Transformer cooler cooling efficiency monitoring system, method and program product

Abstract

The invention relates to the technical field of transformer coolers, in particular to a transformer cooler cooling efficiency monitoring system and method and a program product, and the method comprises the steps: obtaining an inlet oil temperature, an outlet oil temperature, an environment temperature, an actual flow, a load current and a vibration signal of a cooler; calculating the initial cooling efficiency of the cooler; calculating the total thermal load of the transformer based on the load current; calculating a vibration health index of the cooler oil pump based on the vibration signal; correcting the initial cooling efficiency in combination with the total heat load and the vibration health index to obtain final cooling efficiency; according to the method, the evaluation accuracy of the cooling efficiency of the transformer is improved by integrating real-time monitoring of various parameters, the running state of the cooler can be reflected more accurately, transformer faults caused by insufficient cooling are effectively prevented, the service life of equipment is prolonged, and the maintenance cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer coolers, and in particular to a transformer cooler cooling efficiency monitoring system, method and program product. Background Art

[0002] Traditional transformer cooler efficiency monitoring relies heavily on empirical judgment, lacks systematicity and accuracy, and is difficult to achieve real-time monitoring. Existing technologies can usually only monitor a single parameter, and fail to comprehensively consider the impact of multiple factors such as flow, temperature, and load current on cooling efficiency. In addition, vibration signal monitoring is not fully utilized in the health assessment of the cooling system. With the increasing requirements for transformer operation safety and reliability, there is an urgent need for a monitoring system that can comprehensively collect multiple operating parameters and calculate the cooling efficiency in real time to achieve a comprehensive assessment of the transformer cooling status. Summary of the invention

[0003] The technical problem to be solved by the present invention is that the existing transformer cooler efficiency monitoring means are insufficient and cannot comprehensively and real-time evaluate the cooling effect, thus affecting the safe operation and maintenance of the transformer. The purpose is to provide a transformer cooler cooling efficiency monitoring system, method and program product, which realizes real-time monitoring and efficiency evaluation of the cooler operating status, and can comprehensively consider multiple factors such as inlet oil temperature, outlet oil temperature, flow rate, load current and vibration signal, so as to improve the accuracy and reliability of cooling efficiency monitoring, thereby providing a strong guarantee for the safe operation of the transformer. .

[0004] The present invention is achieved through the following technical solutions:

[0005] A transformer cooler cooling efficiency monitoring system, comprising:

[0006] A temperature acquisition module is installed at the oil outlet of the cooler, the oil inlet of the cooler and the outside of the cooler. The temperature acquisition module is used to obtain the inlet oil temperature of the cooler, the outlet oil temperature of the cooler and the ambient temperature;

[0007] A flow collection module is installed at the oil outlet of the cooler and is used to collect the actual flow of the cooler;

[0008] The current acquisition module is installed in the transformer control box and connected to the transformer CT signal. The current acquisition module is used to obtain the load current of the transformer;

[0009] A vibration collection module, which is installed on the cooler oil pump, and is used to obtain a vibration signal of the cooler oil pump;

[0010] A data processing module, whose data input end is electrically connected to the data output ends of the temperature acquisition module, the flow acquisition module, the current acquisition module and the vibration acquisition module, and the data processing module calculates the cooling efficiency of the cooler based on the acquired inlet oil temperature, outlet oil temperature, load current and vibration signal;

[0011] The monitoring module has a data input terminal electrically connected to a data output terminal of the data processing module. The monitoring module is used to compare the calculated cooling efficiency with a threshold value and output the operating status of the cooler.

