CN112556828A - Transformer winding loosening fault detection method - Google Patents
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Abstract
The invention relates to a method for detecting a loosening fault of a transformer winding, which is technically characterized by comprising the following steps of: establishing a winding vibration frequency response characteristic test system; arranging vibration sensors around the transformer along the horizontal direction and the vertical direction; the winding vibration frequency response characteristic test system generates different frequency signals and sets excitation current, the winding generates mechanical vibration, the vibration sensor measures vibration acceleration and sends measured data to analysis software; and the analysis software receives the vibration acceleration data of the transformer and generates a winding vibration response curve, and the loosening fault of the transformer winding is analyzed according to the change of the winding vibration response curve. The vibration sensors are arranged around the transformer, so that the winding vibration signals at different positions and different currents are obtained, the correlation coefficients of different winding vibration response curves are analyzed, the relation of the number of the correlation coefficients in different numerical value intervals is counted, the winding loosening condition is evaluated, and the function of accurately detecting the transformer winding loosening fault is realized.
Description
Technical Field
The invention belongs to the technical field of transformers, relates to transformer fault detection, and particularly relates to a transformer winding looseness fault detection method.
Background
The transformer plays an important role in electric energy conversion, and the safe and reliable operation of the transformer has important significance for maintaining the stability of a power system. In the running process of the transformer, the short-circuit current with far excess of a rated value and huge short-circuit electrodynamic force are generated under the influence of factors such as external sudden short circuit and the like, so that the internal lead and the insulating material of the transformer are deformed and damaged under the dual action of thermal force and stress, the transformer winding is loosened, and the fault shutdown risk of the transformer is increased.
At present, the detection method of the winding looseness mainly comprises a frequency response method, a capacitance method and a low-voltage impedance method, wherein the capacitance method and the low-voltage impedance method are single in obtained test data, only the whole deformation condition of the transformer winding can be judged, and the reason of the winding looseness cannot be deeply analyzed. The frequency response method evaluates the deformation of the winding by analyzing the voltage response of the winding at different frequencies, but cannot reflect the fastening condition of the winding and the insulating material.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a method for detecting the loosening fault of a transformer winding, which solves the problem that the prior art cannot analyze the winding compression characteristic reflected by mechanical vibration under current excitation by using a mode of combining a vibration signal and an electric signal.
The technical problem to be solved by the invention is realized by adopting the following technical scheme:
a transformer winding looseness fault detection method comprises the following steps:
step 1, establishing a winding vibration frequency response characteristic test system;
step 2, arranging vibration sensors around the transformer along the horizontal direction and the vertical direction;
step 3, after the winding vibration frequency response characteristic test system generates different frequency signals and sets excitation current, the winding generates mechanical vibration, the vibration sensor measures vibration acceleration and sends the measured vibration acceleration data to analysis software;
and 4, receiving the vibration acceleration data of the transformer by analysis software, generating a winding vibration response curve, and analyzing the loosening fault of the transformer winding according to the change of the winding vibration response curve.
The winding vibration frequency response characteristic test system is formed by connecting a harmonic source, an intermediate frequency transformer, a vibration sensor, a data acquisition card and analysis software; the harmonic source generates a variable frequency sinusoidal voltage of 50-500Hz and supplies electric energy to the intermediate frequency transformer; the intermediate frequency transformer plays a role in regulating voltage and current and applies current of 10-30A to a transformer winding; the vibration sensor collects acceleration change caused by vibration of the transformer; the data acquisition card performs A/D conversion on the output signal of the vibration sensor and then transmits the output signal to analysis software; the analysis software is responsible for harmonic source frequency control and collected data analysis.
Moreover, the arrangement method of the vibration sensor is as follows: firstly, determining the arrangement of measuring points of a sensor in the horizontal direction, wherein the measuring points are uniformly arranged around the axle center of a transformer winding and are preferably arranged on spokes outside the transformer winding; and then, determining the arrangement of measuring points of the sensor in the vertical direction, uniformly selecting 5-7 measuring points from the vertical distance determined by the upper insulating pressing plate and the lower insulating pressing plate of the winding, keeping the measuring points longitudinally aligned, and arranging the measuring points on the upper insulating pressing plate and the lower insulating pressing plate.
