CN117129076A - Method, device, storage medium and equipment for testing torsional natural frequency of steam turbine generator unit - Google Patents
Method, device, storage medium and equipment for testing torsional natural frequency of steam turbine generator unit Download PDFInfo
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- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H13/00—Measuring resonant frequency
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- G—PHYSICS
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- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
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Abstract
The application discloses a method, a device, a storage medium and equipment for testing torsional natural frequency of a steam turbine generator unit, which belong to the technical field of torsional natural frequency testing and comprise the steps of obtaining instantaneous angular velocity of the steam turbine generator unit sampled at equal time intervals in the load shedding process; converting the instantaneous angular velocity into an instantaneous angular displacement; performing frequency analysis on the instantaneous angular displacement to obtain a frequency analysis result, removing harmonic components corresponding to the rotation frequency and harmonic components corresponding to a plurality of integer multiples of the rotation frequency from the frequency analysis result to obtain a torsional vibration modal frequency component excited during load shedding, wherein the frequency corresponding to the torsional vibration modal frequency component is torsional vibration natural frequency; the application can improve the test accuracy and safety.
Description
Technical Field
The application relates to a method, a device, a storage medium and equipment for testing torsional natural frequency of a steam turbine generator unit, and belongs to the technical field of torsional natural frequency testing.
Background
Torsional vibration is a key factor affecting the safe and stable operation of the turbo generator set. The disturbance of the power system such as two-phase short circuit or grounding, three-phase automatic quick reclosing, single-phase grounding and the like can generate impact torsion excitation on the generator set shaft system, and the interaction of the high-capacity turbine set and the series compensation power transmission line can also cause the subsynchronous resonance problem under the specific operation working condition. These problems all lead to the risk of torsional oscillations in the machine axis.
If the external excitation frequency coincides with the natural frequency of torsional vibration, torsional resonance occurs, and the shafting generates large torsional vibration. In order to avoid torsional resonance, the natural frequency of torsional vibration of the unit is generally required to avoid about 10% of the external excitation frequency, and the natural frequency of torsional vibration of the unit shafting needs to be accurately known. When the turbo generator set is designed, the torsional vibration natural frequency point of the set can avoid the excitation frequency by changing the shafting model, and the torsional vibration caused by resonance is prevented. The method has important significance for guaranteeing the safe and stable operation of the unit.
In the prior art, the following method is generally adopted to test the natural frequency of torsional vibration:
(1) The calculation method comprises the following steps: the natural frequency of torsional vibration can be obtained by a calculation method, and the method is widely applied to torsional vibration force characteristic analysis of the steam turbine generator unit. The modeling can adopt a continuous quality model or a centralized quality model, and also can establish a three-dimensional entity model of the steam turbine generator unit. The calculation can be performed by a transfer matrix method, a finite element method, or the like.
(2) Test methods. External torsion excitation is applied to the shaft system of the steam turbine generator unit, and the excitation method can be divided into instant/continuous excitation and balanced/unbalanced excitation. For example, when three-phase balanced line switches are used for switching, transient impact moment is caused to a shafting due to loss of magnetization. The instantaneous impact moment can be generated by adopting single-phase line switching or switching the grid-connected unit switch to another single-phase open-circuit parallel line. The negative sequence current method is a continuous torsion excitation mode, and uses the alternating torque of a negative sequence magnetic field rotating at twice the rotating speed to excite the rotor. The single-phase grounding, the two-phase short circuit and the like can lead a negative sequence magnetic field to appear in the stator, and the implementation place can be at the outlet of the generator or at the high-voltage side of a step-up transformer (main transformer) or at the high-voltage side of a high-voltage plant.
However, the above methods have certain drawbacks, specifically as follows:
(1) A calculation method. The modeling method of the rotating part, the equivalent method of the rigidity of the rotating shaft, the material characteristics of the rotating shaft, the characteristics of the coupling, the boundary conditions, the stress concentration and other factors have larger influence on the calculation result, and the error of the calculation result is larger.
