CN111551853A - Hydro-generator stator core lamination loosening fault detection method - Google Patents

Hydro-generator stator core lamination loosening fault detection method Download PDF

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Publication number
CN111551853A
CN111551853A CN202010480810.7A CN202010480810A CN111551853A CN 111551853 A CN111551853 A CN 111551853A CN 202010480810 A CN202010480810 A CN 202010480810A CN 111551853 A CN111551853 A CN 111551853A
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stator core
value
generator
frequency vibration
vibration amplitude
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CN111551853B (en
Inventor
邢志江
吴明波
杨昶宇
孙卫
王江
张兴明
禹跃美
郗发刚
张宏
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Huaneng Lancang River Hydropower Co Ltd
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Huaneng Lancang River Hydropower Co Ltd
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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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
    • G01K1/02—Means for indicating or recording specially adapted for thermometers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit

Abstract

The invention provides a method for detecting the loosening fault of a stator core lamination of a hydraulic generator, which comprises the following steps: setting a normal temperature value, a highest temperature alarm value, a normal vertical polar frequency vibration amplitude value and an alarm value of a stator core of the generator set; acquiring a temperature value of a stator core of a generator set, active power of a generator, exciting current of the generator and a vertical polar frequency vibration amplitude value of the stator core; establishing a mathematical model to obtain a maximum temperature value, a synthetic value and an average value of the vertical polar frequency vibration amplitude; calculating the maximum temperature of the stator core, the vertical pole frequency vibration slow variable and the primary and secondary alarm predicted values, determining the loosening direction of the stator core lamination, finally detecting the loosening fault of the stator core lamination, making maintenance and treatment plans and measures, and treating the stator core lamination of the generator. Accurate detection of the loosening fault of the stator core lamination of the hydraulic generator is achieved.

Description

Hydro-generator stator core lamination loosening fault detection method
Technical Field
The invention relates to a detection method, in particular to a method for detecting a loosening fault of a lamination of a stator core of a generator, and belongs to the technical field of generator fault detection.
Background
The loosening of the lamination sheets of the stator core is one of the important reasons causing the fault of the generator, and the main reasons causing the loosening of the lamination sheets of the stator of the generator are as follows: 1) defects of structural design, lamination material, manufacturing and the like of the generator; 2) the installation requirements are not met due to insufficient tension force or compression density in the stator core lamination installation process; 3) the stator core lamination of the generator is polluted due to oil leakage of the oil basin of the guide bearing. When the lamination of the stator core of the generator is loosened, hysteresis loss of the stator core is increased, local temperature is increased and vibration of the core is increased, and the insulation damage and the deformation of the stator core or the winding bar are aggravated under the environment of long-term high temperature, high heat and vibration of the stator core or the winding bar of the generator, so that the loosening condition of the lamination of the stator of the generator is detected in real time, and the safe and stable operation of the generator is very necessary.
The detection of the prior art to the loosening fault of the lamination of the stator core of the generator has the following steps: 1) the looseness of the stator core lamination is analyzed through the tightness of a tension screw of the generator stator core, the work needs to be carried out after a machine set is stopped when the machine set is overhauled or the looseness of the stator core lamination is suspected, and the real-time performance is insufficient; 2) the method is characterized in that the looseness of the lamination of the stator core is analyzed through noise detection in the running state of the generator, and the method is easily influenced by the running working condition of the generator and restricted by the technical level of detection personnel; 3) the method comprises the following steps that the temperature of a stator core of a generator is detected and analyzed, the lamination looseness of the stator core is detected, temperature change cannot be found timely due to more temperature detection points, and meanwhile, the factors causing the temperature change of the core are more, and manual analysis and removal are needed; 4) the method comprises the following steps of detecting and analyzing the looseness of stator core laminations through vibration data of a generator stator core, wherein due to the fact that a plurality of influence factors of core vibration are caused, manual analysis and elimination are needed; 5) when in maintenance, the iron loss test or the magnetization test is carried out on the stator core, the lamination looseness of the stator core is analyzed, the working procedure is complex, the manpower investment is large, and the required time is long. Therefore, there is a need for improvements in the prior art.
Disclosure of Invention
According to the reason of stator lamination looseness, aiming at the defects of the existing detection and analysis method for the stator core lamination looseness of the generator, in order to avoid the situations that the insulation damage fault of the generator stator, the service life of the generator and the like are reduced due to the fact that the lamination looseness of the generator stator core cannot be found in time, the invention provides the detection method for the stator core lamination looseness fault of the hydraulic generator based on the maximum temperature of the stator core and the change mechanism of the vertical polar frequency vibration composite value of the stator core and in combination with a mallat wavelet algorithm and a principal component analysis method of PCA data.
