CN113311328B - Rotor static eccentricity diagnosis method based on vibration characteristics of stator-winding system - Google Patents
Rotor static eccentricity diagnosis method based on vibration characteristics of stator-winding system Download PDFInfo
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- CN113311328B CN113311328B CN202110441808.3A CN202110441808A CN113311328B CN 113311328 B CN113311328 B CN 113311328B CN 202110441808 A CN202110441808 A CN 202110441808A CN 113311328 B CN113311328 B CN 113311328B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
- G01R31/343—Testing dynamo-electric machines in operation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
- G01R31/346—Testing of armature or field windings
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Abstract
The invention discloses a rotor static eccentricity diagnosis method based on vibration characteristics of a stator-winding system, which comprises the following steps of: s1, arranging measuring points at intervals along the circumferential direction at the position of the stator end winding of the generator, and measuring the radial vibration of the stator end winding of the generator at the measuring points by adopting an acceleration sensor; s2, filtering and denoising the acceleration signal measured by the acceleration sensor, and then carrying out Fourier transform to obtain a second harmonic amplitude; s3, calculating effective values of the acceleration second harmonic amplitudes of the measuring points according to the obtained second harmonic amplitudes; and S4, calculating the eccentric position and the eccentricity of the static eccentricity of the generator rotor according to the effective value of the acceleration second harmonic amplitude of each measuring point. The invention can accurately determine the fault degree, simplifies the process of checking and maintaining the fault and can make up for the defects of the prior art.
Description
Technical Field
The invention relates to the technical field of generator detection, in particular to a rotor static eccentricity diagnosis method based on vibration characteristics of a stator-winding system.
Background
Due to machining installation errors, insufficient shafting support rigidity, long-term operation and the like, most of motors have the phenomenon of stator and rotor air gap eccentricity, namely the air gap eccentricity is one of common mechanical faults of the generator. When the eccentricity exceeds 10%, a serious air gap eccentricity fault exists, which can cause the increase of the electromagnetic force of a part of windings, the working condition of a bearing of the generator is worsened, the vibration of a stator and a rotor is aggravated, and the deformation of a stator core, the vibration abrasion of the windings and the damage of the strength are caused.
According to different eccentric causes, the air gap eccentricity has three types of static eccentricity, dynamic eccentricity and dynamic and static mixed eccentricity. For such rotor vibration characteristics and electrical fault characteristics under faults, there have been many researches and summaries in the existing patents and papers. However, most of the methods are directed to how to distinguish and identify the faults by using the vibration characteristics of the rotor and the electrical fault characteristics, few articles are provided for identifying the severity of the faults, and the estimation of the severity of the faults is mostly based on the severity of the vibration of the rotor and the magnitude of electrical parameters, and if the severity of the faults is accurately determined, the generator needs to be stopped, disassembled, assembled and inspected, so that the maintenance process of the generator is complex.
Disclosure of Invention
The invention aims to provide a rotor static eccentricity diagnosis method based on vibration characteristics of a stator-winding system, and aims to solve the problems that the conventional generator rotor static eccentricity fault detection method cannot accurately determine the fault degree and the process of checking and maintaining the fault is complex.
In order to achieve the purpose, the invention provides the following technical scheme:
a rotor static eccentricity diagnosis method based on vibration characteristics of a stator-winding system comprises the following steps:
s1, arranging measuring points at intervals along the circumferential direction at the position of the stator end winding of the generator, wherein the measuring points adopt an acceleration sensor to measure the radial vibration of the stator end winding of the generator;
s2, filtering and denoising the acceleration signal measured by the acceleration sensor, and then carrying out Fourier transform to obtain a second harmonic amplitude;
s3, calculating effective values of the acceleration second harmonic amplitudes of the measuring points according to the obtained second harmonic amplitudes;
and S4, calculating the eccentric position and the eccentricity of the static eccentricity of the generator rotor according to the effective value of the acceleration second harmonic amplitude of each measuring point.
Preferably, the measuring points are arranged at intervals of 60 degrees along the circumferential direction of the stator end winding of the generator, and the measuring points are arranged in total four.
Preferably, in step S3, the calculation formula of the effective value of the measured point acceleration second harmonic amplitude is as follows:
in the formula (1), A ip The second harmonic amplitude of the p sample of the ith measuring point is m, and the sampling times are m.
Preferably, in step S4, the calculation formula of the eccentric position of the static eccentricity of the generator rotor is as follows:
in the formula (2), lambda is the eccentric position of the static eccentricity of the generator rotor, A 1～ A 4 The effective values of the acceleration second harmonic amplitudes of the four measuring points are respectively.
