Design and Operation of Thyristor-Based Converter Stations

A DC link consists of a DC line connecting at least two AC networks via converter stations. Two types of AC/DC converters are currently used in converter stations.

The first of these, which appeared in the 1970s to replace converters using mercury vapor valves, are thyristor converters. They are the subject of this article. These converters are available with high power and DC voltage (up to 12,000 MW and 1,100 kV in China with the Zhundong–Wannan link); their cost has stabilized and they have a good track record. They consume reactive power, generate harmonics, require good short-circuit power and are sensitive to AC voltage dips.

The second category, which emerged in 1997 from the variable-speed motor converter industry, are stand-alone converters known as "voltage sources".

The first part of this article describes the components making up thyristor converters. In the second part, it describes the functionalities, characteristics, advantages and disadvantages of this type of converter.