CN111208424B - Automatic detection and early warning method and device for generator stator and rotor gap unevenness fault - Google Patents
Automatic detection and early warning method and device for generator stator and rotor gap unevenness fault Download PDFInfo
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- CN111208424B CN111208424B CN202010036878.6A CN202010036878A CN111208424B CN 111208424 B CN111208424 B CN 111208424B CN 202010036878 A CN202010036878 A CN 202010036878A CN 111208424 B CN111208424 B CN 111208424B
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Abstract
The invention discloses a generator stator and rotor gap nonuniformityA fault automatic detection early warning method and a device relate to the field of generators, and the method comprises the following steps: s1, collecting stator current time domain signals; s2, obtaining a current frequency domain signal according to the current time domain signal; s3, obtaining a frequency domain amplitude signal according to the current frequency domain signal; s4, determining the frequency domain amplitude signal at the current power frequency f1The maximum value of the amplitude of the interval near the fault characteristic frequency points on the two sides; s5, determining the maximum value, judging whether the maximum value exceeds an early warning threshold value R, and sending out early warning signals corresponding to the uneven clearance between the stator and the rotor; the stator current signals are analyzed, whether the real-time maximum value and the predicted maximum value of future time exceed an early warning threshold value or not is determined through the maximum value near the electrical fault characteristic frequency point, automatic detection and prediction are achieved for faults of uneven gaps of the stator and the rotor, detection accuracy is improved, detection difficulty is reduced, early warning is achieved for future bad trends, and the method has obvious advantages compared with a conventional gap sensor detection mode.
Description
Technical Field
The invention relates to the field of generators, in particular to a method and a device for automatically detecting and early warning faults of uneven gaps of a stator and a rotor of a generator.
Background
The generator has wide application in industrial and agricultural production, national defense, science and technology and daily life. The invention provides a method and a device for automatically detecting and early warning the motor stator and rotor gap unevenness faults, wherein the motor stator and rotor gap unevenness faults are common faults of a motor and can influence the safe and stable operation of the motor and the service life of the motor.
Disclosure of Invention
The invention aims to solve the problems and designs an automatic detection and early warning method for the fault of the uneven clearance between the stator and the rotor of the generator.
The invention realizes the purpose through the following technical scheme:
the automatic detection and early warning method for the fault of the uneven clearance of the stator and the rotor of the generator comprises the following steps:
s1, collecting a generator stator current time domain signal X (t) at regular time;
s2, obtaining a current frequency domain signal X (jw) according to the collected current time domain signal X (t);
s3, obtaining a frequency domain amplitude signal X according to the current frequency domain signal X (jw)Amplitude value(jw)；
S4, determining frequency domain amplitude signal XAmplitude value(jw) at current power frequency f1The maximum value of the amplitude of the interval near the fault characteristic frequency points on two sides, wherein the fault characteristic frequency point is f1±f2Interval is (f)1+f2—Δf，f1+f2+ Δ f) and (f)1—f2—Δf，f1—f2+ Δ f), Δ f being the self-setting frequency range, f1Is the current power frequency, f2Is the rotor rotational frequency;
and S5, judging that the maximum value of the amplitude exceeds an alarm threshold value R, and sending out an alarm signal of uneven clearance between the stator and the rotor.
The embodiment of the invention also provides an automatic detection and early warning device for the fault of the uneven clearance between the stator and the rotor of the generator, which comprises a storage, a processor and a computer program which is stored in the storage and can run on the processor, wherein the processor realizes the steps of the automatic detection and early warning method for the fault of the uneven clearance between the stator and the rotor of the generator when executing the computer program.
The embodiment of the invention also provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to realize the automatic detection and early warning method for the generator stator and rotor gap unevenness fault.
The invention has the beneficial effects that: the stator current signals are analyzed, whether the real-time maximum value and the predicted maximum value in the future 10 days exceed the early warning threshold value or not is determined through the maximum value near the fault characteristic frequency point of the current frequency domain signals, the automatic detection and prediction are realized for the faults of uneven gaps between the stator and the rotor, the detection accuracy is improved, the detection difficulty is reduced, meanwhile, the early warning is realized for the future adverse trend, the method has obvious advantages compared with the conventional gap sensor detection mode, and the method has important significance for the safe and stable operation of a generator, particularly a large generator of a power station.
Drawings
FIG. 1 is a flow chart of an automatic detection and early warning method for a generator stator and rotor gap unevenness fault.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "inside", "outside", "left", "right", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, or the orientations or positional relationships that the products of the present invention are conventionally placed in use, or the orientations or positional relationships that are conventionally understood by those skilled in the art, and are used for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is also to be noted that, unless otherwise explicitly stated or limited, the terms "disposed" and "connected" are to be interpreted broadly, and for example, "connected" may be a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; the connection may be direct or indirect via an intermediate medium, and may be a communication between the two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The following detailed description of embodiments of the invention refers to the accompanying drawings.
