Study on the development and reliability of HVDC transmission systems in China

Over the past decade years, China has seen rapid development in HVDC technologies with the world highest operational voltage of ±800kV commissioned in 2010. By 2013, there are more than 24 HVDC transmission projects commissioned or in operation across China to facilitate bulk transfer of power from western and northern parts of the country to the load centres in the central or eastern regions. A majority of HVDC projects land in the central, eastern and southern grids of China. Reliability of HVDC systems and their interaction with AC transmission systems have become a major concern to the system operators in the State Grid Corporation of China (SGCC) and China Southern Grid (CSG). This paper presents the latest development and future trend of HVDC transmission systems in China. It describes the commutation failure mechanism of HVDC systems and analyzes historical HVDC commutation failures reported in China. Finally the paper presents the reliability analysis of HVDC transmission systems and their impact on hybrid AC/DC system performance.