System and method for detecting oil immersion degree of insulating paperboard based on sound velocity

Abstract

The invention discloses a sound velocity-based insulation paperboard oil immersion degree detection system and method, and belongs to the technical field of electrical equipment detection and fault diagnosis, and the system comprises a signal generator, an insulation paperboard oil immersion part, an oscilloscope and a control unit. The insulating paper board oil immersion part comprises an oil immersion experiment testing cavity, transformer oil, an insulating paper board, an ultrasonic transmitter and an ultrasonic receiver, and the control unit controls the signal generator to generate an electric signal; the ultrasonic transmitter transmits ultrasonic waves based on the electric signals; the ultrasonic receiver receives an ultrasonic signal carrying oil immersion degree information of the insulating paperboard; the oscilloscope processes, displays and transmits the ultrasonic signals to the control unit; the control unit is used for processing data of the ultrasonic signal and continuously monitoring the oil immersion degree of the insulating paperboard. The oil immersion degree of the insulating paperboard can be continuously monitored in real time, changes of the oil immersion degree can be captured in time, and accurate and effective data support can be provided for operators.

Description

Technical Field

[0001] The present invention belongs to the technical field of power cable fault detection, and particularly relates to a detection system and method for the oil immersion degree of insulating paperboard based on sound velocity. Background Art

[0002] In an oil-paper insulation structure, the oil immersion degree of insulating paperboard directly affects its dielectric properties. When the oil immersion process is insufficient or the oil permeability decreases, the liquid insulating oil cannot completely fill the microporous structure of the cellulose material, resulting in residual unimpregnated air gaps inside the insulating paper. These tiny air gaps are prone to partial discharge under the action of an electric field, promoting the ionization of the gas inside the air gaps to form bubble defects. Such bubble defects will not only significantly reduce the breakdown strength of the composite insulation system, but the partial discharge they cause will also accelerate the depolymerization of cellulose chains, resulting in irreversible deterioration of the insulating material. This kind of microbubble defect caused by insufficient oil immersion has the characteristics of strong concealment and rapid development, and has become an important inducement for the insulation failure of oil-immersed equipment, and even seriously threatens the operation reliability of power equipment.

[0003] In the prior art, the detection methods for the oil immersion degree of insulating paperboard include the gravimetric method, the manual visual inspection method, and the traditional ultrasonic method. Generally, these methods have defects such as sample destruction, subjective dependence, sensitivity to environmental interference, and lack of dynamic monitoring. The gravimetric method requires cutting and drying the sample, which is highly destructive and cannot be monitored in-situ; the manual method relies on experience to judge the spread of oil stains, with an error exceeding 20%; the traditional ultrasonic method is easily affected by temperature and humidity fluctuations in an open environment (a temperature change of 1 °C can cause a sound velocity deviation of 3 - 5 m / s), with poor data repeatability, and only supports static single-point measurement, making it difficult to capture the oil immersion penetration rate and pore dynamic changes, resulting in low detection efficiency and insufficient accuracy, and unable to meet the requirements of non-destructive continuous monitoring in intelligent manufacturing. Therefore, in summary, among the current detection methods for the oil immersion degree of insulating paperboard, there may be problems such as easy sample destruction, certain subjective dependence, sensitivity to environmental interference, and difficulty in performing efficient and high-precision dynamic monitoring. Summary of the Invention

[0004] The present invention provides a detection system and method for the oil immersion degree of insulating paperboard based on sound velocity, aiming to solve the problems in the current detection methods for the oil immersion degree of insulating paperboard, such as easy sample destruction, certain subjective dependence, sensitivity to environmental interference, and difficulty in performing efficient and high-precision dynamic monitoring.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a detection system for the oil immersion degree of insulating paperboard based on sound velocity, including a signal generator, an insulating paperboard oil immersion part, an oscilloscope, and a control unit. The insulating paperboard oil immersion part includes an oil immersion experiment test chamber and transformer oil, insulating paperboard, an ultrasonic transmitter, and an ultrasonic receiver placed therein, wherein: The control unit is used to control the signal generator to emit an electrical signal, and the signal generator can transmit the electrical signal to the ultrasonic transmitter; The ultrasonic transmitter is used to emit ultrasonic waves based on the electrical signal, and the ultrasonic waves can act on the oil-impregnated part of the insulating cardboard; The ultrasonic receiver is used to: receive the ultrasonic signal carrying the information of the oil impregnation degree of the insulating cardboard and transmit the ultrasonic signal to the oscilloscope; The oscilloscope is used to process the received ultrasonic signal, display it in the form of a waveform and transmit it to the control unit; The control unit is used to analyze, process and save the parameter data of the ultrasonic signal, and then continuously monitor the oil impregnation degree of the insulating cardboard.