(2) The test mode can reflect shafting torsional vibration characteristics more truly, and is an effective method for determining the torsional vibration natural frequency of the unit. In order to measure the torsional vibration frequency, the torque excitation is applied to the rotating shaft by simulating the harmful disturbance of the electric power system in the test, and the safety of the shaft system is affected to a certain extent. For example, the maximum value of the transient electromagnetic torque of the generator at the time of three-phase short circuit is 6 times of rated torque, and the maximum value of the transient torque depends on the natural frequency margin of the shafting. When the torque excitation amplitude is small, the torsional vibration signal is weak, and the torsional vibration natural frequency cannot be accurately measured. When the amplitude of torsional vibration excitation is large, the safety of equipment is endangered. The special torsional vibration test is less developed on the actually installed turbo generator set.
Disclosure of Invention
The application aims to provide a method, a device, a storage medium and equipment for testing torsional natural frequency of a steam turbine generator unit, which solve the problems of larger error and low safety in the prior art.
In order to achieve the above purpose, the application is realized by adopting the following technical scheme:
in a first aspect, the application provides a method for testing torsional natural frequency of a turbo generator set, comprising the following steps:
acquiring the instantaneous angular speed of the turbo generator set sampled at equal time intervals in the load shedding process;
converting the instantaneous angular velocity into an instantaneous angular displacement;
and carrying out frequency spectrum analysis on the instantaneous angular displacement to obtain a frequency analysis result, removing harmonic components corresponding to the rotation frequency and harmonic components corresponding to a plurality of integer multiples of the rotation frequency from the frequency analysis result to obtain a torsional vibration modal frequency component excited during load shedding, wherein the frequency corresponding to the torsional vibration modal frequency component is torsional vibration natural frequency.
With reference to the first aspect, further, the instantaneous angular velocity sampled at equal time intervals is obtained by:
acquiring an original instantaneous angular velocity measured by a high-frequency counter, wherein the original instantaneous angular velocity is sampled at equal angles;
the original instantaneous angular velocity sampled at equal angles is converted into the instantaneous angular velocity sampled at equal time intervals by an interpolation method.
With reference to the first aspect, further, a calculation formula of the original instantaneous angular velocity is:
ω i ′＝2π/(NT i )
wherein omega i ' is the original instantaneous angular velocity corresponding to the ith pulse signal period, N is the number of teeth of a speed measuring gear disc on the shaft of the steam turbine generator unit, T i Is the ith pulse signal period, T i The calculation formula of (2) is as follows:
T i ＝(2 l -1-k i )/f c
where l is the number of high frequency counter bits, k i Is the output value of the high-frequency counter, f c Is the count pulse signal frequency.
With reference to the first aspect, further, the converting the instantaneous angular velocity into the instantaneous angular displacement is performed by the following formula:
wherein θ i Is the instantaneous angular displacement omega i-1 Is the instantaneous angular velocity corresponding to the i-1 th pulse signal period, delta t is the time interval omega i Is the instantaneous angular velocity corresponding to the i-th pulse signal period.
With reference to the first aspect, further, after the instantaneous angular velocity sampled at the equal time interval is obtained, the following preprocessing is performed:
the instantaneous angular velocity sampled at equal time intervals is divided into a plurality of segments, the average value of the instantaneous angular velocity of each segment is calculated, and the average value is removed from the instantaneous angular velocity.
In combination with the first aspect, further, the removing of the harmonic component corresponding to the rotation frequency and the harmonic component corresponding to the integer multiple frequencies of the rotation frequency from the spectrum analysis result is completed through the shafting torsional vibration calculation and analysis software of the turbo generator set.
