KEMA has been appointed by the China Southern Power Grid Company to act as owner’s consultant, providing quality assurance services relating to key primary equipment for use in the world’s first 800-kV HVDC transmission project.

China leads the way with the construction of ultra-high-voltage and ultra-high-power transmission links. The enormous distances between the hydroelectric and coal-fired power plants in the country’s interior and the densely populated eastern coastal provinces make DC connections the most efficient.

5000 MW
To connect the ten-gigawatt hydropower plant in the southwestern province of Yunnan to the load center in the southeastern province of Guangdong, the China Southern Power Grid Company is building an 800-kV DC link with a capacity of 5000 MW. Erection of the 1400 kilometers of high-voltage lines began late last year. The converter station equipment for each end of the transmission link is to be designed, produced and commissioned by Siemens, working in collaboration with its Chinese partners.

Unprecedented project
The Yun-Guang bi-pole link will be the highest-voltage and highest-power DC transmission link in the world. At present, no bi-pole link of more than 600 kV or with a rated power above 3150 MW is in use. Naturally, the project will involve major technical challenges. Furthermore, the Chinese grid operator is determined that the complete system should be performing as specified by the projected completion date. China Southern Power Grid Company has appointed KEMA to provide support throughout the realization of this unprecedented project. KEMA will focus on four crucial categories of primary equipment: converter transformers, thyristor valves, DC wall bushings and smoothing reactors. The appointment recognizes KEMA’s great experience with primary equipment of this kind, gained in the context of similarly challenging projects in China, such as the Three Gorges HVDC transmission projects and the 1000-kV and 750-kV AC transmission projects.

Highest quality
KEMA’s quality assurance work will involve evaluating the manufacturer’s design, reviewing the manufacturer’s production quality control system and checking crucial processes, as well as witnessing and evaluating the final acceptance tests. The object is to help the owner to ensure that the project achieves the highest possible quality levels and is completed on time.

KEMA’s appointment is effective until the end of 2009, with the link expected to enter commercial service by the summer of 2010.