[0006] In some embodiments, the control unit can control the signal generator to generate an electrical signal with a frequency that meets the detection requirements according to different detection scenarios and the characteristics of the insulating cardboard.

[0007] Furthermore, the signal generator adopts a frequency synthesis type signal generator.

[0008] In some embodiments, the ultrasonic transmitter can convert the electrical energy of the electrical signal into mechanical energy and emit ultrasonic waves to the insulating cardboard in a preset direction and angle, so as to provide a signal source for detecting the oil impregnation degree of the insulating cardboard according to the propagation characteristics of ultrasonic waves in the insulating cardboard.

[0009] Furthermore, the ultrasonic transmitter adopts a piezoelectric ultrasonic transmitter.

[0010] In some embodiments, after the ultrasonic signal emitted by the ultrasonic transmitter enters the insulating cardboard, it will interact with the insulating cardboard and the transformer oil inside it. The propagation speed, amplitude and phase characteristics of ultrasonic waves passing through insulating cardboard with different oil impregnation degrees change, and then provide an ultrasonic signal carrying the information of the oil impregnation degree of the insulating cardboard for the ultrasonic receiver.

[0011] Furthermore, the ultrasonic receiver adopts a piezoelectric ultrasonic receiver.

[0012] In some embodiments, the control unit can calculate the propagation speed of the ultrasonic signal in the insulating cardboard based on the parameter data of the ultrasonic signal, and determine the oil impregnation degree of the insulating cardboard according to the relationship model established in advance between the sound speed change rate and the oil impregnation degree of the insulating cardboard.

[0013] In some embodiments, the control unit is also used to evaluate the oil impregnation degree of the insulating cardboard according to the result of continuously monitoring the oil impregnation degree of the insulating cardboard.

[0014] The present invention also provides a method for detecting the oil immersion degree of insulating cardboard based on sound velocity. This method is carried out based on the above-mentioned detection system for the oil immersion degree of insulating cardboard based on sound velocity, and the method includes the following steps: S1. Place the insulating cardboard in the oil immersion experiment test chamber, inject the preset transformer oil, and install the ultrasonic transmitter and ultrasonic receiver at the preset positions in the oil immersion experiment test chamber; S2. The control unit controls the signal generator to generate an electrical signal with a frequency that meets the detection requirements, and the electrical signal is transmitted to the ultrasonic transmitter; S3. The ultrasonic transmitter emits ultrasonic waves based on the electrical signal, and the ultrasonic waves act on the oil immersion part of the insulating cardboard; S4. The ultrasonic receiver receives the ultrasonic signal carrying the information of the oil immersion degree of the insulating cardboard, and transmits the ultrasonic signal to the oscilloscope; S5. The oscilloscope processes the received ultrasonic signal, displays it in the form of a waveform, and transmits it to the control unit; S6. The control unit analyzes, processes, and saves the parameter data of the ultrasonic signal; S7. Repeat the operations of S2 to S6 to continuously monitor the oil immersion degree of the insulating cardboard.

