Transformer direct current magnetic bias and harmonic injection identification method based on vibration technology

Abstract

The invention discloses a transformer DC magnetic bias and harmonic injection identification method based on a vibration technology, and relates to the technical field of health monitoring and fault diagnosis of a transformer in an electric power system, and the method comprises the steps: collecting vibration data, and identifying DC magnetic bias and harmonic injection phenomena; calculating a characteristic value, and quantifying a vibration mode; and identification is carried out according to the direct current magnetic bias and the harmonic injection on the vibration time domain frequency and a threshold value. According to the invention, high-efficiency identification and accurate monitoring of direct current magnetic bias and harmonic injection phenomena of the transformer are realized, all-directional and high-density data acquisition is ensured, and later data processing difficulty and calculation amount are reduced; key information is ensured not to be lost; according to the method, the accuracy and reliability of fault detection are improved, a solid guarantee is provided for stable operation of a power system, and the method has remarkable technical advantages and wide application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of health monitoring and fault diagnosis of transformers in power systems, and particularly to a method for identifying DC bias and harmonic injection of transformers based on vibration technology. Background Art

[0002] With the acceleration of the modern industrial and urbanization processes, the power demand continues to grow, posing higher requirements for the safe and stable operation of the power grid. Especially in the context of large-scale access of new energy and wide application of power electronic devices, as a key device in the power system, the health status of transformers directly affects the stability and reliability of the entire power grid. The phenomena of DC bias and harmonic injection frequently occur, not only threatening the safe operation of transformers but also possibly triggering a series of chain reactions and affecting the power supply quality. Therefore, how to effectively monitor and identify these potential risks has become an important issue faced by the current power industry.

[0003] Currently, in the existing technology, the monitoring of the phenomena of DC bias and harmonic injection in transformers mainly relies on traditional electrical quantity measurement methods, such as the detection of parameters such as voltage and current. However, these methods often fail to accurately capture the subtle changes caused by the vibration of the internal mechanical structure, resulting in inaccurate fault diagnosis. In addition, the traditional methods lack an effective mechanism for excluding environmental interference and are prone to misjudgment. Summary of the Invention

[0004] In view of the problems existing in the existing methods for identifying DC bias and harmonic injection of transformers based on vibration technology, the present invention is proposed.

[0005] Therefore, aiming at the defects of inaccurate monitoring of the phenomena of DC bias and harmonic injection in transformers and being prone to misjudgment due to environmental interference in the existing technology, the present invention adopts a multi-dimensional data coverage based on vibration analysis, intelligent sensor configuration, and environmental interference exclusion mechanism to achieve accurate identification and effective elimination of these problems.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides a method for identifying DC bias and harmonic injection of transformers based on vibration technology, which includes,

[0008] Deploy acceleration sensors on three sides of the transformer except the fan side to collect vibration data and identify the phenomena of DC bias and harmonic injection;

[0009] After completing the deployment of the acceleration sensors, calculate the characteristic values from the vibration signals obtained from the acceleration sensors to quantify the vibration mode;

[0010] Identify based on the DC bias and harmonic injection in the vibration time domain frequency with the threshold.

[0011] As a preferred solution of the method for identifying DC bias and harmonic injection of a transformer based on vibration technology according to the present invention, wherein: the deployment of acceleration sensors on three sides of the transformer except the fan side includes constructing a data acquisition framework, and the data acquisition framework includes multi-dimensional data coverage, intelligent sensor selection and configuration, dynamic data acquisition strategy, and environmental interference elimination mechanism;

[0012] The multi-dimensional data coverage includes deploying acceleration sensors on three sides of the transformer except the fan side respectively, arranging sensors evenly on each side, and completing the data acquisition network;

[0013] The intelligent sensor selection and configuration includes selecting acceleration sensors with adaptive noise suppression function, and equipping each sensor with an independent data processing unit. This acceleration sensor automatically adjusts its sensitivity to complete different working environments and obtains vibration signals;

[0014] The dynamic data acquisition strategy includes designing a dynamic data acquisition strategy according to the change of the transformer operation state. The dynamic data acquisition strategy allows the sensor to automatically adjust the sampling frequency according to the preset time interval or the detected change of vibration intensity;

[0015] The environmental interference elimination mechanism includes setting an additional group of reference sensors at a position close to the fan side to distinguish the vibration anomalies caused by DC bias and harmonic injection from the influence of external factors, and excluding fan interference by comparing and analyzing the data differences between the data acquisition area and the reference area.

