Transformer oil level and oil temperature monitoring and alarming system adopting double ultrasonic sensors

Abstract

The invention relates to a transformer oil level and oil temperature monitoring and alarming system adopting double ultrasonic sensors, which comprises an ultrasonic sensor module, an oil temperature sensor module, an oil level and oil temperature data acquisition and analysis module, a communication module and a monitoring background, the ultrasonic sensor module and the oil temperature sensor module transmit measured transformer oil level and oil temperature data to the oil level and oil temperature data acquisition and analysis module, and the oil level and oil temperature data acquisition and analysis module processes the data and then transmits related oil level and oil temperature data and alarm information to the communication module. And the communication module transmits the data to a monitoring background. The oil level of the transformer is measured based on the ultrasonic ranging principle, meanwhile, the measured oil level and temperature data of the transformer are compared with the standard oil level and temperature curve data, whether the transformer operates safely and normally or not is judged, related oil level and temperature data and alarm signals are transmitted to the monitoring background, and operation and maintenance personnel can conveniently monitor the operation condition of the transformer in real time.

Description

Technical Field

[0001] The invention relates to a transformer oil level and oil temperature monitoring and alarm system, and in particular to a transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors. Background Art

[0002] In substations, oil level and oil temperature are important parameters for monitoring the safe operation of power transformers. Transformer oil temperature is measured by oil temperature sensors. The current method of measuring transformer oil level is for operation and maintenance personnel to observe the oil level gauge on the transformer oil pillow to read data, and then manually compare the data with the standard oil level and oil temperature curve provided by the transformer manufacturer to judge the safe operation of the transformer. However, the installation position of the transformer oil level gauge is generally relatively high, which is not easy for operation and maintenance personnel to read the data. At the same time, due to factors such as water corrosion of the oil level gauge, unreasonable oil tank capacity, and abnormal operation of the main transformer radiator, the oil level gauge is frequently stuck and incorrect indication occurs. Manual comparison of the oil level and oil temperature curve is also time-consuming and labor-intensive, and is prone to misjudgment.

[0003] With the continuous development of intelligent detection technology, the advantages of ultrasound in liquid level measurement are becoming more and more prominent. Ultrasonic liquid level measurement uses ultrasonic pulses as the signal source to complete liquid level measurement by collecting corresponding ultrasonic echo information.

[0004] Aiming at these problems existing in the current transformer oil level and oil temperature monitoring, a more automated and intelligent transformer oil level and oil temperature monitoring and alarm system based on the ultrasonic ranging principle is designed. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors. The transformer oil level is measured based on the ultrasonic ranging principle, and the measured transformer oil level and oil temperature data are compared with the standard oil level and oil temperature curve data to determine whether the transformer is operating safely and normally. The relevant oil level and oil temperature data and alarm signals are transmitted to the monitoring background, which is convenient for operation and maintenance personnel to monitor the operation of the transformer in real time.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors, including: an ultrasonic sensor module, an oil temperature sensor module, an oil level and oil temperature data acquisition and analysis module, a communication module and a monitoring background. The ultrasonic sensor module and the oil temperature sensor module transmit the measured transformer oil level and oil temperature data to the oil level and oil temperature data acquisition and analysis module. After the oil level and oil temperature data acquisition and analysis module processes the data, the relevant oil level and oil temperature data and alarm information are transmitted to the communication module, and then transmitted to the monitoring background by the communication module.

[0007] Further, the ultrasonic sensor module includes: ultrasonic sensor module A and ultrasonic sensor module B, which mainly have the following functions: S1.1 Ultrasonic sensor module A and ultrasonic sensor module B respectively emit ultrasonic signals and collect corresponding echo signals; S1.2 Denoise the collected ultrasonic signals to reduce the influence of noise in the substation on the measurement results; S1.3 Calculate the oil level data H1 measured by ultrasonic sensor module A and the oil level data H2 measured by ultrasonic sensor module B respectively based on the denoised ultrasonic data, and transmit the calculated oil level data H1 and oil level data H2 to the oil level and oil temperature data acquisition and analysis module.

[0008] Further, the transformer oil temperature sensor module has the following functions: S2.1 Measure the transformer oil temperature and transmit the measured oil temperature data T to the oil level and oil temperature data acquisition and analysis module and the communication module.

