A low-voltage motor partial discharge monitoring device based on a TMR sensor

Abstract

The utility model discloses a low -voltage motor partial discharge monitoring devices based on TMR sensor, including TMR sensor, motor terminal block, U / V / W three -phase power supply wiring terminal, power line cable, motor winding, the power line cable 9 of U / V / W three -phase power supply wiring terminal connection on motor terminal block 3 is led out from the wiring terminal and first respectively passes through TMR sensor through -hole 10 again, passes through cable incoming wire hole 6 and is accessed motor winding. The external connecting device of TMR sensor includes signal enhancement amplifier, filter, ADC (A / DConverter) analog -to -digital converter, power carrier communication technology device, remote acceptance decoding device, motor partial discharge diagnosis and evaluation device. The integration of TMR sensor greatly promotes the detection sensitivity and anti -interference ability of low -voltage motor partial discharge signal, realizes higher precision monitoring. Secondly, with the aid of advanced signal processing technology and intelligent diagnosis algorithm, not only environmental adaptability is strengthened, also the ability of real -time monitoring is ensured.

Description

Technical Field

[0001] This utility model mainly relates to the field of power equipment condition monitoring technology, specifically providing a low-voltage motor partial discharge monitoring device based on a TMR sensor. Background Technology

[0002] In the operation of power equipment, especially low-voltage motors, partial discharge serves as an early sign of fault, and its effective monitoring is crucial for timely detection of potential hazards and prevention of major accidents. Currently, mainstream partial discharge monitoring technologies typically employ coupling capacitors, which are installed in parallel to detect partial discharge signals. However, due to their large size, this not only increases installation complexity but also makes it difficult to meet explosion-proof requirements. Furthermore, coupling capacitors have poor electromagnetic compatibility and limited sensitivity, making it difficult to accurately capture partial discharge signals under complex operating conditions. Existing technological solutions: Current partial discharge monitoring schemes mostly rely on CT or high-frequency CT (HFCT) sensors. These schemes indirectly determine the occurrence of partial discharge by detecting pulse currents in high-voltage lines. The shortcomings of existing technical solutions are as follows: the above solutions have obvious limitations in the monitoring of partial discharge in low-voltage motors: a) HFCT sensors have a weak response to signals in low-voltage environments, resulting in a low signal-to-noise ratio and difficulty in accurately identifying partial discharge signals; b) CT sensors are mainly designed for power frequency current and cannot effectively capture high-frequency signals; and HFCT sensors need to be installed through wires or cables, which means that the cables must be disconnected or there must be enough space for the sensor to pass through, making the operation cumbersome; c) these solutions lack real-time monitoring functions, cannot achieve continuous feedback and trend analysis, resulting in delayed fault warnings and reduced system safety.

[0003] Therefore, this utility model urgently needs to overcome the following key challenges: 1) Existing monitoring equipment is large in size, requiring the junction box to be opened during installation, which cannot meet the requirements of explosion-proof environments and increases the complexity of installation and maintenance. 2) Traditional monitoring schemes perform poorly in complex electromagnetic environments and are easily affected by electromagnetic interference, leading to instability and unreliability of monitoring data. 3) Current monitoring systems typically lack the ability to provide real-time data feedback and long-term trend analysis, resulting in insufficient early warning capabilities for partial discharge phenomena, which may lead to equipment not being inspected or maintained in a timely manner before a failure occurs. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention proposes a low-voltage motor partial discharge monitoring device based on a TMR sensor, using a TMR (Tunnel Magnetoresistive) sensor as the solution. First, the TMR sensor is compact, allowing the junction box to be properly closed after installation, meeting explosion-proof requirements and greatly simplifying the installation process. Second, the TMR sensor possesses a wide-bandwidth response capability, capable of capturing not only high-frequency pulse current signals but also simultaneously acquiring AC and DC signals, significantly improving monitoring sensitivity and accuracy. Its high precision allows it to adapt to various complex environments and is not prone to saturation, ensuring long-term stable operation. Furthermore, compared to traditional sensors, the TMR sensor has low power consumption, good temperature adaptability, strong anti-interference capability, and is easy to integrate, providing a more flexible and efficient solution for low-voltage motor partial discharge monitoring, enabling high-quality real-time signal acquisition and remote fault early warning.

[0005] The technical solution of this utility model is implemented as follows:

[0006] A partial discharge monitoring device for a low-voltage motor based on a TMR sensor includes a TMR sensor, a motor terminal block, U / V / W three-phase power supply terminals, a power cable, and motor windings; characterized in that...