[0016] As a preferred solution of the method for identifying DC bias and harmonic injection of a transformer based on vibration technology according to the present invention, wherein:

[0017] The calculation of characteristic values includes vibration amplitude calculation, odd-even harmonic ratio calculation, and spectrum complexity calculation. The vibration amplitude calculation includes calculating the average intensity of the vibration signal in the time domain, and the specific formula is:

[0018] ,

[0019] Wherein, represents the vibration amplitude, represents the vibration signal within the time period, represents the total length of the time period;

[0020] The odd-even harmonic ratio calculation includes performing spectrum analysis on the collected vibration signal and paying attention to the proportional relationship between odd and even harmonics. The formula for calculating the odd-even harmonic ratio is:

[0021] ,

[0022] Among them, represents the odd-even harmonic ratio, represents the degree of odd harmonic components when the transformer has DC bias, represents the odd harmonic components when the transformer has DC bias.

[0023] As a preferred solution of the method for identifying DC bias and harmonic injection of a transformer based on vibration technology according to the present invention, wherein: the calculation of the spectral complexity includes using energy entropy as a measurement criterion, and the energy entropy includes the degree of dispersion of the energy of each frequency component in the spectrum of the transformer sound signal. When the value of the degree of dispersion decreases, the spectral energy is concentrated;

[0024] Otherwise, when the value of the degree of dispersion increases, the spectral energy is dispersed;

[0025] Then the threshold calculation formula for concentration or dispersion is:

[0026] ,

[0027] ,

[0028] Among them, represents the energy entropy, represents the th energy proportion of the frequency component, represents the th amplitude of the frequency component, represents the index variable, represents the total number of frequency components, represents the sum of the squares of the amplitudes of the frequency components, represents the th sum of the amplitudes of the frequency components.

[0029] As a preferred solution of the method for identifying DC bias and harmonic injection of a transformer based on vibration technology according to the present invention, wherein: the identification according to DC bias and harmonic injection on the vibration time-frequency domain and the threshold includes an identification method, a secondary identification, and a feature distinction;

[0030] The identification method includes analyzing according to the vibration amplitude, odd-even harmonic ratio, and spectral complexity exceeding the threshold, and excluding the influence of the fan;

[0031] When the odd-even harmonic ratio eigenvalue of the vibration sensor exceeds the threshold, there is a phenomenon of DC bias or harmonic injection. At this time, the factor of the fan is excluded;

[0032] When the eigenvalue of the odd-even harmonic ratio of the vibration data on the fan side exceeds the threshold, there is a phenomenon of DC bias or harmonic injection, and at this time, it is analyzed as a factor of the fan.

[0033] As a preferred scheme of the method for identifying DC bias and harmonic injection of a transformer based on vibration technology according to the present invention, wherein: the secondary identification includes, after excluding the fan, performing secondary identification, making a judgment based on the operation mode of the power system, and finding the sources of the DC source and the harmonic source;

[0034] The DC source has a single-stage ground operation mode of a DC project, and the harmonic sources are new energy power stations and metallurgical plants. The generated harmonics will be transmitted to the main transformer through wires;

[0035] The feature discrimination includes that if the odd-even multiple frequency ratio of 50 Hz is high, it is considered harmonic injection or DC bias. Mark the part of the odd harmonics that exceeds 10 dB around, and calculate the proportion of the part before 1000 Hz of the odd harmonics in the total energy of the odd harmonics.