In a second aspect, the present application further provides a device for testing torsional natural frequency of a turbo generator set, including:
the instantaneous angular velocity acquisition module is used for: acquiring the instantaneous angular speed of the turbo generator set sampled at equal time intervals in the load shedding process;
the instantaneous angular displacement conversion module is used for: converting the instantaneous angular velocity into an instantaneous angular displacement;
an analysis test module for: and carrying out frequency spectrum analysis on the instantaneous angular displacement to obtain a frequency analysis result, removing harmonic components corresponding to the rotation frequency and harmonic components corresponding to a plurality of integer multiples of the rotation frequency from the frequency analysis result to obtain a torsional vibration modal frequency component excited during load shedding, wherein the frequency corresponding to the torsional vibration modal frequency component is torsional vibration natural frequency.
With reference to the second aspect, further, the instantaneous angular displacement conversion module is specifically configured to:
converting the instantaneous angular velocity into an instantaneous angular displacement by the following formula:
wherein θ i Is the instantaneous angular displacement omega i-1 Is the instantaneous angular velocity corresponding to the i-1 th pulse signal period, delta t is the time interval omega i Is the instantaneous angular velocity corresponding to the i-th pulse signal period. In a third aspect, the present application also provides a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a method for testing torsional natural frequency of a turbo generator set as in any one of the first aspects.
In a fourth aspect, the present application also provides an apparatus comprising:
a memory for storing instructions;
a processor configured to execute the instructions, cause the apparatus to perform operations for implementing a method for testing torsional natural frequency of a turbo generator set according to any one of the first aspect.
Compared with the prior art, the application has the following beneficial effects:
according to the method, the device, the storage medium and the equipment for testing the torsional natural frequency of the turbo generator set, when the load is thrown, the load torque suddenly drops, the torsional deformation suddenly becomes small, so that the free response of the torsional vibration of the shafting is excited, the free vibration response signal contains the natural frequency characteristic, the torsional natural frequency is extracted by adopting the method, special torque excitation is not required to be applied to the turbo generator set, special test points and sensors are not required to be arranged, the influence of the torsional vibration test on the shafting safety of the turbo generator set can be reduced, the test workload and the complexity are reduced, and the feasibility in the actual scene is improved; the torsional vibration natural frequency is extracted after the instantaneous angular velocity is converted into the instantaneous angular displacement, the torsional vibration characteristics contained in the instantaneous angular displacement signal are more obvious, and the accuracy of the test is improved.
Drawings
FIG. 1 is a flow chart of a method for testing torsional natural frequency of a turbo generator set according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a high frequency counter measuring pulse time interval according to an embodiment of the present application;
FIG. 3 is a schematic view of a waveform of torque angular velocity due to indexing error provided by an embodiment of the present application;
FIG. 4 is a schematic diagram of a torsional angular velocity spectrum from indexing errors provided by an embodiment of the present application;
FIG. 5 is a schematic diagram of a shafting model of a turbo generator set according to an embodiment of the present application;
FIG. 6 is a schematic wave recording diagram of an instantaneous angular velocity signal in the load shedding process according to the embodiment of the application;
FIG. 7 is an enlarged partial schematic view of a 50% load operation instantaneous angular velocity signal provided by an embodiment of the present application;
FIG. 8 is a schematic diagram of an instantaneous angular velocity signal after subtracting a segment average value according to an embodiment of the present application;
FIG. 9 is a schematic diagram showing the relationship between instantaneous angular displacement and time during a load dump test according to an embodiment of the present application;
FIG. 10 is a schematic diagram of a partial amplified signal at the moment of load shedding provided by an embodiment of the present application;
fig. 11 is a schematic diagram of a spectrum of an instantaneous angular displacement signal in a load shedding process according to an embodiment of the present application.
Detailed Description
The present application will be further described with reference to the accompanying drawings, and the following examples are only for more clearly illustrating the technical aspects of the present application, and are not to be construed as limiting the scope of the present application.
Example 1
As shown in fig. 1, the application provides a method for testing the torsional natural frequency of a turbo generator set, which comprises the following steps:
s1, acquiring the instantaneous angular speed of the turbo generator set sampled at equal time intervals in the load shedding process.
The instantaneous angular velocity in step S1 is obtained by the following method:
in order to monitor the rotating speed, a speed measuring gear disc is arranged on a shaft of the turbo generator set, a magneto-electric sensor is arranged, an output signal of the magneto-electric sensor is led to a protecting system of the turbo generator set, and a rotating speed pulse signal is led out from a rotating speed signal output channel of the protecting system.