The invention is realized by the following technical scheme: a hydro-generator stator core lamination loosening fault detection method is characterized by comprising the following steps:
(15) setting normal temperature value T of each part of stator core of hydroelectric generating setzAlarm value T of maximum temperature of stator coreaNormal vertical pole frequency vibration amplitude A of each part of stator corezStator core vertical pole frequency vibration alarm value Aa；
(16) Obtaining the iron core temperature value T of each part of the stator of the generator set by the existing temperature sensor, active power transmitter, current transmitter and vibration sensor of the water-turbine generator set and the connected computer and state detection systemiThe active power of the generator, the exciting current of the generator and the vertical polar frequency vibration amplitude of each part of the stator core;
(17) according to the temperature value T of each part of the stator core obtained in the step (2)iFinding out the maximum temperature T of the stator coremax；
(18) Obtaining the vertical polar frequency vibration amplitude A of each part of the stator core according to the step (2)iCalculating the resultant A of the vibration amplitudes of the vertical polar frequencies of the stator core according to the following formulat：
Figure BDA0002517296600000031
In the formula, AtA resultant value, A, representing the amplitude of the vertical pole frequency vibration of the stator coreiRepresenting the vertical polar frequency vibration amplitude of the stator core at the corresponding position;
(19) the highest temperature value T of the stator core found in the step (3)maxAnd (3) establishing a mathematical model with the generator active power and the generator exciting current obtained in the step (2), and obtaining the current highest temperature value T of the stator core by using a computer, the existing mallat wavelet algorithm and a PCA data principal component analysis methodg；
(20) Establishing a mathematical model according to the active power and exciting current of the generator obtained in the step (2) and the composite value of the vertical polar frequency vibration amplitude of the iron core obtained in the step (4), and obtaining the composite value A of the current vertical polar frequency vibration amplitude of the stator iron core by using a computer, the existing mallat wavelet algorithm and a PCA data principal component analysis method;
(21) according to the current maximum temperature value T of the stator core in the step (5)gThe average value of the maximum temperature of the stator core in the past 180 days is calculated according to the following formula
Figure BDA0002517296600000032
Figure BDA0002517296600000033
In the formula, TgnThe maximum temperature value of the stator core is the daily average of the last 180 days; (ii) a
(22) According to the composite value A of the current vertical polar frequency vibration amplitude of the stator core in the step (6), calculating the vertical polar frequency vibration amplitude of the stator core in the past 180 days according to the following formulaMean value of
Figure BDA0002517296600000034
Figure BDA0002517296600000041
In the formula, AnThe composite value of the daily average vertical polar frequency vibration amplitude of the past 180 days;
(23) according to the current maximum temperature value T of the stator core in the step (5)gAnd (7) average value of maximum temperature of stator core in past 180 days
Figure BDA0002517296600000042
Calculating the maximum temperature slow variable △ T of the stator core according to the following formula:
Figure BDA0002517296600000043
(24) according to the composite value A of the current vertical polar frequency vibration amplitude of the stator core in the step (6) and the average value of the composite value A of the vertical polar frequency vibration amplitude of the stator core in the past 180 days in the step (8)
Figure BDA0002517296600000044
Calculating a stator core vertical pole frequency vibration slow variable △ A:
Figure BDA0002517296600000045
(25) according to the current highest temperature value T of the stator core in the step (5)gAnd (4) calculating a first-level alarm predicted value T of the highest temperature of the stator core by using the slow variation △ T in the step (9)p1Second-level alarm predicted value Tp2：
Tp1＝Tg+ΔT·D1；
Tp2＝Tg+ΔT·D2；
Wherein D1、D2For a set number of days of early warning, D2＜D1；
(26) Calculating a primary alarm predicted value A of the vertical polar frequency vibration of the stator core according to the composite value A of the current vertical polar frequency vibration amplitude of the stator core in the step (6) and the slow variation △ A in the step (10)p1Second-level alarm prediction value Ap2：
Ap1＝A+ΔA·D1；
Ap2＝A+ΔA·D2；
Wherein D1、D2For a set number of days of early warning, D2＜D1；
(27) According to the primary alarm predicted value and the secondary alarm predicted value of the highest temperature of the stator core in the step (11) and the primary alarm predicted value and the secondary alarm predicted value of the vertical polar frequency vibration of the stator core in the step (12), performing Fourier transform on the vertical vibration amplitude of the stator core through a computer, and calculating the vertical polar frequency vibration phase of the stator core to determine the loosening direction of the lamination of the stator core;
fourier expanded signal function:
Figure BDA0002517296600000051
vibration phase position:
Figure BDA0002517296600000052
in the formula: a is0、an、bnAre Fourier coefficients;
(28) comparing the data from steps (2) - (13) with the set data from step (1) as follows:
the maximum temperature value T of the stator core in the step (5)gStator core normal temperature value T > setz；
The composite value A of the stator core vertical polar frequency vibration amplitude in the step (6) is larger than the set normal stator core vertical polar frequency vibration amplitude Az；
Drawing a curve by taking the composite value of the maximum temperature value of the stator core and the vertical polar frequency vibration amplitude of the stator core as a vertical coordinate and time as a horizontal coordinate, and observing the data change trend;
the primary alarm prediction value T of the highest temperature of the stator core in the step (11)p1Set maximum temperature alarm value T of stator core greater than seta；
The primary alarm prediction value A of the composite value of the vertical polar frequency vibration amplitude of the stator core in the step (12)p1Stator core vertical polar frequency vibration alarm amplitude A greater than seta；
Detecting a slight loosening fault of the stator core lamination, and checking and fastening the tension force or the compression density of the stator lamination of the generator by a maintainer by selecting a machine, and checking oil contamination conditions of a generator room and the surrounding environment;
the secondary alarm prediction value T of the maximum temperature of the stator core in the step (11)p2Set maximum temperature alarm value T of stator core greater than seta；
The secondary alarm prediction value A of the composite value of the vertical polar frequency vibration amplitude of the stator core obtained in the step (12)p2Stator core vertical polar frequency vibration alarm amplitude A greater than seta；
And detecting the serious loosening fault of the stator core lamination, making a maintenance and treatment plan and measure, and treating the stator core lamination of the generator.