And the vibration sensor adopts a double-shaft or three-shaft acceleration sensor, and axial vibration and radial vibration acceleration of the transformer are measured through the double-shaft or three-shaft acceleration sensor.
Moreover, the specific implementation method of the step 4 is as follows:
firstly, under the normal operation condition, receiving vibration acceleration data of a transformer by using analysis software and generating a winding vibration frequency response curve as a reference curve;
then, the vibration frequency response curve of the winding of the transformer with possible winding looseness is retested, the change of the vibration frequency response curve of the winding and the reference curve is analyzed, and the correlation coefficient rho of the vibration frequency response curves of different measuring points is calculatediObtaining n curve correlation coefficients rho1,ρ2,…,ρn；
Finally, setting correlation coefficient threshold values B1 and B2, wherein 0< B1<0.5< B2<1, respectively counting the numbers m1, m2 and m3 of correlation coefficients in the ranges from 0 to B1, B1 to B2 and B2 to 1, and evaluating the loosening condition of the winding according to the relation of the numbers of the correlation coefficients falling in different sections, wherein the larger m1 is, the higher the possibility of reflecting the loosening fault of the winding is, and the larger m3 is, the lower the possibility of reflecting the loosening fault of the winding is.
And the reference curve is a winding vibration response curve S at different measuring points obtained by measuring the transformer for the first time1,S2,…,Sn(ii) a The test conditions at the time of measurement at the time of fault detection are completely the same as those of the reference curve measurement.
The horizontal axis of the vibration response curve of the winding is the frequency f of the harmonic source, the vertical axis is the ratio K of the vibration acceleration to the square of the excitation current, and K is alpha/I2Where α is the axial or radial acceleration and I is the excitation current output by the transformer.
And, the correlation coefficient ρiThe calculation formula is as follows:
wherein, Cov (S)i,Ti) Is the covariance of curves S and T, D (S)i) And D (T)i) The variances of the curves S and T, respectively.
The invention has the advantages and positive effects that:
1. the vibration sensors are arranged around the transformer along the horizontal direction and the vertical direction, so that winding vibration signals at different positions and at different currents are obtained, the change of a winding vibration frequency response curve is analyzed by using a Pearson correlation coefficient method, the relation of the number of curve correlation coefficients in different numerical intervals is counted, the condition of winding looseness is evaluated, and the function of accurately detecting the looseness fault of the transformer winding is realized.
2. The invention can obtain the response condition of the winding under the comprehensive action of mechanical excitation and electric excitation by combining the vibration signal and the electric signal, is convenient to analyze the mutual influence of the vibration signal and the electric signal, more comprehensively masters the deformation condition and the fastening condition of the winding, and solves the problems that the traditional method only utilizes the electric signal to judge the deformation of the winding and cannot analyze the compression characteristic of the winding reflected by the mechanical vibration under the current excitation.
Drawings
FIG. 1 is a connection diagram of a winding vibration frequency response characteristic testing system of the present invention;
fig. 2 is a graph of winding vibration response.
Detailed Description
The embodiments of the present invention will be described in detail with reference to the accompanying drawings.
A transformer winding looseness fault detection method comprises the following steps:
step 1, establishing a winding vibration frequency response characteristic test system.
The invention realizes the fault detection function by using the winding vibration frequency response characteristic test system shown in figure 1. The system for testing the vibration frequency response characteristics of the winding mainly comprises a harmonic source, an intermediate frequency transformer, a vibration sensor, a data acquisition card and analysis software. The harmonic source generates a variable frequency sinusoidal voltage of 50-500Hz, and supplies electric energy to the intermediate frequency transformer. The intermediate frequency transformer plays a role in voltage and current regulation, and current with the magnitude of 10-30A is applied to a transformer winding. The vibration sensor collects acceleration changes caused by vibration of the transformer. The data acquisition card performs A/D conversion on the output signal of the vibration sensor and then transmits the output signal to analysis software. The analysis software is responsible for harmonic source frequency control and collected data analysis.
And 2, arranging vibration sensors around the transformer along the horizontal direction and the vertical direction.
In the step, in order to measure the axial vibration acceleration and the radial vibration acceleration of the transformer, vibration sensors are arranged in the horizontal direction and the vertical direction of the transformer, and acceleration data measured by the vibration sensors can be sent to analysis software through a data acquisition card.
