A transformer cooler cooling efficiency monitoring system, method, and program product

Abstract

The present application relates to the technical field of transformer cooler, in particular to a kind of transformer cooler cooling efficiency monitoring system, method and program product, method includes: obtaining the inlet oil temperature, outlet oil temperature, ambient temperature, actual flow, load current, vibration signal of cooler;Calculate the preliminary cooling efficiency of cooler;Based on load current, the total heat load of transformer is calculated;Based on vibration signal, the vibration health index of cooler oil pump is calculated;Combined with total heat load and vibration health index, preliminary cooling efficiency is corrected, and final cooling efficiency is obtained;The present application improves the evaluation accuracy of transformer cooling efficiency by real-time monitoring of a variety of parameters, the present application can more accurately reflect the running state of cooler, effectively prevent the transformer failure caused by insufficient cooling, thereby prolong the service life of equipment and reduce maintenance cost.

Description

Technical Field

[0001] This invention relates to the field of transformer cooler technology, and specifically to a transformer cooler cooling efficiency monitoring system, method, and program product. Background Technology

[0002] Traditional transformer cooler efficiency monitoring relies heavily on experience-based judgment, lacking systematicity and accuracy, and making real-time monitoring difficult. Existing technologies typically monitor only a single parameter, failing to comprehensively consider the impact of multiple factors such as flow rate, temperature, and load current on cooling efficiency. Furthermore, vibration signal monitoring is not fully utilized in the health assessment of cooling systems. With increasingly stringent requirements for transformer operational safety and reliability, there is an urgent need for a monitoring system capable of comprehensively collecting multiple operating parameters and calculating cooling efficiency in real time to achieve a comprehensive assessment of the transformer's cooling status. Summary of the Invention

[0003] The technical problem this invention aims to solve is the inadequacy of existing transformer cooler efficiency monitoring methods, which fail to comprehensively and in real-time assess the cooling effect, thus affecting the safe operation and maintenance of transformers. The purpose is to provide a transformer cooler cooling efficiency monitoring system, method, and program product that enables real-time monitoring and efficiency assessment of the cooler's operating status. It comprehensively considers multiple factors such as inlet oil temperature, outlet oil temperature, flow rate, load current, and vibration signals, improving the accuracy and reliability of cooling efficiency monitoring, thereby providing strong protection for the safe operation of transformers.

[0004] This invention is achieved through the following technical solution:

[0005] A transformer cooler cooling efficiency monitoring system includes:

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

[0007] The flow acquisition module is installed at the oil outlet of the cooler and is used to collect the actual flow rate of the cooler.

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

[0009] The vibration acquisition module is installed on the cooler oil pump and is used to acquire the vibration signal of the cooler oil pump.

[0010] The data processing module has its data input terminal electrically connected to the data output terminals of the temperature acquisition module, flow acquisition module, current acquisition module and vibration acquisition module. Based on the acquired inlet oil temperature, outlet oil temperature, load current and vibration signal, the data processing module calculates the cooling efficiency of the cooler.

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

[0012] A method for monitoring the cooling efficiency of a transformer cooler, based on a transformer cooler cooling efficiency monitoring system as described above, the monitoring method comprising:

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

[0014] Obtain 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] The actual flow rate, inlet oil temperature, outlet oil temperature, load current, and vibration signals are synchronized and preprocessed in time.

[0018] The initial cooling efficiency of the cooler is calculated 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 vibration signals;

[0021] The initial cooling efficiency is corrected by combining the total heat load and vibration health index to obtain the final cooling efficiency.

[0022] Specifically, methods for calculating the initial cooling efficiency of a cooler include:

[0023] Calculate the flow correction factor φ of the cooler flow , Where Q is the actual flow rate of the cooler, Q norm The design flow rate of the cooler;

[0024] Calculate the heat loss correction factor φ for the cooler loss , Where e is the natural constant, h is the convective heat transfer coefficient, A is the heat transfer area of ​​the cooler, k is the thermal conductivity coefficient, and T in T represents the inlet oil temperature of the cooler. amb Ambient temperature;

[0025] Calculate the initial cooling efficiency η of the cooler initial , Among them, T out This refers to the oil temperature at the cooler outlet.