Embodiment 1, as shown in fig. 1, an automatic detection and early warning method for a generator stator and rotor gap unevenness fault includes the following steps:
s1, collecting a generator stator current time domain signal X (t) at regular time;
s2, obtaining a current frequency domain signal X (jw) according to the collected current time domain signal X (t);
s21, using Fourier transform formula to make current time domain signal X (t)
Performing Fourier transform on the current time domain signal X (t) to obtain a current frequency domain signal X (jw), wherein the current frequency domain signal X (jw) comprises amplitude information and phase information, and the current frequency domain signal X (jw) is a complex number for a certain frequency W, X (jw);
s22, under an ideal operation condition, the cosine signal of the generator stator current time domain signal which is standard is expressed as X (t) ═ Acos (2 pi f)1t + theta), A is the current amplitude and is determined according to the actual working condition; f. of1The current frequency is the power frequency of 50 HZ; theta is a phase and is determined according to the signal extraction time; when the stator and the rotor of the generator have the gap-nonuniformity fault, the magnetic field of the rotor generates a frequencyThe method is characterized in that the method is a periodic fluctuation signal of the rotor rotation frequency, the magnetic field fluctuation causes electromagnetic torque to generate periodic fluctuation with the same frequency, namely amplitude modulation and frequency modulation are generated on the electromagnetic torque, and the amplitude modulation and the frequency modulation are generated on the original standard cosine signal by the linear relation T ═ ki of the electromagnetic torque and the stator current (wherein T is the electromagnetic torque; k is a torque coefficient and is a constant; i is the stator current), so that the stator current can be known to generate the amplitude modulation and the frequency modulation on the original standard cosine signal, namely the current time domain signal is expressed as
In the formula (I), the compound is shown in the specification,
the non-uniform fault amplitude modulation of the characteristic gap,
characterizing gap-mura fault frequency modulation, wherein f2The rotor rotation frequency is determined as a constant according to the actual condition of each unit;
s23, theory and practice can prove that the influence of the gap non-uniformity fault on the frequency modulation of the stator current is small, the problem is simplified and can be ignored, only amplitude modulation needs to be researched, and therefore, a current time domain signal when the gap non-uniformity fault occurs to the stator and the rotor of the generator is simplified and is expressed as the simplified signal
The current frequency domain signal X (jw) after Fourier transformation of the formula has amplitude information on a fault characteristic frequency point;
s3, obtaining a frequency domain amplitude signal X according to the current frequency domain signal X (jw)Amplitude value(jw) obtaining amplitude information of the stator current frequency domain signal x (jw), assuming that x (jw) is a (w) + b (w) j, j is an imaginary unit, calculating a modulus from the complex numberThe formula is calculated according to the formula,
namely obtaining a frequency domain amplitude signal XAmplitude value(jw)；
S4, determining frequency domain amplitude signal XAmplitude value(jw) at current power frequency f1The maximum value of the amplitude of the interval near the fault characteristic frequency points on two sides, wherein the fault characteristic frequency point is f1±f2Interval is (f)1+f2—Δf，f1+f2+ Δ f) and (f)1—f2—Δf，f1—f2+ Δ f), Δ f being the self-setting frequency range, f1Is the current power frequency, f2Is the rotor rotational frequency; the current time domain signal X (t) is the multiplication of two signals, after Fourier transformation, the current frequency domain signal X (jw) becomes the convolution of two frequency domain signals, which is shown as the current power frequency f1Two sides f1±f2(i.e., fault signature frequency point) frequency point exhibits a maximum value, for XAmplitude value(jw) the maximum value in the section of the fault characteristic frequency point, and the sections near the fault characteristic frequency points on both sides are (f)1+f2—Δf，f1+f2+ Δ f) and (f)1—f2—Δf，f1—f2+ Δ f), where Δ f is a self-settable frequency range;
s5, judging that the maximum value of the amplitude exceeds an alarm threshold value R, and sending out an alarm signal of uneven clearance between the stator and the rotor;
s6, determining the relation between the maximum amplitude value and the time according to the maximum historical amplitude value of the previous period; to XAmplitude value(jw) performing unary linear regression analysis on the maximum amplitude value near the fault characteristic frequency point, namely calculating coefficients a and b of an unary linear regression equation Y which is the maximum amplitude value dependent variable and X which is the time independent variable by using the historical maximum amplitude value of the previous period; y is (f)1+f2—Δf，f1+f2+ Δ f) and (f)1—f2—Δf，f1—f2+ Δ f) maximum value of the amplitude in two intervals; determining a time in the futureIf the maximum value of the amplitude exceeds the alarm threshold value R, the function of early warning of faults is realized, and X is obtained in the preset future time period by using the formulaAmplitude value(jw) when the maximum value of the amplitude value near the fault characteristic frequency point is 10 days, the current preset future time period is 10 days, namely X is 10, and when Y reaches or exceeds an alarm threshold value R in the future 10 days, an early warning signal of uneven clearance between a stator and a rotor is sent out, so that the function of early warning of faults is realized.