[0036] As a preferred scheme of the method for identifying DC bias and harmonic injection of a transformer based on vibration technology according to the present invention, wherein: the harmonic injection includes the 3rd harmonic and the 5th harmonic of the power grid, which cause abnormal changes in the low-order odd harmonics of 50 Hz in the transformer sound signal within 1000 Hz;

[0037] The DC bias includes the existence of a DC component in the system, which changes the odd harmonics of 50 Hz in the overall sound signal and the DC bias.

[0038] In a second aspect, an embodiment of the present invention provides a system for identifying DC bias and harmonic injection of a transformer based on vibration technology, which includes:

[0039] A face deployment module deploys acceleration sensors on three faces of the transformer except the fan side, collects vibration data, and identifies the phenomena of DC bias and harmonic injection;

[0040] A quantization vibration mode module, after completing the deployment of the acceleration sensors, obtains vibration signals from the acceleration sensors, calculates eigenvalues, and quantizes the vibration mode;

[0041] A module for identifying DC bias and harmonic injection of a transformer, which identifies according to the DC bias and harmonic injection with a threshold in the vibration time domain frequency.

[0042] In a third aspect, an embodiment of the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and: when the processor executes the computer program, any step of the method for identifying DC bias and harmonic injection of a transformer based on vibration technology described above is implemented.

[0043] Fourthly, an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, where: when the computer program is executed by a processor, any step of the above-mentioned identification method for DC bias and harmonic injection of a transformer based on vibration technology is implemented.

[0044] The beneficial effects of the present invention are as follows: By innovatively applying vibration analysis technology, the present invention realizes the efficient identification and precise monitoring of the phenomena of DC bias and harmonic injection in transformers. Firstly, a multi-dimensional data coverage strategy is adopted, and acceleration sensors are evenly deployed on three sides of the transformer except the fan side, ensuring all-round and high-density data acquisition; Secondly, the selection and configuration of intelligent sensors, especially sensors with adaptive noise suppression functions and independent data processing units, enable pure vibration signals to be obtained even in complex environments, reducing the difficulty of subsequent data processing and the amount of calculation; The dynamic data acquisition strategy automatically adjusts the sampling frequency according to the operating state of the transformer to ensure that key information is not lost; The environmental interference elimination mechanism effectively distinguishes the vibration anomalies caused by DC bias and harmonic injection from the influence of other external factors, improving the diagnostic accuracy. In summary, the present invention not only improves the accuracy and reliability of fault detection, but also provides a solid guarantee for the stable operation of the power system, having significant technical advantages and broad application prospects. Description of the Drawings

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:

[0046] Figure 1 It is a flowchart of the identification method for DC bias and harmonic injection of a transformer based on vibration technology.

[0047] Figure 2 It is a schematic diagram of the fan's influence on the vibration signal frequency of the transformer for the identification method of DC bias and harmonic injection of the transformer based on vibration technology. Detailed Embodiments

[0048] To make the above-mentioned objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0049] In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the spirit of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0050] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that mutually excludes other embodiments.

[0051] The present invention is described in detail in conjunction with schematic diagrams. When elaborating on the embodiments of the present invention, for the convenience of explanation, the cross-sectional views showing the device structure are enlarged locally not in accordance with the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention herein. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0052] Meanwhile, in the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper, lower, inner, and outer" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first, second, or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0053] Unless otherwise clearly defined and limited in the present invention, the terms "installed, connected, and coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection, an electrical connection, or a direct connection, and can also be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0054] Embodiment 1

[0055] Referring to Figures 1 to 2 , which is the first embodiment of the present invention. This embodiment provides a method for identifying DC bias and harmonic injection of a transformer based on vibration technology, including:

[0056] S1: Deploy acceleration sensors on three sides of the transformer except the fan side, collect vibration data, and identify the phenomena of DC bias and harmonic injection.

[0057] Among them, deploying acceleration sensors on three sides of the transformer except the fan side includes constructing a data acquisition framework, which includes multi-dimensional data coverage, intelligent sensor selection and configuration, dynamic data acquisition strategy, and environmental interference elimination mechanism.