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

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

[0028] Based on the skin effect coefficient k skin and 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 winding losses of the transformer, i.e., the copper loss P. Cu P Cu =3I 2 R w，eff Where I is the transformer load current;

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

[0031] Calculate the stray loss P of the transformer. stray P stray =k stray P Cu , where k stray This 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 for the vibration health index of the cooler oil pump includes:

[0034] Time-domain features were extracted from the preprocessed vibration signal to obtain the root mean square (RMS) value and peak value (V). peak and kurtosis K, V peak =max(V(t)), Where V(t) is the preprocessed vibration signal, V(t) i () represents the vibration signal at the i-th timestamp, and N is the number of timestamps;

[0035] Frequency domain features are extracted from the preprocessed vibration signal to obtain the spectral energy E. Among them, f low f is the lowest frequency of vibration. high V(f) represents the highest frequency of vibration, and V(f) is the frequency domain representation of the vibration signal.

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

[0037] Specifically, the methods for achieving the final cooling efficiency include:

[0038] The heat load correction factor φ is calculated based on the total heat load of the transformer. load , Where, k load P is the heat load influence coefficient. total P represents the total heat load of the transformer. norm This is the rated heat load of the transformer;

[0039] The vibration correction factor φ is calculated using the vibration health index of the cooler oil pump. vib , Where, k vib HI is the heat load influence coefficient, and HI is the actual vibration health index of the cooler oil pump. norm This refers to the vibration health index of a transformer under normal conditions.

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

[0041] Optionally, a cooling efficiency threshold can be set. If the final cooling efficiency is lower than the cooling efficiency threshold, the cooling efficiency is determined to be insufficient.

[0042] Specifically, methods for timing synchronization and preprocessing include:

[0043] The actual flow rate, inlet oil temperature, outlet oil temperature, load current, and vibration signal were collected at the same time intervals, and the timestamps were recorded.

[0044] All signal data are converted into a uniform time format, and interpolation is used to process data with inconsistent time, so that all signal data have the same time base;

[0045] All signal data are subjected to filter denoising and Z-score normalization.

[0046] The dataset is obtained by integrating all the processed data.

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

[0048] Calculate the overall heat transfer coefficient U of the cooler. Among them, h in h is the convective heat transfer coefficient inside the pipe. out δ is the external convective heat transfer coefficient, δ is the tube wall thickness, and k is the heat transfer coefficient. w R is the thermal conductivity of the pipe wall material. f For the thermal resistance of oil stains;

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

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

[0051] Given an error Δ, if |η initial -η cool If | < Δ, then the preliminary cooling efficiency calculation is considered normal; if | η initial -η cool If |≥Δ, then the preliminary cooling efficiency calculation is considered abnormal.

[0052] A computer program product includes a computer program / instructions that, when executed by a processor, implement the method described in any of the above.

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

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

[0055] This invention improves the accuracy of transformer cooling efficiency assessment by comprehensively monitoring multiple parameters in real time. It more accurately reflects the operating status of the cooler, effectively preventing transformer failures caused by insufficient cooling, thereby extending equipment lifespan and reducing maintenance costs. Simultaneously, the system's automated monitoring capabilities provide strong support for the safe operation of the transformer, ensuring its stability and reliability under high load conditions. Attached Figure Description

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

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

[0058] Figure 2 This is a flowchart illustrating a method for monitoring the cooling efficiency of a transformer cooler according to the present invention. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

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

[0061] Where there is no conflict, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0062] Example 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. It is used to acquire the inlet oil temperature, outlet oil temperature, and ambient temperature of the cooler. It can use thermocouples or PT100 temperature sensors, and has the advantages of fast response and high accuracy, making it 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 flow meter or an electromagnetic flow meter can be selected, which can provide high flow measurement accuracy and is suitable for oily fluids.

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

[0067] The vibration acquisition module is installed on the cooler oil pump. The vibration acquisition module is used to acquire the vibration signal of the cooler oil pump. An accelerometer or 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 its data input terminal electrically connected to the data output terminals of the temperature acquisition module, flow acquisition module, current acquisition module, and vibration acquisition module. Based on the acquired inlet oil temperature, outlet oil temperature, load current, and vibration signal, the data processing module calculates the cooling efficiency of the cooler. It can use an embedded microprocessor and has strong computing and data processing capabilities.

[0069] The monitoring module, whose data input terminal is electrically connected to the data output terminal of the data processing module, compares the calculated cooling efficiency with a threshold value and outputs the operating status of the cooler. A graphical display module or LED indicators can be used to visually display the operating status.