[0015] Compared with the prior art, the detection system and method for the oil immersion degree of insulating cardboard based on sound velocity of the present invention have the following beneficial effects: The detection system for the oil immersion degree of insulating cardboard based on sound velocity of the present invention generates an electrical signal with a precise and stable waveform through the signal generator, reducing the detection error; the ultrasonic transmitter emits ultrasonic waves to the insulating cardboard based on the electrical signal, and the ultrasonic receiver receives the different propagation speeds of ultrasonic waves in the insulating cardboard with different oil immersion degrees. The higher the oil immersion degree, the faster the ultrasonic wave propagation speed, and the oil immersion degree of the insulating cardboard is monitored. The present invention cooperates with the oscilloscope to accurately measure the signal parameters; and the computer uses a specific algorithm and a pre-established relationship model for in-depth analysis, and then can accurately determine the oil immersion degree of the insulating cardboard, greatly improving the accuracy of the detection result of the oil immersion degree of the insulating cardboard. The present invention can perform real-time and continuous monitoring of the oil immersion degree of the insulating cardboard, capture the changes in the oil immersion degree in a timely manner, enabling the operator to quickly understand the insulation state of the electrical equipment, so as to take measures in a timely manner to prevent faults, and thus ensure the safe and reliable operation of the equipment, having better practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings in the specification are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation to the present invention.

[0017] Figure 1Schematic diagram of the architecture of a detection system for the oil immersion degree of insulating cardboard based on sound velocity according to the present invention; Figure 2 Flow chart of a detection method for the oil immersion degree of insulating cardboard based on sound velocity according to the present invention; Figure 3 Schematic diagram of the propagation velocity-time curve of ultrasonic waves during the oil immersion process of insulating cardboard provided in Embodiment 1 of a detection method for the oil immersion degree of insulating cardboard based on sound velocity according to the present invention; Figure 4 Schematic diagram of the oil immersion degree-time curve of insulating cardboard provided in Embodiment 1 of a detection method for the oil immersion degree of insulating cardboard based on sound velocity according to the present invention.

[0018] Reference numerals: 1, signal generator; 2, oil immersion experiment test chamber; 3, ultrasonic wave transmitter; 4, ultrasonic wave receiver; 5, oscilloscope; 6, computer; 7, insulating cardboard; 8, transformer oil. Detailed implementation manners

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] It should be noted that: Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0022] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the present invention is usually placed when in use, 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, and thus cannot be construed as a limitation to the present invention. In addition, terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0023] In addition, when the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and it does not mean that the structure must be completely horizontal, but it can be slightly inclined.

[0024] In the description of the embodiments of the present invention, it should also be noted that unless otherwise clearly defined and limited, when the terms "arranged", "installed", "connected", and "coupled" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. 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 situations.

[0025] How to accurately determine the oil immersion degree of insulating cardboard, improve the accuracy of detection results, monitor the oil immersion degree of insulating cardboard in real time and continuously, capture the changes in the oil immersion degree in a timely manner, and provide technical support for the safe and reliable operation and maintenance of equipment.

[0026] Based on this, the present invention provides a detection system for the oil immersion degree of insulating cardboard based on sound velocity, which includes a signal generator 1, an insulating cardboard oil immersion part, an oscilloscope 5, and a control unit. The insulating cardboard oil immersion part includes an oil immersion experiment test chamber 2 and a transformer oil 8, an insulating cardboard 7, an ultrasonic transmitter 3, and an ultrasonic receiver 4 placed therein, where: The control unit is used to control the signal generator 1 to send an electrical signal, and the signal generator 1 can transmit the electrical signal to the ultrasonic transmitter 3; The ultrasonic transmitter 3 is used to emit ultrasonic waves based on the electrical signal, and the ultrasonic waves can act on the insulating cardboard oil immersion part; The ultrasonic receiver 4 is used to: receive the ultrasonic signal carrying the oil immersion degree information of the insulating cardboard 7 and transmit the ultrasonic signal to the oscilloscope 5; The oscilloscope 5 is used to process the received ultrasonic signal, display it in the form of a waveform and transmit it to the control unit; The control unit is used to analyze, process, and save the parameter data of the ultrasonic signal, and then continuously monitor the oil immersion degree of the insulating cardboard 7.

