Rotor of World's First 1 Million kW Hydropower Generator Unit Hoisted

The rotor of the first generator unit of the Baihetan Hydropower Station on the Jinsha River on the border of Southwest China's Sichuan and Yunnan provinces was hoisted on Aug 18.

Developed by Dongfang Electric Corporation (DEC), the rotor is the world's first of its kind to be installed on a 1 million kW hydropower generator unit.

The rotor is the core and the heaviest component of a hydro-generator. The rotor hoisted on Aug 18 weighed about 2,000 tons, has an outer diameter of 16.2 meters and a maximum height of 4.1 meters.

With a total installed capacity of 16 million kW, the Baihetan Hydropower Station is a major hydropower project to develop and improve the water environment of the upper reaches of the Yangtze River, a main part of the river's flood control system and a backbone power supply node in the national “west-to-east" power transmission project.

There are eight 1 million kW hydropower generator units on each side of the Jinsha River and DEC was responsible for development of the units on the left bank.

Upon completion, the station is expected to produce 62.44 billion kWh of power annually, which equals more than half of the power consumption in Beijing in 2019.

The power amount is equivalent to that produced by burning of about 19.68 million tons of standard coal and reduces emissions of carbon dioxide by 51.6 million tons, of sulfur dioxide by 170,000 tons and of oxynitride by about 150,000 tons.

The normal pool level of the Baihetan Hydropower Station's reservoir is 825 meters, which means the reservoir can store 20.6 billion square meters of water and has a flood control capacity of 7.5 billion square meters.

It will be used together with other cascade reservoir to improve flood control capacity of cities along the rivers, including Yibin and Luzhou of Sichuan and Chongqing. Moreover, the reservoir will help reduce floodwater flowing into the Three Gorges reservoir and reduce flood damage to regions of the middle and lower reaches of the Yangtze River.

It's worth mentioning that the fully air-cooled hydropower generator has the world's largest unit installed capacity.

The maximum winding temperature rise of the stator is 63K and that of the rotor is 58K, which is much better than international and Chinese standards.

Strict temperature controls guarantee safe and reliable long-term operation of the generator unit.

Its rated voltage, which is 24kV, is also the highest level in the hydropower industry.

Low-loss bearings are used in the generator units to lower loss of thrust and bottom guide bearings. In the meantime, load-carrying property of the thrust bearings and cooling effectiveness are improved but the oil mist is reduced, so that the generator units meet requirements of high load, reliability and efficiency as well as low environmental impact.

An assessment standard on 24kV stator winding insulating property was initiated by DEC to test the highest voltage level of the 24kV hydropower generator unit.

All performance indicators were proved better than required after testing of simulation calculations, insulating properties, multi-stress aging life spans and terminal diameter pitch winding simulation discharge.

What's more, all 1,620 winding bars on a single generator unit passed on-site electrical performance testing and the entire winding of the first generator unit passed inspection on July 30 this year.

The rotor of the world's first 1 million hydropower generator unit at the Baihetan Hydropower Station is hoisted on Aug 18. [Photo/sasac.gov.cn]

(Executive editor: Wang Ruoting)