High-voltage iron tower comprehensive performance on-line monitoring device and monitoring method thereof

Abstract

The invention discloses a high-voltage iron tower comprehensive performance on-line monitoring device and a monitoring method thereof, and the device comprises a comprehensive monitoring unit which is configured to obtain a monitoring instruction sent by a microprocessor unit to monitor a high-voltage iron tower. The microprocessor unit processes various data of the detected iron tower monitored by the comprehensive monitoring unit and then sends the data to the display unit; the comprehensive monitoring unit comprises a grounding resistance measuring module; an iron tower attitude measurement module; an iron tower screw loosening measurement module and an iron tower temperature measurement module; according to the high-voltage iron tower comprehensive performance on-line monitoring device and the monitoring method thereof, based on a multi-sensing technology, by arranging a plurality of measuring modules electrically connected with the microprocessor unit, the grounding resistance, the space attitude, the screw loosening condition and the iron tower temperature of the high-voltage iron tower can be monitored on line at the same time, manpower and material resources are saved, and meanwhile potential safety hazards are reduced.

Description

Technical Field

[0001] This invention belongs to the field of power technology, and in particular to an online monitoring device and method for the comprehensive performance of high-voltage iron towers. Background Technology

[0002] With my country's rapid economic development and energy structure transformation and upgrading, the power system is rapidly evolving towards larger capacity, longer distances, and greater intelligence. High-voltage transmission towers, as key infrastructure supporting the physical architecture of modern power grids, directly affect the safety and economy of cross-regional power distribution. During operation, towers are subjected to the combined effects of various factors such as soil desertification and corrosion, dynamic loads, and harsh external environments, leading to increasingly prominent issues with grounding resistance and stability. Currently, monitoring of high-voltage towers still relies to some extent on manual inspections, which is not only time-consuming and labor-intensive but also poses certain safety hazards. Therefore, to address these problems, this invention proposes an online monitoring device and method for the comprehensive performance of high-voltage transmission towers based on multiple sensors. Summary of the Invention

[0003] Purpose of the invention: To provide an online monitoring device and method for the comprehensive performance of high-voltage transmission towers, which can monitor the grounding resistance, spatial orientation, screw loosening, and tower temperature of high-voltage transmission towers online, saving manpower and reducing safety hazards.

[0004] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0005] Firstly, a comprehensive online monitoring device for the performance of high-voltage transmission towers is provided, comprising:

[0006] The integrated monitoring unit is configured to acquire monitoring instructions sent by the microprocessor unit to monitor the high-voltage tower. The microprocessor unit processes the various data of the tower under test monitored by the integrated monitoring unit and sends them to the display unit.

[0007] The integrated monitoring unit includes:

[0008] The grounding resistance measurement module is used to receive the voltage signal sent by the microprocessor unit and the voltage generation circuit and generate a current. The microprocessor unit obtains the grounding resistance of the tower under test based on the current.

[0009] The tower attitude measurement module is used to monitor the spatial attitude of the tower under test in real time. The microprocessor unit performs attitude calculation based on the spatial attitude to obtain modeling data for modeling.

[0010] The tower screw loosening measurement module is used to collect real-time time-domain vibration signals of the tower screws under test. The microprocessor unit converts the time-domain vibration signals into frequency-domain signals and extracts spectral features to determine the working state of the screws based on the spectral features.

[0011] The tower temperature measurement module is used to convert the collected temperature signal of the tower under test into an oscillation frequency signal, and the microprocessor unit obtains the temperature measurement value based on the oscillation frequency signal.

[0012] In some possible embodiments, the grounding resistance measurement module includes a voltage-excited iron core coil and a current-measuring iron core coil, which are coaxially arranged and coupled in a stacked manner along the axial direction, such that the grounding resistance lead of the tower under test passes through both the voltage-excited iron core coil and the current-measuring iron core coil simultaneously.

[0013] A shield is provided outside the voltage-excited iron core coil and the current-measuring iron core coil, and the shield is in an open state.

[0014] In a further embodiment, both the voltage-excited core coil and the current-measuring core coil comprise elliptical cores, and the two cores are of the same size.

[0015] The voltage-excited core coil has a first number of turns wound on its core, and the current-measuring core coil has a second number of turns wound on its core, with the first number of turns being greater than the second number of turns.

[0016] In a further embodiment, the voltage-excited core coil is connected to the microprocessor unit, the output terminal of the current-measuring core coil is connected to a full-bridge rectifier circuit, the output terminal of the full-bridge rectifier circuit is provided with a conversion resistor in parallel, and the microprocessor unit collects the voltage across the conversion resistor.