[0007] The power cable 9, which is connected to the U / V / W three-phase power terminals on the motor terminal block 3, is led out from the terminal block and first passed through the TMR sensor through hole 10, and then connected to the motor winding through the cable inlet hole 6.

[0008] The low-voltage motor partial discharge monitoring device based on TMR sensor is characterized in that the TMR sensor is bolted to a metal base plate or bracket fixed on the junction box bottom plate 2 inside the junction box bottom shell 1 of the motor using two fixing holes at the bottom of the TMR sensor.

[0009] The low-voltage motor partial discharge monitoring device based on TMR sensor is characterized in that the motor terminal block 3 is fixed on the junction box bottom plate 2 of the junction box bottom shell 1 of the motor.

[0010] The low-voltage motor partial discharge monitoring device based on a TMR sensor is characterized in that the external connection device of the TMR sensor includes a signal enhancement amplifier, a filter, an ADC (A / D Converter) analog-to-digital converter, a power line communication (PLC) device, a remote receiving and decoding device, and a motor partial discharge diagnosis and evaluation device.

[0011] The low-voltage motor partial discharge monitoring device based on a TMR sensor is characterized in that a TMR sensor through hole 10 is provided in the center of the TMR sensor.

[0012] The low-voltage motor partial discharge monitoring device based on a TMR sensor is characterized in that the motor is equipped with a frequency converter.

[0013] The beneficial effects of this utility model are:

[0014] This invention employs a TMR sensor, providing excellent measurement accuracy and maintaining stable performance over a wide frequency range. This enables its widespread application in three-phase current monitoring of various electrical equipment, particularly excelling in detecting high-frequency signals and currents with small amplitude variations. Compared to traditional sensors, the TMR sensor used in this invention is compact and can be flexibly integrated into limited spaces, making it especially suitable for installation in explosion-proof and compact environments, thus improving the installation flexibility of electrical equipment. The TMR sensor in this invention has excellent anti-saturation capabilities, maintaining stable measurement results under large current variations. Simultaneously, it is less affected by external magnetic fields and can operate reliably in complex electromagnetic environments. The integration of the TMR sensor significantly improves the detection sensitivity and anti-interference capability of partial discharge signals in low-voltage motors, achieving higher-precision monitoring. Secondly, with the help of advanced signal processing technology and intelligent diagnostic algorithms, not only is environmental adaptability enhanced, but real-time monitoring capabilities are also ensured, significantly reducing fault warning delays and improving the overall system stability and reliability. Thirdly, the addition of an automated self-testing mechanism further improves system robustness, reduces maintenance costs, and extends service life. In summary, this technical solution solves the inherent problems of traditional partial discharge monitoring technology when applied to low-voltage motors, and represents a cutting-edge advancement in the field of power equipment condition monitoring. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating the connection principle between the TMR sensor, the low-voltage motor, and the frequency converter in this utility model.

[0016] Figure 2 This is a structural diagram of the bottom shell of the junction box for a low-voltage motor.

[0017] Figure 3 This is a schematic diagram of the TMR sensor structure in this utility model.

[0018] Figure 4 This is a schematic diagram of the connection structure between the power supply line of the low-voltage motor and the TMR sensor in this utility model.

[0019] Figure 5 This is a block diagram illustrating the working principle of the network connection of the low-voltage motor partial discharge online monitoring device of this utility model.

[0020] Explanation of the attached drawing numbers:

[0021] 1. Junction box bottom shell; 2. Junction box base plate; 3. Motor terminal block; 4. Bolt mounting hole; 5. TMR sensor; 6. Cable inlet hole; 7. Rib; 8. Power cable; 9. TMR sensor through hole; 10. U / V / W are the three-phase power supply terminals (used to describe the motor or frequency converter). Detailed Implementation

[0022] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings.

[0023] See Figure 1-4 As shown, in order to overcome the bottleneck of traditional partial discharge monitoring technology in low-voltage motor applications, this utility model proposes the following solution:

[0024] This invention employs a TMR (Tunnel Magneto-Resistance) sensor to construct an online monitoring device specifically designed for partial discharge in low-voltage motors. The TMR sensor, with its superior sensitivity, excellent anti-interference performance, and ease of integration, is an ideal choice.

[0025] The specific implementation plan is as follows:

[0026] The installation and connection method is as follows:

[0027] 1. The U, V, and W three-phase power cables pass through the TMR sensor's 5-hole connector respectively.

