Frequency Sweep Method for Measuring Modal Frequency of Generating Set Shafting System

Abstract

The frequency sweeping method for measuring the modal frequency of the shaft system of the generator set disclosed by the present invention includes: a. obtaining multiple modal frequencies of the subsynchronous oscillation of the simulated generator set; b. using a signal generator at the input end of the subsynchronous oscillation suppression device Input a modal frequency as the excitation signal; c. Change the input amplitude of the excitation signal until the excited generator speed change modal data stabilizes at the predetermined modal signal amplitude; d. Record the excitation signal at the modal frequency and the detected generator speed change modal data; e. scan within the predetermined range of the modal frequency with a predetermined step size, repeating step b, step c and step d; f. according to the recorded generator speed change Modal data to determine the subsynchronous oscillation single mode frequency value of the generator set. Compared with the existing test means, the present invention can accurately determine the modal frequencies of multiple generating sets without using other special equipment.

Description

technical field [0001] The invention relates to a frequency sweeping method for measuring the modal frequency of a shaft system of a generating set. Background technique [0002] The large-scale thermal steam turbine unit is one of the key equipment of my country's power system. The shafting of the high-power unit has the characteristics of light weight and flexibility, multiple supports, large span, and high power density. The natural frequency spectrum of the shafting system is relatively dense, and the vibration induced The energy is low; at the same time, the power grid is also developing in the direction of ultra-high voltage and long-distance. The potential factors are increasing day by day, which makes the torsional vibration problem of generator set shafting more and more serious. The torsional vibration of the shafting of the motor set will also stimulate the oscillation of the power grid, causing line tripping or unit decoupling, which directly affects the stability...

AI Technical Summary

Problems solved by technology

[0004] The disadvantage of this test method is that it cannot guarantee that the test is fully effective every time, and it is destructive to the operation of the unit and the power grid.

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