[0017] In a further embodiment, the tower attitude measurement module includes a six-axis inertial measurement unit for collecting three-axis acceleration and three-axis angular velocity data of the tower under test.

[0018] The microprocessor unit reads triaxial acceleration and triaxial angular velocity data to perform attitude calculation and obtains the spatial attitude parameters of the tower under test. The attitude parameters are quaternions or Euler angles.

[0019] In a further embodiment, the six-axis inertial measurement unit is configured in the carrier coordinate system, and all data information collected by the six-axis inertial measurement unit is based on the carrier coordinate system, the origin of the carrier coordinate system being coincident with the centroid of the six-axis inertial measurement unit.

[0020] In a further embodiment, the carrier coordinate system is associated with the inertial navigation coordinate system through an attitude transformation matrix;

[0021] The attitude transformation matrix is ​​either an attitude transformation matrix established based on the Euler angle algorithm or an attitude transformation matrix represented by quaternions.

[0022] In a further embodiment, the tower screw loosening measurement module includes a PVDF piezoelectric film sensor and a dual-T type 50Hz notch filter circuit.

[0023] The PVDF piezoelectric thin film sensor acquires the real-time time-domain vibration signal of the tower under test. The microprocessor unit converts the time-domain vibration signal into a frequency-domain signal through the DFT algorithm, extracts the spectral features, and determines the working state of the screw based on the spectral features.

[0024] The output terminal of the PVDF piezoelectric film sensor is connected to the input terminal of the dual-T 50Hz notch filter circuit, which is used to filter out power frequency interference.

[0025] In a further embodiment, the tower temperature measurement module includes a thermistor and a 555 multivibrator circuit. The thermistor serves as the control element of the 555 multivibrator circuit, used to convert the temperature signal into an oscillation frequency signal for output. The microprocessor unit is optically isolated from the 555 multivibrator circuit and acquires the oscillation frequency signal.

[0026] Secondly, a method for online monitoring of the comprehensive performance of high-voltage transmission towers is provided, employing the aforementioned monitoring device. The method includes the following steps:

[0027] The monitoring unit receives monitoring commands, enabling it to perform online monitoring of the high-voltage tower.

[0028] The grounding resistance measurement module receives a voltage signal from the microprocessor and generates a current, enabling the microprocessor unit to obtain the grounding resistance of the tower under test based on the current and send it to the display unit.

[0029] The tower attitude measurement module monitors the spatial attitude of the tower under test in real time, enabling the microprocessor unit to perform attitude calculation based on the spatial attitude to obtain modeling data for modeling, and then send it to the display unit.

[0030] The tower screw loosening measurement module collects the real-time time-domain vibration signal of the tower screw under test, so that the microprocessor unit converts the time-domain vibration signal into a frequency-domain signal, extracts the spectral features, determines the working state of the screw based on the spectral features, and sends it to the display unit.

[0031] The tower temperature measurement module converts the collected temperature signal of the tower under test into an oscillation frequency signal, enabling the microprocessor unit to obtain the temperature measurement value based on the oscillation frequency signal and send it to the display unit.

[0032] The beneficial effects of this invention are as follows: By employing a dual-core coil—one voltage excitation coil and one current measurement coil—both coils allow the grounding resistance lead to be measured to pass through, thus solving the problem of accurate online monitoring of the grounding resistance of high-voltage towers. Simultaneously, it proposes using an inertial measurement unit to monitor the spatial attitude of the high-voltage tower in real time. By reading the triaxial acceleration data from the accelerometer and the triaxial angular velocity data from the gyroscope, attitude calculation is performed to obtain the quaternion or Euler angles of the tower's spatial attitude. Furthermore, Kalman filtering or complementary filtering algorithms are used to reduce errors caused by the gyroscope itself and the attitude calculation. The data obtained from the attitude calculation is then transmitted to a microprocessor for processing by SolidWorks. The spatial 3D model obtained from KS modeling is displayed in real time, facilitating direct observation of the tower's spatial attitude. Furthermore, a PVDF piezoelectric film sensor, combined with a dual-T 50Hz notch filter to remove power frequency interference, transforms the acquired time-domain signal into a frequency-domain signal using an FFT algorithm. By analyzing the components of each harmonic in the spectrum, abnormal vibration at the screw can be identified relatively intuitively. A thermistor, combined with a 555 multivibrator circuit, converts the temperature signal into a frequency signal, achieving temperature measurement while improving resistance to strong electromagnetic interference. Considering the influence of the tower's own temperature while monitoring screw loosening further enhances the reliability of the assessment. Attached Figure Description

[0033] Figure 1 This is a circuit principle block diagram of an online monitoring device for the comprehensive performance of high-voltage iron towers based on multi-sensor technology, provided in one embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram illustrating the grounding resistance measurement principle according to an embodiment of the present invention.