[0012] A transformer cooler cooling efficiency monitoring method is based on the transformer cooler cooling efficiency monitoring system as described above, and the monitoring method comprises:

[0013] Obtain the inlet oil temperature, outlet oil temperature and ambient temperature of the cooler;

[0014] Get the actual flow rate of the cooler;

[0015] Obtain the load current of the transformer;

[0016] Obtain the vibration signal of the cooler oil pump;

[0017] Perform timing synchronization and preprocessing on actual flow, inlet oil temperature, outlet oil temperature, load current and vibration signals;

[0018] Calculate the preliminary cooling efficiency of the cooler based on the inlet oil temperature, outlet oil temperature and actual flow rate;

[0019] Calculate the total thermal load of the transformer based on the load current;

[0020] Calculate the vibration health index of the cooler oil pump based on the vibration signal;

[0021] The preliminary cooling efficiency is corrected based on the total heat load and vibration health index to obtain the final cooling efficiency.

[0022] Specifically, the method for calculating the preliminary cooling efficiency of the cooler includes:

[0023] Calculate the flow correction factor φ for the cooler flow , Among them, Q is the actual flow rate of the cooler, Q norm is the design flow rate of the cooler;

[0024] Calculate the heat loss correction factor φ of the cooler loss , Among them, e is a natural constant, h is the convection heat transfer coefficient, A is the heat transfer area of ​​the cooler, k is the heat conduction coefficient, T in is the cooler inlet oil temperature, T amb is the ambient temperature;

[0025] Calculate the preliminary cooling efficiency η of the cooler initial , Among them, T out is the cooler outlet oil temperature.

[0026] Specifically, the calculation method of the total heat load of the transformer includes:

[0027] Calculate the real-time resistance R of the transformer winding at the winding temperature T wT , R wT =R w0 [1+α Cu (T-T0)], where R wo is the winding resistance at reference temperature T0, α Cu is the temperature resistivity of copper;

[0028] Based on the skin effect coefficient k skin and the proximity effect coefficient k proximtiy Correct the winding resistance to obtain the corrected effective winding resistance R w，eff , R w，eff =R wT ·(1+k skin +k proximity );

[0029] Calculate the transformer winding loss, that is, the copper loss P Cu , P Cu =3I 2 R w，eff , where I is the transformer load current;

[0030] Calculate the transformer core loss, i.e. iron loss P Fe , Among them, V Fe is the core volume, k h is the hysteresis loss coefficient, n h is the hysteresis loss index, k e is the eddy current loss coefficient, d is the thickness of the iron core, B m is the magnetic flux density, f is the frequency;

[0031] Calculate the transformer stray loss P stray , P stray =k stray P Cu , where k stray is the stray loss coefficient;

[0032] Calculate the total heat load P of the transformer total , P total =P Cu +P Fe +P stray .

[0033] Specifically, the calculation method of the vibration health index of the cooler oil pump includes:

[0034] The pre-processed vibration signal is extracted in the time domain to obtain the root mean square value RMS and peak value V peak and kurtosis K, V peak =max(V(t)), Among them, V(t) is the vibration signal after preprocessing, V(t i ) is the vibration signal at the i-th timestamp, and N is the number of timestamps;

[0035] The pre-processed vibration signal is subjected to frequency domain feature extraction to obtain the spectrum energy E. Among them, f low is the lowest frequency of vibration, f high is the highest vibration frequency, V(f) is the representation of the vibration signal in the frequency domain;

[0036] Calculate the vibration health index HI, HI = w1·RMS + w2·V peak +w3·K+w4·E, where w1, w2, w3, and w4 are weight coefficients.

[0037] Specifically, the method for obtaining the final cooling efficiency includes:

[0038] Calculate the heat load correction factor φ from the total heat load of the transformer load , Among them, k load is the heat load influence coefficient, P total is the total heat load of the transformer, P norm is the rated thermal load of the transformer;

[0039] Calculate the vibration correction factor φ through the vibration health index of the cooler oil pump vib , Among them, k vib is the heat load influence coefficient, HI is the actual vibration health index of the cooler oil pump, HI norm is the vibration health index of the transformer under normal conditions;

[0040] Establish a correction model to obtain the final cooling efficiency η final , η final =η initial ×φ load ×φ vib .

