Views:0 Author:Site Editor Publish Time: 2020-12-08 Origin:Site
From the perspective of the development history of steam turbine generators (including gas turbine generators and gas-steam combined cycle generators), it has been more than 100 years for a single unit capacity to grow from a few hundred kilowatts to more than one million kilowatts. The capacity is 1600MVA, and the 2-pole turbo generator has a capacity of 1200MW.
The capacity of a single unit is gradually increasing with the development of science and technology, as well as the growth of power consumption in industry, agriculture and society; the formation of the power grid has prompted the development of large-capacity units to solve the stability problem of the power grid; in the market economy, increase power generation The requirements for efficiency have also prompted the development of large-capacity units.
The apparent power of the generator is proportional to the effective length of the stator core, the square of the inner diameter of the stator core, the stator wire load, the air gap flux density and the synchronous speed. At the same time, it can be regarded as proportional to the length and diameter of the rotor. The length and diameter of the rotor are related to the characteristics of the rotor metal material and the smelting and forging capacity. The stator wire load and the air gap magnetic density are related to the heat capacity of the conductor and the heat conduction and heat dissipation capacity of the cooling medium.
To increase the capacity of a single generator, on the one hand, it is necessary to improve the smelting and forging capacity, forging a rotor with a larger diameter, improving the performance of the raw materials, using better insulating materials, etc., and another important way is to apply new cooling methods to Improve heat transfer and heat dissipation capabilities.
The development history of the generator shows that every time the cooling method of the generator is improved or improved, the single generator capacity is pushed to a new level.
1. Overview of the development of foreign turbo-generator cooling methods
As mentioned earlier, the capacity of a single generator is mainly increased with the development of cooling methods. The development history of several well-known motor manufacturing companies in the world for more than 100 years has roughly gone through several stages such as air cooling→hydrogen cooling→water-hydrogen mixed cooling→full water cooling. Because the stator and rotor ventilation structures of the generators of each company are different, the capacity is different under the same cooling method.