[0027] As Figure 1 shown, in the detection system of the present invention, it includes a signal generator 1, an oil immersion experiment test chamber 2, an ultrasonic transmitter 3, an ultrasonic receiver 4, an oscilloscope 5, a computer 6, an insulating cardboard 7, and a transformer oil 8.

[0028] The signal generator 1 in the present invention can generate an electrical signal with a precise and stable waveform at a frequency that meets the detection requirements according to different detection scenarios and the characteristics of the insulating cardboard 7. The precise and stable waveform helps to accurately analyze the propagation of ultrasonic waves in the insulating cardboard at the receiving end, reduce the detection error caused by signal fluctuations, and thus improve the accuracy and repeatability of the detection.

[0029] Furthermore, the signal generator 1 of the present invention is preferably a frequency synthesis type signal generator, which has high frequency accuracy and stability, can ensure that the detection results remain consistent under different conditions, and make the detection more reliable; it also has a high-precision frequency selection function, which can accurately adapt to the characteristics of different insulating cardboard 7 to meet the strict detection accuracy requirements.

[0030] The insulating cardboard 7, transformer oil 8, ultrasonic transmitter 3, and ultrasonic receiver 4 of the present invention are placed in the oil immersion experiment test chamber 2, providing a relatively stable and enclosed space environment for the propagation of the insulating cardboard 7 and ultrasonic waves, enabling the ultrasonic waves to be emitted and received along a predetermined path, avoiding interference from external environmental factors such as air flow, temperature change, humidity change, etc. during the propagation and detection process of ultrasonic waves, which is beneficial to improving the accuracy and stability of the detection and ensuring the consistency and repeatability of the detection data.

[0031] Based on the electrical signal with a specific frequency and waveform provided by the signal generator 1, the ultrasonic transmitter 3 of the present invention converts electrical energy into mechanical energy, and then emits ultrasonic waves towards the insulating cardboard 7 in a specific direction and angle, providing a signal source for subsequent detection of the oil immersion degree according to the propagation characteristics of ultrasonic waves in the insulating cardboard 7, ensuring that the ultrasonic waves can accurately act on the area of the insulating cardboard 7 to be detected, and minimizing scattering and energy loss during the propagation process, so that the ultrasonic receiver 4 can receive a clear and stable ultrasonic signal.

[0032] Furthermore, the ultrasonic transmitter 3 of the present invention is preferably a piezoelectric ultrasonic transmitter, and by reasonably designing its structure and emission surface, better directivity of ultrasonic wave emission can be achieved. When detecting the oil immersion degree of the insulating cardboard 7, it can accurately emit ultrasonic waves to the area of the insulating cardboard 7 to be detected, reduce the scattering and energy loss of ultrasonic waves, enable the ultrasonic receiver 4 to receive a clear and stable ultrasonic signal, improve the quality and reliability of the detection signal, and provide a strong guarantee for subsequent accurate analysis of the oil immersion degree of the insulating cardboard 7.

[0033] After the ultrasonic signal emitted by the ultrasonic transmitter 3 of the present invention enters the insulating cardboard 7, it will interact with the insulating cardboard 7 and the oil impregnated therein. The propagation speed, amplitude, phase and other characteristics of the ultrasonic wave passing through the insulating cardboard 7 with different oil impregnation degrees will change. Through this interaction, the ultrasonic receiver 4 receives the ultrasonic wave carrying the information related to the oil impregnation degree of the insulating cardboard 7, providing a basis for subsequent detection and analysis.

[0034] Furthermore, the ultrasonic receiver 4 of the present invention is preferably a piezoelectric ultrasonic receiver, which has a fast response speed to ultrasonic signals and can timely convert the received ultrasonic mechanical vibration into an electrical signal. In the monitoring of the oil impregnation degree of the insulating cardboard 7 based on the sound velocity, the change of the ultrasonic signal can be captured in real time, and the dynamic change of the oil impregnation degree of the insulating cardboard 7 can be quickly fed back, enabling the detection system to timely and accurately grasp the state change of the insulating cardboard 7 and providing strong support for timely discovery of potential insulation problems.