[0009] Further, the oil level and oil temperature data acquisition and analysis module has the following functions S3.1 Receive the oil level height H1 data and oil level height H2 data transmitted from the ultrasonic sensor module, and calculate the oil level deviation measured by the two ultrasonic sensors. The calculation formula is: ΔH = H1 - H2; S3.2: K is the discrimination coefficient for the accuracy of oil level measurement, and its value is determined according to different characteristics of the oil conservator; When the condition of ΔH < K is not satisfied, it indicates that the oil levels measured by ultrasonic sensor module A and ultrasonic sensor module B are quite different, and the measured oil level is inaccurate. At this time, the signal transmitted to the communication module is: "ultrasonic sensor abnormal" alarm signal, as well as the oil level height H1 data and oil level height H2 data; When the "ultrasonic sensor abnormal" alarm signal is sent, the operation and maintenance personnel can compare the mechanical oil level indication data of the transformer oil conservator with the oil level height H1 data and oil level height H2 data measured by the two ultrasonic sensors to determine which ultrasonic sensor is abnormal, and then carry out maintenance; When the condition of ΔH < K is satisfied, it indicates that the oil levels measured by ultrasonic sensor module A and ultrasonic sensor module B are not very different, and the measured oil level is accurate; S3.3: At this time, calculate the average oil level based on the oil level height H1 data and oil level height H2 data. The formula for calculating the average oil level is: Hv = (H1 + H2) / 2; S3.4: Based on the average oil level data Hv and the received oil temperature data T, determine whether the transformer oil level and oil temperature are normal based on the standard oil level and oil temperature curve data of the transformer. The discrimination condition is: Condition 1: |Hv - h| < g, where h is the oil level data of the transformer in the transformer standard oil level - oil temperature curve corresponding to the actually measured transformer oil temperature data T, and g is the corresponding oil level comparison coefficient, whose value is set according to the oil level - oil temperature characteristics of different oil conservators; Condition 2: |T - t| < e, where t is the oil temperature data of the transformer in the transformer standard oil level - oil temperature curve corresponding to the actually measured oil level data Hv, and e is the corresponding temperature comparison coefficient, whose value is set according to the oil level - oil temperature characteristics of different oil conservators; S3.5: When Conditions 1 and 2 are met, it indicates that the oil level and oil temperature are normal. At this time, the signals transmitted to the communication module are: "Transformer oil level and oil temperature normal" signal, and the oil level data H1, H2, Hv measured by the sensor; S3.6: When either of Conditions 1 and 2 is not met, it indicates that the oil level and oil temperature are abnormal. At this time, the signals transmitted to the communication module are: "Transformer oil level and oil temperature abnormal" signal, and the oil level data H1, H2, Hv measured by the sensor.

[0010] Furthermore, the communication module has the following functions: S4.1 Receive the relevant alarm signals transmitted from the oil level - oil temperature data acquisition and analysis module, the measured oil level data H1, H2, Hv, and the oil temperature data T transmitted from the transformer oil temperature sensor module, and send these alarm signals and data to the monitoring background.

[0011] Furthermore, the functions of the monitoring background are: Receive the relevant alarm signals transmitted from the communication module, the measured oil level data H1, H2, Hv, and the oil temperature data T, and design the monitoring background interface into 2 sub - interfaces, specifically S5.1 Interface 1 shows the curves of the measured oil level data H1, the oil level data H2, and the average oil level data Hv changing with the transformer oil temperature T, a total of three curves; at the same time, when the ultrasonic sensor is abnormal, it shows the "ultrasonic sensor abnormal" alarm signal transmitted from the communication module; S5.2 Interface 2 shows the standard transformer oil level - oil temperature curve coordinate interface, and the transformer average oil level data Hv and the transformer oil temperature T are presented in the form of coordinate points on the standard transformer oil level - oil temperature curve coordinate interface, so that the degree to which the transformer oil level - oil temperature data deviates from the standard transformer oil level - oil temperature curve can be visually observed. Interface 2 also shows the "Transformer oil level and oil temperature normal" or "Transformer oil level and oil temperature abnormal" alarm signal transmitted from the communication module.

[0012] Furthermore, the ultrasonic sensor module A is installed in the middle position above the transformer oil pillow, and the ultrasonic sensor module B is installed in the middle position below the transformer oil pillow. Ultrasonic coupling agent is applied to the installation positions of the ultrasonic sensor modules A and B to reduce the influence of the air layer between the probe and the object to be measured and improve the measurement accuracy; the outer shells of the ultrasonic sensor modules A and B are designed to have ferromagnetic adsorption characteristics and are adsorbed on the outer wall of the iron material of the transformer oil pillow.

[0013] Furthermore, the ultrasonic sensor module A and the ultrasonic sensor module B are fixed to the transformer oil pillow by a hoop, and the hoop includes: two semicircular hoops and bolts for connection. The two semicircular hoops are wrapped around the transformer oil pillow to respectively wrap the ultrasonic sensor module A and the ultrasonic sensor module B, and the semicircular hoops are fastened to the transformer oil pillow by adjusting the bolts on the semicircular hoops, so that the ultrasonic sensor module A and the ultrasonic sensor module B clamped between the semicircular hoops and the oil pillow are fastened to the transformer oil pillow, and the ultrasonic sensor module A is connected to the ultrasonic sensor module B through a power supply and a communication cable.

[0014] Furthermore, the ultrasonic signal emitted by the ultrasonic sensor module A is transmitted from the air above the oil pillow to the transformer oil level and then reflected. The propagation speed of the ultrasonic signal emitted by the ultrasonic sensor module A in the air above the transformer oil pillow is V1. The time taken by the ultrasonic sensor module A from transmitting to receiving the ultrasonic signal is T1. The height of the transformer oil pillow is H. The oil level height H1 measured by the ultrasonic sensor module A can be calculated as: H1=H-h1=H-(V1*T1) / 2; The ultrasonic signal emitted by the ultrasonic sensor module B is transmitted from the transformer oil at the bottom of the oil pillow to the air and then reflected. The propagation speed of the ultrasonic signal emitted by the ultrasonic sensor module B in the transformer oil at the bottom of the transformer oil pillow is V2. The time taken by the ultrasonic sensor module B from transmitting to receiving the ultrasonic signal is T2. The height of the transformer oil pillow is H. The oil level height H2 measured by the ultrasonic sensor module B can be calculated as: H2=h2=(V2*T2) / 2.