[0070] Example 2

[0071] A method for monitoring the cooling efficiency of a transformer cooler, based on a transformer cooler cooling efficiency monitoring system as described above, the monitoring method comprising:

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

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

[0074] Obtain the load current of the transformer; the load current directly affects the heat generation of the transformer.

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

[0076] The actual flow rate, inlet oil temperature, outlet oil temperature, load current, and vibration signals are synchronized and preprocessed in time. Time synchronization ensures that all data are consistent in time, and preprocessing includes filtering, noise reduction, and standardization.

[0077] The initial cooling efficiency of the cooler is calculated based on the inlet oil temperature, outlet oil temperature, and actual flow rate.

[0078] The total heat load of a transformer is calculated based on the load current; this involves calculating winding losses, core losses, and stray losses, thereby obtaining the overall heat load of the transformer.

[0079] The vibration health index of the cooler oil pump is calculated based on vibration signals; the operational health status of the oil pump is assessed by extracting time-domain and frequency-domain features.

[0080] The initial cooling efficiency is corrected by combining the total heat load and vibration health index to obtain the final cooling efficiency.

[0081] Example 3

[0082] This embodiment provides a method for calculating the preliminary cooling efficiency in Embodiment 2, the method including:

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

[0084] The heat loss correction factor φ of the cooler is calculated based on the heat loss characteristics of the cooler. loss , Where e is the natural constant, approximately equal to 2.718, h is the convective heat transfer coefficient, representing 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, a parameter describing the thermal conductivity of the material, obtained by consulting references or relevant handbooks, and T in T represents the inlet oil temperature of the cooler. amb The ambient temperature.

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

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

[0087] Example 4

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

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

[0090] Based on the skin effect coefficient k skin and 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 proximity effect coefficient k proximtiy It can be estimated through electromagnetic field theory and experiments, and is usually related to frequency and conductor geometry.

[0091] Calculate the winding losses of the transformer, i.e., the copper loss P. Cu P Cu =3I 2 R w,eff Where I is the transformer load current.

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

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

[0094] Calculate the total heat load P of the transformer. total P total =P Cu +P Fe +P stray Total heat load refers to all the heat generated by a transformer during operation, including copper losses caused by current flowing through the windings, magnetic losses in the core, and other possible stray losses. Total heat load essentially represents the heat that the cooler needs to handle and dissipate to ensure the transformer does not overheat and become damaged. An effective cooling system can maintain the transformer's safe operation within the range of total heat load.

[0095] Example 5

[0096] This embodiment provides a method for calculating the vibration health index of the cooler oil pump in Embodiment 2. The method includes:

[0097] Time-domain features are extracted from the preprocessed vibration signal to obtain the root mean square (RMS) value used to evaluate the energy level of the vibration signal and the peak value V representing the maximum instantaneous value of the vibration signal. peak And kurtosis K, which describes the sharpness of the vibration signal. V peak =max(V(t)), Where V(t) is the preprocessed vibration signal, V(t) i () represents 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 using Fourier transform, and the spectral energy of the signal is calculated. Frequency domain features are then extracted from the preprocessed vibration signal to obtain the spectral energy E. Among them, f low f is the lowest frequency of vibration. high V(f) represents the highest frequency of vibration, and V(f) is the frequency domain representation of the vibration signal.

[0099] Calculate the vibration health index HI, HI = w1·RMS + w2·V peak+w3·K+w4·E, where w1, w2, w3, and w4 are weighting coefficients, which are adjusted according to the degree of 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 equipment.

[0100] Example 6

[0101] The methods for achieving final cooling efficiency include:

[0102] The heat load correction factor φ is calculated based on the total heat load of the transformer. load , Where, k load P is the heat load influence coefficient. total P represents the total heat load of the transformer. norm The rated thermal load of the transformer; the correction factor can be used to adjust the initial cooling efficiency to better suit the actual working conditions, taking into account the performance changes of the transformer under different loads.

[0103] The vibration correction factor φ is calculated using the vibration health index of the cooler oil pump. vib , Where, k vib HI is the heat load influence coefficient, and HI is the actual vibration health index of the cooler oil pump. norm This is the vibration health index of the transformer under normal conditions; the vibration correction factor aims to adjust the cooling efficiency according to the vibration state of the oil pump, ensuring that the calculation of cooling efficiency can reflect potential problems when abnormal vibration occurs in the oil pump.