[0058] Multi-dimensional data coverage includes deploying acceleration sensors on three sides of the transformer except the fan side respectively, arranging sensors evenly on each side, and completing the data acquisition network.

[0059] Intelligent sensor selection and configuration includes selecting acceleration sensors with adaptive noise suppression function and equipping each sensor with an independent data processing unit. This acceleration sensor automatically adjusts its sensitivity to complete different working environments and obtains vibration signals.

[0060] The dynamic data acquisition strategy includes designing a dynamic data acquisition strategy according to the changes in the operating state of the transformer. The dynamic data acquisition strategy allows the sensor to automatically adjust the sampling frequency according to the preset time interval or the detected change in vibration intensity.

[0061] The environmental interference elimination mechanism includes setting an additional group of reference sensors near the fan side to distinguish the vibration anomalies caused by DC bias and harmonic injection from the influence of external factors. By comparing and analyzing the data differences between the data acquisition area and the reference area, the fan interference is excluded.

[0062] S2: After completing the deployment of acceleration sensors, calculate the eigenvalue from the vibration signals obtained from the acceleration sensors and quantify the vibration mode.

[0063] Among them, calculating the eigenvalue includes vibration amplitude calculation, odd-even harmonic ratio calculation, and spectrum complexity calculation. Vibration amplitude calculation includes calculating the average intensity of the vibration signal in the time domain, and the specific formula is:

[0064] ,

[0065] Among them, represents the vibration amplitude, represents the vibration signal within a time period, represents the total length of the time period.

[0066] Odd-even harmonic ratio calculation includes performing spectrum analysis on the collected vibration signals and paying attention to the proportional relationship between odd and even harmonics. The formula for odd-even harmonic ratio calculation is:

[0067] ,

[0068] Among them, represents the odd-even harmonic ratio, represents the degree of odd harmonic component when DC bias occurs in the transformer, It represents the odd - harmonic component when the transformer has DC bias magnetization.

[0069] Furthermore, the influence of the signal amplitude is not significant. The influence of the fan group on the vibration signal frequency of the nearby transformer results in the appearance of odd - harmonics in the transformer vibration spectrum that are consistent with the vibration of the fan body. Therefore, the generation of odd - harmonics in the vibration spectrum of an operating power transformer may be caused by the operation of the fan group in addition to reasons such as DC bias magnetization effect and measurement system interference. Therefore, when selecting the installation position of the vibration acceleration sensor, the position near the fan group should be avoided to ensure that the transformer vibration signal is not contaminated by it.

[0070] S2.1: The calculation of the spectrum complexity includes using energy entropy as a measure. The energy entropy includes the degree of dispersion of the energies of each frequency component in the spectrum of the transformer sound signal. When the value of the degree of dispersion decreases, the spectrum energy is concentrated;

[0071] Otherwise, when the value of the degree of dispersion increases, the spectrum energy is dispersed;

[0072] The formula for the threshold of concentration or dispersion is:

[0073] ,

[0074] ,

[0075] Among them, represents the energy entropy, represents the th energy proportion of the frequency component, represents the th amplitude of the frequency component, represents the index variable, represents the total number of frequency components, represents the cumulative sum of the squares of the amplitudes of the frequency components, represents the th cumulative sum of the amplitudes of the frequency components.

[0076] S2.2: The identification based on DC bias magnetization and harmonic injection in the vibration time - frequency domain with the threshold includes identification methods, secondary identification, and feature differentiation.

[0077] The identification methods include analyzing based on the vibration amplitude, odd - even harmonic ratio, and spectrum complexity exceeding the threshold to exclude the influence of the fan.

[0078] When the odd - even harmonic ratio eigenvalue of the vibration sensor exceeds the threshold, there is a phenomenon of DC bias magnetization or harmonic injection. At this time, the factor of the fan is excluded.

[0079] When the eigenvalue of the odd - even harmonic ratio of the vibration data on the fan side exceeds the threshold, there is a phenomenon of DC bias or harmonic injection, and at this time, it is analyzed as a factor of the fan.