The mathematical model of the step (5) is established by the following steps:
51) the highest temperature value T of the stator core of the generator set found in the step (3)maxThe active power P 'of the generator obtained in the step (2) is effective value within the range of 90-250MW, and the excitation current I' of the generator is effective value within the range of 1000-3600A;
52) the active power P of the generator is taken as an X coordinate, the exciting current I of the generator is taken as a Y coordinate, and the highest temperature T of the stator core is takenmaxEstablishing a three-dimensional graph for the Z coordinate; obtaining a cross point A of the generator exciting current I 'and the generator active power P' at the same moment on an X, Y plane of the three-dimensional graph; from the intersection A, a straight line parallel to the Z axis is formed until the maximum temperature T of the stator core is reachedmaxThe intersection of the horizontal planes forms a point B, which is thenB corresponding maximum temperature value T of stator coremaxThat is, the highest temperature T of the stator core at the same timemaxDetermining the highest temperature value of the stator core through a three-dimensional relation model according to the active power P 'of the generator and the exciting current I' of the generator;
53) using the three-dimensional relation model of the step 52) and the maximum temperature value T of the stator coremaxThe highest temperature value T of the current stator core is obtained by the existing mallat wavelet algorithm and PCA data principal component analysis method as the source data of the mallat wavelet algorithm and the PCA data principal component analysis methodg。
The mathematical model of the step (6) is established by the following steps:
61) and (4) obtaining a resultant value A of the vertical polar frequency vibration amplitude of the stator coretAn effective range of' is 0-50 um; the effective range of the active power P' of the generator is 90-250 MW; the effective range of the generator exciting current I' is 1000-3600A;
62) the active power P of the generator is taken as an X coordinate, the exciting current I of the generator is taken as a Y coordinate, and the resultant value A of the vertical polar frequency vibration amplitude of the stator coretEstablishing a three-dimensional graph for the Z coordinate; acquiring a cross point A of a generator exciting current I 'and a generator active power P' at the same moment on an X, Y plane of a graph; from the intersection point A, making a straight line parallel to the Z axis to a resultant value A of the vibration amplitude of the stator core vertical polar frequency with the Z axistThe horizontal plane is intersected to form a point B, and the resultant value A of the vertical polar frequency vibration amplitude of the stator core corresponding to the point Bt' is the composite value A of the vertical polar frequency vibration amplitude of the stator core at the same timet', the active power P ' of the generator and the exciting current I ' of the generator are determined by a three-dimensional relation model, and the synthetic value A of the vertical polar frequency vibration amplitude of the stator coret’；
63) Using the three-dimensional relation model of the step 62) and the composite value A of the vertical polar frequency vibration amplitude of the stator coretThe method is used as source data of a mallat wavelet algorithm and a principal component analysis method of PCA data, and a composite value A of the vibration amplitude of the vertical polar frequency of the current stator core is obtained through the existing mallat wavelet algorithm and the PCA data principal component analysis method.
The basic principle of the invention is that the judgment and the positioning of the stator core lamination loosening condition are realized by the variation trend of the maximum temperature value of the stator core and the vertical polar frequency vibration value of the stator core, and by the existing mallat wavelet algorithm, the PCA data principal component analysis method and the phase analysis of the vertical polar frequency vibration signal of the stator core, and the specific method is as follows: taking the maximum temperature value of the stator core and the vertical polar frequency vibration amplitude of the stator core as main observed quantities, if the two quantity values have the trend of increasing, and taking the current numerical value and the slow variable as calculation bases, if the two quantity values exceed the alarm value within 30 days, reporting a first-level alarm, and if the two quantity values exceed the alarm value within 10 days, reporting a second-level alarm; after the operation and maintenance personnel receive the alarm information, the computer analyzes the stator core vertical vibration polar frequency signal to determine the stator core vibration direction and inspect and process the generator stator core lamination.
