention, delivery of the fan can be realized, and meanwhile, the problem of overvoltage caused by locking of a power electronic device is solved.

Description

technical field [0001] The invention belongs to the field of low-frequency power transmission, and relates to a flexible low-frequency power transmission system suitable for offshore wind power access and an overvoltage suppression method thereof. Background technique [0002] With the advancement of the development of medium and long-distance offshore wind power, the traditional power frequency (50Hz) power transmission system has been unable to meet the needs of large-capacity wind power transmission. The main reason is that as the distance increases, the main transmission medium submarine cable also becomes longer, and its capacitive effect also becomes larger, which eventually leads to the dominant capacitive current in the submarine cable, while the active current of the transmission power becomes smaller, so that it cannot be Satisfy the delivery of wind power. [0003] Reducing the frequency of the power transmission system can effectively reduce the capacitive curre...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to overcome the defects of the above-mentioned prior art, and provide a flexible low-frequency output system suitable for offshore wind power access and its overvoltage suppression method, so as to realize the external delivery of wind turbines, and at the same time solve the problems caused by power electronics Overvoltage problems caused by device latch-up

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