[0041] Optionally, a cooling efficiency threshold is set, and if the final cooling efficiency is lower than the cooling efficiency threshold, it is determined that the cooling efficiency is insufficient.

[0042] Specifically, the method for performing timing synchronization and preprocessing includes:

[0043] The actual flow rate, inlet oil temperature, outlet oil temperature, load current and vibration signal are collected at the same time interval and the timestamp is recorded;

[0044] Convert all signal data into a unified time format and use interpolation to process inconsistent time data so that all signal data have the same time base;

[0045] All signal data were subjected to filter denoising and Z-score normalization;

[0046] All processed data are integrated to obtain a data set.

[0047] Furthermore, it also includes judging the preliminary cooling efficiency based on the total heat load, and the judging method includes:

[0048] Calculate the overall heat transfer coefficient U of the cooler, Among them, h in is the convection heat transfer coefficient in the tube, h out is the convection heat transfer coefficient outside the tube, δ is the tube wall thickness, k w is the thermal conductivity of the pipe wall material, R f It is the heat resistance of oil scale;

[0049] Calculate the heat Q removed by the cooler removed , Where A is the heat dissipation area of ​​the cooler, T in is the cooler inlet oil temperature, T out is the cooler outlet oil temperature, T amb is the ambient temperature;

[0050] Calculate the comparative cooling efficiency η of the cooler cool ,

[0051] Setting error Δ, if |η initial -η cool |<Δ, the preliminary cooling efficiency calculation is judged to be normal; if |η initial -η cool |≥Δ, the preliminary cooling efficiency calculation is judged to be abnormal.

[0052] A computer program product comprises a computer program / instruction, wherein when the computer program / instruction is executed by a processor, the method described in any one of the above items is implemented.

[0053] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0054] The system of the present invention mainly includes a temperature acquisition module, a flow acquisition module, a current acquisition module and a vibration acquisition module. Through sensors installed at various parts of the cooler and the transformer, the inlet oil temperature, the outlet oil temperature, the actual flow, the load current and the oil pump vibration signal are collected in real time. The data processing module calculates the preliminary cooling efficiency based on these data, and corrects the efficiency in combination with the load current and the vibration signal, and finally outputs the final cooling efficiency of the cooler. The monitoring module compares the calculated cooling efficiency with the set threshold to determine whether the cooling effect meets the requirements.

[0055] The present invention improves the accuracy of transformer cooling efficiency assessment by integrating real-time monitoring of multiple parameters. The present invention can more accurately reflect the operating status of the cooler and effectively prevent transformer failures caused by insufficient cooling, thereby extending the service life of the equipment and reducing maintenance costs. At the same time, the system's automated monitoring capabilities provide strong support for the safe operation of the transformer, ensuring its stability and reliability under high-load operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention, and the accompanying drawings are included in and constitute a part of this specification and do not constitute a limitation of the embodiments of the present invention.

[0057] Figure 1 The present invention is a structural block diagram of a transformer cooler cooling efficiency monitoring system.

[0058] Figure 2 It is a flow chart of a transformer cooler cooling efficiency monitoring method according to the present invention. DETAILED DESCRIPTION

[0059] To make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation methods. It is understood that the specific implementation methods described herein are only used to explain the relevant content, rather than to limit the present invention.

[0060] It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the drawings.

[0061] In the absence of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0062] Embodiment 1

[0063] like Figure 1As shown, this embodiment provides a transformer cooler cooling efficiency monitoring system, including:

[0064] The temperature acquisition module is installed at the oil outlet, oil inlet and outside of the cooler. The temperature acquisition module is used to obtain the inlet oil temperature, outlet oil temperature and ambient temperature of the cooler. A thermocouple or PT100 temperature sensor can be used, which has the advantages of fast response and high precision and is suitable for real-time temperature monitoring.

