Generalized frequency conversion system used for steam turbine generator unit

Abstract

The invention discloses a generalized frequency conversion system for a steam turbine generator set, which at least includes a steam turbine with adjustable speed, a feed water pump, a generator, a speed-increasing gearbox, a frequency conversion bus and auxiliary machines connected thereto; Change, correspondingly adjust (change) the steam parameters and extraction steam entering the steam turbine, so that the speed of the steam turbine changes accordingly, so that on the one hand, the speed of the feed pump is changed through the speed-increasing gearbox, and on the other hand, the frequency of the alternating current output by the generator is changed. The invention does not need additional frequency converters of other types, and the system is simple, reliable, low in cost and high in efficiency.

Description

technical field [0001] The invention relates to the field of turbogenerators, in particular to a generalized frequency conversion system for turbogenerators. Background technique [0002] During the production process of the power plant, water is heated in the boiler and turned into steam, and then the steam is used to drive the steam turbine to rotate, which drives the generator to rotate, and finally converts the chemical energy of the fuel into electrical energy. In the process of power generation, a large number of rotating auxiliary machines such as pumps and fans in power plants need to consume a lot of electricity. The current general practice is to draw a part of the generated electricity through the plant transformer for use by the plant auxiliary machine. [0003] In the engineering design of power plants, the capacity of auxiliary machines is generally selected according to the maximum demand plus a certain margin, so the auxiliary machines in actual operation ha...

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Problems solved by technology

However, the disadvantage is that with the continuous increase of unit capacity, the capacity of the feedwater pump itself is relatively large. If the generator is further driven, the power will be relatively larger. Taking a 1000MW unit as an example, the design power of the feedwater pump is about 38MW, and the speed is generally at 4500~5300rpm, plus the power of the auxiliary engine of the generator, the power of the feedwater pump steam turbine is at least 53MW. However, the current manufacturing process capability of the feedwater pump steam turbine is limited by factors such as cylinder structure and blade strength, especially under high-speed rotation. , the high stress at the root of the long blade caused by high centrifugal force, the length of the final blade and the steam exhaust area of ​​the steam turbine are limited, and the exhaust pressure of the feedwater pump steam turbine under rated working conditions will be very high. In this way, not only the economy is poor, but even Difficult to match feed pump speed

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