In the arrangement process of the vibration sensor, firstly, the arrangement of measuring points of the sensor in the horizontal direction is determined, and the measuring points are uniformly arranged around the axle center of the transformer winding and are preferably arranged on spokes outside the transformer winding; and then, determining the arrangement of measuring points of the sensor in the vertical direction, uniformly selecting 5-7 measuring points from the vertical distance determined by the upper insulating pressing plate and the lower insulating pressing plate of the winding, wherein the measuring points are longitudinally aligned and are arranged on the upper insulating pressing plate and the lower insulating pressing plate.
In this embodiment, the vibration sensor is a two-axis or three-axis acceleration sensor, and the axial vibration and radial vibration acceleration of the transformer are measured by the two-axis or three-axis acceleration sensor.
And 3, after the winding vibration frequency response characteristic test system generates different frequency signals and sets excitation current, the vibration sensor measures vibration acceleration and sends measured acceleration data to analysis software through a data acquisition card.
And 4, receiving the acceleration data of the transformer by analysis software, generating a winding vibration response curve, and analyzing the loosening fault of the transformer winding according to the winding vibration response curve.
In this step, the analysis software receives the transformer acceleration data and generates a winding vibration response curve. As shown in FIG. 2, the horizontal axis of the vibration response curve of the winding is the frequency f (in Hz) of the harmonic source, and the vertical axis is the ratio K (in m · s) of the vibration acceleration to the square of the excitation current-2·A-2) The calculation formula is K ═ alpha/I2Wherein alpha is axial or radial acceleration, and I is excitation current output by the intermediate frequency transformer.
In the invention, the vibration response curve S of the winding at different measuring points obtained by the first measurement of the transformer can be obtained1,S2,…,SnShould be used as the reference curve; after the transformer is operated for a period of time, if the winding is suspected to be loose, the vibration response curve T should be remeasured under the same conditions (sensor arrangement, exciting current)1,T2,…,Tn。
Analyzing the change of the vibration response curve by using a Pearson correlation coefficient method, and calculating the correlation coefficient rho of the vibration response curve of different measuring pointsiObtaining n curve correlation coefficients rho1,ρ2,…,ρn. Correlation coefficient ρiThe calculation formula is as follows:
wherein, Cov (S)i,Ti) Is the covariance of curves S and T, D (S)i) And D (T)i) The variances of the curves S and T, respectively.
Setting correlation coefficient thresholds B1 and B2(0< B1<0.5< B2<1), respectively counting the numbers m1, m2 and m3 of the correlation coefficients in three sections (0, B1), [ B1 and B2), [ B2 and 1), and estimating the loosening condition of the winding according to the relation of the numbers of the correlation coefficients in different sections, wherein the larger m1 is, the higher the possibility of reflecting the loosening fault of the winding is, and the larger m3 is, the lower the possibility of reflecting the loosening fault of the winding is.
It should be emphasized that the embodiments described herein are illustrative rather than restrictive, and thus the present invention is not limited to the embodiments described in the detailed description, but also includes other embodiments that can be derived from the technical solutions of the present invention by those skilled in the art.
Claims (8)
1. A transformer winding looseness fault detection method is characterized in that: the method comprises the following steps:
step 1, establishing a winding vibration frequency response characteristic test system;
step 2, arranging vibration sensors around the transformer along the horizontal direction and the vertical direction;
step 3, after the winding vibration frequency response characteristic test system generates different frequency signals and sets excitation current, the winding generates mechanical vibration, the vibration sensor measures vibration acceleration and sends the measured vibration acceleration data to analysis software;
and 4, receiving the vibration acceleration data of the transformer by analysis software, generating a winding vibration response curve, and analyzing the loosening fault of the transformer winding according to the change of the winding vibration response curve.
2. The transformer winding loosening fault detection method of claim 1, wherein: the winding vibration frequency response characteristic test system is formed by connecting a harmonic source, an intermediate frequency transformer, a vibration sensor, a data acquisition card and analysis software; the harmonic source generates a variable frequency sinusoidal voltage of 50-500Hz and supplies electric energy to the intermediate frequency transformer; the intermediate frequency transformer plays a role in regulating voltage and current and applies current of 10-30A to a transformer winding; the vibration sensor collects acceleration change caused by vibration of the transformer; the data acquisition card performs A/D conversion on the output signal of the vibration sensor and then transmits the output signal to analysis software; the analysis software is responsible for harmonic source frequency control and collected data analysis.