[0065] The flow acquisition module is installed at the oil outlet of the cooler. The flow acquisition module is used to collect the actual flow of the cooler. A turbine flowmeter or an electromagnetic flowmeter can be selected, which can provide higher flow measurement accuracy and is suitable for oil fluids.

[0066] The current acquisition module is installed in the control box of the transformer and connected to the transformer CT signal. The current acquisition module is used to obtain the load current of the transformer. The Hall effect current sensor can be used to measure the current value without interfering with the current, and has good linearity and a wide range.

[0067] The vibration collection module is installed on the cooler oil pump and is used to obtain the vibration signal of the cooler oil pump. An accelerometer or a vibration sensor can be selected to detect the vibration of the oil pump during operation, thereby reflecting its health status.

[0068] The data processing module has a data input terminal electrically connected to the data output terminals of the temperature acquisition module, the flow acquisition module, the current acquisition module and the vibration acquisition module. The data processing module calculates the cooling efficiency of the cooler based on the acquired inlet oil temperature, outlet oil temperature, load current and vibration signal. An embedded microprocessor can be used, which has strong computing and data processing capabilities.

[0069] The monitoring module has a data input terminal electrically connected to a data output terminal of the data processing module. The monitoring module is used to compare the calculated cooling efficiency with the threshold value and output the operating status of the cooler. A graphic display module or an LED indicator light can be used to intuitively display the operating status.

[0070] Embodiment 2

[0071] A transformer cooler cooling efficiency monitoring method is based on the transformer cooler cooling efficiency monitoring system as described above, and the monitoring method comprises:

[0072] Obtain the inlet oil temperature, outlet oil temperature and ambient temperature of the cooler;

[0073] Get the actual flow rate of the cooler;

[0074] Get the load current of the transformer; the load current directly affects the heating of the transformer.

[0075] Obtain the vibration signal of the cooler oil pump; the vibration signal reflects the operating status and health of the oil pump.

[0076] The actual flow rate, inlet oil temperature, outlet oil temperature, load current and vibration signal are synchronized and preprocessed; the timing synchronization can ensure that each data remains consistent in time, and the preprocessing includes filtering, denoising and standardization.

[0077] Calculate the preliminary cooling efficiency of the cooler based on the inlet oil temperature, outlet oil temperature and actual flow rate;

[0078] Calculate the total thermal load of the transformer based on the load current; this involves calculating the winding losses, core losses and stray losses to obtain the combined thermal load of the transformer.

[0079] The vibration health index of the cooler oil pump is calculated based on the vibration signal; the operating health of the oil pump is evaluated by extracting time domain and frequency domain features.

[0080] The preliminary cooling efficiency is corrected based on the total heat load and vibration health index to obtain the final cooling efficiency.

[0081] Embodiment 3

[0082] This embodiment provides a method for calculating the preliminary cooling efficiency in the second embodiment, the method comprising:

[0083] Calculate the flow correction factor φ of the cooler according to the flow conditions of the cooler flow , Among them, Q is the actual flow rate of the cooler, Q norm is the design flow of the cooler; the flow correction factor is used to evaluate the impact of flow deviation on cooling efficiency. The closer the flow is to the design value, the closer the correction factor is to 1.

[0084] Calculate the heat loss correction factor φ of the cooler based on the heat loss of the cooler loss , Among them, e is a natural constant, which is approximately equal to 2.718, h is the convection heat transfer coefficient, which represents the heat exchange capacity between the fluid and the solid surface, A is the heat transfer area of ​​the cooler, k is the thermal conductivity coefficient, which is a parameter describing the thermal conductivity of the material and can be obtained by consulting references or related manuals, T in is the cooler inlet oil temperature, T amb is the ambient temperature.

[0085] The convective heat transfer coefficient can be calculated based on the flow characteristics (laminar or turbulent) and fluid properties (viscosity, density, thermal conductivity, etc.) of the fluid using appropriate correlation formulas (such as the Nusselt number formula). Nu is the Nusselt number, and L0 is the characteristic length of laminar flow.