And measuring the time of the speed measuring gear disc passing through the magneto-electric sensor by using a high-frequency counter to obtain the original instantaneous angular velocity. As shown in fig. 2, the crystal oscillator in the high-frequency counter obtains high-frequency and high-precision counting pulses through the frequency divider. The output value of the high-frequency counter is recorded as k i The number of bits of the high-frequency counter is l, and the ith pulse signal period is:
T i ＝(2 l -1-k i )/f c (1)
wherein f c Is the count pulse signal frequency.
The original instantaneous angular velocity is:
ω i ′＝2π/(NT i ) (2)
wherein omega i ' is the original instantaneous angular velocity corresponding to the ith pulse signal period, N is the number of teeth of a speed measuring gear disc on the shaft of the steam turbine generator unit, T i Is the i-th pulse signal period.
The original instantaneous angular velocity obtained in the formula (2) is an equiangular sampling result, and in order to facilitate the subsequent integration and spectrum analysis of the signal, the original instantaneous angular velocity needs to be converted into an equal time interval sampling. Record the time of N teeth rotating past the sensor as t 1 ,t 2 ,...,t N Recording the sampling interval as delta t, and obtaining the instantaneous angular velocity omega sampled at equal time intervals by an interpolation method i 。
S2, converting the instantaneous angular velocity into instantaneous angular displacement.
The instantaneous angular velocity omega can be calculated by adopting a three-point Dragon lattice tower formula i Conversion into instantaneous angular displacement theta i ：
Wherein θ i Is the instantaneous angular displacement omega i-1 Is the instantaneous angular velocity corresponding to the i-1 th pulse signal period, delta t is the time interval omega i Is the instantaneous angular velocity corresponding to the i-th pulse signal period.
S3, carrying out frequency spectrum analysis on the instantaneous angular displacement to obtain a frequency analysis result, removing harmonic components corresponding to the rotation frequency and harmonic components corresponding to a plurality of integer multiples of the rotation frequency from the frequency analysis result to obtain excited torsional vibration modal frequency components during load shedding, wherein the frequency corresponding to the torsional vibration modal frequency components is torsional vibration natural frequency.
Under the conditions of uneven gear indexing, eccentric installation and vibration of a rotating shaft, the instantaneous angular displacement signal also fluctuates. The signals have the characteristic of periodicity, and can be decomposed into harmonic components corresponding to the rotation frequency, integer multiple harmonic components of the rotation frequency and torsional vibration mode frequency components. Fig. 3 and fig. 4 respectively show an instantaneous angular velocity waveform and a corresponding spectrogram caused by a random indexing error in the process of uniformly rotating the speed measuring gear plate with 1 tooth of 60 teeth, and the rotation frequency is 50Hz.
Wherein A is i Andrespectively representing the amplitude and the phase of the ith harmonic component, f is the rotation frequency, y represents the rotation frequency and the instantaneous angular displacement corresponding to the integral multiple thereof when the situation of uneven gear graduation/installation eccentricity/rotation shaft vibration exists, m represents the highest harmonic order with obvious influence on the natural frequency of torsion vibration, i= … m, and y represents the instantaneous angle corresponding to the rotation frequency when the situation of uneven gear graduation/installation eccentricity/rotation shaft vibration exists when i=1And (3) displacement. Without loss of generality, the application regards the rotational frequency and a plurality of integer multiples thereof in the torsional vibration signal as being caused by the indexing error of the gear.
Fig. 5 shows a turbo generator set object in this embodiment, which is composed of a steam turbine and a generator.
The load dump test was performed under 50% load. Fig. 6 shows a wave chart of the instantaneous angular velocity signal in the whole load shedding process. The instantaneous angular velocity flies from 3 000r/min to 3 075r/min, then drops to 2 850r/min, and rises again to 3 000r/min for constant speed.