[0035] The present invention precisely measures various parameters of the ultrasonic signal carrying the information of the oil impregnation degree of the insulating cardboard 7 received by the ultrasonic receiver 4 in real time and transmits them to the oscilloscope 5 for intuitive waveform display.

[0036] The computer 6 of the present invention controls the signal generator 1 to generate an electrical signal with a specific frequency and waveform that meets the detection requirements, receives various data about the ultrasonic signal transmitted from devices such as the oscilloscope 5, deeply processes and analyzes these data using specific algorithms and software, calculates the propagation speed of the ultrasonic wave in the insulating cardboard 7, and accurately determines the oil impregnation degree of the insulating cardboard 7 according to the relationship model between the sound velocity change rate and the oil impregnation degree of the insulating cardboard established in advance, and presents the results such as the oil impregnation degree of the insulating cardboard 7 obtained from the detection and analysis in the form of a curve.

[0037] As Figure 2 shown, the present invention also provides a method for detecting the oil impregnation degree of an insulating cardboard based on the sound velocity, including: Step 1: Place the insulating cardboard 7 in the oil impregnation experiment test chamber 2, inject an appropriate amount of transformer oil 8, and install and fix the ultrasonic transmitter 3 and the ultrasonic receiver 4 at appropriate positions in the oil impregnation experiment test chamber 2.

[0038] Step 2: The computer 6 controls the signal generator 1 to generate an electrical signal with a frequency that meets the detection requirements.

[0039] Step 3: The ultrasonic transmitter 3 emits ultrasonic waves based on the electrical signal provided by the signal generator 1.

[0040] Step 4: The ultrasonic receiver 4 receives the ultrasonic signal carrying the information related to the oil impregnation degree of the insulating cardboard 7 and transmits it to the oscilloscope 5.

[0041] Step 5, the oscilloscope 5 processes the received electrical signal, displays it in waveform form and transmits it to the computer 6.

[0042] Step 6, the computer 6 uses algorithms and software to process, analyze and save the ultrasonic parameter data.

[0043] Step 7, repeat the steps of Step 2 to Step 6 in real time to continuously monitor the oil immersion degree of the insulating cardboard 7.

[0044] Further, in Step 1, after installing each unit in the oil immersion experiment test chamber 2, it is necessary to check that the signal generator 1, the oscilloscope 5, and the computer 6 are connected properly, then turn on the system and perform an initialization setting on the system to ensure the reliability of the monitoring results.

[0045] In Step 2, the computer 6 sends instructions to the signal generator 1 according to different detection scenarios and the characteristics of the insulating cardboard 7, and controls the signal generator 1 to generate an electrical signal with a precise and stable waveform that meets the detection requirement frequency.

[0046] In Step 3, the ultrasonic transmitter 3 converts the electrical energy provided by the signal generator into mechanical energy, emits ultrasonic waves to the insulating cardboard 7 in a specific direction and angle. The ultrasonic waves propagating in the insulating cardboard 7 interact with the insulating cardboard 7 and the oil immersion inside it, and the ultrasonic signal parameters change.

[0047] Furthermore, in Step 6, the computer calculates the propagation speed of ultrasonic waves in the insulating cardboard 7, and accurately determines the oil immersion degree of the insulating cardboard 7 according to the pre-established relationship model between the sound velocity change rate and the oil immersion degree of the insulating cardboard 7. The results such as the oil immersion degree of the insulating cardboard 7 obtained from the detection and analysis are presented in the form of a curve. At the same time, the computer 6 stores the data during the entire detection process, including the original ultrasonic signal data, the processed analysis results, and relevant detection parameters, etc., for subsequent query, comparison and research.

[0048] As an optimization, in Step 7, the computer 6 timely evaluates the oil immersion degree of the insulating cardboard 7 according to the continuous monitoring results, solving the defects such as sample destruction, subjective dependence, environmental interference sensitivity and lack of dynamic monitoring in the existing detection methods for the oil immersion degree of the insulating cardboard 7.

[0049] The following further details a detection system and method for the oil immersion degree of an insulating cardboard based on sound velocity according to the present invention through specific embodiments.

