LCC based MTDC for grid integration of large onshore wind farms in Northwest China

In recent years, many large onshore wind farms are constructed or under construction all over the world. In northwest region of China, the planned capacity of onshore wind farms has reached over 20GW in total. However, the locations of those wind farms are very remote and far away from load centers, and their distance to load centers are beyond 1000km. Therefore, it´s of primary importance to address the issues concerned with bulk wind power transmission over long distance. This paper is aimed at development and application of using the line-commutated converter based multi-terminal HVDC (LCC-MTDC) technology for grid integration of large remote onshore wind farms located at Northwest China region. The studies have firstly focused on the design of LCC-MTDC system configuration and its parameters, taking into consideration the practical operation requirements for wind farm grid integration. The control strategy for the LCC-MTDC operation is then proposed, and the comparison in control strategy with and without coordinated operation is also carried out and verified by PSCAD/EMTDC simulation. Various operation scenarios such as ac fault on rectifier and inverter sides are simulated to investigate the system performance during disturbances. Results show that the proposed LCC-MTDC configuration and its control strategy are effective and the LCC-MTDC system is well controlled over the whole operating range.