[0015] Furthermore, the hardware part of the ultrasonic sensor module A includes: an MCU processor, a power module, an output module, a module A transmitting circuit, a module A receiving circuit, and an ultrasonic sensor A probe. The specific connection method is: the MCU processor provides control and acquisition signals for the module A transmitting circuit and the module A receiving circuit to send and receive ultrasonic signals, the module A transmitting circuit controls the ultrasonic sensor A probe to send ultrasonic signals, the ultrasonic sensor A probe then transmits the received ultrasonic signals to the module A receiving circuit, the module A receiving circuit transmits the received ultrasonic signals back to the MCU processor, the power module provides power to the MCU processor, the module A transmitting circuit and the module A receiving circuit, the MCU processor transmits the calculated oil level signal data to the output module, and the output module transmits it to the oil level and oil temperature data acquisition and analysis module; The hardware part of the ultrasonic sensor module B in the ultrasonic sensor module includes: module B transmitting circuit, module B receiving circuit, and ultrasonic sensor B probe. In order to save resources and reduce volume, the ultrasonic sensor module B and the ultrasonic sensor module A share a MUC processing module, power module, and output module. The ultrasonic sensor module B is connected to the MUC processing module, power module, and output module of the ultrasonic sensor module A through a power supply and communication cable. The connection method and function of each component of the ultrasonic sensor module B are the same as those in the ultrasonic sensor module A.

[0016] Furthermore, the ultrasonic frequency range of the ultrasonic sensor module A and the ultrasonic sensor module B in the ultrasonic sensor module is 20-200kHz, and the frequency of the ultrasonic wave to be used is determined according to the actual application debugging effect; in order to prevent mutual interference between the ultrasonic sensor module A and the ultrasonic sensor module B, two wave emission schemes are adopted here, scheme 1 and scheme 2, as follows: The ultrasonic sensor module oil level measurement process of scheme 1 is as follows: after the system starts, the ultrasonic sensor module A first transmits a frequency of f The ultrasonic signal is then determined whether an echo is received. If no echo is received, the ultrasonic sensor module A is again transmitted at a frequency of f The ultrasonic signal is sent until it is determined that the ultrasonic echo is received, and the received ultrasonic signal is subjected to noise reduction processing. The transformer oil level height H1 measured by the ultrasonic sensor module A is calculated based on the ultrasonic signal after noise reduction processing, and then the ultrasonic sensor module B is set to transmit at the same frequency. f The ultrasonic signal is also used to determine whether an echo is received. If no echo is received, the ultrasonic sensor module B is again sent with a frequency of fThe ultrasonic signal is received until it is determined that the ultrasonic echo is received, the ultrasonic signal sent and received is subjected to noise reduction processing, and the transformer oil level height H2 measured by the ultrasonic sensor module B is calculated according to the ultrasonic signal after the noise reduction processing, and finally the measured oil level height data H1 and H2 are transmitted to the oil level and oil temperature data acquisition and analysis module; The ultrasonic sensor module oil level measurement process of scheme 2 is as follows: after the system starts, ultrasonic sensor module A and ultrasonic sensor module B simultaneously send out signals with a frequency of f1 and f2 Then determine whether the ultrasonic sensor module A and the ultrasonic sensor module B have received the echo. If no echo is received, clear the received ultrasonic echo data, and let the ultrasonic sensor module A and the ultrasonic sensor module B send out the ultrasonic signal with a frequency of f1 and f2 The ultrasonic signal is sent and received until it is determined that the ultrasonic sensor module A and the ultrasonic sensor module B have received the ultrasonic echo, and the ultrasonic signal sent and received is subjected to noise reduction processing. The oil level heights H1 and H2 measured by the ultrasonic sensor module A and the ultrasonic sensor module B are calculated respectively according to the ultrasonic signal after the noise reduction processing, and finally the measured oil level height data H1 and H2 are transmitted to the oil level and oil temperature data acquisition and analysis module.

