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

摘要

The present disclosure provides a high-frequency uncontrolled rectifier-based DC transmission system for an offshore wind farm, including a DC system and an offshore AC system. The offshore AC system mainly includes wind turbines based on permanent magnet synchronous generators with full-scale power converters, AC submarine cables, and offshore step-up stations. The DC system includes an offshore station and an onshore station that are connected by DC submarine cables, where a converter of the offshore is a three-phase six-pulse uncontrolled rectifier bridge, while a converter of the onshore station is MMC. Each of the offshore AC system and the offshore station has a rated frequency far above 50 Hz, which can usually be chosen to be in a range of about 100 Hz to 400 Hz. Compared with the conventional flexible DC transmission schemes, the disclosed transmission system is simple in structure. Moreover, with increased rated frequencies of the offshore station and the offshore AC system, transformers, reactive power components and AC filters for the offshore platform can be reduced in size and weight, allowing for a great reduction in construction costs and demonstrating great application potentials in actual engineering.