Fig. 7 shows a partial magnified view of the instantaneous angular velocity signal at 50% load operation. The signal has a strong periodic characteristic. When the load-carrying device runs stably, the torsional vibration signal is weak, and the instantaneous angular velocity fluctuation is caused by gear indexing errors. The fluctuation amplitude peak-to-peak value b in FIG. 6 reached 2.8rad/s.
The instantaneous angular velocity change amplitude is larger during load shedding, the torsional vibration signal is weaker, and the signal characteristics are covered. The whole process is divided into a plurality of sections, and each section lasts for 0.16s. The mean value of each segment of data was calculated and subtracted from the signal, and the resulting instantaneous angular velocity signal waveform for the entire process is shown in fig. 8. There is a transient disturbance in the load dump, but the characteristic of the excited signal is masked by the initial indexing error signal.
The signal shown in fig. 8 is integrated by the method of equation (3) to obtain the instantaneous angular displacement, as shown in fig. 9 and 10. When the load is thrown, the torsion angular displacement has a large disturbance, and the free vibration response of the angular displacement is excited in the following transition process. The vibration characteristics appear more pronounced than the instantaneous angular velocity signal.
The spectrum analysis is performed on the signals shown in fig. 9, and fig. 11 shows the spectrum change situation of the instantaneous angular displacement signals in the load shedding process, wherein the spectrum change situation of the instantaneous angular displacement signals is the spectrum analysis result. The spectral analysis duration was taken to be 1.28s and the spectral resolution was 0.78Hz. Rotational frequencies of 50Hz, 100Hz, 150Hz, 200Hz, 250Hz, 300Hz, 350Hz, 400Hz, 450Hz, and several integer multiples of the rotational frequency, where 50Hz is the rotational frequency, are present throughout the process. When the rotation frequency changes at the moment of load shedding, the harmonic frequency components also synchronously change. These components are due to gear indexing non-uniformities. In the process of eliminating, harmonic components (at 50 Hz) corresponding to the rotation frequency and harmonic components (at 100Hz, 150Hz, 200Hz, 250Hz, 300Hz, 350Hz, 400Hz and 450 Hz) corresponding to a plurality of integer multiples of the rotation frequency are eliminated, so that torsional vibration modal frequency components (at 29.6 Hz) excited during load shedding are obtained, the frequency corresponding to the torsional vibration modal frequency components is 29.6Hz which is the torsional vibration natural frequency, and the elimination of the harmonic components is completed through turbine generator unit shafting torsional vibration calculation and analysis software (RorTorVib v 1.0).
At the moment of load shedding, as indicated by the label in the figure, a new harmonic component with a frequency of 29.6Hz appears. The component is excited in the load shedding process, reflects the torsional vibration characteristic of the rotating shaft and is a torsional vibration natural frequency point, the component is called a torsional vibration mode frequency component, and the frequency corresponding to the torsional vibration mode frequency component is the torsional vibration natural frequency.
In this embodiment, the sensor signal is taken from an original rotation speed signal of the turbo generator set protection system, where the sensor may be a magneto-resistive sensor, an eddy current sensor, a capacitive sensor, or the like, and the sensor signal may also be taken from an output rotation speed signal of the set monitoring system.
When the gear indexing is uniform, the gear disk is installed without eccentricity and the vibration of the rotating shaft is small, the output pulse interval of the sensor is uniform, the time interval between pulses is calculated to obtain the instantaneous angular velocity, and the calculation formula is shown in formula (1) and formula (2). After torsional vibration occurs, the interval between tooth tops is changed, the output pulse of the sensor becomes uneven in density, the time interval of adjacent teeth is unequal, the instantaneous angular velocity is unequal, and a torsional vibration signal can be obtained after demodulation processing.
When the gear indexing is uneven, the gear disc is provided with eccentricity and the vibration of the rotating shaft is large, the output rotating speed pulse interval is uneven, so that the instantaneous angular velocity fluctuation can be caused, and the test result is influenced. The application considers that the signals with uneven pulse intervals caused by errors and interference have the characteristic of periodicity, and the signal period is a rotation period. At this time, the torsional natural frequency can be extracted from the instantaneous angular velocity signal by the method of the present embodiment.