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

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

[0106] To ensure the safe and efficient operation of the transformer, a cooling efficiency threshold is set. If the calculated final cooling efficiency is lower than this threshold, the cooling efficiency is considered insufficient. This mechanism can promptly detect problems in the cooling system, allowing for maintenance or adjustments to prevent damage caused by overheating.

[0107] In addition, to further enhance transformer protection, two thresholds can be set: a warning threshold and a control threshold. When the cooling efficiency falls below the warning threshold, the system issues a warning. When the cooling efficiency falls below the control threshold, the system triggers an alarm, and immediate inspection is recommended.

[0108] Example 7

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

[0110] Data on actual flow rate, inlet oil temperature, outlet oil temperature, load current, and vibration signals are collected at the same time intervals (e.g., per second, per minute). A timestamp is recorded for each data acquisition. Ensure that all data acquisition devices are synchronized to minimize 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 handle missing or inconsistent data, so that all signal data have the same time base. This ensures that the data of each signal are corresponding at the same point in time, which is convenient for subsequent analysis.

[0112] All signal data undergoes denoising and Z-score normalization. Commonly used filtering methods include low-pass filters and Kalman filters. Denoising can effectively remove high-frequency noise and improve signal quality. Normalization ensures that data with different characteristics have the same scale.

[0113] All processed data are integrated to obtain a dataset. All preprocessed signal data are integrated into a unified dataset, including information such as timestamps, flow rates, oil temperatures, load currents, and vibration signals.

[0114] Example 8

[0115] Based on Example 2, a method for judging the initial cooling efficiency based on the total heat load is provided. The accuracy of the judgment of the initial cooling efficiency is determined by the following methods:

[0116] Calculate the overall heat transfer coefficient U of the cooler. Among them, h in h is the convective heat transfer coefficient inside the pipe, which is usually obtained through calculations based on fluid dynamics characteristics. out The external convective heat transfer coefficient is δ, which is determined based on environmental conditions and flow state. δ represents the pipe wall thickness, and k... w R is the thermal conductivity of the pipe wall material. f The thermal resistance is determined by oil residue; the overall 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, and T in T represents the inlet oil temperature of the cooler. outT represents the cooler outlet oil temperature. awb The ambient temperature;

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

[0119] Given an error Δ, if |η initial -n cool If |<Δ, then the preliminary cooling efficiency calculation is considered normal; if |η initial -n cool If |≥Δ, then the preliminary cooling efficiency calculation is considered abnormal. If the preliminary cooling efficiency fails, it indicates that there may be a malfunction in a sensor or other device in the entire system, requiring necessary adjustments to reduce the risk of failure.

[0120] Example 9

[0121] A computer program product includes a computer program / instructions that, when executed by a processor, implement the method described in any of the above.

[0122] Computer program products include computer programs or instruction sets used to perform specific tasks or achieve 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 disks, solid-state drives, optical discs, or other forms of digital storage devices. It may exist in the form of compiled binary code or in the form of scripts or bytecode that can be executed by an interpreter. Through carefully designed algorithms and logical instructions, the program product enables the processor to process data in a specific order and manner, performing various functions such as data analysis, user interaction, and device control.

[0123] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0124] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0125] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above invention, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A transformer cooler cooling efficiency monitoring method, characterized by, The application discloses a transformer cooler cooling efficiency monitoring system, which comprises the following components: a temperature acquisition module installed at the oil outlet of the cooler, the oil inlet of the cooler and outside the cooler, which is used to acquire the inlet oil temperature of the cooler, the outlet oil temperature of the cooler and the ambient temperature; a flow acquisition module installed at the oil outlet of the cooler, which is used to acquire the actual flow of the cooler; a current acquisition module installed in the transformer control box and connected to the transformer CT signal, which is used to acquire the load current of the transformer; a vibration acquisition module installed on the cooler oil pump, which is used to acquire the vibration signal of the cooler oil pump; a data processing module 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, which is used to calculate the cooling efficiency of the cooler based on the acquired inlet oil temperature, outlet oil temperature, load current and vibration signal; a monitoring module electrically connected to the data output end of the data processing module, which is used to compare the calculated cooling efficiency with a threshold value and output the running state of the cooler. The monitoring method comprises the following steps: acquiring the inlet oil temperature, the outlet oil temperature and the ambient temperature of the cooler; acquiring the actual flow of the cooler; acquiring the load current of the transformer; acquiring the vibration signal of the cooler oil pump; performing time sequence synchronization and preprocessing on the actual flow, the inlet oil temperature, the outlet oil temperature, the load current and the vibration signal; calculating the preliminary cooling efficiency of the cooler based on the inlet oil temperature, the outlet oil temperature and the actual flow; calculating the total heat load of the transformer based on the load current; calculating the vibration health index of the cooler oil pump based on the vibration signal; correcting the preliminary cooling efficiency in combination with the total heat load and the vibration health index to obtain the final cooling efficiency. The method for calculating the total heat load of the transformer comprises the following steps: Calculate the transformer winding temperature Real-time resistance , ,in, Reference temperature The winding resistance below, The temperature resistivity of copper; Based on skin effect coefficient And proximity effect coefficient Correct the winding resistance to obtain a corrected effective winding resistance , ; calculating the winding losses, i.e. the copper losses, of the transformer , , is the transformer load current; calculating the core loss of the transformer, i.e. iron loss , wherein is the core volume, is the hysteresis loss coefficient, is the hysteresis loss exponent, is the eddy current loss coefficient, is the core sheet thickness, is the magnetic flux density, is the frequency; Calculating stray loss of a transformer , , wherein, is a stray loss coefficient; Calculating total thermal load of a transformer , .

