Research on the design principle of the contact terminal in large DC current loop of ±800kV, 10,000MW UHVDC converter station

The abnormal heating phenomena of contact terminal in large DC current loop of the ultra-high voltage direct current (UHVDC) converter station became one of the most serious problems, which caused serious impact on the operation reliability of the power grid. Based on existing codes and standards of contact terminal temperature rise and the results of large current temperature rise test, the design principle of the contact terminal in large DC current loop of DC voltage +/- 800kV, capacity 10,000MW converter station is put forward and introduced detailedly in this study. Then, taking the design of three typical contact terminals in large DC current loop of Taizhou +/- 800kV converter station as an example, the infrared temperature measurement results of contact terminals on the large current operation condition are analysed. The infrared temperature measurement results indicate that the design principle of the contact terminal in large DC current loop proposed in this study is able to meet the requirements of existing codes and standards of the temperature (temperature rise) limit of the contact terminal. This design principle is significant to improve the maintenance ability and operation reliability of the UHVDC converter station.