The invention has the following advantages and effects: by adopting the scheme, the loosening condition of the stator core lamination can be detected and analyzed on line in real time, and the early warning of the loosening change condition can be realized by respectively carrying out primary warning and secondary warning on the highest temperature of the stator core and the vertical polar frequency vibration amplitude of the stator core. The problems that conventional inspection and data analysis means are insufficient in instantaneity, easily influenced by the operating condition of the generator and the technical level of detection personnel, more interference factors, more complex in elimination, higher in test development input cost and the like are solved, the sensing, analyzing and diagnosing capabilities of abnormal conditions of the loosening of the stator core lamination are finally improved, timely and effective measures are taken for operation and maintenance personnel, the accident enlargement is prevented, the economic loss is reduced, the powerful support is provided, and the operating life of the generator is prolonged.
Drawings
Fig. 1 and 2 are schematic diagrams of the layout of stator core temperature and vertical polar frequency vibration detection points;
FIG. 3 is a three-dimensional relationship model diagram of the maximum temperature of the stator core;
FIG. 4 is a three-dimensional relationship model diagram of the vertical pole frequency vibration amplitude of the stator core;
FIGS. 5 and 6 are frequency spectrum and phase diagrams of stator vertical pole frequency vibration with loose stator core laminations;
FIG. 7 is a graph of maximum temperature of the stator core and amplitude of vertical pole frequency vibration.
Detailed Description
The present invention will be further described with reference to the following examples;
example 1
In the embodiment 1, the actual detection is performed by taking the operation condition of a No. 2 hydraulic generator set of a certain power plant as an example, the temperature of a stator core of the hydraulic generator is 34 temperature measurement detection points in total, and the circumference of the generator is divided into an upper layer, a middle layer and a lower layer of temperature measurement arrangement; the number of the stator core vertical polar frequency vibration sensors is 3, and the sensors are uniformly distributed around the upper end of the generator according to an included angle of 120 degrees, and are shown in attached figures 1 and 2;
the method for detecting the loosening fault of the stator core lamination of the hydraulic generator comprises the following steps:
(1) setting normal temperature value T of each part of stator core of hydroelectric generating setz46 deg.C, alarm value T of maximum temperature of stator coreaThe normal vertical polar frequency vibration amplitude of each part of the stator core is A at 50 DEG Cz9.9um, alarm value A of stator core vertical polar frequency vibrationa＝30um；
(2) Through the existing temperature sensor, active power transmitter, current transmitter and vibration sensor of No. 2 generator set and the connected computer and state detection system, respectively obtain the stator core temperature data under the condition of 34 stator core lamination operation, and the stator core vertical polar frequency vibration amplitude, generator active power data and generator exciting current data collected by 3 stator core vertical polar frequency vibration sensors, see Table 1;
TABLE 1
Figure BDA0002517296600000091
Figure BDA0002517296600000101
(3) Finding out the highest temperature value from the 34 stator core temperature values obtained in the step (2):
Tmax＝T5＝46.3℃；
(4) obtaining 3 vertical polar frequency vibration amplitudes A obtained from the step (2)iCalculating the resultant A of the vibration amplitudes of the vertical polar frequencies of the 3 stator cores according to the following formulat：
Figure BDA0002517296600000102
(5) Establishing a mathematical model according to the following steps by using the maximum temperature value 46.3 ℃ of the stator core found in the step (3) and the generator active power 125MW and the generator exciting current 1500A obtained in the step (2):
51) maximum temperature value T of stator core of generator setmax' is 46.3 ℃, has effective value in the range of 5-125 ℃, has the active power P ' of 125MW, is effective in the range of 90-250MW, has the excitation current I ' of 1500A, and is effective in the range of 1000-3600A, see Table 2;
TABLE 2
Maximum temperature value T of stator coremax’(℃) 46.3
Generator active power P' (MW) 125
Generator exciting current I' (A) 1500
52) The active power P of the generator is taken as an X coordinate, the exciting current I of the generator is taken as a Y coordinate, and the highest temperature T of the stator core is takenmaxAs a Z coordinate, constructSetting up a three-dimensional graph; obtaining a cross point A of the generator exciting current I 'and the generator active power P' at the same moment on an X, Y plane of the three-dimensional graph; from the intersection A, a straight line parallel to the Z axis is formed until the maximum temperature T of the stator core is reachedmaxThe horizontal planes intersect to form a point B, and the maximum temperature value T of the stator core corresponding to the point BmaxThat is, the highest temperature T of the iron core at the same timemax', the active power P ' of the generator and the exciting current I ' of the generator are determined by a three-dimensional relation model to obtain the highest temperature value T of the stator coremax' -46.3 ℃, see fig. 3;
53) using the three-dimensional relation model of the step 52) and the maximum temperature value T of the stator coremaxThe highest temperature value T of the current stator core is obtained by the existing mallat wavelet algorithm and PCA data principal component analysis method as the source data of the mallat wavelet algorithm and the PCA data principal component analysis methodgSee table 3, fig. 3;
TABLE 3
Figure BDA0002517296600000111