[0017] The beneficial effects of the present invention are: (1) Compared with the traditional method in which substation operation and maintenance personnel manually read the transformer oil level gauge data and transformer oil temperature data and manually compare them with the standard oil level and oil temperature curve data provided by the transformer manufacturer to determine whether the transformer is operating safely and normally, the method proposed in the present invention measures the transformer oil level data and transformer oil temperature data through ultrasonic sensors and temperature sensors and transmits them to the MCU processor. The MCU processor compares the measured oil level and oil temperature data with the standard oil level and oil temperature curve data to determine whether the transformer is operating safely and normally, and uploads the relevant alarm signals and oil level and oil temperature data to the monitoring background for real-time monitoring, which is more intelligent and automated; (2) The ultrasonic sensor used in the present invention is installed outside the transformer oil conservator, which will not damage the transformer oil conservator body, and the installation is simple and firm; (3) The present invention uses two ultrasonic sensors to measure the oil level of the transformer oil conservator, and compares the oil levels measured by the two ultrasonic sensors, thereby improving the accuracy of oil level measurement. When the deviation of the oil level of the transformer oil conservator measured by the two ultrasonic sensors is large, the ultrasonic sensors are compared with the transformer oil conservator oil level gauge in time to determine which ultrasonic sensor is abnormal and perform maintenance; (4) The hardware circuit parts of the ultrasonic sensor module A and the ultrasonic sensor module B in the present invention share a MUC processing module, a power module and an output module. The ultrasonic sensor module B is connected to the ultrasonic sensor module A through a power supply and a communication cable, which saves hardware resources and reduces the hardware size. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the structural diagram of the transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors; Figure 2 This is a flow chart of the transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors; Figure 3 This is the overall schematic diagram of the ultrasonic sensor module installation structure; Figure 4 This is a side view of the ultrasonic sensor module installation structure; Figure 5 Design the framework diagram for the ultrasonic sensor module hardware; Figure 6 This is the oil level measurement flow chart of the ultrasonic sensor module in Scheme 1; Figure 7 This is the oil level measurement flow chart of the ultrasonic sensor module in scheme 2; DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below through the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0021] like Figure 1-2 As shown, a transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors includes: an ultrasonic sensor module, an oil temperature sensor module, an oil level and oil temperature data acquisition and analysis module, a communication module and a monitoring background. The ultrasonic sensor module and the oil temperature sensor module transmit the measured transformer oil level and oil temperature data to the oil level and oil temperature data acquisition and analysis module. After the oil level and oil temperature data acquisition and analysis module processes the data, it transmits the relevant oil level and oil temperature data and alarm information to the communication module, and then the communication module transmits it to the monitoring background.

[0022] The S1 ultrasonic sensor module includes: ultrasonic sensor module A and ultrasonic sensor module B, which mainly have the following functions: S1.1 Ultrasonic sensor module A and ultrasonic sensor module B respectively emit ultrasonic signals and collect corresponding echo signals; S1.2 Denoise the collected ultrasonic signals to reduce the influence of noise in the substation on the measurement results; S1.3 Based on the ultrasonic data after denoising, calculate the oil level data H1 measured by ultrasonic sensor module A and the oil level data H2 measured by ultrasonic sensor module B respectively, and transmit the calculated oil level data H1 and oil level data H2 to the oil level and oil temperature data acquisition and analysis module.

[0023] The S2 transformer oil temperature sensor module has the following functions: S2.1 Measure the transformer oil temperature and transmit the measured oil temperature data T to the oil level and oil temperature data acquisition and analysis module and the communication module.

[0024] The S3 oil level and oil temperature data acquisition and analysis module has the following functions: S3.1 Receive the oil level height H1 data and oil level height H2 data transmitted from the ultrasonic sensor module, and calculate the oil level deviation measured by the two ultrasonic sensors. The calculation formula is: ΔH = H1 - H2; S3.2: K is the discriminant coefficient for the accuracy of oil level measurement, and its value is determined according to different characteristics of the oil conservator; When the condition of ΔH < K is not met, it indicates that the oil levels measured by ultrasonic sensor module A and ultrasonic sensor module B are quite different, and the measured oil level is inaccurate. At this time, the signal transmitted to the communication module is: "ultrasonic sensor abnormal" alarm signal, as well as the oil level height H1 data and oil level height H2 data; When the "ultrasonic sensor abnormal" alarm signal is sent, the operation and maintenance personnel can compare the mechanical oil level indication data of the transformer oil conservator with the oil level height H1 data and oil level height H2 data measured by the two ultrasonic sensors to determine which ultrasonic sensor is abnormal, and then carry out maintenance; When the condition of ΔH < K is met, it indicates that the oil levels measured by ultrasonic sensor module A and ultrasonic sensor module B are not very different, and the measured oil level is accurate; at this time, calculate the average oil level based on the oil level height H1 data and oil level height H2 data; S3.3: The formula for calculating the average oil level is: Hv = (H1 + H2) / 2; S3.4: Based on the average oil level data Hv and the received oil temperature data T, determine whether the transformer oil level and oil temperature are normal based on the transformer standard oil level and oil temperature curve data. The discriminant condition is: Condition 1: |Hv - h| < g, where h is the oil level data of the transformer in the transformer standard oil level - oil temperature curve corresponding to the actually measured transformer oil temperature data T, and g is the corresponding oil level comparison coefficient, whose value is set according to the oil level - oil temperature characteristics of different oil conservators; Condition 2: |T - t| < e, where t is the oil temperature data of the transformer in the transformer standard oil level - oil temperature curve corresponding to the actually measured oil level data Hv, and e is the corresponding temperature comparison coefficient, whose value is set according to the oil level - oil temperature characteristics of different oil conservators; S3.5: When Conditions 1 and 2 are met, it indicates that the oil level and oil temperature are normal. At this time, the signals transmitted to the communication module are: "Transformer oil level and oil temperature normal" signal, and the oil level data H1, H2, Hv measured by the sensor; S3.6: When either of Conditions 1 and 2 is not met, it indicates that the oil level and oil temperature are abnormal. At this time, the signals transmitted to the communication module are: "Transformer oil level and oil temperature abnormal" signal, and the oil level data H1, H2, Hv measured by the sensor.

[0025] S4 The communication module has the following functions: S4.1 Receive the relevant alarm signals transmitted from the oil level - oil temperature data acquisition and analysis module, the measured oil level data H1, H2, Hv, and the oil temperature data T transmitted from the transformer oil temperature sensor module, and send these alarm signals and data to the monitoring background.