[0035] Figure 3 This is a schematic diagram of the circuit of the ICM-42688 six-axis inertial measurement unit provided in one embodiment of the present invention.

[0036] Figure 4 This is a schematic diagram of coordinate transformation provided in one embodiment of the present invention.

[0037] Figure 5 This is a circuit diagram of a dual-T type 50Hz notch filter provided in one embodiment of the present invention.

[0038] Figure 6 This is a schematic diagram of the time-domain signal to frequency-domain signal waveform transformation of a PVDF piezoelectric thin film sensor provided in an embodiment of the present invention.

[0039] Figure 7 This is a schematic diagram illustrating the trend prediction over time provided by the Prophet model in one embodiment of the present invention.

[0040] Figure 8 This is a circuit diagram for measuring the temperature of a steel tower provided in one embodiment of the present invention.

[0041] Figure 9 This is a schematic diagram of the relationship between oscillation frequency and temperature provided in one embodiment of the present invention.

[0042] Figure 10 This is a schematic diagram of attitude calculation remote transmission provided in one embodiment of the present invention.

[0043] Figure 11 This is a circuit diagram of a serial port isolation driver chip provided in one embodiment of the present invention.

[0044] Figure 12 This is an RS485 automatic transceiver circuit diagram provided in one embodiment of the present invention.

[0045] Figure 13 This is a 24V to 12V circuit diagram provided in one embodiment of the present invention.

[0046] Figure 14 This is a circuit diagram of a 12VDC to 5VDC converter provided in one embodiment of the present invention.

[0047] Figure 15 This is a circuit diagram for converting 5VDC to 3.3VDC according to an embodiment of the present invention.

[0048] Figure 16 This is a 3.3V isolated power supply circuit diagram provided in one embodiment of the present invention.

[0049] Figure 17 This is a schematic diagram of the minimum system principle of STM32F103RCT6 provided in one embodiment of the present invention. Detailed Implementation

[0050] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0051] The present invention will be further described in detail below with reference to the accompanying drawings.

[0052] Example 1: Refer to Figure 1This embodiment discloses an online monitoring device for the comprehensive performance of high-voltage transmission towers, which includes a comprehensive monitoring unit configured to acquire monitoring instructions sent by a microprocessor unit to monitor the high-voltage transmission tower. The microprocessor unit processes the various data of the transmission tower under test monitored by the comprehensive monitoring unit and sends them to the display unit.

[0053] The display unit includes a display module, which is a touch-screen color LCD.

[0054] The microprocessor unit uses an STM32F103RCT6 microcontroller as the microprocessor for the data acquisition node. Its minimum system is as follows: Figure 17 As shown. The microprocessor provides multiple commonly used data interfaces such as I2C, SDIO, SPI, and USART, which can receive data information sent by sensors from various measurement modules to meet the requirements.

[0055] Specifically, the integrated monitoring unit includes a grounding resistance measurement module, a tower attitude measurement module, a tower screw loosening measurement module, and a tower temperature measurement module.

[0056] The grounding resistance measurement module is used to receive the voltage signal sent by the microprocessor unit and the voltage generation circuit and generate a current. The microprocessor unit obtains the grounding resistance of the tower under test based on the current.

[0057] Furthermore, the output terminal of the grounding resistance measurement module is connected to the A / D port of the microprocessor unit input terminal.

[0058] Reference Figure 2 The grounding resistance measurement module includes a voltage-excited iron core coil and a current-measuring iron core coil. The voltage-excited iron core coil and the current-measuring iron core coil are coaxially arranged and coupled in a stacked manner along the axial direction, so that the grounding resistance lead of the tower under test passes through both the voltage-excited iron core coil and the current-measuring iron core coil.

[0059] Both the voltage-excited iron core coil and the current-measuring iron core coil are covered by an open shield. The voltage-excited iron core coil and the current-measuring iron core coil are placed inside a non-magnetic, non-closed-loop pure iron shield to eliminate interference from surrounding electromagnetic fields. The principle behind this interference removal is that if an electromagnetic field is generated around the grounding resistance measurement module, the induced electromotive force on the shield cannot form a closed magnetic field because the shield is open.

[0060] Both the voltage-excited iron core coil and the current-measuring iron core coil include elliptical iron cores. The two iron cores are the same size, and the specific size of the iron cores can be arbitrarily determined according to the diameter of the grounding resistance lead wire of the tower under test, so that the grounding resistance lead wire of the tower under test can pass smoothly through the two iron cores.