[0028] See Figure 2-4 As shown, select three phases of the three-phase power supply line, and lead the power cable 9, which is connected to the U / V / W three-phase power supply terminal, out of the terminal and first pass through the TMR sensor through hole 10, and then through the cable inlet hole 6 to the motor winding.

[0029] 2. Fix the TMR sensor

[0030] Using the two mounting holes at the bottom of the TMR sensor, it can be firmly fixed to the metal base plate or bracket fixed on the junction box base plate 2 inside the junction box bottom shell 1 of the motor. It can be fixed with bolts.

[0031] 3. Connect the TMR sensor signal cable

[0032] The TMR sensor leads are connected to an external acquisition board via a 4-pin header or ribbon cable.

[0033] - Step 1: The TMR sensor is carefully installed behind the critical area of ​​the low-voltage motor to accurately sense the subtle current changes generated during operation. This arrangement ensures the quality and stability of the initial signal.

[0034] - Step 2: Using a high-precision amplifier, see Figure 5As shown, the signal captured by the TMR sensor is enhanced, and then a dedicated bandpass filter is used to remove background noise to ensure the purity of the partial discharge signal.

[0035] Step 3: Use a high-speed ADC (A / D Converter) to convert the purified analog signal into a digital signal, ensuring lossless signal conversion.

[0036] Step 4: Use Power Line Communication (PLC) technology to load digital signals onto power lines and send them to the remote monitoring center, thereby replacing the need to lay separate communication lines and simplifying the network architecture.

[0037] Step 5: The remote monitoring point receives the signal through the power line and decodes and restores the original partial discharge data.

[0038] Step 6: Finally, the motor partial discharge diagnostic component combines multiple frequency domain analysis methods to find fault characteristic frequencies in the frequency domain signal, accurately diagnose partial discharge characteristics, and complete the comprehensive health status evaluation.

[0039] Specific Example: Assume a typical industrial production environment where a three-phase low-voltage motor operating at 400V is running, with a normal operating current level of approximately 100A. We place a TMR sensor near the motor windings to capture any weak partial discharge current caused by insulation aging, expected to be only a few mA in intensity. Once a partial discharge event occurs, the sensor immediately detects and outputs the corresponding electrical signal, which then enters the amplification and filtering stage. After initial amplification, the signal is fed into a customized bandpass filter with a frequency window set between 10kHz and 50kHz to eliminate most irrelevant noise. Next, the signal is sampled by a high-speed ADC at a sampling rate of 1MHz to ensure data integrity. Then, using PLC technology, the digital signal is encoded and transmitted via the motor's power supply cable to a monitoring room located on the other side of the plant, approximately 300 meters away. The receiving device in the monitoring room decodes the signal and recovers the partial discharge data stream. Finally, the data is analyzed in depth by a motor partial discharge diagnostic component to identify partial discharge modes, such as surface flashover and air gap breakdown, and provides a motor health status report to guide subsequent maintenance strategies.

[0040] 2) Optimization Scheme 1: To further improve the intelligence and automation level of the monitoring system, integrate AI models for data analysis, automatically identify and classify different types of partial discharge modes, reduce the need for manual intervention, and speed up the response.

[0041] Implementation method 1:

[0042] Building upon the basic solution, a deep learning neural network model is added and pre-trained to identify various partial discharge morphologies. The specific steps include: First, collecting a large amount of historical partial discharge data samples, covering various typical discharge types; second, using the TensorFlow framework to build a convolutional neural network (CNN) model to extract the temporal and frequency features of the signal; third, using the Adam optimizer to train the model, minimizing the cross-entropy loss function until convergence; fourth, in the testing phase, inputting new data not used in training into the model to verify its recognition accuracy; fifth, after deployment, the system continuously monitors the motor status, and when a suspected partial discharge signal is detected, immediately activates the neural network for classification and judgment, quickly determining the discharge category and its severity level.

[0043] 3) Optimization Scheme 2: In addition, considering the continuity and integrity of monitoring data under harsh environmental conditions,

[0044] This solution incorporates a self-testing mechanism to periodically check the operational status of the TMR sensor and other critical components.

[0045] Ensure the system is stable and reliable.

[0046] Implementation Method 2:

[0047] Building upon the basic solution, a new periodic system self-test process is added, consisting of the following steps: First, the self-test program is initiated, and the TMR sensor is excited by a preset excitation signal to verify its normal response; Second, the gain and frequency characteristics of the amplifier and filter are tested to ensure that the signal link quality meets the standards; Third, the accuracy of the AD converter is checked to prevent the accumulation of quantization errors; Fourth, the data packet loss rate and bit error rate of the PLC module are tested to confirm unimpeded communication; Fifth, based on the self-test results, the system automatically generates a health report. If a potential fault is found, an early warning notification is triggered, and necessary maintenance activities are arranged.

