CN114779130A - Transient sound vibration signal-based fault diagnosis method for transformer winding after short circuit impact - Google Patents

Transient sound vibration signal-based fault diagnosis method for transformer winding after short circuit impact Download PDF

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CN114779130A
CN114779130A CN202210188281.2A CN202210188281A CN114779130A CN 114779130 A CN114779130 A CN 114779130A CN 202210188281 A CN202210188281 A CN 202210188281A CN 114779130 A CN114779130 A CN 114779130A
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short circuit
winding
transient
vibration signal
fault
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李锐
黎大健
陈梁远
易辰颖
韩方源
张磊
芦宇峰
余长厅
苏毅
饶夏锦
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Electric Power Research Institute of Guangxi Power Grid 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
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/72—Testing of electric windings
    • 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
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/52—Testing for short-circuits, leakage current or ground faults
    • 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
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/62—Testing of transformers

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Abstract

The invention discloses a fault diagnosis method after short circuit impact of a transformer winding based on transient sound vibration signals, which relates to the technical field of fault diagnosis of electrical equipment, and is used for analyzing normalized transient sound vibration signal characteristic parameters and short circuit impedance changes in a winding short circuit impact test; and setting a fault diagnosis process after the short circuit impact of the transformer winding according to the normalized transient acoustic vibration signal characteristic parameters and the analysis result of the short circuit impedance change. The method has the advantages of high sensitivity, large difference of test times, and consistent reflecting rule, and can show the universality of reflecting the mechanical state of the winding by using transient signals. The transient vibration signal is not easy to be interfered by the environment, but is greatly influenced by the position of a measured point, the transient acoustic signal contains more information, the selection of the measured point is easy, but is easily influenced by the environment, the comprehensive transient vibration and the acoustic signal can be fully complemented by the method, and the defect of inaccurate detection of the fault state of the winding of the existing transformer is overcome.

Description

Transient sound vibration signal-based fault diagnosis method for transformer winding after short circuit impact
Technical Field
The invention belongs to the technical field of electrical equipment fault diagnosis, and particularly relates to a transient acoustic vibration signal-based fault diagnosis method for a transformer winding after short circuit impact.
Background
The current flowing through the winding is increased rapidly when the short circuit occurs outside the transformer, so that a huge electromagnetic impact force is generated, and the damage to the transformer can be the winding deformation and insulation damage caused by the overlarge electrodynamic force at one time, or the electrodynamic force acts on the winding for multiple times, so that the winding cushion block is loosened gradually due to the gradual accumulation, the winding deformation and other structural changes are caused.
Although the transient short-circuit current has a short duration, under the action of such a large impact force, the winding may also deform, shift, and have turns insulated and fall off, so that the winding is broken, and the like, so that the transformer fails, and the safe operation of the power grid is seriously damaged. Meanwhile, short circuit impact has an accumulative effect, so that the mechanical structure of the transformer can generate fatigue under multiple times of short circuit impact, turn insulation and structural parts of the winding can be damaged, the insulation grade of the power transformer is influenced, turn-to-turn short circuit is caused to burn the winding, and the service life of the transformer is greatly shortened. The main manifestation of the accident is as follows: (1) external short circuit impact is carried out for multiple times, the accumulated deformation of the winding is serious, and finally, insulation breakdown damage is more; (2) the outside is damaged by idle surge current impact for multiple times in a short time; (3) even with a short circuit shock.
The change of the short-circuit impact on the mechanical state of the winding is difficult to quantify, the mapping relation between the state of the winding and the characteristic parameters is very complex, the boundary of the characteristic parameters between adjacent states is fuzzy, and the conventional method has low sensitivity, is easy to be interfered by the environment and has inaccurate detection results, so that a fault diagnosis method for the transformer winding after the short-circuit impact based on the transient acoustic vibration signal is needed.
