China to upgrade Hunan power grid

The State Grid Corporation of China (SGC) (Beijing) has decided to invest $340 million this year to improve the Hunan power grid's ability to withstand ice, according to Hunan Electric Power Company (Changsha), a subsidiary of SGC in Hunan Province.

From mid-January to mid-February of this year, the grid was greatly affected by the severe snowstorms that hit the country. The grid's transmission lines were encased in ice about 70 millimeters to 90 millimeters thick; the lines' designed limit was 15 millimeters to 20 millimeters.

The $340 million upgrade will cover six transmission lines with a total length of 531 kilometers and 38 crossovers at the 500-kilovolt (kV) level; 20 transmission lines with a total length of 733 kilometers and 38 crossovers at the 220 kV level; and 26 transmission lines with a total length of 452 kilometers and 165 crossovers at the 110 kV level.

Related departments of the SGC have been planning for various stages of the project, including tendering and construction. During construction, new technologies, new materials and new processes will be used. For instance, the application of multi-circuit, compact and narrow foundation steel pipe assembled towers will be adopted in 220 kV and 110 kV transmission lines.