[0086] After obtaining the flow correction factor and heat loss correction factor, calculate the initial cooling efficiency η of the cooler initial , Among them, T out is the cooler outlet oil temperature.

[0087] Embodiment 4

[0088] This embodiment provides a method for calculating the total heat load of the transformer in Embodiment 2, the method comprising:

[0089] Calculate the real-time resistance r of the transformer winding at the winding temperature T wT , R wT =R w0 [1+α Cu (T-T0)], where R wo is the winding resistance at reference temperature T0, usually obtained through experimental measurement, α Cu is the temperature resistivity of copper, usually 0.00393℃ -1 .

[0090] Based on the skin effect coefficient k skin and the proximity effect coefficient k proximtiy Correct the winding resistance to obtain the corrected effective winding resistance R w,eff , R w,eff =R wT ·(1+k skin +k proximity ); Skin effect coefficient k skin and the proximity effect coefficient k proximtiy It can be estimated through electromagnetic field theory and experiment and is usually related to frequency and conductor geometry.

[0091] Calculate the transformer winding loss, that is, the copper loss P Cu , P Cu =3I 2 R w,eff , where I is the transformer load current.

[0092] Calculate the transformer core loss, i.e. iron loss P Fe , Among them, V Fe is the core volume obtained from the design parameters, k n is the hysteresis loss coefficient obtained through material testing, n h is the hysteresis loss index obtained through material testing, k e is the eddy current loss coefficient obtained through material testing, d is the thickness of the iron core, B mis the magnetic flux density, f is the frequency; the remaining parameters can be obtained from the design documentation.

[0093] Calculate the transformer stray loss P stray , P stray =k stray P Cu , where k stray is the stray loss coefficient, obtained through experiments or experience.

[0094] Calculate the total heat load P of the transformer total , P total =P Cu +P Fe +P stray The total heat load refers to the total heat generated by the transformer during operation, including copper loss caused by current passing through the winding, magnetic loss of the core, and other possible stray losses. The total heat load is actually the heat that the cooler needs to handle and dissipate to ensure that the transformer is not damaged by overheating. An effective cooling system can keep the transformer running safely within the range of the total heat load.

[0095] Embodiment 5

[0096] This embodiment provides a method for calculating the vibration health index of the cooler oil pump in the second embodiment, and the method includes:

[0097] The preprocessed vibration signal is subjected to time domain feature extraction to obtain the root mean square value RMS used to evaluate the energy level of the vibration signal and the maximum instantaneous peak value V representing the vibration signal. peak and the kurtosis K that describes the sharpness of the vibration signal, V peak =max(V(t)), Among them, V(t) is the vibration signal after preprocessing, V(t i ) is the vibration signal at the i-th timestamp, and N is the number of timestamps;

[0098] The time domain signal is converted to the frequency domain through Fourier transform, the spectrum energy of the signal is calculated, and the frequency domain features of the pre-processed vibration signal are extracted to obtain the spectrum energy E. Among them, f low is the lowest frequency of vibration, f high is the highest vibration frequency, and V(f) is the representation of the vibration signal in the frequency domain.

[0099] Calculate the vibration health index HI, HI = w1·RMS + w2·V peak+w3·K+w4·E, where w1, w2, w3, and w4 are weight coefficients, which are adjusted according to the influence of different characteristics on the overall health index. The weights can be obtained through experiments or historical data analysis to ensure that the health index can effectively reflect the status of the device.

[0100] Embodiment 6

[0101] The final cooling efficiency is obtained by:

[0102] Calculate the heat load correction factor φ from the total heat load of the transformer load , Among them, k load is the heat load influence coefficient, P total is the total heat load of the transformer, P norm is the rated heat load of the transformer; the correction factor can be used to adjust the initial cooling efficiency to make it more in line with actual working conditions by taking into account the performance changes of the transformer under different loads.