Disclosure of Invention
The invention aims to provide a fault diagnosis method for a transformer winding after short circuit impact based on a transient sound vibration signal, thereby overcoming the defect of inaccurate detection of the fault state of the existing transformer winding.
In order to achieve the purpose, the invention provides a fault diagnosis method for a transformer winding after short circuit impact based on transient acoustic vibration signals, which comprises the following steps:
in a winding short circuit impact test, analyzing normalized transient state acoustic vibration signal characteristic parameters and short circuit impedance change;
and setting a fault diagnosis process after the short circuit impact of the transformer winding according to the normalized transient state acoustic vibration signal characteristic parameters and the analysis result of the short circuit impedance change.
Preferably, the normalized transient vibro-acoustic signal characteristic parameter includes: and normalizing the information entropy, the dominant frequency energy ratio and the half-frequency energy ratio of the transient sound vibration signal.
Preferably, analyzing the short circuit impedance variation specifically includes:
respectively carrying out multiple high-centering short circuit impact tests on three phases of the transformer until the short circuit impedance of the winding exceeds 2%, and recording test data;
calculating a normalized transient sound vibration signal characteristic parameter value according to the test data, and acquiring a short circuit impedance value through the test data;
and analyzing the winding state according to the transient sound vibration signal characteristic parameter value and the short circuit impedance value.
Preferably, analyzing the winding state according to the transient sound vibration signal characteristic parameter value and the short circuit impedance value specifically includes:
firstly, the main frequency ratio is gradually reduced, the information entropy and the half-frequency ratio are gradually increased and slightly fluctuate to reach a local extreme value, which indicates that the loose faults are mainly accumulated in the process and are accompanied by slight winding deformation; the winding at the extreme value has serious loosening fault and moderate deformation, the short-circuit resistance of the winding is poor at the moment, but the short-circuit resistance does not exceed 2 percent;
after the local extreme value is reached, the main frequency ratio is gradually increased, the information entropy and the half-frequency ratio are gradually reduced, the local extreme value is reached again, the process mainly accumulates deformation faults, and the loosening condition is slightly relieved due to deformation; the winding is endangered to collapse, the looseness and the deformation are serious at extreme values, the short-circuit resistance is completely lost, and the short-circuit resistance still does not exceed 2 percent;
when the characteristic parameter of the last short circuit impact is greatly changed, the short circuit impedance exceeds 2 percent, and the winding respectively has cushion block falling, local deformation, penetrating deformation and insulation damage.
Preferably, the short-circuit impedance of the winding is measured off line after each test, the test is stopped when the change of the short-circuit impedance exceeds 2 percent, and finally the hanging cover is disassembled.
Preferably, the fault diagnosis process after the short circuit impact of the transformer winding comprises the following steps:
firstly, judging whether the voltage transformation is subjected to short circuit impact for the first time, if so, judging without a reference value through an absolute value of information entropy;
if short-circuit impact happens, the information entropy after the first short-circuit impact is taken as a reference, the change rate is specifically judged, the fault type is judged by combining the main frequency ratio and the half-frequency ratio, and looseness and deformation possibly exist in the fault at the same time;
and respectively carrying out fault diagnosis on the transient acoustic signals at the outgoing line side of the high-low voltage sleeve to preliminarily determine fault positions, and specifically analyzing which phase winding has a fault or the fault degree of each phase winding through the transient vibration signals of different measuring points.
Preferably, the short circuit impact comprises a factory short circuit impact test or a field burst short circuit.
Preferably, the preliminary determined fault location comprises a high voltage outgoing line side or a low voltage outgoing line side.