3. The transformer winding loosening fault detection method of claim 2, wherein: the arrangement method of the vibration sensor comprises the following steps: firstly, determining the arrangement of measuring points of a sensor in the horizontal direction, wherein the measuring points are uniformly arranged around the axle center of a transformer winding and are preferably arranged on spokes outside the transformer winding; and then, determining the arrangement of measuring points of the sensor in the vertical direction, uniformly selecting 5-7 measuring points from the vertical distance determined by the upper insulating pressing plate and the lower insulating pressing plate of the winding, keeping the measuring points longitudinally aligned, and arranging the measuring points on the upper insulating pressing plate and the lower insulating pressing plate.
4. A transformer winding loosening fault detection method according to any one of claims 1 to 3, characterized by: the vibration sensor adopts a double-shaft or three-shaft acceleration sensor, and axial vibration and radial vibration acceleration of the transformer are measured through the double-shaft or three-shaft acceleration sensor.
5. The transformer winding loosening fault detection method of claim 2, wherein: the specific implementation method of the step 4 comprises the following steps:
firstly, under the normal operation condition, receiving vibration acceleration data of a transformer by using analysis software and generating a winding vibration frequency response curve as a reference curve;
then, the vibration frequency response curve of the winding of the transformer with possible winding looseness is retested, the change of the vibration frequency response curve of the winding and the reference curve is analyzed, and the correlation coefficient rho of the vibration frequency response curve of different measuring points is calculatediObtaining n curve correlation coefficients rho1,ρ2,…,ρn；
Finally, setting correlation coefficient threshold values B1 and B2, wherein 0< B1<0.5< B2<1, respectively counting the numbers m1, m2 and m3 of correlation coefficients in the ranges from 0 to B1, B1 to B2 and B2 to 1, and evaluating the loosening condition of the winding according to the relation of the numbers of the correlation coefficients falling in different sections, wherein the larger m1 is, the higher the possibility of reflecting the loosening fault of the winding is, and the larger m3 is, the lower the possibility of reflecting the loosening fault of the winding is.
6. The transformer winding loosening fault detection method of claim 5, wherein: the reference curve is a winding vibration response curve S at different measuring points obtained by measuring the transformer for the first time1,S2,…,Sn(ii) a The test conditions at the time of measurement at the time of fault detection are completely the same as those of the reference curve measurement.
7. Method for detecting transformer winding loosening fault according to claim 5 or 6The method is characterized in that: the horizontal axis of the vibration response curve of the winding is the frequency f of a harmonic source, the vertical axis of the vibration response curve is the ratio K of vibration acceleration to the square of excitation current, and K is alpha/I2Where α is the axial or radial acceleration and I is the excitation current output by the transformer.
8. The transformer winding loosening fault detection method according to claim 5 or 6, wherein: the correlation coefficient ρiThe calculation formula is as follows:
wherein, Cov (S)i,Ti) Is the covariance of curves S and T, D (S)i) And D (T)i) The variances of the curves S and T, respectively.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114019298A (en) * | 2021-09-28 | 2022-02-08 | 中电华创(苏州)电力技术研究有限公司 | PCC-SVM-based generator rotor turn-to-turn short circuit online monitoring method |
| CN114113939A (en) * | 2021-11-24 | 2022-03-01 | 国网宁夏电力有限公司宁东供电公司 | Transient vibration signal-based transformer fault detection method |
| CN114167842A (en) * | 2021-12-08 | 2022-03-11 | 中国船舶科学研究中心 | Fault prediction and health management method based on vibration active control system |
| CN114485379A (en) * | 2022-01-27 | 2022-05-13 | 重庆电子工程职业学院 | Transformer winding on-line monitoring method |
