China Southern Power Grid: UHV AC project is still to be demonstrated

“The China Southern Power Grid Corporation is building an ultra-high voltage transmission project in Yunnan Zhazadu to Jiangmen, Guangdong and is expected to be completed in 2013.”

Li Lijun, Secretary-General of China Southern Power Grid Expert Committee: "The UHV AC project is still to be demonstrated"

“The China Southern Power Grid Company is currently constructing a plus-minus 800 kV DC UHV power transmission project in Yunnan Zhaduo to Jiangmen, Guangdong, which is expected to be completed in 2013.” said Li Lijun, Secretary General of the China South China Power Grid Corporation Expert Committee and Academician of the Chinese Academy of Engineering.

Li Lizhen made the above statement to this reporter at the Asian Smart Power Summit held in Shanghai yesterday. This project is the third UHV DC transmission project to start construction in China. The project has a transmission power of 5 million kilowatts and a transmission length of 1,450 kilometers. After the completion of the project, China Southern Power Grid will have two West-East power transmission UHVDC transmission lines.

Li Lizhen introduced that unlike the national grid's smart grid strategy, the same high-power long-distance transmission, the South China Power Grid does not plan the UHV exchange project. Li Lijun believes that if we do not do UHV AC projects, we must first look at the characteristics of the power grid, and how UHV exchanges are used in the end. There is still great controversy.

Li Lijun revealed that although the U.S. UHV AC project passed the acceptance check, none of the projects planned by the State Grid could be started in the near future. However, there are several approved UHV DC projects.

According to the data from the China Energy News, when the first domestic UHV AC project for the construction of the State Grid, the “Southeast-Nanyang-Jingmen UHV AC pilot demonstration project” was accepted this year, “the transmission capacity could be up to 2.5 million-2.8 million kilowatts.” There is a big gap between the 4 million to 5 million kilowatts of power previously claimed.

Li Lizheng is a member of the acceptance team of the “Southeastern Jinnan-Nanyang-Jingmen UHV AC pilot demonstration project”. He believes that the reason why there is a big gap is because the power to reach 5 million kilowatts of design power is "only reached under ideal conditions, but it is difficult. DC is not the same, if the design of the DC is to reach 5 million. The capacity of kilowatts is not much different from this data in actual operation. This is the characteristic of DC."

DC transmission solves the point-to-point problem, while AC transmission involves network problems. The power of UHV AC transmission needs to be coordinated by the network. “So although the national grid is applying for expansion in the country, it hopes to make the power reach 5 million kilowatts, but it depends on the overall situation of the power network.” Li Lizhen said.