Compared with the prior art, the invention has the following beneficial effects:
according to the transformer winding short circuit impact fault diagnosis method based on the transient sound vibration signal, normalized transient sound vibration signal characteristic parameters and short circuit impedance changes are analyzed in a winding short circuit impact test; and setting a fault diagnosis process after the short circuit impact of the transformer winding according to the normalized transient acoustic vibration signal characteristic parameters and the analysis result of the short circuit impedance change. The prior method has low sensitivity and is easy to be interfered by the environment, the three characteristic parameters of the method are not completely independent, but have sensitivity, the normalized transient state sound vibration signal information entropy comprises all frequency information and can reflect the global characteristics of the time domain and the frequency domain of the signal, so the method is suitable for taking the three characteristic parameters as the main criterion for fault diagnosis; the main frequency energy ratio has stronger sensitivity to winding looseness faults, and the half-frequency energy ratio has stronger sensitivity to deformation faults, so that the main frequency energy ratio and the half-frequency energy ratio are jointly used as auxiliary criteria. The method has high sensitivity, the difference of the test times is large, but the reflecting rules are consistent, and the universality of reflecting the mechanical state of the winding by using the transient signal can be explained. The transient vibration signal is not easy to be interfered by the environment, but is greatly influenced by the position of a measured point, the transient acoustic signal contains more information, the selection of the measured point is easy, but is easily influenced by the environment, the comprehensive transient vibration and the acoustic signal can be fully complemented by the method, and the defect of inaccurate detection of the fault state of the winding of the existing transformer is overcome.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only one embodiment of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a flow chart of a method for diagnosing faults after short circuit impact of a transformer winding based on transient acoustic vibration signals according to the present invention;
FIG. 2 is a diagram showing the variation trend of the characteristic parameters of the transient acoustic vibration signal after short-circuit impact according to the present invention;
FIG. 3 is a graph of the results of the disintegration after short circuit impact of the present invention;
fig. 4 is a flow chart of the method for diagnosing transformer winding fault after short circuit impact.
Detailed Description
The technical solutions in the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive efforts based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.
As shown in fig. 1, the method for diagnosing the fault after the short-circuit impact of the transformer winding based on the transient acoustic vibration signal provided by the invention comprises the following steps:
s1, analyzing the normalized transient acoustic vibration signal characteristic parameters and short circuit impedance changes in a winding short circuit impact test;
the normalized transient acoustic vibration signal characteristic parameters comprise: and normalizing the information entropy, the dominant frequency energy ratio and the half-frequency energy ratio of the transient sound vibration signal.
The information entropy of the normalized transient sound vibration signal represents the characteristic parameters of the complex distribution of the time-frequency diagram, and p is added in the wavelet time-frequency domain of the transient signaliDefined as the sum of the energy of the entire time domain signal at a certain frequency and the energy of the entire frequency domainThe ratio of (c):
Figure BDA0003523565590000041
in the above formula, EiThe signal energy at the ith frequency, equal to the sum of the squares of the amplitudes over the entire time domain at that frequency, mjI.e. the amplitude at the j-th time instant, and t is a time instant when the frequency is in the whole time domain.
Because the electromechanical coupling action and the nonlinear action exist in the short circuit impact, parametric resonance, over-harmonic resonance and sub-harmonic resonance can be caused, and signals are mainly concentrated within 0-1000Hz, the method mainly aims at the frequency of 0-1000 Hz.
In order to make the transient information entropy interval [01], according to the characteristics of equation (1), the normalized transient vibro-acoustic information entropy is defined as:
Figure BDA0003523565590000051
HTthe closer the value is to 0, the more concentrated the transient sound vibration signal energy is, the simpler the time-frequency diagram is, the closer the value is to 1, the more dispersed the signal energy is, the more complex the time-frequency diagram is.
The dominant frequency energy. The basic solution of the short-circuit impact excitation of the winding comprises frequency components of 50Hz and 100Hz, so that 50Hz and 100Hz are defined as the main frequencies E of the transient acoustic vibration signal2And E4And then the ratio of the main frequency energy is:
Figure BDA0003523565590000052
the ratio of main frequency energy to p is deteriorated with the deterioration of the mechanical state of the windingmainIn a downward trend.