[0080] Furthermore, for harmonic injection: Generally, consider the common 3rd and 5th harmonics of the power grid. The abnormal enhancement of the low - order odd harmonics of 50Hz in the transformer sound signal is caused, generally within 1000Hz. In special cases (such as rail transit, etc.), certain specific orders of the odd harmonics of 50Hz will be enhanced.

[0081] For DC bias: There is a DC component in the system, resulting in the enhancement of all odd harmonics of 50Hz in the overall sound signal, and the stronger the DC bias, the more obvious this enhancement of the odd harmonics of 50Hz.

[0082] Generally speaking, our system generally first checks the odd - even multiple frequency ratio of 50hz, and then takes 1000hz as a dividing line. For the odd harmonics that are basically concentrated below 1k and have concentrated energy in only a few orders, it is calculated according to harmonic injection; for those with all orders, it is calculated according to bias.

[0083] S2.3: The secondary identification includes, after excluding the fan, performing secondary identification, making a judgment using the operation mode of the power system to find the sources of the DC source and the harmonic source.

[0084] The DC source has the single - pole ground operation mode of the DC project, and the harmonic sources are new - energy power stations and metallurgical plants. The generated harmonics will be transmitted to the main transformer through the wire.

[0085] Feature distinction includes that if the odd - even multiple frequency ratio of 50hz is high, it is considered harmonic injection or DC bias. Mark the part of the odd harmonics that exceeds 10db around, and calculate the proportion of the part before 1000hz of the odd harmonics in the total energy of the odd harmonics.

[0086] S3: Identify according to the DC bias and harmonic injection with the threshold in the vibration time - frequency domain.

[0087] Preferably, harmonic injection includes the 3rd and 5th harmonics of the power grid, which cause the abnormal enhancement of the low - order odd harmonics of 50Hz in the transformer sound signal, within 1000Hz.

[0088] DC bias includes that there is a DC component in the system, which enhances all odd harmonics of 50Hz in the overall sound signal, and the DC bias changes.

[0089] In a preferred embodiment, a system for identifying DC bias and harmonic injection of a transformer based on vibration technology, the system includes a face - deployment module, deploying acceleration sensors on three faces of the transformer except the fan side, collecting vibration data, and identifying the phenomena of DC bias and harmonic injection.

[0090] A quantization vibration mode module, which, after completing the deployment of an acceleration sensor, obtains vibration signals from the acceleration sensor, calculates eigenvalue, and quantizes the vibration mode.

[0091] A discrimination module for DC bias and harmonic injection of a transformer, which discriminates according to DC bias and harmonic injection with a threshold value in the vibration time domain and frequency domain.

[0092] Each of the above unit modules can be embedded in a processor in a computer device in hardware form or be independent of the processor, or can be stored in a memory in the computer device in software form, so as to facilitate the processor to call and execute operations corresponding to each of the above modules.

[0093] The computer device can be a terminal. The computer device includes a processor, a memory, a communication interface, a display screen, and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner. The wireless manner can be implemented through WIFI, a carrier network, NFC (Near Field Communication), or other technologies. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer covered on the display screen, or can be a button, a trackball, or a touchpad set on the shell of the computer device, or can also be an external keyboard, a touchpad, or a mouse, etc.

[0094] In summary, through the innovative application of vibration analysis technology, the present invention realizes the efficient identification and precise monitoring of the phenomena of DC bias and harmonic injection of a transformer. First, a multi-dimensional data coverage strategy is adopted to evenly deploy acceleration sensors on three surfaces of the transformer except the fan side, ensuring all-round and high-density data acquisition; secondly, the selection and configuration of intelligent sensors, especially sensors with an adaptive noise suppression function and independent data processing units, enable pure vibration signals to be obtained even in a complex environment, reducing the difficulty of subsequent data processing and the amount of calculation; the dynamic data acquisition strategy automatically adjusts the sampling frequency according to the operating state of the transformer to ensure that key information is not lost; the environmental interference elimination mechanism effectively distinguishes the vibration anomalies caused by DC bias and harmonic injection from the influence of other external factors, improving the diagnostic accuracy. In summary, the present invention not only improves the accuracy and reliability of fault detection, but also provides a solid guarantee for the stable operation of the power system, having significant technical advantages and broad application prospects.