[0050] Place the insulating cardboard 7 in the oil immersion test chamber 2, and inject an appropriate amount of transformer oil 8. At the same time, install and fix the ultrasonic transmitter 3 and the ultrasonic receiver 4 at appropriate positions in the oil immersion test chamber 2 to ensure that the ultrasonic waves can propagate along the predetermined path. Check whether the connections of devices such as the signal generator 1, the oscilloscope 5, and the computer 6 are normal, and then turn on the system and perform the initialization settings.

[0051] As Figure 3 and Figure 4 shown, the computer 6 sends instructions to the signal generator 1 according to different detection scenarios and the characteristics of the insulating cardboard 7, controlling it to generate an accurate and stable waveform electrical signal with a frequency that meets the detection requirements. Based on the electrical signal provided by the signal generator 1, the ultrasonic transmitter 3 converts electrical energy into mechanical energy and emits ultrasonic waves to the insulating cardboard 7 in a specific direction and angle. The ultrasonic waves propagate in the insulating cardboard 7 and interact with the insulating cardboard 7 and the oil immersed in it, resulting in changes in their propagation speed, amplitude, phase and other characteristics. The ultrasonic receiver 4 receives the ultrasonic signal carrying information related to the oil immersion degree of the insulating cardboard 7, converts it into an electrical signal, and transmits it to the oscilloscope 5. The oscilloscope 5 processes the received electrical signal, accurately measures various parameters of the ultrasonic signal in real time, and displays them in an intuitive waveform form. The oscilloscope 5 transmits the measured ultrasonic signal parameter data to the computer 6. The computer 6 uses algorithms and software to deeply process and analyze these data, and calculates the propagation speed of the ultrasonic waves in the insulating cardboard 7. According to the pre-established relationship model between the sound speed change rate and the oil immersion degree of the insulating cardboard 7, the oil immersion degree of the insulating cardboard 7 is accurately determined. The computer 6 presents the results such as the oil immersion degree of the insulating cardboard 7 obtained from the detection and analysis in the Figure 3 and Figure 4 shown, in the form of a curve, which is convenient for the operator to view intuitively. At the same time, the computer 6 stores the data during the entire detection process, including the original ultrasonic signal data, the processed analysis results, and the relevant detection parameters, etc., for subsequent query, comparison and research. According to the actual needs, the above steps can be repeated regularly or in real time to continuously monitor the oil immersion degree of the insulating cardboard 7. According to the monitoring results, the oil immersion degree of the insulating cardboard 7 is evaluated in a timely manner, solving the defects such as sample destruction, subjective dependence, environmental interference sensitivity and lack of dynamic monitoring in the existing detection methods for the oil immersion degree of insulating cardboard. It optimizes the efficiency and accuracy of the detection of the oil immersion degree of the insulating cardboard, provides technical support for the operation and maintenance of the operator, and has a certain practicality. Finally, it should be noted that the above description is only a preferred embodiment of the present invention and does not impose any formal restrictions on the present invention. Any ordinary technician in the industry can smoothly implement the present invention according to the instructions and the above description. Slight changes, modifications, and equivalent variations made by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A detection system for the oil immersion degree of insulating cardboard based on the sound velocity, characterized in that It includes a signal generator (1), an insulating cardboard oil immersion part, an oscilloscope (5) and a control unit. The insulating cardboard oil immersion part includes an oil immersion experiment test chamber (2) and the transformer oil (8), insulating cardboard (7), ultrasonic transmitter (3), and ultrasonic receiver (4) placed therein. Among them: The control unit is used to control the signal generator (1) to emit an electrical signal, and the signal generator (1) can transmit the electrical signal to the ultrasonic transmitter (3); The ultrasonic transmitter (3) is used to emit ultrasonic waves based on the electrical signal, and the ultrasonic waves can act on the insulating cardboard oil immersion part; The ultrasonic receiver (4) is used to: receive the ultrasonic signal carrying the oil immersion degree information of the insulating cardboard (7) and transmit the ultrasonic signal to the oscilloscope (5); The oscilloscope (5) is used to process the received ultrasonic signal, display it in the form of a waveform and transmit it to the control unit; The control unit is used to analyze, process and save the parameter data of the ultrasonic signal, and then continuously monitor the oil immersion degree of the insulating cardboard (7).

