China’s largest direct-drive wind turbines passes critical grid test

China’s largest direct-drive wind turbine recently passed a critical international test on its capacity to withstand power dips in the national grid, announced the Sino-German maker Friday.

The 2.5 MW direct-drive permanent magnetic wind turbine, independently developed by Guangxi Yinhe Avantis Wind Power Co., Ltd (GYAW), recently passed a low-voltage ride through (LVRT) test, said Lars Andreasen, general manager of the wind turbine maker in Beijing.

"This is so far the largest direct-drive permanent magnetic wind turbine passing the LVRT test in the world," said Lars. The test measures the capacity of a wind turbine to maintain continuous online operations when the voltage of the grid dips.

The GYAW wind turbine was connected to the national grid for a trial operation in June 2009, making it the first grid-connected 2.5 MW wind turbine in China. On March 5 this year, the wind turbine, located on a testing site in Beihai, south China’s Guangxi, successfully passed two-phase and three-phase LVRT tests, carried out by China Electric Power Research Institute (CEPRI).

On March 7, the prototype successfully passed the LVRT test based on the International Electrotechnical Commission (IEC) standard. Few of China’s popular 1.5MW wind turbines have passed the test.

In October 2010, a 5MW direct-drive wind turbine rolled off the production line of Xingtan Electric Manufacturing Corporation (XEMC), a wind turbine maker in central China’s Hunan. The wind turbine is so far the largest in the country, but XEMC is planning to develop 6MW and 7.5 MW direct-drive wind turbines.

In March 2010, the National Energy Bureau (NEB) announced it had established a technical committee of wind energy industry standardization to draft the Standard for Wind Power Grid Connection. At present, the main components of the national standard have been made ready and submitted to the central government for examination.

"Compared with the current technical rules for connecting wind farms to the State Grid, the national standard concerning the LVRT test is stricter, adding requirements for response time and duration of reactive compensation under three-phase short-circuit of wind farm," said, Amanda Yang, an engineer with GYAW. Chinese wind farm operators have been perplexed and disappointed with the quality of wind turbines.

According to Dai Huizhu, a professor with CEPRI, 598 wind turbines were disconnected from the grid during voltage sags in February this year in Jiuquan, northwest China’s Gansu Province. Hundreds of wind turbines met the same problem in January in northeast Jilin Province.

Xie Wenbo, from the wind power branch of China Guangdong Nuclear Power Group, said "The 1.5MW wind turbines could operate soundly only for three years. After that, they will show problems one way or the other." "As a wind farm operator, we are most concerned with the rate of return on investment," said Xie.

Liu Bin from China Wind Power, a leading wind farm developer, said "With wind turbines of the present quality, China cannot realize its ambitious installed capacity objective in 2020." To upgrade the existing thousands of wind turbines in operation, mostly without the LVRT function, a huge amount of money will be needed, perhaps up to 1 percent of the value of the turbines, industry officials say.

China aims to have 290 GW of power generation capacity from new energy sources in 2020. Wind power will amount to 150 GW. By the end of 2010, China had 44.7 GW cumulative wind energy installed capacity, replacing the United States to be the largest in the world.

Following explosions at a Japanese nuclear power plant wreaked by the March 11 earthquake and tsunami, the Chinese government announced on March 16 that it had suspended the approval process for the country’s nuclear power stations, including pre-construction works of all new nuclear power plants, so that safety standards could be revised.

"Wind power will play an even greater role now in achieving the government’s 2020 objectives," said Li Junfeng, deputy director of the energy research institute under the National Development and Reform Commission.