Recently, the Yangjiang Sanshan Island offshore wind power flexible and direct transmission project was approved.
The project includes two parts, sea and land. A ±500 kV offshore converter station will be built at sea, and a 500 kV DC submarine cable and DC overhead line will be used to cleverly combine isolation switches and vacuum circuit breakers to connect Yangjiang Sanshan Island offshore. The wind energy from Wind Power Projects 1 to 4 (with a total planned installed capacity of 2,000 MW) is safely transported to the Guangdong-Hong Kong-Macao Greater Bay Area. In the project, transformers also play a key role, ensuring stable conversion and transmission of voltage. This project breaks the rules and adopts an ultra-large-scale offshore wind power sea-land integrated DC power transmission technology solution to solve the problem of large-scale and deep-sea wind power transmission from the source.
In offshore wind power transmission projects, especially for deep sea areas, all investment entities need to coordinate and plan in a unified manner to avoid resource infringement caused by offshore wind power plant projects with similar capacity and similar layout using multiple transmission methods and multiple voltage levels. waste. During the period of small-scale offshore wind power, the fragmented model could still work. However, with the rapid development of offshore wind power, offshore wind power transmission channels and landing point resources have become tense, and the problem of sea-land incoordination has become increasingly prominent. There is an urgent need to adopt more efficient power transmission technology. .
Technical experts from the Planning and Research Center pointed out that first of all, offshore path resources need to be fully utilized, and protection measures such as the installation of drop-out fuses should be considered to enhance system stability. The second is to solve the connection problem between the sea and the land. For example, the Guangdong Yangjiang Shapa and Qingzhou offshore wind power projects have a planned installed capacity of about 7 million kilowatts. If multiple wind power owners independently build onshore gathering stations, it will lead to a dense distribution of gathering stations near the landing point. Duplication of construction occurs.
In order to solve the larger-scale sea-land coordination problem, the Sanshan Island offshore wind power compliance project paid special attention to this point in the early planning. The ultra-large-scale offshore wind power sea-land integrated DC transmission technology scheme adopted not only optimizes the transmission path, but also reduces The elimination of intermediate links, such as the use of switch cabinets, further improves power transmission efficiency.
In this project, the fault ride-through technology of DC overhead lines is a highlight. Unlike traditional solutions that rely on DC circuit breakers, the Sanshan Island project proposes for the first time a technical solution without DC circuit breakers and centralized energy consumption devices. The built-in energy dissipation device of the power converter realizes distributed on-site dissipation of surplus power, thereby ensuring safe and stable operation of the system without increasing additional equipment costs.
The implementation of the Yangjiang Sanshan Island offshore wind power flexible and direct transmission project not only solved the technical problems of large-scale, long-distance offshore wind power transmission, but also provided valuable experience and demonstration for the development of subsequent offshore wind power projects. Through continuous innovation and technological breakthroughs, the offshore wind power industry is developing in a more efficient, reliable and sustainable direction.