The accident took place in the Second Zhurihe Wind Farm, Tongliao city, north China’s Inner Mongolia. Huaneng has not officially released information on the accident. Huaneng Tongliao Wind Power Company, which runs the Second Zhurihe Wind Farm, said the incident is under investigation.

At about 16:00 of 7 February, the wind farm, undergoing an overhaul when one of the turbines caught fire. Two maintenance personnel were in the nacelle eliminating frequency converter faults.

The wind turbine is made by China South Locomotive and Rolling Stock (CSR) and the frequency converter was made by AMSC. CSR said the cause of the accident was unclear and that it was investigating the accident with Huaneng and the local safe production regulators.

The first stage of the Second Zhurihe Wind Farm has 300MW installed capacity. To date, all the other 100-odd turbines have been operating normally, according to sources in the wind farm.

Since the fire fighting apparatus could not reach the hub height of 80-metres, the fire fighters failed to control the fire. It burnt for about 12 hours and extinguished by itself at about 3:00a.m in the second morning. The wind turbine nacelle was burnt away, and the three blades were damaged to varying degrees.

The fire fighters found a body at the second platform of the wind tower, who had died as a result of head injuries. The other engineer has not been found.

CSR says that when the accident took place, the wind turbine was shut down for overhaul, and this means the accident was not caused by turbine quality problems. "We will not say the turbine is flawless, but there must be other reasons," said CSR.

In recent years, China has seen many cases of wind turbines catching fire, as more and more wind farms go into operation.

Yang Kun, the chief engineer of State Electricity Regulatory Commission, recently said that since 2010, there has been a rise in the number of accidents with Chinese wind turbines. In the first seven months of 2011, eight wind turbines were burned down due to various reasons.

Chinese wind farms largely keep only a number of portable fire extinguishers in the turbine engine room and the bottom of the wind tower. The ground-based fire fighting apparatuses are helpless to fire burning in the engine room, because they cannot reach the height.

Industry officials say that China remains backward in the standard with fire fighting system in wind farms, and wind farm developers have not paid enough attention to the problem.

Huaneng Tongliao Wind Power Company has installed over 1GW in Tongliao. It plans to expand this to 2.13GW by 2015.