For half frequency energy. Due to the electromechanical coupling effect, when the winding mode meets a certain condition, parametric resonance appears in the transient acoustic vibration signal, and the obvious characteristic of the transient acoustic vibration signal is 25Hz oddSeveral times, so 20 frequencies of 25Hz, 75Hz, 125Hz, …, 975Hz, etc. are defined as half-frequency, the half-frequency energy ratio phaifComprises the following steps:
Figure BDA0003523565590000053
the half-frequency energy ratio is an important sign of the parametric resonance, and the more pronounced the parametric resonance, the larger the value.
The analyzing of the short circuit impedance change specifically includes:
respectively carrying out multiple high-centering short circuit impact tests on three phases of the transformer until the short circuit impedance of a winding exceeds 2%, and recording test data;
calculating a normalized transient sound vibration signal characteristic parameter value according to the test data, and acquiring a short circuit impedance value through the test data;
analyzing the winding state according to the transient sound vibration signal characteristic parameter value and the short circuit impedance value; the method specifically comprises the following steps:
firstly, the main frequency ratio is gradually reduced, the information entropy and the half-frequency ratio are gradually increased, and slight fluctuation exists to reach a local extreme value, which shows that the loosening faults are mainly accumulated in the process and are accompanied by slight winding deformation; the winding at the extreme value has serious loosening fault and moderate deformation, the short-circuit resistance of the winding is poor at the moment, but the short-circuit resistance does not exceed 2 percent;
after the local extreme value is reached, the main frequency ratio is gradually increased, the information entropy and the half-frequency ratio are gradually reduced, the local extreme value is reached again, the process mainly accumulates deformation faults, and the loosening condition is slightly relieved due to deformation; the winding is extremely damaged, loosened and deformed seriously by imminent collapse at extreme values, the short-circuit resistance is completely lost, and the short-circuit resistance still does not exceed 2 percent;
when the characteristic parameter of the last short circuit impact is greatly changed, the short circuit impedance exceeds 2 percent finally, and the winding respectively has cushion block falling, local deformation, penetrating deformation, insulation damage and the like.
And measuring the short-circuit impedance of the winding off line after each test, stopping the test when the change of the short-circuit impedance exceeds 2 percent, and finally disassembling the hanging cover.
S2, setting a fault diagnosis process after short circuit impact of the transformer winding according to the normalized transient acoustic vibration signal characteristic parameters and the analysis result of the short circuit impedance change, wherein the fault diagnosis process specifically comprises the following steps:
firstly, judging whether the voltage transformation is subjected to short circuit impact for the first time, if so, judging without a reference value through an absolute value of information entropy;
if the fault is subjected to short-circuit impact once, the information entropy after the short-circuit impact for the first time is used as a reference, the change rate is specifically judged, and the fault type is judged by combining a main frequency ratio and a half frequency ratio, so that the fault may have looseness and deformation at the same time; wherein, the short circuit impact comprises a factory short circuit impact test or a field burst short circuit;
and respectively carrying out fault diagnosis on the transient acoustic signals at the outgoing line side of the high-low voltage bushing to preliminarily determine fault positions, and specifically analyzing which phase winding has a fault or the fault degree of each phase winding through the transient vibration signals of different measuring points, wherein the preliminarily determined fault positions comprise the outgoing line side of the high-low voltage bushing or the outgoing line side of the low voltage bushing.
The implementation routine of the fault diagnosis method after the short circuit impact of the transformer winding based on the transient sound vibration signal is described in detail so as to enable the person skilled in the art to understand the invention:
and (3) respectively carrying out multiple times of 'high centering' short circuit impact tests on three phases of an actual 110kV transformer until the short circuit impedance of the winding exceeds 2% so as to obtain the change rule of the short circuit impedance.
The yield strength of the medium-voltage coil wire in the phase winding of the transformer A is 160MPa, the yield strength of the high-voltage coil wire is 160MPa, the test working condition settings are shown in table 1, the test is totally carried out for 33 times, wherein transient sound vibration signals at the 17 th and 22 th short circuit impact times are lacked due to field incompatibilities. The high-voltage side 100% short-circuit test current is 6221A, and the test current is changed from 70% to 105%.