Example 2
The embodiment of the application also provides a device for testing the torsional natural frequency of the steam turbine generator unit, which comprises the following components:
the instantaneous angular velocity acquisition module is used for: acquiring the instantaneous angular speed of the turbo generator set sampled at equal time intervals in the load shedding process;
the instantaneous angular displacement conversion module is used for: converting the instantaneous angular velocity into an instantaneous angular displacement;
an analysis test module for: and carrying out frequency spectrum analysis on the instantaneous angular displacement to obtain a frequency analysis result, removing harmonic components corresponding to the rotation frequency and harmonic components corresponding to a plurality of integer multiples of the rotation frequency from the frequency analysis result to obtain a torsional vibration modal frequency component excited during load shedding, wherein the frequency corresponding to the torsional vibration modal frequency component is torsional vibration natural frequency.
The instantaneous angular displacement conversion module is specifically used for:
converting the instantaneous angular velocity into an instantaneous angular displacement by the following formula:
wherein θ i Is the instantaneous angular displacement omega i-1 Is the instantaneous angular velocity corresponding to the i-1 th pulse signal period, delta t is the time interval omega i Is the instantaneous angular velocity corresponding to the i-th pulse signal period.
Example 3
The embodiment of the present application also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the torsional natural frequency testing method as provided in embodiment 1:
acquiring the instantaneous angular speed of the turbo generator set sampled at equal time intervals in the load shedding process;
converting the instantaneous angular velocity into an instantaneous angular displacement;
and carrying out frequency spectrum analysis on the instantaneous angular displacement to obtain a frequency analysis result, removing harmonic components corresponding to the rotation frequency and harmonic components corresponding to a plurality of integer multiples of the rotation frequency from the frequency analysis result to obtain a torsional vibration modal frequency component excited during load shedding, wherein the frequency corresponding to the torsional vibration modal frequency component is torsional vibration natural frequency.
Example 4
The embodiment of the application also provides equipment, which comprises:
a memory for storing instructions;
a processor, configured to execute the instructions, so that the device performs an operation of implementing a method for testing a torsional natural frequency of a turbo generator set as provided in embodiment 1:
acquiring the instantaneous angular speed of the turbo generator set sampled at equal time intervals in the load shedding process;
converting the instantaneous angular velocity into an instantaneous angular displacement;
and carrying out frequency spectrum analysis on the instantaneous angular displacement to obtain a frequency analysis result, removing harmonic components corresponding to the rotation frequency and harmonic components corresponding to a plurality of integer multiples of the rotation frequency from the frequency analysis result to obtain a torsional vibration modal frequency component excited during load shedding, wherein the frequency corresponding to the torsional vibration modal frequency component is torsional vibration natural frequency.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing is merely a preferred embodiment of the present application, and it should be noted that modifications and variations could be made by those skilled in the art without departing from the technical principles of the present application, and such modifications and variations should also be regarded as being within the scope of the application.
Claims (10)
1. The method for testing the torsional vibration natural frequency of the steam turbine generator unit is characterized by comprising the following steps of:
acquiring the instantaneous angular speed of the turbo generator set sampled at equal time intervals in the load shedding process;
converting the instantaneous angular velocity into an instantaneous angular displacement;
and carrying out frequency spectrum analysis on the instantaneous angular displacement to obtain a frequency analysis result, removing harmonic components corresponding to the rotation frequency and harmonic components corresponding to a plurality of integer multiples of the rotation frequency from the frequency analysis result to obtain a torsional vibration modal frequency component excited during load shedding, wherein the frequency corresponding to the torsional vibration modal frequency component is torsional vibration natural frequency.