[0103] Calculate the vibration correction factor φ through the vibration health index of the cooler oil pump vib , Among them, k vib is the heat load influence coefficient, HI is the actual vibration health index of the cooler oil pump, HI norm It is the vibration health index of the transformer under normal conditions; the vibration correction factor is intended to adjust the cooling efficiency according to the vibration state of the oil pump to ensure that the calculation of the cooling efficiency can reflect potential problems when abnormal vibration occurs in the oil pump.

[0104] Establish a correction model to obtain the final cooling efficiency η final , η final =η initial ×φ load ×φ vib .

[0105] A cooling efficiency threshold is set. If the final cooling efficiency is lower than the cooling efficiency threshold, it is determined that the cooling efficiency is insufficient.

[0106] In order to ensure the safety and efficient operation of the transformer, a threshold of cooling efficiency is set. If the final cooling efficiency calculated is lower than this threshold, the cooling efficiency is judged to be insufficient. This mechanism can detect problems in the cooling system in time and perform maintenance or adjustments to prevent damage caused by overheating of the equipment.

[0107] In addition, in order to further increase the protection of the transformer, two thresholds can be set, including warning value and control value. When the cooling efficiency is lower than the warning value, the system will issue an early warning. When the cooling efficiency is lower than the control value, the system will trigger an alarm and it is recommended to check immediately.

[0108] Embodiment 7

[0109] This embodiment provides a method for performing timing synchronization and preprocessing, including:

[0110] The actual flow rate, inlet oil temperature, outlet oil temperature, load current and vibration signal are collected at the same time interval (such as every second, every minute, etc.), and the corresponding timestamp is recorded at each collection. Ensure that all data acquisition devices are time synchronized to reduce the impact of time differences on subsequent analysis.

[0111] Convert all signal data into a unified time format (such as ISO 8601 format). For time inconsistencies between different signals, use interpolation methods (such as linear interpolation or spline interpolation) to process missing or inconsistent data so that all signal data have the same time reference, thereby ensuring that the data of each signal corresponds to each other at the same time point, which is convenient for subsequent analysis.

[0112] All signal data are subjected to filter denoising and Z-score standardization processing; commonly used filtering methods include low-pass filters, Kalman filters, etc. Denoising processing can effectively remove high-frequency noise and improve signal quality; standardization processing makes data with different characteristics have the same scale.

[0113] Integrate all processed data to obtain a data set. Integrate all pre-processed signal data into a unified data set, including information such as timestamp, flow, oil temperature, load current, and vibration signal.

[0114] Embodiment 8

[0115] Based on the second embodiment, a method for judging the preliminary cooling efficiency based on the total heat load is provided to judge the accuracy of the preliminary cooling efficiency. The judging method includes:

[0116] Calculate the overall heat transfer coefficient U of the cooler, Among them, h in is the convection heat transfer coefficient in the tube, which is usually obtained by calculating the fluid mechanics characteristics. out is the convection heat transfer coefficient outside the tube, which is determined according to the environmental conditions and flow state. δ is the tube wall thickness, k w is the thermal conductivity of the pipe wall material, R f is the oil scale thermal resistance; the total heat transfer coefficient is used to evaluate the heat exchange capacity of the cooler.

[0117] Calculate the heat Q removed by the cooler removed , Where A is the heat dissipation area of ​​the cooler, T in is the cooler inlet oil temperature, T outis the cooler outlet oil temperature, T awb is the ambient temperature;

[0118] Calculate the comparative cooling efficiency η of the cooler cool ,

[0119] Setting error Δ, if |η initial -n cool |<Δ, the preliminary cooling efficiency calculation is considered normal; if |η initial -n cool |≥Δ, the calculation of the preliminary cooling efficiency is judged to be abnormal. If the preliminary cooling efficiency appears, it proves that there may be a sensor or other device failure in the entire system, and necessary adjustment measures need to be taken to reduce the risk of failure.

[0120] Embodiment 9

[0121] A computer program product comprises a computer program / instruction, wherein when the computer program / instruction is executed by a processor, the method described in any one of the above items is implemented.