Embodiment 2, the automatic detection and early warning device for the generator stator and rotor gap unevenness fault comprises a storage, a processor and a computer program which is stored in the storage and can run on the processor, wherein the processor implements the steps of the automatic detection and early warning method for the generator stator and rotor gap unevenness fault when executing the computer program.
Embodiment 3 is a computer-readable storage medium storing a computer program. When being executed by a processor, the computer program realizes the embodiment of the automatic detection and early warning method for the generator stator and rotor gap unevenness fault.
That is, as can be understood by those skilled in the art, all or part of the steps in the method for implementing the embodiments described above may be implemented by a program instructing related hardware, where the program is stored in a storage medium and includes several instructions to enable a device (which may be a single chip, a chip, or the like) or a processor (processor) to execute all or part of the steps of the method described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The technical solution of the present invention is not limited to the limitations of the above specific embodiments, and all technical modifications made according to the technical solution of the present invention fall within the protection scope of the present invention.
Claims (4)
1. The automatic detection and early warning method for the fault of the uneven clearance between the stator and the rotor of the generator is characterized by comprising the following steps of:
s1, collecting a generator stator current time domain signal X (t) at regular time;
s2, obtaining a current frequency domain signal x (jw) according to the collected current time domain signal x (t), specifically including:
s21, Fourier transform is carried out on the current time domain signal X (t) to obtain a current frequency domain signal X (jw),
；
s22, under ideal operation condition, the cosine signal of the generator stator current time domain signal as the standard is expressed as
(ii) a When the generator stator and rotor have gap non-uniform fault, the rotor magnetic field generates a periodic fluctuation signal with the frequency of the rotor rotation frequency, the magnetic field fluctuation causes the electromagnetic torque to generate periodic fluctuation with the same frequency, namely, the electromagnetic torque generates amplitude modulation and frequency modulation, and the linear relation between the electromagnetic torque and the stator current shows that the stator current also generates amplitude modulation and frequency modulation on the original standard cosine signal, namely, the current time domain signal when the generator stator and rotor have gap non-uniform fault is
In the formula (I), wherein,
the non-uniform fault amplitude modulation of the characteristic gap,
characterizing gap-mura fault frequency modulation, wherein,
is at current power frequency, and
is at a frequency of 50Hz and is,
for the phase of the current time domain signal at the time of acquisition in S1,
is the rotational frequency of the rotor, and
is a constant, a is the amplitude of the stator current,
is the phase;
s23, when the stator and the rotor of the generator have the gap-inequality fault, neglecting the frequency modulation influence of the gap-inequality fault on the stator current to simplify the current time domain signal X (t), and simplifying the signal
X (t) is the convolution of the two frequency domain signals obtained by multiplying the two signals and performing Fourier transform on the multiplied signals, and the current frequency domain signal X (jw) is expressed as the current power frequency
Two sides
Appears in the vicinity of a frequency point of (a), wherein,
a fault characteristic frequency point;
s3, obtaining a frequency domain amplitude signal according to the current frequency domain signal X (jw)
（jw）；
S4, determining frequency domain amplitude signal
(jw) at Current Power frequency
The maximum amplitude value of the interval near the fault characteristic frequency points on two sides, wherein the interval is (f)1+f2-Δf，f1+f2+ Δ f) and (f)1-f2-Δf，f1-f2+ Δ f), Δ f is the self-set frequency range;
s5, judging that the maximum value of the amplitude exceeds an alarm threshold value R, and sending out an alarm signal of uneven clearance between the stator and the rotor;
s6, determining the relation between the maximum amplitude value and the time according to the maximum historical amplitude value of the previous period; and determining whether the maximum value of the amplitude at a certain time in the future exceeds an alarm threshold value R, so as to realize the function of early warning of faults, wherein the relation between the maximum value of the amplitude and the time is Y = mX + n, and coefficients m and n of a unitary linear regression equation Y = mX + n are calculated according to the maximum value of the historical amplitude at the previous period, wherein Y is a dependent variable of the maximum value of the amplitude, and X is a time independent variable.
2. The method of claim 1, wherein in S3, amplitude information is obtained for frequency domain signal X (jw) of stator current, and if X (jw) = a (w) + b (w) j, j is an imaginary unit, then according to a complex modulo calculation formula,
to obtain a frequency domain amplitude signal
（jw）。
3. The device for automatically detecting and warning the generator stator and rotor gap unevenness fault comprises a storage, a processor and a computer program which is stored in the storage and can run on the processor, and is characterized in that the processor executes the computer program to realize the steps of the method for automatically detecting and warning the generator stator and rotor gap unevenness fault according to any one of claims 1-2.
4. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the method for automatic detection and warning of generator stator/rotor gap irregularity fault according to any of claims 1-2.
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