2. The method for testing the torsional natural frequency of the turbo generator set according to claim 1, wherein the instantaneous angular velocity sampled at equal time intervals is obtained by the following method:
acquiring an original instantaneous angular velocity measured by a high-frequency counter, wherein the original instantaneous angular velocity is sampled at equal angles;
the original instantaneous angular velocity sampled at equal angles is converted into the instantaneous angular velocity sampled at equal time intervals by an interpolation method.
3. The method for testing the torsional natural frequency of the turbo generator set according to claim 2, wherein the calculation formula of the original instantaneous angular velocity is:
ω i ′＝2π/(NT i )
wherein omega i ' is the original instantaneous angular velocity corresponding to the ith pulse signal period, N is the number of teeth of a speed measuring gear disc on the shaft of the steam turbine generator unit, T i Is the ith pulse signal period, T i The calculation formula of (2) is as follows:
T i ＝(2 l -1-k i )/f c
where l is the number of high frequency counter bits, k i Is the output value of the high-frequency counter, f c Is the count pulse signal frequency.
4. The method for testing the natural frequency of torsional vibration of a turbo generator set according to claim 1, wherein the converting the instantaneous angular velocity into the instantaneous angular displacement is performed by the following formula:
wherein θ i Is the instantaneous angular displacement omega i-1 Is the instantaneous angular velocity corresponding to the i-1 th pulse signal period, delta t is the time interval omega i Is the instantaneous angular velocity corresponding to the i-th pulse signal period.
5. The method for testing the torsional natural frequency of the turbo generator set according to claim 1, wherein after the instantaneous angular velocity sampled at equal time intervals is obtained, the following pretreatment is further performed:
the instantaneous angular velocity sampled at equal time intervals is divided into a plurality of segments, the average value of the instantaneous angular velocity of each segment is calculated, and the average value is removed from the instantaneous angular velocity.
6. The method for testing the torsional natural frequency of the turbo unit according to claim 1, wherein the removing of the harmonic component corresponding to the rotation frequency and the harmonic component corresponding to a plurality of integer multiples of the rotation frequency from the spectrum analysis result is completed by the turbo unit shafting torsional vibration calculation and analysis software.
7. The utility model provides a turbo generator set torsional vibration natural frequency testing arrangement which characterized in that includes:
the instantaneous angular velocity acquisition module is used for: acquiring the instantaneous angular speed of the turbo generator set sampled at equal time intervals in the load shedding process;
the instantaneous angular displacement conversion module is used for: converting the instantaneous angular velocity into an instantaneous angular displacement;
an analysis test module for: and carrying out frequency spectrum analysis on the instantaneous angular displacement to obtain a frequency analysis result, removing harmonic components corresponding to the rotation frequency and harmonic components corresponding to a plurality of integer multiples of the rotation frequency from the frequency analysis result to obtain a torsional vibration modal frequency component excited during load shedding, wherein the frequency corresponding to the torsional vibration modal frequency component is torsional vibration natural frequency.
8. The device for testing torsional natural frequency of a turbo generator set according to claim 7, wherein the instantaneous angular displacement conversion module is specifically configured to:
converting the instantaneous angular velocity into an instantaneous angular displacement by the following formula:
wherein θ i Is the instantaneous angular displacement omega i-1 Is the instantaneous angular velocity corresponding to the i-1 th pulse signal period, delta t is the time interval omega i Is the instantaneous angular velocity corresponding to the i-th pulse signal period.
9. A computer readable storage medium having stored thereon a computer program, which when executed by a processor, implements a method of testing a torsional natural frequency of a turbo generator set according to any one of claims 1-5.
10. An apparatus, comprising:
a memory for storing instructions;
a processor configured to execute the instructions, causing the apparatus to perform operations for implementing a method for testing torsional natural frequency of a turbo generator set according to any one of claims 1 to 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310901566.0A CN117129076A (en) | 2023-07-20 | 2023-07-20 | Method, device, storage medium and equipment for testing torsional natural frequency of steam turbine generator unit |
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| CN202310901566.0A CN117129076A (en) | 2023-07-20 | 2023-07-20 | Method, device, storage medium and equipment for testing torsional natural frequency of steam turbine generator unit |
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