Application Of Inverter In The Direct Air-cooling System Of Coal-fired Power Plant

With the rapid development of our country in the electric power industry, coal-fired power plants in the large capacity, high parameter steam turbine unit increasing. These units in coal and, at the same time, consumed large amount of water resource. Coal-fired power plants direct air-cooling technology has set up a file in our country has rapidly developed in north China, solve the rich coal power plant construction area of poor water problem.First of all, this passage has introduced the principle, the constituent and the type of the direct air system. By analyzing the requirement of the2×600MW units’air-cooling condenser, it has introduced the selection of the configuration of the air-cooled fan, electric motor, gearbox and the frequency device which are included in the air-cooled system.Secondly, it has introduced the air-cooled system’s working principle of the inverter and the voltage source inverter. Introducing the composition of the air-cooling system inverter cabinet, control requirements, advantages and characters of VVVF. A direct air cold units using frequency technology to flexible change the operation mode, the fan regulate steam turbine back pressure to save energy and reduce emissions, ape, improve the efficiency of the unit. It has also proposed that the use of inverter energy also produce a large number of harmonics, and the harmonic currents will produce harmonic voltage of50Hz, this may make the network voltage distorted and it will also reach the end of the network. Harmonics will affect other electrical equipments and that will cause the system itself and the equipments that are connected to the system failure. Thus, a method of harmonic controlling is proposed.Thirdly, in this paper, the2×600MW direct air-cooling unit as an example, discusses the theory and principle of the DC inverter. In this project, the series converter can be as the research object, and expounds the communication technology of frequency conversion of the main contents and related theory, and demonstrates the air cold fan of the frequency converter working characteristics and advantages of variable frequency speed regulation, and the economy further analysis. Demonstrates the variable frequency adjust air cooling fan speed is feasible, energy saving effect is obvious. By analyzing the data of the direct air-cooled units, it is proved that electric energy consumption dropped significantly when the speed of motor drops. And the wear, heat and noise of the motor will be significantly reduced so that it will improved the economic effect greatly.To make the shinade series converter as the research object in this paper, demonstrates many of the inverter air cold island the harmonics stack with each other, make harmonic pollution become more complex, and other equipment to the normal operation of the effect is more serious. Through to the power plant of direct air-cooling system frequency converter the harmonics in detail and puts forward the ape system harmonic control measure. The work of this paper for inverter in600MW unit direct air cold the application to provide certain reference value.Finally, the development of low-carbon economy has become a global consensus, saving energy and reducing consumption, building a resource-saving and environment-friendly society is an eternal topic in the modern society. In this green revolution, saving energy is of great economic to promote the value. Low energy consumption, low pollution and low-carbon economy will be the only way for China’s future development. With the rapid development of air-cooling technology, direct air-cooling technology has been applied widely in coal-fired power plants, thermal power equipment in air-cooling technology has created the conditions to improve the efficiency of its diverse areas of development Difinetely, the direct air-cooling technology in the power industry in China will have a more broad prospect for development.