Preferably, in step S4, the calculation formula of the eccentricity of the static eccentricity of the generator rotor is as follows:
in the formula (3), ζ is the eccentricity of the static eccentricity of the generator rotor.
By adopting the technical scheme, the invention has the following beneficial technical effects:
because the vibration acceleration magnitude of the stator and the winding of the generator is far greater than the magnitude of the speed and the displacement, the second harmonic is obvious, and other higher harmonics are very weak, the invention provides the method for calculating the eccentric position and the eccentricity through the second harmonic of the vibration acceleration of the winding, the vibration characteristic in normal operation is not needed, the fault degree can be accurately determined, the fault checking and maintaining process is simple, and the defects in the prior art can be overcome.
Drawings
FIG. 1 is a flow chart of a method for diagnosing static eccentricity of a rotor based on vibration characteristics of a stator-winding system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the air gap eccentricity of a generator according to a method for diagnosing the static eccentricity of a rotor based on the vibration characteristics of a stator-winding system provided by an embodiment of the present invention;
fig. 3 is a schematic view of measuring point arrangement of a rotor static eccentricity diagnosis method based on vibration characteristics of a stator-winding system according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the following figures and detailed description:
the basic principle is as follows:
the air gap magnetomotive force of the generator in normal operation is as follows:
wherein: f sn And F rn Are respectively the n-th harmonic amplitude, F, of the magnetomotive force of the stator and rotor windings cn Is the amplitude of the synthesized magnetomotive force,β n the included angle between the magnetic dynamic forces of the stator and the rotor is psi, the internal power angle of the motor is psi, and omega is the rotation angular speed of the rotor. When the air gap is statically eccentric, the unit area permeance of the air gap is as follows:
wherein: lambda 0 ＝μ 0 /δ 0 Is the normal magnetic conductance (mu) 0 And delta 0 Respectively, vacuum permeability and normal air gap), delta (alpha) is the length of the air gap at different positions, and zeta is e/delta 0 The relative eccentricity (e is absolute eccentricity), lambda is the eccentric position, each geometric parameter is shown in FIG. 2, XY in FIG. 2 is the stator coordinate system, x r y r Is the rotor coordinate system.
Ignoring the connection relationship between the stator bars, the nose micro-arc electromagnetic force can be described approximately as:
wherein: k is the ratio of the end part of the same circumferential position to the magnetic density of the iron core, B is the magnetic density of the iron core, I is the stator current, dl is the length of a micro-arc at the nose end, L is the length of a straight line section of the winding, v is the speed of a stator bar cutting a magnetic line of force, theta is the included angle between the magnetic density and the current, and Z is the winding impedance.
The second harmonic amplitudes of the end windings are known as follows:
radial magnetic tension per unit area of the stator core:
the amplitude of the second harmonic wave of the magnetic tension of the stator is known as follows:
the stator winding can generate primary forced vibration under the action of the electromagnetic force of the end winding, and the vibration of the stator core generated by the magnetic pull can cause secondary forced vibration to the winding. As can be seen from equations (7) and (9), the second harmonic amplitudes of the two vibrations are consistent with the eccentric position and eccentricity, and the resultant acceleration second harmonic can be expressed as:
therefore, the eccentric position and the eccentric degree can be analyzed by using the second harmonic characteristics of the vibration acceleration of the stator end winding of the generator.
The detection method comprises the following steps:
as shown in fig. 1, a method for diagnosing static eccentricity of a rotor based on vibration characteristics of a stator-winding system includes the following steps:
s1, arranging measuring points at intervals along the circumferential direction at the position of the stator end winding of the generator, and measuring the radial vibration of the stator end winding of the generator at the measuring points by adopting an acceleration sensor;
specifically, the measuring points are arranged at intervals of 60 ° in the circumferential direction of the stator end winding of the generator, and four measuring points are arranged, namely, number 1 (0 °), number 2 (60 °), number 3 (120 °), and number 4 (180 °), respectively, see fig. 3.
S2, filtering and denoising the acceleration signal measured by the acceleration sensor, and then carrying out Fourier transform to obtain a second harmonic amplitude;
s3, calculating effective values of the acceleration second harmonic amplitudes of the measuring points according to the obtained second harmonic amplitudes;
specifically, the effective value calculation formula of the acceleration second harmonic amplitude of each measuring point is as follows:
in the formula (1), A ip The second harmonic amplitude of the p sample of the ith measuring point is m, and the sampling times are m.