A-phase short circuit impact working condition of table 1110 kV transformer
Figure BDA0003523565590000071
And measuring the short-circuit impedance of the winding according to the standard GB1094.5 after short-circuit impact is finished every time, and because the cost for frequently hanging the cover to observe the state of the winding is too high, the short-circuit impedance of the winding is measured off line after each test, when the change of the short-circuit impedance exceeds 2%, the test is stopped, and finally the hanging cover is disassembled. The whole test process completely simulates the damage process of the winding state, and no fault is artificially preset.
According to the above feature parameter calculation formula, the change rule of the 31-order transient-acoustic-vibration signal feature parameter and the Short-circuit impedance (SCI) shown in table 2 can be obtained. The rate of change of each characteristic variable with respect to the first short-circuit impact is denoted as RaThe rate of change with respect to the previous short circuit impact is denoted as RbWherein the short-circuit resistance is based on the state before the first short-circuit impact test (23.87 omega). It was found that the characteristic variables based on transient acoustic vibration signals are significantly more sensitive than the short-circuit impedance method specified in the standard, which still does not exceed the specified permissible value by more than 2% in the case of already severely deformed windings.
TABLE 2110 kV Transformer A phase characteristic parameter variation
Figure BDA0003523565590000072
Figure BDA0003523565590000081
Transient acoustic vibration signals in the whole accumulated damage process are similar to the results of the model transformer and also go through the process from simple to complex to simple, and the specific characteristic parameter change is shown in figure 2.
(1) All characteristic variables change more slowly since no fault is set manually. Firstly, the main frequency ratio is gradually reduced, the information entropy and the half-frequency ratio are gradually increased, slight fluctuation exists, and the 21 st time reaches a local extreme value, which shows that the loosening type faults are mainly accumulated in the process and are accompanied by slight winding deformation. The winding at the extreme value has serious loosening fault and moderate deformation, the short-circuit resistance of the winding is poor at the moment, but the short-circuit resistance does not exceed 2 percent;
(2) after the 21 st time, the main frequency ratio is gradually increased, the information entropy and the half-frequency ratio are gradually reduced, and the local extreme value is reached at the 30 th time, so that the process mainly accumulates deformation faults, and the loosening condition is slightly relieved due to deformation. The winding is extremely damaged, loosened and deformed seriously by imminent collapse at extreme values, the short-circuit resistance is completely lost, and the short-circuit resistance still does not exceed 2 percent;
(3) the last short circuit impact characteristic parameter is greatly changed, and the short circuit impedance finally exceeds 2 percent and reaches 21.85 percent. As a result of the disassembly of the suspension cover, as shown in fig. 3, the winding was subject to the occurrence of the pad detachment, local deformation, penetration deformation, dielectric breakdown, and the like.
In the 110kV transformer short circuit impact test, the A-phase winding changes most gradually and the times are the most, and the A-phase winding can represent the accumulation process of the winding, so that a fault diagnosis method which is universally suitable for all transformers is provided based on the A-phase test result. Generally, it is desirable to timely remove the transformer before the short-circuit resistance of the winding is completely lost, so as to reduce the huge loss caused by sudden damage of the transformer. According to the rule in the test, the characteristic parameters can be rapidly turned over after the pole appears, and finally the winding state is rapidly deteriorated, so that the threshold value for the transformer to be retreated is reasonably selected as the extreme value point. In 31 short-circuit impacts of the A phase, when the three characteristic parameters have extreme values at the 21 st time, the short-circuit resistance of the winding is considered to be incapable of ensuring whether the next short-circuit impact can still be endured, so that the characteristic parameters are used as the threshold values for the transformer to be retreated. The normalized transient state acoustic vibration signal information entropy contains all frequency information and can reflect the global characteristics of time-frequency domains of signals, so that the normalized transient state acoustic vibration signal information entropy is suitable to be used as a main criterion for fault diagnosis; the main frequency energy ratio has stronger sensitivity to winding loosening faults, and the half-frequency energy ratio has stronger sensitivity to deformation faults, so that the main frequency energy ratio and the half-frequency energy ratio are jointly used as auxiliary criteria. The specific diagnostic flow is shown in fig. 4.