[0026] S5 The functions of the monitoring background are: Receive the relevant alarm signals transmitted from the communication module, the measured oil level data H1, H2, Hv, and the oil temperature data T, and design the monitoring background interface into 2 sub - interfaces, specifically S5.1 Interface 1 shows the curves of the measured oil level data H1, oil level data H2, and average oil level data Hv changing with the transformer oil temperature T, a total of three curves; at the same time, when the ultrasonic sensor is abnormal, it shows the "ultrasonic sensor abnormal" alarm signal transmitted from the communication module; S5.2 Interface 2 shows the standard transformer oil level - oil temperature curve coordinate interface, and the transformer average oil level data Hv and the transformer oil temperature T are presented in the form of coordinate points on the standard transformer oil level - oil temperature curve coordinate interface, so that the degree to which the transformer oil level - oil temperature data deviates from the standard transformer oil level - oil temperature curve can be visually observed. Interface 2 also shows the "Transformer oil level and oil temperature normal" or "Transformer oil level and oil temperature abnormal" alarm signal transmitted from the communication module.

[0027] Such as Figure 1-2As shown in the figure, the ultrasonic sensor module is one of the main innovations, and its design details are further specified and explained here. The ultrasonic sensor module A is installed in the middle position above the transformer oil pillow, and an ultrasonic coupling agent is applied at the installation position of the ultrasonic sensor module A to reduce the influence of the air layer between the probe and the object to be measured and improve the measurement accuracy; the shell of the ultrasonic sensor module A is designed to have ferromagnetic adsorption characteristics and adsorbed on the outer wall of the iron material above the transformer oil pillow; Ultrasonic sensor module B is installed in the middle of the transformer oil pillow. Ultrasonic coupling agent is also applied to the installation position of ultrasonic sensor module B to reduce the influence of the air layer between the probe and the object to be measured and improve the measurement accuracy. The shell of ultrasonic sensor module B has ferromagnetic adsorption characteristics and is adsorbed on the outer wall of the iron material under the transformer oil pillow.

[0028] like Figure 3-4 As shown, the specific installation method of the ultrasonic sensor module A and the ultrasonic sensor module B is: fixed on the transformer oil pillow by a hoop, the hoop includes: a semicircular hoop A, a semicircular hoop B and bolts A and bolts B for connection, the semicircular hoop A and the semicircular hoop B are wrapped around the transformer oil pillow, the bolts A and the bolts B are installed at the punched holes on both sides of the semicircular hoop A and the semicircular hoop B, the semicircular hoop A and the semicircular hoop B are fastened to the transformer oil pillow by adjusting the nuts on the bolts A and the bolts B, and the ultrasonic sensor module A and the ultrasonic sensor module B clamped between the semicircular hoop A, the semicircular hoop B and the oil pillow are also fastened to the transformer oil pillow, and the ultrasonic sensor module A and the ultrasonic sensor module B are connected through power and communication cables.

[0029] The basic principle of oil level detection by ultrasonic sensor is that the ultrasonic transmitting probe sends an ultrasonic pulse signal to the object to be measured. When the ultrasonic pulse encounters the liquid interface during propagation, it is reflected. The reflected ultrasonic signal is received by the ultrasonic receiving probe, and the time from the emission of the ultrasonic wave to the reception of the echo is measured. According to the speed of sound in the medium, the liquid level is calculated.

[0030] The ultrasonic signal emitted by the ultrasonic sensor module A is transmitted from the air above the oil pillow to the transformer oil level and then reflected. The propagation speed of the ultrasonic signal emitted by the ultrasonic sensor module A in the air above the transformer oil pillow is V1. The time taken by the ultrasonic sensor module A from transmitting to receiving the ultrasonic signal is T1. The height of the transformer oil pillow is H. The oil level height H1 measured by the ultrasonic sensor module A1 can be calculated as: H1=H-h1=H-(V1*T1) / 2; The ultrasonic signal emitted by the ultrasonic sensor module B is transmitted from the transformer oil at the bottom of the oil pillow to the air and then reflected. The propagation speed of the ultrasonic signal emitted by the ultrasonic sensor module B in the transformer oil at the bottom of the transformer oil pillow is V2. The time taken by the ultrasonic sensor module B from transmitting to receiving the ultrasonic signal is T2. The height of the transformer oil pillow is H. The oil level height H2 measured by the ultrasonic sensor module B2 can be calculated as: H2=h2=(V2*T2) / 2.