2. A method of monitoring the cooling efficiency of a transformer cooler as claimed in claim 1, wherein, The method for calculating the preliminary cooling efficiency of the cooler comprises the following steps: Computing a flow correction factor for a chiller , wherein, is an actual flow of the chiller, is a design flow of the chiller; Computing a heat loss correction factor for a chiller ; Calculating a preliminary cooling efficiency of a chiller , , wherein, is the chiller outlet oil temperature, is the chiller inlet oil temperature, is the ambient temperature.

3. The method of claim 1, wherein, The method for calculating the vibration health index of the cooler oil pump comprises the following steps: The preprocessed vibration signal is subjected to time domain feature extraction to obtain a root mean square value , a peak value , and a kurtosis , , , , , wherein the preprocessed vibration signal is , the vibration signal at the i th timestamp is , and the number of timestamps is n. The preprocessed vibration signal is subjected to frequency domain feature extraction to obtain a frequency spectrum energy , wherein, is a vibration lowest frequency, is a vibration highest frequency, is a representation of the vibration signal in the frequency domain; Computing a vibration health index , , wherein, , , , is a weight coefficient.

4. The method of claim 1, wherein, The method for obtaining the final cooling efficiency comprises the following steps: A thermal load correction factor is calculated from the total thermal load of the transformer , wherein is a thermal load influence coefficient, is the total thermal load of the transformer, is the rated thermal load of the transformer; Vibration correction factor is calculated by vibration health index of cooler oil pump , , wherein, is a thermal load influence coefficient, is an actual vibration health index of the cooler oil pump, is a vibration health index of the transformer in a normal state; A correction model is established to obtain the final cooling efficiency , .

5. The method of claim 1, wherein, setting a cooling efficiency threshold value, and determining that the cooling efficiency is insufficient if the final cooling efficiency is lower than the cooling efficiency threshold value.

6. The method of claim 1, wherein, The method for performing time sequence synchronization and preprocessing comprises the following steps: collecting the actual flow, the inlet oil temperature, the outlet oil temperature, the load current and the vibration signal at the same time interval and recording the time stamp; converting all the signal data into a unified time format and processing the data inconsistent in time by using an interpolation method so that all the signal data have the same time reference; performing filter denoising processing and Z-score standardization processing on all the signal data; integrating all the processed data to obtain a data set.

7. The method of claim 1, wherein, The method for judging the preliminary cooling efficiency based on the total heat load comprises the following steps: Calculating the overall heat transfer coefficient of a chiller , where, is the in-tube convective heat transfer coefficient, is the out-tube convective heat transfer coefficient, is the tube wall thickness, is the thermal conductivity of the tube wall material, is the oil fouling resistance; Heat removed by the cooler , wherein, Acooler is the heat dissipation area of the cooler, Tcoolerin is the oil temperature at the inlet of the cooler, Tcoolerout is the oil temperature at the outlet of the cooler, Tambient is the ambient temperature; Comparative cooling efficiency of a cooler , ; Set error If , it is determined that the preliminary cooling efficiency calculation is normal; if , it is determined that the preliminary cooling efficiency calculation is abnormal.

8. A computer program product comprising computer programs / instructions, characterized in that, The computer program / instruction is executed by the processor to realize the method in any one of claims 1-7.

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