[0122] A computer program product includes a computer program or set of instructions for performing specific tasks or achieving specific functions. These programs or instructions are designed to be executed by a processor to implement a series of predefined steps or operations. The program product may be stored in various forms of computer storage media, such as memory, hard disk, solid-state drive, optical disk or other forms of digital storage devices. It may exist in the form of compiled binary code or in the form of scripts or bytecodes that can be executed by an interpreter. The program product uses carefully designed algorithms and logical instructions to enable the processor to process data in a specific order and manner to complete various functions such as data analysis, user interaction, device control, etc.

[0123] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0124] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0125] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above invention, and these changes or modifications are still within the scope of the present invention.

Claims

1. A transformer cooler cooling efficiency monitoring system, characterized in that: include: A temperature acquisition module is installed at the oil outlet of the cooler, the oil inlet of the cooler and the outside of the cooler. The temperature acquisition module is used to obtain the inlet oil temperature of the cooler, the outlet oil temperature of the cooler and the ambient temperature; A flow collection module is installed at the oil outlet of the cooler and is used to collect the actual flow of the cooler; The current acquisition module is installed in the transformer control box and connected to the transformer CT signal. The current acquisition module is used to obtain the load current of the transformer; A vibration collection module, which is installed on the cooler oil pump, and is used to obtain a vibration signal of the cooler oil pump; A data processing module, whose data input end is electrically connected to the data output ends of the temperature acquisition module, the flow acquisition module, the current acquisition module and the vibration acquisition module, and the data processing module calculates the cooling efficiency of the cooler based on the acquired inlet oil temperature, outlet oil temperature, load current and vibration signal; The monitoring module has a data input terminal electrically connected to a data output terminal of the data processing module. The monitoring module is used to compare the calculated cooling efficiency with a threshold value and output the operating status of the cooler.

2. A method for monitoring cooling efficiency of a transformer cooler, characterized in that: Based on the transformer cooler cooling efficiency monitoring system according to claim 1, the monitoring method comprises: Obtain the inlet oil temperature, outlet oil temperature and ambient temperature of the cooler; Get the actual flow rate of the cooler; Obtain the load current of the transformer; Obtain the vibration signal of the cooler oil pump; Perform timing synchronization and preprocessing on actual flow, inlet oil temperature, outlet oil temperature, load current and vibration signals; Calculate the preliminary cooling efficiency of the cooler based on the inlet oil temperature, outlet oil temperature and actual flow rate; Calculate the total thermal load of the transformer based on the load current; Calculate the vibration health index of the cooler oil pump based on the vibration signal; The preliminary cooling efficiency is corrected based on the total heat load and vibration health index to obtain the final cooling efficiency.

3. A transformer cooler cooling efficiency monitoring method according to claim 2, characterized in that: Methods for calculating the preliminary cooling efficiency of a chiller include: Calculate the flow correction factor φ for the cooler flow , Among them, Q is the actual flow rate of the cooler, Q norm is the design flow rate of the cooler; Calculate the heat loss correction factor φ of the cooler loss , Among them, e is a natural constant, h is the convection heat transfer coefficient, A is the heat transfer area of ​​the cooler, k is the heat conduction coefficient, T in is the cooler inlet oil temperature, T amb is the ambient temperature; Calculate the preliminary cooling efficiency η of the cooler initial , Among them, T out is the cooler outlet oil temperature.