[0031] like Figure 5 As shown, the hardware part of the ultrasonic sensor module A includes: an MCU processor 1-1, a power module 1-2, an output module 1-3, a module A transmitting circuit 1-4, a module A receiving circuit 1-5, and an ultrasonic sensor A probe 1-6; the specific connection method is: the MCU processor 1-1 provides the module A transmitting circuit 1-4 and the module A receiving circuit 1-5 with control and acquisition signals for sending and receiving ultrasonic signals, the module A transmitting circuit 1-4 controls the ultrasonic sensor A probe 1-6 to send ultrasonic signals, and the ultrasonic sensor A probe 1-6 then transmits the received ultrasonic signals to the module A receiving circuit 1-5, and the module A receiving circuit 1-5 transmits the received ultrasonic signals back to the MCU processor 1-1, the power module 1-2 provides power for the MCU processor 1-1, the module A transmitting circuit 1-4 and the module A receiving circuit 1-5, the MCU processor 1-1 transmits the calculated oil level signal data to the output module 1-3, and the output module 1-3 transmits it to the oil level and oil temperature data acquisition and analysis module; The hardware part of ultrasonic sensor module B includes: module B transmitting circuit 2-1, module B receiving circuit 2-2, ultrasonic sensor B probe 2-3. In order to save resources and reduce volume, ultrasonic sensor module B and ultrasonic sensor module A share a MUC processing module 1-1, power module 1-2, and output module 1-3. Ultrasonic sensor module B is connected to the MUC processing module 1-1, power module 1-2, and output module 1-3 of ultrasonic sensor module A through power and communication cables. The connection method and function of each component of ultrasonic sensor module B are the same as those in ultrasonic sensor module A.

[0032] The ultrasonic frequency range of the ultrasonic sensor module A and the ultrasonic sensor module B in the ultrasonic sensor module is 20~200kHz. The frequency of the ultrasonic wave to be used is determined according to the actual application debugging effect. To prevent mutual interference between the ultrasonic sensor module A and the ultrasonic sensor module B, two wave emission schemes are adopted here, Scheme 1 and Scheme 2, as follows: like Figure 6 As shown in the figure, the ultrasonic sensor module oil level measurement process of scheme 1 is as follows: after the system starts, the ultrasonic sensor module A first transmits a frequency of fThe ultrasonic signal is then determined whether an echo is received. If no echo is received, the ultrasonic sensor module A is again transmitted at a frequency of f The ultrasonic signal is sent until it is determined that the ultrasonic echo is received, and the received ultrasonic signal is subjected to noise reduction processing. The transformer oil level height H1 measured by the ultrasonic sensor module A is calculated based on the ultrasonic signal after noise reduction processing, and then the ultrasonic sensor module B is set to transmit at the same frequency. f The ultrasonic signal is also used to determine whether an echo is received. If no echo is received, the ultrasonic sensor module B is again sent with a frequency of f The ultrasonic signal is sent and received until it is determined that the ultrasonic echo is received, the ultrasonic signal sent and received is subjected to noise reduction processing, and the transformer oil level height H2 measured by the ultrasonic sensor module B1 is calculated according to the ultrasonic signal after the noise reduction processing, and finally the measured oil level height data H1 and H2 are transmitted to the oil level and oil temperature data acquisition and analysis module; like Figure 7 As shown in the figure, the ultrasonic sensor module oil level measurement process of scheme 2 is as follows: after the system starts, ultrasonic sensor module A and ultrasonic sensor module B simultaneously send out signals with a frequency of f1 and f2 Then determine whether the ultrasonic sensor module A and the ultrasonic sensor module B have received the echo. If no echo is received, clear the received ultrasonic echo data, and let the ultrasonic sensor module A and the ultrasonic sensor module B send out the ultrasonic signal with a frequency of f1 and f2 The ultrasonic signal is sent and received until it is determined that the ultrasonic sensor module A and the ultrasonic sensor module B have received the ultrasonic echo, and the ultrasonic signal sent and received is subjected to noise reduction processing. The oil level heights H1 and H2 measured by the ultrasonic sensor module A and the ultrasonic sensor module B are calculated respectively according to the ultrasonic signal after the noise reduction processing, and finally the measured oil level height data H1 and H2 are transmitted to the oil level and oil temperature data acquisition and analysis module.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors, characterized in that: Including: An ultrasonic sensor module, an oil temperature sensor module, an oil level and oil temperature data acquisition and analysis module, a communication module, and a monitoring background. The ultrasonic sensor module and the oil temperature sensor module transmit the measured transformer oil level and oil temperature data to the oil level and oil temperature data acquisition and analysis module. After the oil level and oil temperature data acquisition and analysis module processes the data, it transmits the relevant oil level and oil temperature data and alarm information to the communication module, and then the communication module transmits it to the monitoring background.

2. A transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors as claimed in claim 1, characterized in that: The ultrasonic sensor module includes: ultrasonic sensor module A and ultrasonic sensor module B, and it mainly has the following functions: S1.1 Ultrasonic sensor module A and ultrasonic sensor module B respectively emit ultrasonic signals and collect the corresponding echo signals; S1.2 Perform noise reduction processing on the collected ultrasonic signals to reduce the influence of noise in the substation on the measurement results; S1.3 Respectively calculate the oil level data H1 measured by ultrasonic sensor module A and the oil level data H2 measured by ultrasonic sensor module B based on the ultrasonic data after noise reduction processing, and transmit the calculated oil level data H1 and oil level data H2 to the oil level and oil temperature data acquisition and analysis module.

3. A transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors as claimed in claim 1, characterized in that: The transformer oil temperature sensor module has the following functions: S2.1 Measure the transformer oil temperature and transmit the measured oil temperature data T to the oil level and oil temperature data acquisition and analysis module and the communication module.

