China's first 1,100kV UHV bushing and ± 800kV UHV dry DC casing with independent intellectual property rights have passed State appraisal and can be put into production, according to Xi'an Jiaotong University in Shaanxi province.

They are the greatest achievements made by the Xi'an-based China XD Group and Xi'an Jiaotong University since both sides started co-operation in 2006.

The UHV technology has long been monopolized by only a few countries in the world. The UHV bushing and ± 800kV UHV dry DC casing are nodus in the technology.

All the UHV bushings and casings used by Chinese transformer companies are foreign products. And UHV AC and DC casings are the biggest constraints in China's UHV project construction and the bottleneck hindering development of its power industry.

In 2006, the China XD Group and Xi'an Jiaotong jointly launched a scientific research team to study UHV AC and DC casings, taking on the important task of revitalizing China's national industry.

UHV bushings and casings involve a number of key technologies and face difficulties in the research into their material performance, multi-field analysis, structural design, process handling and testing.

According to the foreign offer, the unit price of the ± 800kV DC bushing and casing is around 5 million yuan ($693,651).

The UHV DC transmission projects of the State Grid Corporation and China Southern Power Grid Company plan to build need around 3 billion yuan worth of UHV DC bushings and casings.

The successful research and development of China's first 1,100kV UHV bushing and ± 800kV UHV dry-DC casing has broken foreign monopoly.

(Source: China Daily)