[0095] Embodiment 2

[0096] Refer toFigures 1 to 2 , which is the second embodiment of the present invention. This embodiment provides a method for identifying DC bias and harmonic injection in transformers based on vibration technology. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through simulation experiments.

[0097] Feature discrimination includes that if the 50Hz odd-even multiple frequency ratio is high, it is considered harmonic injection or DC bias. Mark the odd harmonics that exceed 10dB around. Calculate the proportion of the part before 1000Hz in the total energy of odd harmonics. The data analysis of feature discrimination is shown in Table 1 below:

[0098] Table 1 Data analysis table of feature discrimination

[0099]

[0100] Continued Table 1

[0101]

[0102] According to the description in Table 1, after comparison with other values, the above data are finally selected: the 50Hz odd-even multiple frequency ratio, the 10dB threshold, and the proportion of odd harmonic energy before 1000Hz. These data can not only effectively identify the phenomena of DC bias and harmonic injection, but also maintain high detection accuracy and stability in complex environments.

[0103] The identification process data of the method for identifying DC bias and harmonic injection in transformers based on vibration technology are shown in Table 2 below:

[0104] Table 2 Data table of identification process

[0105]

[0106] Table 2 describes that these thresholds are used to monitor and evaluate the operating state of the transformer to ensure that it operates within a safe range.

[0107] The comparison between the present invention and the prior art is shown in Table 3 below:

[0108] Table 3 Comparison table between the present invention and the prior art

[0109]

[0110] Continued Table 3

[0111]

[0112] Table 3 shows that effective solutions are proposed for the deficiencies existing in the prior art, improving the monitoring accuracy and reliability of the phenomena of DC bias and harmonic injection in transformers, and providing strong support for the stable operation of the power system.

[0113] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. Identification method for DC bias and harmonic injection of transformer based on vibration technology, characterized in that: including Deploy acceleration sensors on three sides of the transformer except the fan side to collect vibration data and identify DC bias and harmonic injection phenomena; After the deployment of acceleration sensors is completed, calculate the eigenvalues from the vibration signals obtained from the acceleration sensors to quantify the vibration modes; Identify according to the DC bias and harmonic injection with the threshold in the vibration time domain and frequency domain.

2. The identification method of transformer DC bias and harmonic injection based on vibration technology according to claim 1, characterized in that: The deployment of acceleration sensors on three sides of the transformer except the fan side includes constructing a data acquisition framework, and the data acquisition framework includes multi-dimensional data coverage, intelligent sensor selection and configuration, dynamic data acquisition strategy, and environmental interference elimination mechanism; The multi-dimensional data coverage includes deploying acceleration sensors on three sides of the transformer except the fan side, arranging sensors evenly on each side to complete the data acquisition network; The intelligent sensor selection and configuration includes selecting acceleration sensors with adaptive noise suppression function and equipping each sensor with an independent data processing unit. This acceleration sensor automatically adjusts its sensitivity to complete different working environments and obtains vibration signals; The dynamic data acquisition strategy includes designing a dynamic data acquisition strategy according to the change of the transformer operation state. The dynamic data acquisition strategy allows the sensor to automatically adjust the sampling frequency according to the preset time interval or the detected vibration intensity change; The environmental interference elimination mechanism includes setting an additional group of reference sensors at a position close to the fan side to distinguish the vibration anomalies caused by DC bias and harmonic injection from the influence of external factors, and excluding the fan interference by comparing and analyzing the data differences between the data acquisition area and the reference area.