4. A transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors as claimed in claim 1, characterized in that: The oil level and oil temperature data acquisition and analysis module has the following functions S3.1 Receive the oil level height H1 data and oil level height H2 data transmitted from the ultrasonic sensor module, and calculate the oil level deviation measured by the two ultrasonic sensors. The calculation formula is: ΔH = H1 - H2; S3.2: K is the discrimination coefficient for the accuracy of oil level measurement, and its value is determined according to different characteristics of the oil conservator; When the condition of ΔH < K is not met, it indicates that the oil levels measured by ultrasonic sensor module A and ultrasonic sensor module B are quite different, and the measured oil level is inaccurate. At this time, the signal transmitted to the communication module is: "ultrasonic sensor abnormal" alarm signal, as well as the oil level height H1 data and oil level height H2 data; When the "ultrasonic sensor abnormal" alarm signal is issued, the operation and maintenance personnel can compare the mechanical oil level indication data of the transformer oil conservator with the oil level height H1 data and oil level height H2 data measured by the two ultrasonic sensors to determine which ultrasonic sensor is abnormal, and then carry out maintenance; When the condition of ΔH < K is met, it indicates that the oil levels measured by ultrasonic sensor module A and ultrasonic sensor module B are not very different, and the measured oil level is accurate; S3.3: At this time, calculate the average oil level based on the oil level height H1 data and oil level height H2 data. The formula for calculating the average oil level is: Hv = (H1 + H2) / 2; S3.4: Based on the average oil level data Hv and the received oil temperature data T, determine whether the transformer oil level and oil temperature are normal based on the transformer standard oil level and oil temperature curve data. The discrimination condition is: Condition 1: |Hv - h| < g, where h is the oil level data of the transformer in the transformer standard oil level - oil temperature curve corresponding to the actually measured transformer oil temperature data T, and g is the corresponding oil level comparison coefficient, whose value is set according to the oil level - oil temperature characteristics of different oil conservators; Condition 2: |T - t| < e, where t is the oil temperature data of the transformer in the transformer standard oil level - oil temperature curve corresponding to the actually measured oil level data Hv, and e is the corresponding temperature comparison coefficient, whose value is set according to the oil level - oil temperature characteristics of different oil conservators; S3.5: When Conditions 1 and 2 are met, it indicates that the oil level and oil temperature are normal. At this time, the signals transmitted to the communication module are: the signal of "normal transformer oil level and oil temperature", and the oil level data H1, H2, Hv measured by the sensor; S3.6: When either of Conditions 1 and 2 is not met, it indicates that the oil level and oil temperature are abnormal. At this time, the signals transmitted to the communication module are: the signal of "abnormal transformer oil level and oil temperature", and the oil level data H1, H2, Hv measured by the sensor.

5. A transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors as claimed in claim 1, characterized in that: The communication module has the following functions: S4.1 Receive the relevant alarm signals transmitted from the oil level - oil temperature data acquisition and analysis module, the measured oil level data H1, H2, Hv, and the oil temperature data T transmitted from the transformer oil temperature sensor module, and send these alarm signals and data to the monitoring background.

6. A transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors as claimed in claim 1, characterized in that: The functions of the monitoring background are: Receive the relevant alarm signals transmitted from the communication module, the measured oil level data H1, H2, Hv, and the oil temperature data T, and design the monitoring background interface into 2 sub - interfaces, specifically S5.1 Interface 1 shows the curves of the measured oil level data H1, the oil level data H2, and the average oil level data Hv changing with the transformer oil temperature T, a total of three curves; at the same time, when the ultrasonic sensor is abnormal, it shows the alarm signal of "abnormal ultrasonic sensor" transmitted from the communication module; S5.2 Interface 2 shows the coordinate interface of the standard transformer oil level - oil temperature curve, and the transformer average oil level data Hv and the transformer oil temperature T are presented in the form of coordinate points on the standard transformer oil level - oil temperature curve coordinate interface, so that the degree to which the transformer oil level - oil temperature data deviates from the standard transformer oil level - oil temperature curve can be visually observed. Interface 2 also shows the alarm signal of "normal transformer oil level and oil temperature" or "abnormal transformer oil level and oil temperature" transmitted from the communication module.

7. A transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors as claimed in claim 2, characterized in that: The ultrasonic sensor module A is installed at the exact middle position above the transformer oil conservator, and the ultrasonic sensor module B is installed at the exact middle position below the transformer oil conservator. Ultrasonic coupling agent is applied at the installation positions of the ultrasonic sensor module A and the ultrasonic sensor module B to reduce the influence of the air layer between the probe and the measured object and improve the measurement accuracy; the outer shells of the ultrasonic sensor module A and the ultrasonic sensor module B are designed to have ferromagnetic adsorption characteristics and are adsorbed on the outer wall of the iron - made material of the transformer oil conservator.

8. A transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors as claimed in claim 7, characterized in that: The ultrasonic sensor module A and the ultrasonic sensor module B are fixed on the transformer oil pillow through a hoop, and the hoop includes: two semicircular hoops and bolts for connection. The two semicircular hoops are wrapped around the transformer oil pillow to respectively wrap the ultrasonic sensor module A and the ultrasonic sensor module B. The semicircular hoops are fastened to the transformer oil pillow by adjusting the bolts on the semicircular hoops, so that the ultrasonic sensor module A and the ultrasonic sensor module B clamped between the semicircular hoops and the oil pillow are fastened to the transformer oil pillow, and the ultrasonic sensor module A is connected to the ultrasonic sensor module B through a power supply and a communication cable.