(6) Obtaining the active power 125MW and the exciting current 1500A of the generator obtained in the step (2), and the composite value A of the vertical polar frequency vibration amplitude of the stator core in the step (4)tThe mathematical model is established according to the following steps:
61) resultant value A of vertical polar frequency vibration amplitude of generator stator coret' is 10.0um, effective in the range of 0-50 um; the active power P' of the generator is 125MW and is effective in the range of 90-250 MW; generator excitation current I' 1500A is valid within the range of 1000-;
TABLE 4
Figure BDA0002517296600000112
Figure BDA0002517296600000121
62) With an electric generator havingThe work power P is X coordinate, the generator exciting current I is Y coordinate, and the resultant value A of the vertical polar frequency vibration amplitude of the stator coretEstablishing a three-dimensional graph for the Z coordinate; acquiring a cross point A of a generator exciting current I 'and a generator active power P' at the same moment on an X, Y plane of a graph; from the intersection point A, making a straight line parallel to the Z axis to a resultant value A of the vibration amplitude of the stator core vertical polar frequency with the Z axistThe horizontal plane is intersected to form a point B, and the resultant value A of the vertical polar frequency vibration amplitude of the stator core corresponding to the point Bt' is the composite value A of the vertical polar frequency vibration amplitude of the stator core at the same timet', the active power P ' of the generator and the exciting current I ' of the generator are determined by a three-dimensional relation model, the synthetic value of the vertical polar frequency vibration amplitude of the stator core is 10.0um, and the figure is shown in figure 4;
63) using the three-dimensional relation model of the step 62) and the composite value A of the vertical polar frequency vibration amplitude of the stator coretThe current composite value A of the vertical polar frequency vibration amplitude of the stator core is obtained by the existing mallat wavelet algorithm and PCA data principal component analysis method as the source data of the mallat wavelet algorithm and the PCA data principal component analysis method, and is shown in the table 5 and the figure 4;
TABLE 5
Figure BDA0002517296600000122
(7) According to the maximum temperature value T of the stator core in the step (5)gThe average value of the maximum temperature of the stator core in the past 180 days is calculated according to the following formula
Figure BDA0002517296600000123
Figure BDA0002517296600000124
In the formula, TgnThe maximum temperature value of the stator core is the daily average of the last 180 days;
(8) according to the composite value A of the vertical polar frequency vibration amplitude of the stator core in the step (6), calculating the stator core in the past 180 days according to the following formulaAverage value of vertical polar frequency vibration amplitude
Figure BDA0002517296600000131
Figure BDA0002517296600000132
In the formula, AnSetting the iron core vertical polar frequency vibration amplitude composite value for the average day of the past 180 days;
(9) according to the current maximum temperature value T of the stator core in the step (5)gAnd (7) average value of maximum temperature of stator core in past 180 days
Figure BDA0002517296600000133
Calculating the maximum temperature slow variable △ T of the stator core according to the following formula:
Figure BDA0002517296600000134
Figure BDA0002517296600000135
Figure BDA0002517296600000136
analogizing in turn, calculating the delta T4………………ΔT12The values of (a) are shown in Table 6:
TABLE 6
Figure BDA0002517296600000137
(10) According to the combined value A of the current vertical polar frequency vibration amplitude of the stator core in the step (6) and the average value of the combined values of the vertical polar frequency vibration amplitude of the stator core in the past 180 days in the step (8)
Figure BDA0002517296600000138
Calculating stator core vertical polar frequency vibration slow change according to the following formulaAmount △ A:
Figure BDA0002517296600000139
Figure BDA00025172966000001310
Figure BDA0002517296600000141
analogizing in turn, calculating delta A4……………ΔA12The values of (a) are shown in Table 7:
TABLE 7
Figure BDA0002517296600000142
(11) According to the current highest temperature value T of the stator core in the step (5)gAnd (4) calculating a first-level alarm predicted value T of the highest temperature of the stator core by using the slow variation △ T in the step (9)p1Second-level alarm predicted value Tp2：
Tp1＝Tg+ΔT·D1；
Tp2＝Tg+ΔT·D2；
Wherein D 130 days, D2Day 10, as in table 8:
TABLE 8
Figure BDA0002517296600000143
First-level alarm (take column 1 data as an example):
Tp1＝Tg+ΔT·D146.3+0.30 × 30 ═ 55.3 ℃ > 50 ℃, and T is within 30 days according to the current temperature value and the buffer quantityp1The variation value of (2) exceeds the alarm value of 50 ℃;
secondary alarm (take column 4 data as an example):
Tp2＝Tg+ΔT·D2＝46.5+0.50 × 10 ═ 51.5 ℃ > 50 ℃, T within 10 days according to the current temperature value and the buffer quantityp2The variation value of (2) exceeds the alarm value of 50 ℃;
(12) according to the combined value A of the current vertical polar frequency vibration amplitude of the stator core in the step (6) and the slow variable △ A in the step (10), calculating a primary alarm predicted value A of the combined value of the vertical polar frequency vibration of the stator corep1Second-level alarm prediction value Ap2：
Ap1＝A+ΔA·D1；
Ap2＝A+ΔA·D2；
Wherein D 130 days, D2Day 10, as in table 9:
TABLE 9
Figure BDA0002517296600000151
First-level alarm (take column 2 data as an example):
Ap1＝A+ΔA·D1when the amplitude of the vertical vibration of the stator core is 11.9+1.9 × 30 and the amplitude of the vertical vibration of the stator core is 68.9um > 30um, A is within 30 days according to the composite value and the gentle variation of the current amplitude of the vertical vibration of the stator corep1Will exceed the alarm value by 30 um;
secondary alarm (take column 3 data as an example):