4. A transformer cooler cooling efficiency monitoring method according to claim 2, characterized in that: The calculation method of the total heat load of the transformer includes: Calculate the real-time resistance R of the transformer winding at the winding temperature T wT , R wT =R w0 [1+α Cu (T-T0)], where R wo is the winding resistance at reference temperature T0, α Cu is the temperature resistivity of copper; Based on the skin effect coefficient k skin and the proximity effect coefficient k proximtiy Correct the winding resistance to obtain the corrected effective winding resistance R w,eff , R w，eff =R wT ·(1+k skin +k proximity ); Calculate the transformer winding loss, that is, the copper loss P Cu , P Cu =3I 2 R w,eff , where I is the transformer load current; Calculate the transformer core loss, i.e. iron loss P Fe , Among them, V Fe is the core volume, k h is the hysteresis loss coefficient, n h is the hysteresis loss index, k e is the eddy current loss coefficient, d is the thickness of the iron core, B m is the magnetic flux density, f is the frequency; Calculate the transformer stray loss P stray , P stray =k stray P Cu , where k stray is the stray loss coefficient; Calculate the total heat load P of the transformer total , P total =P Cu +P Fe +P stray .

5. A transformer cooler cooling efficiency monitoring method according to claim 2, characterized in that: The calculation method of the vibration health index of the cooler oil pump includes: The pre-processed vibration signal is extracted in the time domain to obtain the root mean square value RMS and peak value V peak and kurtosis K, V peak =max(V(t)), Among them, V(t) is the vibration signal after preprocessing, V(t i ) is the vibration signal at the i-th timestamp, and N is the number of timestamps; The pre-processed vibration signal is subjected to frequency domain feature extraction to obtain the spectrum energy E. Among them, f low is the lowest frequency of vibration, f high is the highest vibration frequency, V(f) is the representation of the vibration signal in the frequency domain; Calculate the vibration health index HI, HI = w1·RMS + w2·V peak +w3·K+w4·E, where w1, w2, w3, and w4 are weight coefficients.

6. A transformer cooler cooling efficiency monitoring method according to claim 2, characterized in that: The final cooling efficiency is obtained by: The heat load correction factor φload is calculated by the total heat load of the transformer, Among them, k load is the heat load influence coefficient, P total is the total heat load of the transformer, P norm is the rated thermal load of the transformer; Calculate the vibration correction factor φ through the vibration health index of the cooler oil pump vib , Among them, k vib is the heat load influence coefficient, HI is the actual vibration health index of the cooler oil pump, HI norm is the vibration health index of the transformer under normal conditions; Establish a correction model to obtain the final cooling efficiency η final , η final =η initial ×φ load ×φ vib .

7. A transformer cooler cooling efficiency monitoring method according to claim 2, characterized in that: A cooling efficiency threshold is set. If the final cooling efficiency is lower than the cooling efficiency threshold, it is determined that the cooling efficiency is insufficient.

8. A transformer cooler cooling efficiency monitoring method according to claim 2, characterized in that: Methods for timing synchronization and preprocessing include: The actual flow rate, inlet oil temperature, outlet oil temperature, load current and vibration signal are collected at the same time interval and the timestamp is recorded; Convert all signal data into a unified time format and use interpolation to process inconsistent time data so that all signal data have the same time base; All signal data were subjected to filter denoising and Z-score normalization; All processed data are integrated to obtain a data set.

9. A method for monitoring cooling efficiency of a transformer cooler according to claim 4, characterized in that: The preliminary cooling efficiency is judged based on the total heat load. The judgment methods include: Calculate the overall heat transfer coefficient U of the cooler, Among them, h in is the convection heat transfer coefficient in the tube, h out is the convection heat transfer coefficient outside the tube, δ is the tube wall thickness, k w is the thermal conductivity of the pipe wall material, R f It is the oil scale thermal resistance; Calculate the heat Q removed by the cooler removed , Where A is the heat dissipation area of ​​the cooler, T in is the cooler inlet oil temperature, T out is the cooler outlet oil temperature, T amb is the ambient temperature; Calculate the comparative cooling efficiency η of the cooler cool , Setting error Δ, if |η initial -n cool |<Δ, the preliminary cooling efficiency calculation is judged to be normal; if |η initial -n cool |≥Δ, the preliminary cooling efficiency calculation is judged to be abnormal.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the method according to any one of claims 2 to 9 is implemented.

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