9. A transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors as claimed in claim 7, characterized in that: The ultrasonic signal emitted by the ultrasonic sensor module A is transmitted from the air above the oil pillow to the transformer oil level and then reflected. The propagation speed of the ultrasonic signal emitted by the ultrasonic sensor module A in the air above the transformer oil pillow is V1. The time taken by the ultrasonic sensor module A from transmitting to receiving the ultrasonic signal is T1. The height of the transformer oil pillow is H. The oil level height H1 measured by the ultrasonic sensor module A can be calculated as: H1=H-h1=H-(V1*T1) / 2; The ultrasonic signal emitted by the ultrasonic sensor module B is transmitted from the transformer oil at the bottom of the oil pillow to the air and then reflected. The propagation speed of the ultrasonic signal emitted by the ultrasonic sensor module B in the transformer oil at the bottom of the transformer oil pillow is V2. The time taken by the ultrasonic sensor module B from transmitting to receiving the ultrasonic signal is T2. The height of the transformer oil pillow is H. The oil level height H2 measured by the ultrasonic sensor module B can be calculated as: H2=h2=(V2*T2) / 2.

10. A transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors as claimed in claim 7, characterized in that: The hardware part of the ultrasonic sensor module A includes: MCU processor, power module, output module, module A transmitting circuit, module A receiving circuit, and ultrasonic sensor A probe. The specific connection method is: the MCU processor provides control and acquisition signals for the module A transmitting circuit and the module A receiving circuit to send and receive ultrasonic signals, the module A transmitting circuit controls the ultrasonic sensor A probe to send ultrasonic signals, the ultrasonic sensor A probe then transmits the received ultrasonic signals to the module A receiving circuit, the module A receiving circuit transmits the received ultrasonic signals back to the MCU processor, the power module provides power to the MCU processor, the module A transmitting circuit and the module A receiving circuit, the MCU processor transmits the calculated oil level signal data to the output module, and the output module transmits it to the oil level and oil temperature data acquisition and analysis module; The hardware part of the ultrasonic sensor module B in the ultrasonic sensor module includes: module B transmitting circuit, module B receiving circuit, and ultrasonic sensor B probe. In order to save resources and reduce volume, the ultrasonic sensor module B and the ultrasonic sensor module A share a MUC processing module, power module, and output module. The ultrasonic sensor module B is connected to the MUC processing module, power module, and output module of the ultrasonic sensor module A through a power supply and communication cable. The connection method and function of each component of the ultrasonic sensor module B are the same as those in the ultrasonic sensor module A.

11. A transformer oil level and oil temperature monitoring and alarm system using dual ultrasonic sensors as claimed in claim 7, characterized in that: The ultrasonic frequency range of the ultrasonic sensor module A and the ultrasonic sensor module B in the ultrasonic sensor module is 20~200kHz. The frequency of the ultrasonic wave to be used is determined according to the actual application debugging effect. To prevent mutual interference between the ultrasonic sensor module A and the ultrasonic sensor module B, two wave emission schemes are adopted here, Scheme 1 and Scheme 2, as follows: The ultrasonic sensor module oil level measurement process of scheme 1 is as follows: after the system starts, the ultrasonic sensor module A first transmits a frequency of f The ultrasonic signal is then determined whether an echo is received. If no echo is received, the ultrasonic sensor module A is again transmitted at a frequency of f The ultrasonic signal is sent until it is determined that the ultrasonic echo is received, and the received ultrasonic signal is subjected to noise reduction processing. The transformer oil level height H1 measured by the ultrasonic sensor module A is calculated based on the ultrasonic signal after noise reduction processing, and then the ultrasonic sensor module B is set to transmit at the same frequency. f The ultrasonic signal is also used to determine whether an echo is received. If no echo is received, the ultrasonic sensor module B is again sent with a frequency of f The ultrasonic signal is received until it is determined that the ultrasonic echo is received, the ultrasonic signal sent and received is subjected to noise reduction processing, and the transformer oil level height H2 measured by the ultrasonic sensor module B is calculated according to the ultrasonic signal after the noise reduction processing, and finally the measured oil level height data H1 and H2 are transmitted to the oil level and oil temperature data acquisition and analysis module; The ultrasonic sensor module oil level measurement process of scheme 2 is as follows: after the system starts, ultrasonic sensor module A and ultrasonic sensor module B simultaneously send out signals with a frequency of f1 and f2 Then determine whether the ultrasonic sensor module A and the ultrasonic sensor module B have received the echo. If no echo is received, clear the received ultrasonic echo data, and let the ultrasonic sensor module A and the ultrasonic sensor module B send out the ultrasonic signal with a frequency of f1 and f2 The ultrasonic signal is sent and received until it is determined that the ultrasonic sensor module A and the ultrasonic sensor module B have received the ultrasonic echo, and the ultrasonic signal sent and received is subjected to noise reduction processing. The oil level heights H1 and H2 measured by the ultrasonic sensor module A and the ultrasonic sensor module B are calculated respectively according to the ultrasonic signal after the noise reduction processing, and finally the measured oil level height data H1 and H2 are transmitted to the oil level and oil temperature data acquisition and analysis module.

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