Ap2＝A+ΔA·D212.9+2.89 × 10 ═ 41.8um > 30um, A within 10 days according to the composite value and the gentle variation of the current vertical vibration amplitude of the stator corep2Will exceed the alarm value by 30 um;
(13) according to the primary alarm predicted value and the secondary alarm predicted value of the highest temperature of the stator core in the step (11) and the primary alarm predicted value and the secondary alarm predicted value of the vertical polar frequency vibration composite value of the stator core in the step (12), Fourier transform is carried out on a vertical vibration signal of the stator core through a computer, and the vertical polar frequency vibration phase of the stator core is calculated
Figure BDA0002517296600000161
And visually performing data analysis by using phase map display, see fig. 6, to confirmDetermining the loosening direction of the stator core lamination;
fourier expanded signal function:
Figure BDA0002517296600000162
vibration phase position:
Figure BDA0002517296600000163
in the formula: a is0、an、bnAre Fourier coefficients;
(14) comparing the data from steps (2) - (13) with the set data from step (1) as follows:
the maximum temperature value T of the stator core in the step (5)g46.3 ℃ higher than the set normal temperature value T of the stator corez＝46℃；
Setting the composite value A of the vertical polar frequency vibration amplitude of the stator core in the step (6) to be 10um larger than the composite value A of the vertical polar frequency vibration amplitude of the normal stator corez＝9.9um；
Drawing a curve by taking the composite value of the maximum temperature value of the stator core and the vertical polar frequency vibration amplitude of the stator core as a vertical coordinate and time as a horizontal coordinate, and observing the curve change trend as shown in FIG. 7;
the primary alarm prediction value T of the highest temperature of the stator core, obtained in the step (11)p1Setting a maximum temperature alarm value T for the stator core with the temperature of 55.3 ℃ > settinga＝50℃；
The primary alarm prediction value A of the stator core vertical polar frequency vibration amplitude composite value obtained in the step (12)p168.9um & gt set stator core vertical polar frequency vibration alarm amplitude Aa＝30um；
The maximum temperature of the stator core is detected to be 46.3 ℃, the slow variation is detected to be 0.3, and the secondary alarm prediction value T of the maximum temperature of the stator core is detectedp1The vertical pole frequency vibration amplitude value of the stator core is more than 50 ℃ under 55.3 ℃, the composite value of the vertical pole frequency vibration amplitude of the stator core is 11.9um, the slow variation is 1.9, and the composite value A of the vertical pole frequency vibration of the stator core isp1When the thickness of the laminated stator core is 68.9um larger than 30um, the laminated stator core is slightly loosened and has a fault, and a first-level alarm is started; maintenance personnelThe tension force or the compaction density of the stator lamination of the generator is checked and fastened by selecting the machine, and the oil contamination conditions of the generator room and the surrounding environment are checked;
the secondary alarm prediction value T of the maximum temperature of the stator core, obtained in the step (11)p2The maximum temperature alarm value T is set for the stator core with the temperature of 51.5 ℃ > seta＝50℃；
The secondary alarm prediction value A of the vertical polar frequency vibration amplitude of the stator core obtained in the step (12)p2Stator core vertical polar frequency vibration alarm amplitude A set as 41.8um ≧a＝30um；
Meanwhile, the stator core lamination loose azimuth angle in the step (13)
Figure BDA0002517296600000172
The highest temperature T of the stator core is detected to be 46.5 ℃, the slow variation is detected to be 0.50p251.5 ℃ and more than 50 ℃, the vertical pole frequency vibration composite value of the stator core is 12.9um, the slow variation is 2.89, and the vertical pole frequency vibration composite value A of the stator corep241.8um is more than 30um, the position of the stator core lamination is loosened at 210 degrees, the vertical vibration amplitude of the stator core is 23um, the serious loosening fault of the stator core lamination occurs at the moment, a secondary alarm is started, meanwhile, a maintenance and treatment plan and measures are formulated, and the generator stator core lamination with the position of 210 degrees is treated by using a machine halt opportunity;
(15) the treatment effect is as follows:
1) after the stator laminations are loosened, 34 stator core temperature values after maintenance are again obtained from the computer monitoring system, as shown in table 10:
watch 10
Figure BDA0002517296600000171
Figure BDA0002517296600000181
Obtaining the maximum value of the temperature of the stator core after the lamination processing of the 34 stator cores:
Tmax＝T5＝45.7℃
the maximum temperature value T of the stator core at the moment is calculated by a three-dimensional relation modelg＝45.6℃；
2) After the stator lamination is loosened, 3 stator core vertical vibration polar frequency vibration values are obtained again from the state detection system, as shown in table 11:
TABLE 11
Figure BDA0002517296600000182
And calculating the composite value of the vertical polar frequency vibration of the stator core after the 3 stator core lamination processing according to the following formula:
Figure BDA0002517296600000183
calculating by a three-dimensional relation model, wherein the composite value A of the vertical polar frequency vibration of the stator core is 9.8 um;
after the lamination of the stator core is processed, the maximum temperature value of the stator core is 45.6 ℃, is close to the normal operation value of 46 ℃ and is less than the maximum temperature of the stator core before processing of 48.7 ℃; the stator core vertical polar frequency vibration amplitude is 9.8um, which is close to 10.0um of a normal operation value and is smaller than the stator core vertical polar frequency vibration amplitude 23um before processing, and the detection is proved to be effective, accurate and reliable.