| CN116577716A (en) * | 2023-07-06 | 2023-08-11 | 西安高压电器研究院股份有限公司 | Current sensor vibration characteristic testing method, related equipment and related system |
| CN116755001A (en) * | 2023-08-17 | 2023-09-15 | 杭州博洲电器有限公司 | Detection method and equipment for planar transformer |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101556299A (en) * | 2009-05-18 | 2009-10-14 | 重庆电力科学试验研究院 | Method for detecting micro deformation of transformer winding |
| US20170045481A1 (en) * | 2015-08-13 | 2017-02-16 | Eaton Corporation | Vibration sensor assembly for prognostic and diagnostic health assessment of a power circuit breaker's power transmission and distribution system in real time |
| CN107390081A (en) * | 2017-08-07 | 2017-11-24 | 华北电力大学 | It is a kind of to be used for the device and method being monitored powered to deformation of transformer winding |
| CN107478949A (en) * | 2017-08-07 | 2017-12-15 | 中国电力科学研究院 | A kind of deformation of transformer winding inline diagnosis method and system |
| CN109443714A (en) * | 2018-05-15 | 2019-03-08 | 贵州电网有限责任公司 | A kind of on-load tap changers of transformers machine performance monitoring method |
| CN109697437A (en) * | 2019-02-28 | 2019-04-30 | 国网陕西省电力公司电力科学研究院 | A kind of winding modal analysis method and its application and verification method based on electric excitation |
| CN109765455A (en) * | 2019-02-28 | 2019-05-17 | 国网陕西省电力公司电力科学研究院 | A kind of transformer winding detection platform and its operating method based on harmonic source |
-
2020
- 2020-11-20 CN CN202011312708.2A patent/CN112556828A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101556299A (en) * | 2009-05-18 | 2009-10-14 | 重庆电力科学试验研究院 | Method for detecting micro deformation of transformer winding |
| US20170045481A1 (en) * | 2015-08-13 | 2017-02-16 | Eaton Corporation | Vibration sensor assembly for prognostic and diagnostic health assessment of a power circuit breaker's power transmission and distribution system in real time |
| CN107390081A (en) * | 2017-08-07 | 2017-11-24 | 华北电力大学 | It is a kind of to be used for the device and method being monitored powered to deformation of transformer winding |
| CN107478949A (en) * | 2017-08-07 | 2017-12-15 | 中国电力科学研究院 | A kind of deformation of transformer winding inline diagnosis method and system |
| CN109443714A (en) * | 2018-05-15 | 2019-03-08 | 贵州电网有限责任公司 | A kind of on-load tap changers of transformers machine performance monitoring method |
| CN109697437A (en) * | 2019-02-28 | 2019-04-30 | 国网陕西省电力公司电力科学研究院 | A kind of winding modal analysis method and its application and verification method based on electric excitation |
| CN109765455A (en) * | 2019-02-28 | 2019-05-17 | 国网陕西省电力公司电力科学研究院 | A kind of transformer winding detection platform and its operating method based on harmonic source |
Non-Patent Citations (1)
| Title |
|---|
| 尹磊: "《变压器绕组变形的在线监测研究》", 《中国优秀硕士学位论文全文数据库 工程科技II辑》 * |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114019298A (en) * | 2021-09-28 | 2022-02-08 | 中电华创(苏州)电力技术研究有限公司 | PCC-SVM-based generator rotor turn-to-turn short circuit online monitoring method |
| CN114019298B (en) * | 2021-09-28 | 2023-12-05 | 中电华创(苏州)电力技术研究有限公司 | On-line monitoring method for turn-to-turn short circuit of generator rotor based on PCC-SVM |
| CN114113939A (en) * | 2021-11-24 | 2022-03-01 | 国网宁夏电力有限公司宁东供电公司 | Transient vibration signal-based transformer fault detection method |
| CN114113939B (en) * | 2021-11-24 | 2022-11-18 | 国网宁夏电力有限公司宁东供电公司 | Transient vibration signal-based transformer fault detection method |
| CN114167842A (en) * | 2021-12-08 | 2022-03-11 | 中国船舶科学研究中心 | Fault prediction and health management method based on vibration active control system |
| CN114485379A (en) * | 2022-01-27 | 2022-05-13 | 重庆电子工程职业学院 | Transformer winding on-line monitoring method |
| CN116577716A (en) * | 2023-07-06 | 2023-08-11 | 西安高压电器研究院股份有限公司 | Current sensor vibration characteristic testing method, related equipment and related system |
| CN116577716B (en) * | 2023-07-06 | 2023-10-20 | 西安高压电器研究院股份有限公司 | Current sensor vibration characteristic testing method, related equipment and related system |
| CN116755001A (en) * | 2023-08-17 | 2023-09-15 | 杭州博洲电器有限公司 | Detection method and equipment for planar transformer |
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