3. The identification method for DC bias and harmonic injection of a transformer based on vibration technology according to claim 1, wherein: The calculation of the eigenvalues includes vibration amplitude calculation, odd-even harmonic ratio calculation, and spectrum complexity calculation. The vibration amplitude calculation includes calculating the average intensity of the vibration signal in the time domain, and the specific formula is: ， Among them, represents the vibration amplitude, represents the vibration signal within a time period, represents the total length of the time period; The odd-even harmonic ratio calculation includes performing spectrum analysis on the collected vibration signals and paying attention to the proportional relationship between odd and even harmonics. The formula for the odd-even harmonic ratio calculation is: ， Among them, represents the odd-even harmonic ratio, represents the degree of odd harmonic components when the transformer has DC bias magnetization, represents the odd harmonic components when the transformer has DC bias magnetization.

4. The identification method of DC bias and harmonic injection of a transformer based on vibration technology according to claim 3, characterized in that: The spectrum complexity calculation includes using energy entropy as a measure. The energy entropy includes the degree of dispersion of the energies of each frequency component in the spectrum of the transformer sound signal. When the value of the degree of dispersion decreases, the spectrum energy is concentrated; Otherwise, when the value of the degree of dispersion increases, the spectrum energy is dispersed; The formula for the threshold of concentration or dispersion is: ， ， Among them, represents the energy entropy, represents the energy proportion of the th frequency component, represents the th amplitude of the frequency component, represents the index variable, represents the total number of frequency components, represents the sum of the squares of the amplitudes of the frequency components, represents the th sum of the amplitudes of the frequency components.

5. The identification method for DC bias and harmonic injection of a transformer based on vibration technology according to claim 1, characterized in that: The identification according to the DC bias and harmonic injection with the threshold in the vibration time domain and frequency domain includes identification method, secondary identification, and feature distinction; The identification method includes analyzing according to the vibration amplitude, odd-even harmonic ratio, and spectrum complexity exceeding the threshold and excluding the influence of the fan; When the odd-even harmonic ratio eigenvalue of the vibration sensor exceeds the threshold, there is a phenomenon of DC bias or harmonic injection. At this time, the factor of the fan is excluded; When the odd-even harmonic ratio eigenvalue of the vibration data on the fan side exceeds the threshold, there is a phenomenon of DC bias or harmonic injection. At this time, it is analyzed as the factor of the fan.

6. The identification method for DC bias and harmonic injection of a transformer based on vibration technology according to claim 5, characterized in that: The secondary identification includes performing secondary identification after excluding the fan, making a judgment with the operation mode of the power system, and finding the sources of the DC source and harmonic source; The DC source has a single-stage ground operation mode for DC projects, and the harmonic sources include new energy power stations and metallurgical plants. The generated harmonics will be transmitted to the main transformer through wires; The feature discrimination includes that if the odd-even multiple frequency ratio based on 50 Hz is high, it is considered harmonic injection or DC bias. Mark the odd harmonics that exceed 10 dB around, and calculate the proportion of the part before 1000 Hz of the odd harmonics in the total energy of the odd harmonics.

7. The identification method of DC bias and harmonic injection of a transformer based on vibration technology according to claim 6, characterized in that: The harmonic injection includes the 3rd and 5th harmonics of the power grid, which cause abnormal changes in the low-order odd harmonics of 50 Hz in the transformer sound signal within 1000 Hz; The DC bias includes the existence of a DC component in the system, which changes the odd harmonics of 50 Hz in the overall sound signal and the DC bias changes.

8. An identification system for DC bias and harmonic injection of a transformer based on vibration technology, based on the identification method for DC bias and harmonic injection of a transformer based on vibration technology according to any one of claims 1 to 7, characterized in that: Including, The face deployment module deploys acceleration sensors on three faces of the transformer except the fan side, collects vibration data, and identifies the phenomena of DC bias and harmonic injection; The quantization vibration mode module, after completing the deployment of the acceleration sensors, obtains vibration signals from the acceleration sensors, calculates eigenvalues, and quantizes the vibration mode; The identification module for transformer DC bias and harmonic injection, which identifies according to the DC bias and harmonic injection with the threshold in the vibration time domain frequency.

9. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the identification method for transformer DC bias and harmonic injection based on vibration technology according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the identification method for transformer DC bias and harmonic injection based on vibration technology according to any one of claims 1 to 7.

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