[0061] The voltage-excited core coil has a first number of turns wound on its core, and the current-measuring core coil has a second number of turns wound on its core, with the first number of turns being greater than the second number of turns.

[0062] Optionally, the coil is made of 0.11mm diameter enameled wire, and the core is made of permalloy.

[0063] Optionally, the first number of turns can range from 100 to 400. Further, the first number of turns can be 400, and the second number of turns 50, with the second number always being less than the first. To couple the alternating magnetic field generated by applying an excitation voltage signal to the elliptical voltage-excited iron-core coil to the elliptical current-measuring iron-core coil, the voltage-excited iron-core coil should have as many turns as possible; more turns result in a stronger magnetic field and better coupling.

[0064] The input terminal of the voltage-excited iron core coil is connected to the input I / O port of the microprocessor unit.

[0065] To convert the alternating current signal into a direct current voltage signal, a full-bridge rectifier circuit is connected to the output terminal of the current measuring iron core coil. A conversion resistor is connected in parallel to the output terminal of the full-bridge rectifier circuit. The output terminal of the conversion resistor is connected to the A / D port of the microprocessor unit. The microprocessor unit acquires the voltage U3 across the conversion resistor. The voltage U3 is measured through a resistor and fed to the ADC of the microprocessor unit to acquire the voltage value. The current I2 is then calculated according to Ohm's law.

[0066] Specifically, the microprocessor unit, in conjunction with the sine wave generator circuit, generates a 20-40kHz high-frequency excitation voltage signal U1, which is transmitted to the voltage-excited iron core coil to generate an alternating magnetic field. The alternating magnetic field is transmitted to the current-measuring iron core coil through the grounding resistor lead, and an induced electromotive force e0 is generated at both ends of the current-measuring iron core coil.

[0067] The number of turns of the voltage-excited iron core coil is denoted as Nt, and the number of turns of the current-measuring iron core coil is denoted as Nr. Then the ratio of the number of turns of the two coils is equal to the ratio of the voltages of the two coils, which is expressed as Nt / Nr=U1 / e0.

[0068] Let the current in the grounding resistance loop be I1 and the voltage in the grounding resistance loop be e1. Then the grounding resistance R of the tower under test is... X It is expressed as follows:

[0069] R X =e1 / I1;

[0070] The ratio of the voltage of the current measuring iron core coil to the voltage of the grounding resistance circuit is expressed as follows:

[0071] e0 / e1=Nr;

[0072] The ratio of the current measurement core coil current I2 to the grounding resistance circuit current I1 is expressed as follows:

[0073] I2 / I1=1 / Nr;

[0074] The grounding resistance R of the tower under test X It is expressed as follows:

[0075] .

[0076] Figure 2 In the diagram, i1 and i2 represent instantaneous values, while I1 and I2 above represent effective values. Because the principle of the double-coil method for measuring grounding resistance is based on voltage coupling, only AC signals can be coupled through the coils. The lowercase symbols in the diagram represent AC instantaneous values, for example, the expression i1 = I1sin(wt + 30°). In calculations, only the effective value I1 needs to be used, consistent with the transformer calculation method.

[0077] The tower attitude measurement module is used to monitor the spatial attitude of the tower under test in real time. The microprocessor unit performs attitude calculation based on the spatial attitude to obtain modeling data for modeling.

[0078] Furthermore, the output terminal of the tower attitude measurement module is connected to the input I / O port of the microprocessor unit.

[0079] The tower attitude measurement module includes an ICM-42688-P high-performance six-axis inertial measurement unit (IMU) for acquiring three-axis acceleration and three-axis angular velocity data of the tower under test. Employing ultra-miniature packaging and advanced MEMS technology, it integrates a three-axis accelerometer and a three-axis gyroscope onto a single chip, effectively avoiding inter-axis alignment errors caused by multi-chip architectures and enabling real-time monitoring of the high-voltage tower's spatial attitude.

[0080] Specifically, the ICM-42688-P high-performance six-axis inertial measurement unit supports both I2C and SPI communication methods. Compared to I2C, the SPI bus has a higher data transmission rate and supports full-duplex data transmission. Figure 3 As shown, based on the requirement for real-time data acquisition, a four-wire SPI bus protocol is used to communicate with the ICM-42688-P. In the chip's SPI interface, the SDI and SDO pins serve as the master and slave data input terminals, respectively, forming a bidirectional transmission channel. SCLK is responsible for transmitting the synchronization clock signal, while the CS chip select pin is used for device addressing control. When the chip select pin is pulled low, the ICM-42688-P is selected and can communicate normally with the microprocessor unit.