[0048] 4) Key points of this technical solution:

[0049] - Application of TMR sensors in partial discharge monitoring of low-voltage motors and their specific deployment scheme.

[0050] - Design of high-performance signal processing pipelines, including signal enhancement, bandpass filtering, digital conversion, etc.

[0051] - Wireless transmission of monitoring data is achieved using electromagnetically coupled power line communication (PLC) technology.

[0052] -Integrate AI-based partial discharge pattern recognition algorithms to enhance intelligence.

[0053] - An automated system self-checking and fault diagnosis mechanism ensures long-term reliability.

[0054] This invention uses a TMR sensor to detect changes in the surrounding magnetic field to sense fluctuations in current. In a three-phase current system, each phase of current flow generates a corresponding magnetic field. The TMR sensor can accurately detect these magnetic field changes and convert them into current signals through changes in resistance.

[0055] The TMR sensor of this invention is constructed using conventional technology with multiple layers of metal thin films. The resistance of these films changes with the external magnetic field. When current flows through a conductor, it generates a magnetic field around it. The TMR sensor can sense this change in magnetic field and detect the magnitude of the current based on the change in magnetic field strength.

[0056] This invention utilizes a TMR sensor in a three-phase current system to detect the different magnetic field changes generated by each phase current. It accurately measures the changes in current in each phase by directly passing through the conductor and converts them into current values. The TMR sensor in this invention provides excellent measurement accuracy and maintains stable performance over a wide frequency range; it performs particularly well in detecting high-frequency signals and small-amplitude current changes. Compared to traditional sensors, the TMR sensor used in this invention is compact and can be flexibly integrated into limited spaces, making it particularly suitable for installation in explosion-proof and compact environments, thus improving the installation flexibility of electrical equipment. The TMR sensor also has excellent anti-saturation capabilities, maintaining stable measurement results under large current changes. Furthermore, it is less affected by external magnetic field interference and can operate reliably in complex electromagnetic environments. The TMR sensor also has a fast response speed, enabling real-time tracking of current changes, making it particularly suitable for dynamic load monitoring and fault diagnosis of equipment such as motors and transformers. Its low power consumption during operation makes it suitable for low-power embedded devices, helping the system achieve stable operation for longer periods.

[0057] In summary, the TMR sensor of this invention provides an efficient and reliable current monitoring solution for three-phase current detection, based on its highly sensitive response to changes in magnetic fields, combined with its accurate current measurement, excellent anti-interference capability, and flexible installation method. It performs particularly well in explosion-proof, confined space, and complex electromagnetic environments, such as when installed inside a motor junction box, meeting the demands of modern electrical equipment for high precision, low power consumption, and real-time monitoring.

Claims

1. A partial discharge monitoring device for a low-voltage motor based on a TMR sensor, comprising a TMR sensor, a motor terminal block, U / V / W three-phase power supply terminals, power cables, and motor windings; characterized in that, The power cable (9) connected to the U / V / W three-phase power terminals on the motor terminal block (3) is led out from the terminal block and first passed through the TMR sensor through hole (10), and then connected to the motor winding through the cable inlet hole (6).

2. The low-voltage motor partial discharge monitoring device based on a TMR sensor as described in claim 1, characterized in that, Using the two mounting holes at the bottom of the TMR sensor, bolt it to the metal base plate or bracket fixed inside the junction box bottom shell (1) of the motor and on the junction box bottom plate (2).

3. The low-voltage motor partial discharge monitoring device based on a TMR sensor as described in claim 1, characterized in that, The motor terminal block 3 is fixed on the junction box bottom plate (2) of the junction box bottom shell (1) of the motor.

4. The low-voltage motor partial discharge monitoring device based on a TMR sensor as described in claim 1, characterized in that, The external connection devices of the TMR sensor include a signal enhancement amplifier, a filter, an ADC (A / D Converter) analog-to-digital converter, a power line communication (PLC) device, a remote receiving and decoding device, and a motor partial discharge diagnosis and evaluation device.

5. The low-voltage motor partial discharge monitoring device based on a TMR sensor as described in claim 1, characterized in that, The TMR sensor has a TMR sensor through hole (10) at its center.

6. The low-voltage motor partial discharge monitoring device based on a TMR sensor as described in claim 1, characterized in that, The motor is equipped with a frequency converter.

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