S1, firstly, judging whether the voltage transformation is subjected to short circuit impact for the first time, if so, judging without a reference value by simply using an absolute value of the information entropy;
specifically, when the information entropy is larger than 0.5, the transformer is in a dangerous state and needs to be immediately quit running; and when the information entropy is less than 0.5, continuously judging whether the information entropy is less than 0.35, when the information entropy is less than 0.35, keeping the transformer in a good state, and continuously operating, and when the information entropy is more than 0.35 and less than 0.5, judging by combining other means.
S2, if the short-circuit impact (factory short-circuit impact test or on-site burst short circuit) is suffered once, the information entropy after the first short-circuit impact is taken as a reference, the change rate Ra is specifically judged, and the fault type is judged by combining a main frequency ratio and a half-frequency ratio, so that the fault may have looseness and deformation at the same time; specifically, the method comprises the following steps:
s21, when short circuit impact is not suffered for the first time, whether the change rate of the calculated information entropy relative to the change rate of the information entropy when short circuit impact is suffered for the first time is larger than 20% is judged, and when the change rate is smaller than 20%, the transformer is in a good state and continues to operate; when the change rate is more than 20%, carrying out the judgment of the next step;
s22, judging whether the change rate is more than 40%, when the change rate is small and 40%, enabling the transformer to be in a light fault state, continuing to operate the transformer, and when the change rate is more than 40%, judging in the next step;
s23, judging whether the change rate is greater than 60%, when the change rate is small and 60%, the transformer is in a medium fault state and continues to operate, and when the change rate is greater than 60%, judging the next step;
s24, judging whether the change rate is greater than 80%, if the change rate is small and 80%, the transformer is in a severe fault state, and if the change rate is greater than 80%, the transformer is in a dangerous state and needs to be immediately quit operation;
s25, according to the ratio p of the main frequency energymainAnd half frequency energy ratio phaifFor steps S22-S24Judging the winding fault type of the transformer according to the fault state; the method specifically comprises the following steps:
when the main frequency energy accounts for pmainOr half frequency energy ratio phaifWhen the winding is gradually reduced, the transformer winding is loosened;
when the main frequency energy accounts for pmainOr half frequency energy ratio phaifWhen the winding is gradually increased and gradually decreased, the transformer winding is loosened.
And S3, respectively carrying out fault diagnosis on the transient acoustic signals at the outgoing line side of the high-low voltage sleeve to roughly determine a fault position (the high outgoing line side or the low outgoing line side), and specifically analyzing which phase winding has a fault or the fault degree of each phase winding through transient vibration signals of different measuring points.
According to the judgment process: after 1-11 times of short circuit impact of the phase A, the winding is in a good state, slightly loosens 12-14 times, moderately loosens 15-17 times and deforms, and severely loosens and deforms 18-19 times, so that whether the motor is suitable for continuous operation needs to be comprehensively judged by combining other means, and 20-21 times of dangerous states have serious insufficient short circuit resistance and need to be timely retreated. In addition, the fault degree of the adjacent winding part at the low-voltage bushing side is higher, which is consistent with the hanging cover result.
The above disclosure is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or modifications within the technical scope of the present disclosure may be easily conceived by those skilled in the art and shall be covered by the scope of the present invention.

Claims (8)

1. The method for diagnosing the fault after the short circuit impact of the transformer winding based on the transient sound vibration signal is characterized by comprising the following steps of:
in a winding short circuit impact test, analyzing normalized transient state acoustic vibration signal characteristic parameters and short circuit impedance change;
and setting a fault diagnosis process after the short circuit impact of the transformer winding according to the normalized transient state acoustic vibration signal characteristic parameters and the analysis result of the short circuit impedance change.