Claims (3)

1. A hydro-generator stator core lamination loosening fault detection method is characterized by comprising the following steps:
(1) setting normal temperature value T of each part of stator core of hydroelectric generating setzAlarm value T of maximum temperature of stator coreaNormal vertical pole frequency vibration amplitude A of each part of stator corezStator core vertical pole frequency vibration alarm value Aa；
(2) Current temperature sensor, active power transmitter, current transmitter and vibration sensor through hydroelectric generating set and vibration sensorThe connected computer and the state detection system acquire the temperature value T of the iron core of each part of the stator of the generator setiThe active power of the generator, the exciting current of the generator and the vertical polar frequency vibration amplitude of each part of the stator core;
(3) according to the temperature value T of each part of the stator core obtained in the step (2)iFinding out the maximum temperature T of the stator coremax；
(4) Obtaining the vertical polar frequency vibration amplitude A of each part of the stator core according to the step (2)iCalculating the resultant A of the vibration amplitudes of the vertical polar frequencies of the stator core according to the following formulat：
Figure FDA0002517296590000011
In the formula, AtA resultant value, A, representing the amplitude of the vertical pole frequency vibration of the stator coreiRepresenting the vertical polar frequency vibration amplitude of the stator core at the corresponding position;
(5) the highest temperature value T of the stator core found in the step (3)maxAnd (3) establishing a mathematical model with the generator active power and the generator exciting current obtained in the step (2), and obtaining the current highest temperature value T of the stator core by using a computer, the existing mallat wavelet algorithm and a PCA data principal component analysis methodg；
(6) Establishing a mathematical model according to the active power and exciting current of the generator obtained in the step (2) and the composite value of the vertical polar frequency vibration amplitude of the iron core obtained in the step (4), and obtaining the composite value A of the current vertical polar frequency vibration amplitude of the stator iron core by using a computer, the existing mallat wavelet algorithm and a PCA data principal component analysis method;
(7) according to the current maximum temperature value T of the stator core in the step (5)gThe average value of the maximum temperature of the stator core in the past 180 days is calculated according to the following formula
Figure FDA0002517296590000021
Figure FDA0002517296590000022
In the formula, TgnThe maximum temperature value of the stator core is the daily average of the last 180 days; (ii) a
(8) According to the composite value A of the current vertical polar frequency vibration amplitude of the stator core in the step (6), calculating the average value of the vertical polar frequency vibration amplitude of the stator core in the past 180 days according to the following formula
Figure FDA0002517296590000028
Figure FDA0002517296590000023
In the formula, AnThe composite value of the daily average vertical polar frequency vibration amplitude of the past 180 days;
(9) according to the current maximum temperature value T of the stator core in the step (5)gAnd (7) average value of maximum temperature of stator core in past 180 days
Figure FDA0002517296590000024
Calculating the maximum temperature slow variable △ T of the stator core according to the following formula:
Figure FDA0002517296590000025
(10) according to the composite value A of the current vertical polar frequency vibration amplitude of the stator core in the step (6) and the average value of the composite value A of the vertical polar frequency vibration amplitude of the stator core in the past 180 days in the step (8)
Figure FDA0002517296590000026
Calculating a stator core vertical pole frequency vibration slow variable △ A:
Figure FDA0002517296590000027
(11) according to the current highest temperature value T of the stator core in the step (5)gAnd (9) calculating a slow variation △ TPrimary alarm prediction value T of maximum temperature of stator corep1Second-level alarm predicted value Tp2：
Tp1＝Tg+ΔT·D1；
Tp2＝Tg+ΔT·D2；
Wherein D1、D2For a set number of days of early warning, D2＜D1；
(12) Calculating a primary alarm predicted value A of the vertical polar frequency vibration of the stator core according to the composite value A of the current vertical polar frequency vibration amplitude of the stator core in the step (6) and the slow variation △ A in the step (10)p1Second-level alarm prediction value Ap2：
Ap1＝A+ΔA·D1；
Ap2＝A+ΔA·D2；
Wherein D1、D2For a set number of days of early warning, D2＜D1；
(13) According to the primary alarm predicted value and the secondary alarm predicted value of the highest temperature of the stator core in the step (11) and the primary alarm predicted value and the secondary alarm predicted value of the vertical polar frequency vibration of the stator core in the step (12), performing Fourier transform on the vertical vibration amplitude of the stator core through a computer, and calculating the vertical polar frequency vibration phase of the stator core to determine the loosening direction of the lamination of the stator core;
fourier expanded signal function:
Figure FDA0002517296590000031
vibration phase position:
Figure FDA0002517296590000032
in the formula: a is0、an、bnAre Fourier coefficients;
(14) comparing the data from steps (2) - (13) with the set data from step (1) as follows:
the highest temperature of the stator core in the step (5)Value TgStator core normal temperature value T > setz；
