OFFSHORE WIND FARM HIGH-FREQUENCY UNCONTROLLED RECTIFICATION DIRECT-CURRENT ELECTRIC POWER TRANSMISSION SYSTEM

摘要

The present invention provides an offshore wind farm high-frequency uncontrolled rectification direct-current electric power transmission system, comprising a direct-current system and an offshore alternating-current system. The offshore alternating-current system mainly comprises a full-power converter-type wind turbine generator based on a permanent magnet synchronous motor, an alternating-current submarine cable, and an offshore booster station; the direct-current system comprises an offshore station and an onshore station, and the offshore station and the onshore station are connected by means of a direct-current submarine cable. A three-phase six-pulse uncontrolled rectifier bridge is adopted as a converter of the offshore station, and MMC is adopted as a converter of the onshore station. The rated frequency of the offshore alternating-current system and the offshore station is far larger than 50 Hz, and generally, the rated frequency can be selected to be close to 100 Hz to 400 Hz. Compared with a conventional flexible direct current transmission solution, the structure in the present invention is simple, the sizes and weights of an offshore platform transformer, a reactive power compensation device and an alternating-current filter can be reduced by improving the rated frequency of the offshore station and the offshore alternating-current system, the construction costs can be greatly reduced, and the system has a huge application value in actual engineering.