And S4, calculating the eccentric position and the eccentricity of the static eccentricity of the generator rotor according to the effective value of the acceleration second harmonic amplitude of each measuring point.
Specifically, because the positions of the measuring points in the phase are the same, and the electromagnetic force is the same in normal operation, the amplitude of the second harmonic of the vibration acceleration is the same. When the eccentricity phenomenon occurs, the acceleration second harmonic amplitudes of all the measuring points are not the same any more, and the eccentricity position and the eccentricity degree can be calculated according to the measured data.
The calculation formula of the eccentric position of the static eccentricity of the generator rotor is as follows:
in the formula (2), lambda is the eccentric value of the static eccentricity of the generator rotor, A 1～ A 4 The effective values of the acceleration second harmonic amplitudes of the four measuring points are respectively.
The calculation formula of the eccentricity of the static eccentricity of the generator rotor is as follows:
in the formula (3), ζ represents the eccentricity of the static eccentricity of the generator rotor.
By adopting the rotor static eccentricity diagnosis method based on the vibration characteristics of the stator-winding system, the eccentric position and the eccentricity are calculated through the second harmonic of the vibration acceleration of the winding, the vibration characteristics in normal operation are not needed, the eccentric fault degree of the generator can be objectively identified on the whole, maintenance personnel can find the fault in time, the fault loss is reduced, and the personnel safety is guaranteed.
The foregoing is merely an example of the present invention and common general knowledge in the art of designing and/or characterizing particular aspects and/or features is not described in any greater detail herein. It should be noted that, for those skilled in the art, without departing from the technical solution of the present invention, several variations and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be defined by the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.
Claims (3)
1. A rotor static eccentricity diagnosis method based on vibration characteristics of a stator-winding system is characterized by comprising the following steps:
s1, arranging measuring points at intervals along the circumferential direction at the position of the stator end winding of the generator, and measuring the radial vibration of the stator end winding of the generator at the measuring points by adopting an acceleration sensor;
s2, filtering and denoising the acceleration signal measured by the acceleration sensor, and then carrying out Fourier transform to obtain a second harmonic amplitude;
s3, calculating effective values of the acceleration second harmonic amplitudes of the measuring points according to the obtained second harmonic amplitudes;
s4, calculating the eccentric position and the eccentricity of the static eccentricity of the generator rotor according to the effective value of the acceleration second harmonic amplitude of each measuring point;
in step S4, the calculation formula of the eccentric position of the static eccentricity of the generator rotor is as follows:
in the formula (2), lambda is the eccentric position of the static eccentricity of the generator rotor, A 1 ～A 4 Respectively effective values of acceleration second harmonic amplitudes of the four measuring points;
in step S4, the calculation formula of the eccentricity of the static eccentricity of the generator rotor is as follows:
in the formula (3), ζ represents the eccentricity of the static eccentricity of the generator rotor.
2. The method for diagnosing the static eccentricity of the rotor based on the vibration characteristics of the stator-winding system as claimed in claim 1, wherein: the measuring points are arranged at intervals of 60 degrees in the circumferential direction of a stator end winding of the generator, and the measuring points are arranged in four directions.
3. The method for diagnosing the static eccentricity of the rotor based on the vibration characteristics of the stator-winding system as claimed in claim 2, wherein the calculation formula for measuring the effective value of the acceleration second harmonic amplitude in step S3 is as follows:
in the formula (1), A ip The second harmonic amplitude of the p sample of the ith measuring point is m, and the sampling times are m.
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| CN104655977A (en) * | 2014-12-19 | 2015-05-27 | 华北电力大学（保定） | Generator exciting winding short-circuit fault diagnosis method based on torque comparison principle |
| CN210201572U (en) * | 2019-09-07 | 2020-03-27 | 浙江新能机电科技有限公司 | Rotor structure and rotor assembly of surface-mounted permanent magnet synchronous motor |
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| CN102262215B (en) * | 2011-04-29 | 2013-05-22 | 华北电力大学（保定） | Method for detecting stator and rotor air gap eccentric faults of large generator |
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| CN108759658B (en) * | 2018-06-15 | 2020-10-23 | 哈尔滨工业大学 | Method for analyzing and compensating angle measurement error of induction synchronizer |
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| CN104655977A (en) * | 2014-12-19 | 2015-05-27 | 华北电力大学（保定） | Generator exciting winding short-circuit fault diagnosis method based on torque comparison principle |
| CN210201572U (en) * | 2019-09-07 | 2020-03-27 | 浙江新能机电科技有限公司 | Rotor structure and rotor assembly of surface-mounted permanent magnet synchronous motor |
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