2. The transient acoustic vibration signal-based fault diagnosis method after short circuit impact of the transformer winding according to claim 1, wherein the normalized transient acoustic vibration signal characteristic parameters comprise: and normalizing the information entropy, the dominant frequency energy ratio and the half-frequency energy ratio of the transient sound vibration signal.
3. The transient acoustic vibration signal-based transformer winding fault diagnosis method after short circuit impact according to claim 1, wherein analyzing the short circuit impedance change specifically comprises:
respectively carrying out multiple high-centering short circuit impact tests on three phases of the transformer until the short circuit impedance of a winding exceeds 2%, and recording test data;
calculating a normalized transient sound vibration signal characteristic parameter value according to the test data, and acquiring a short circuit impedance value through the test data;
and analyzing the winding state according to the transient sound vibration signal characteristic parameter value and the short circuit impedance value.
4. The transient sound vibration signal-based transformer winding fault diagnosis method after short circuit impact according to claim 3, wherein the analyzing of the winding state according to the transient sound vibration signal characteristic parameter value and the short circuit impedance value specifically comprises:
firstly, the main frequency ratio is gradually reduced, the information entropy and the half-frequency ratio are gradually increased and slightly fluctuate to reach a local extreme value, which indicates that the loose faults are mainly accumulated in the process and are accompanied by slight winding deformation; the winding at the extreme value has serious loosening fault and moderate deformation, the short-circuit resistance of the winding is poor at the moment, but the short-circuit resistance is not more than 2 percent;
after the main frequency ratio reaches the local extreme value, the main frequency ratio is gradually increased, the information entropy and the half-frequency ratio are gradually reduced, the main frequency ratio reaches the local extreme value again, the process mainly accumulates deformation faults, and the loosening condition is slightly relieved due to deformation; the winding is extremely damaged, loosened and deformed seriously by imminent collapse at extreme values, the short-circuit resistance is completely lost, and the short-circuit resistance still does not exceed 2 percent;
when the characteristic parameter of the last short circuit impact is greatly changed, the short circuit impedance exceeds 2 percent finally, and the winding respectively has cushion block falling, local deformation, penetrating deformation and insulation damage.
5. The method for diagnosing the fault after the short circuit impact of the transformer winding based on the transient acoustic vibration signal according to claim 3, wherein the short circuit impedance of the winding is measured off line after each test, the test is stopped when the change of the short circuit impedance exceeds 2%, and finally the hanging cover is disassembled.
6. The transient acoustic vibration signal-based fault diagnosis method after short circuit impact of the transformer winding according to claim 1, wherein the fault diagnosis process after short circuit impact of the transformer winding comprises:
firstly, judging whether the voltage transformation is subjected to short circuit impact for the first time, if so, judging without a reference value through an absolute value of information entropy;
if the fault is subjected to short-circuit impact once, the information entropy after the short-circuit impact for the first time is used as a reference, the change rate is specifically judged, and the fault type is judged by combining a main frequency ratio and a half frequency ratio, so that the fault may have looseness and deformation at the same time;
and respectively carrying out fault diagnosis on the transient acoustic signals at the outgoing line side of the high-low voltage sleeve to preliminarily determine fault positions, and specifically analyzing which phase winding has a fault or the fault degree of each phase winding through the transient vibration signals of different measuring points.
7. The transient acoustic vibration signal-based fault diagnosis method after short circuit impact of the transformer winding according to claim 6, wherein the short circuit impact comprises a factory short circuit impact test or a field burst short circuit.
8. The transient vibro-acoustic signal-based fault diagnosis method after short circuit impact of a transformer winding according to claim 6, wherein the preliminarily determined fault location comprises a high voltage outgoing line side or a low voltage outgoing line side.
CN202210188281.2A 2022-02-28 2022-02-28 Transient sound vibration signal-based fault diagnosis method for transformer winding after short circuit impact Pending CN114779130A (en)

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