2. The detection system for the oil immersion degree of insulating cardboard based on sound velocity according to claim 1, characterized in that The control unit can control the signal generator (1) to generate an electrical signal with a frequency that meets the detection requirements according to different detection scenarios and the characteristics of the insulating cardboard.

3. The detection system for the oil immersion degree of insulating cardboard based on sound velocity according to claim 2, wherein The signal generator (1) adopts a frequency synthesis type signal generator.

4. The detection system for the oil immersion degree of insulating cardboard based on sound velocity according to claim 1, characterized in that, The ultrasonic transmitter (3) can convert the electrical energy of the electrical signal into mechanical energy and emit ultrasonic waves to the insulating cardboard (7) in a preset direction and angle, so as to provide a signal source for detecting the oil immersion degree of the insulating cardboard (7) according to the propagation characteristics of ultrasonic waves in the insulating cardboard (7).

5. The detection system for the oil immersion degree of insulating cardboard based on sound velocity according to claim 4, wherein The ultrasonic transmitter (3) adopts a piezoelectric ultrasonic transmitter.

6. The detection system for the oil immersion degree of insulating cardboard based on sound velocity according to claim 1, wherein After the ultrasonic signal emitted by the ultrasonic transmitter (3) enters the insulating cardboard (7), it will interact with the insulating cardboard (7) and the transformer oil (8) inside it. The propagation speed, amplitude and phase characteristics of ultrasonic waves passing through the insulating cardboard (7) with different oil immersion degrees change, and then provide an ultrasonic signal carrying the oil immersion degree information of the insulating cardboard (7) for the ultrasonic receiver (4).

7. The detection system for the oil immersion degree of insulating paperboard based on sound velocity according to claim 6, wherein The ultrasonic receiver (4) adopts a piezoelectric ultrasonic receiver.

8. The detection system for the oil immersion degree of insulating cardboard based on sound velocity according to claim 1, characterized in that, The control unit can calculate the propagation speed of the ultrasonic signal in the insulating cardboard (7) based on the parameter data of the ultrasonic signal, and determine the oil immersion degree of the insulating cardboard (7) according to the relationship model between the sound velocity change rate and the oil immersion degree of the insulating cardboard established in advance.

9. The detection system for the oil immersion degree of insulating cardboard based on the sound velocity according to claim 1, characterized in that, The control unit is also used to evaluate the oil immersion degree of the insulating cardboard (7) according to the result of continuously monitoring the oil immersion degree of the insulating cardboard (7).

10. A detection method for the oil immersion degree of insulating cardboard based on the sound velocity, characterized in that, The method is carried out based on the detection system for the oil immersion degree of insulating cardboard based on sound velocity according to any one of claims 1-9. The method includes the following steps: S1. Place the insulating cardboard (7) in the oil immersion experiment test chamber (2), inject the preset transformer oil (8), and install the ultrasonic transmitter (3) and ultrasonic receiver (4) at the preset positions in the oil immersion experiment test chamber (2); S2. The control unit controls the signal generator (1) to generate an electrical signal with a frequency meeting the detection requirements, and the electrical signal is transmitted to the ultrasonic transmitter (3). S3. The ultrasonic transmitter (3) emits ultrasonic waves based on the electrical signal, and the ultrasonic waves act on the oil-impregnated part of the insulating cardboard. S4. The ultrasonic receiver (4) receives the ultrasonic signal carrying the information of the oil impregnation degree of the insulating cardboard (7), and transmits the ultrasonic signal to the oscilloscope (5). S5. The oscilloscope (5) processes the received ultrasonic signal, displays it in the form of a waveform and transmits it to the control unit. S6. The control unit analyzes, processes and saves the parameter data of the ultrasonic signal. S7. Repeat the operations of S2 to S6 to continuously monitor the oil impregnation degree of the insulating cardboard (7).

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