The composite value A of the stator core vertical polar frequency vibration amplitude in the step (6) is larger than the set normal stator core vertical polar frequency vibration amplitude Az；
Drawing a curve by taking the composite value of the maximum temperature value of the stator core and the vertical polar frequency vibration amplitude of the stator core as a vertical coordinate and time as a horizontal coordinate, and observing the data change trend;
the primary alarm prediction value T of the highest temperature of the stator core in the step (11)p1Set maximum temperature alarm value T of stator core greater than seta；
The primary alarm prediction value A of the composite value of the vertical polar frequency vibration amplitude of the stator core in the step (12)p1Stator core vertical polar frequency vibration alarm amplitude A greater than seta；
Detecting a slight loosening fault of the stator core lamination, and checking and fastening the tension force or the compression density of the stator lamination of the generator by a maintainer by selecting a machine, and checking oil contamination conditions of a generator room and the surrounding environment;
the secondary alarm prediction value T of the maximum temperature of the stator core in the step (11)p2Set maximum temperature alarm value T of stator core greater than seta；
The secondary alarm prediction value A of the composite value of the vertical polar frequency vibration amplitude of the stator core obtained in the step (12)p2Stator core vertical polar frequency vibration alarm amplitude A greater than seta；
And detecting the serious loosening fault of the stator core lamination, making a maintenance and treatment plan and measure, and treating the stator core lamination of the generator.
2. A method for detecting the loosening fault of the stator core lamination of a hydraulic generator according to claim 1, wherein the mathematical model of the step (5) is established through the following steps:
51) the highest temperature value T of the stator core of the generator set found in the step (3)maxThe effective value is in the range of 5-125 ℃, and the active power P' of the generator obtained in the step (2) is in the range of 90-250MWThe inner part is an effective value, and the excitation current I' of the generator is an effective value within the range of 1000-3600A;
52) the active power P of the generator is taken as an X coordinate, the exciting current I of the generator is taken as a Y coordinate, and the highest temperature T of the stator core is takenmaxEstablishing a three-dimensional graph for the Z coordinate; obtaining a cross point A of the generator exciting current I 'and the generator active power P' at the same moment on an X, Y plane of the three-dimensional graph; from the intersection A, a straight line parallel to the Z axis is formed until the maximum temperature T of the stator core is reachedmaxThe horizontal planes intersect to form a point B, and the maximum temperature value T of the stator core corresponding to the point BmaxThat is, the highest temperature T of the stator core at the same timemaxDetermining the highest temperature value of the stator core through a three-dimensional relation model according to the active power P 'of the generator and the exciting current I' of the generator;
53) using the three-dimensional relation model of the step 52) and the maximum temperature value T of the stator coremaxThe highest temperature value T of the current stator core is obtained by the existing mallat wavelet algorithm and PCA data principal component analysis method as the source data of the mallat wavelet algorithm and the PCA data principal component analysis methodg。
3. A method for detecting the loosening fault of the stator core lamination of a hydraulic generator according to claim 1, wherein the mathematical model of the step (6) is established through the following steps:
61) and (4) obtaining a resultant value A of the vertical polar frequency vibration amplitude of the stator coretAn effective range of' is 0-50 um; the effective range of the active power P' of the generator is 90-250 MW; the effective range of the generator exciting current I' is 1000-3600A;
62) the active power P of the generator is taken as an X coordinate, the exciting current I of the generator is taken as a Y coordinate, and the resultant value A of the vertical polar frequency vibration amplitude of the stator coretEstablishing a three-dimensional graph for the Z coordinate; acquiring a cross point A of a generator exciting current I 'and a generator active power P' at the same moment on an X, Y plane of a graph; from the intersection point A, making a straight line parallel to the Z axis to a resultant value A of the vibration amplitude of the stator core vertical polar frequency with the Z axist' horizontal intersection forms point B, thenThe resultant value A of the vertical polar frequency vibration amplitude of the stator core corresponding to the point Bt' is the composite value A of the vertical polar frequency vibration amplitude of the stator core at the same timet', the active power P ' of the generator and the exciting current I ' of the generator are determined by a three-dimensional relation model, and the synthetic value A of the vertical polar frequency vibration amplitude of the stator coret’；
63) Using the three-dimensional relation model of the step 62) and the composite value A of the vertical polar frequency vibration amplitude of the stator coretThe method is used as source data of a mallat wavelet algorithm and a principal component analysis method of PCA data, and a composite value A of the vibration amplitude of the vertical polar frequency of the current stator core is obtained through the existing mallat wavelet algorithm and the PCA data principal component analysis method.
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