[0081] The microprocessor unit reads the three-axis acceleration data from the accelerometer and the three-axis angular velocity data from the gyroscope to perform attitude calculations and obtain the spatial attitude parameters of the tower under test. The attitude parameters are quaternions or Euler angles.

[0082] Specifically, refer to Figure 10 The spatial 3D model of the tower under test is obtained by modeling with SolidWorks. The Euler angle data or quaternions obtained by attitude calculation are transmitted to the Vofa+ host computer for real-time display of the tower's spatial attitude, so as to facilitate remote and direct observation of the tower's spatial attitude.

[0083] Furthermore, while performing attitude calculation, the microprocessor unit also uses Kalman filtering or complementary filtering algorithms to reduce the errors introduced by the gyroscope and accelerometer themselves and the attitude calculation itself. Specifically, since the accelerometer has drift errors and the gyroscope has noise errors, complementary filtering combines the six-axis data from the accelerometer and gyroscope to calculate Euler angles, while Kalman filtering reduces noise interference and angle drift through state prediction and updating smooth data; these two algorithms are commonly used in attitude calculation.

[0084] The six-axis inertial measurement unit is configured in the carrier coordinate system. All data collected by the six-axis inertial measurement unit is based on the carrier coordinate system, and the origin of the carrier coordinate system coincides with the centroid of the six-axis inertial measurement unit.

[0085] Specifically, the centroid coincides when the origin of the carrier coordinate system and the centroid of the object are the same point. The centroid of the object is the center of gravity of the object, that is, the sensitive center of the accelerometer and gyroscope coincides with the geometric center of the IMU package, and the overall centroid is also located at this point.

[0086] Furthermore, the Y-axis points directly in front of the vehicle, the X-axis points to the right, and the Z-axis is perpendicular to the vehicle and points upwards. To facilitate subsequent processing and application of the inertial measurement unit (IMU) data, the data must be converted to the inertial navigation coordinate system.

[0087] Reference Figure 4Common coordinate transformation methods include Euler angle algorithms and quaternion algorithms. The Euler angle algorithm involves three angular parameters: yaw (ψ), roll (φ), and pitch (θ). These three parameters collectively describe the rotation of an object relative to the coordinate system. The yaw angle is the angle between the new coordinate system (formed by rotating the object around the Z-axis of the navigation coordinate system) and the original coordinate system, with a value ranging from -π to π, representing the object's rotation about the vertical axis in the horizontal plane. Based on the yaw angle, the object further rotates around the X-axis of the new coordinate system, forming an angle between the new coordinate system and the previous coordinate system called the roll angle, also ranging from -π to π, representing the object's rotation about its own X-axis. Finally, the object rotates around the Y-axis of the new coordinate system, forming an angle between the new coordinate system and the XY plane of the original navigation coordinate system called the pitch angle, with a value ranging from -π / 2 to π / 2, representing the object's rotation about its own Y-axis.

[0088] The carrier coordinate system is associated with the inertial navigation coordinate system through an attitude transformation matrix; the attitude transformation matrix is ​​an attitude transformation matrix established based on the Euler angle algorithm or an attitude transformation matrix represented by quaternions.

[0089] Specifically, the attitude transformation matrix is ​​established based on the yaw angle (ψ), roll angle (φ), and pitch angle (θ) involved in the Euler angle algorithm. This describes the process of transforming the carrier coordinate system to the inertial navigation coordinate system, as shown below:

[0090] (1);

[0091] In the mathematical description of 3D rotations, Euler angles are widely used due to their intuitiveness; however, their inherent gimbal lock problem severely restricts rotational degrees of freedom. When an object rotates in a specific order, if the rotation angle of the intermediate axis reaches 90 degrees, the remaining two rotations will be perfectly aligned, causing the system to be unable to distinguish between rotations around these two axes, thus losing one rotational degree of freedom. To avoid the gimbal lock problem, quaternions are used to describe 3D rotations. Quaternions are a global rotation representation method based on hypercomplex numbers. Their core idea is to map any 3D rotation to a process around a single rotation axis through axis-angle parameterization, thereby avoiding the degree-of-freedom alignment problem caused by axis-by-axis rotation and fundamentally avoiding gimbal lock.

[0092] The 3D rotation is described using a quaternion algorithm, as follows:

[0093] (2);

[0094] The formula describing the quaternion update between the current time step and the previous time step is as follows:

[0095] (3);

[0096] Assuming that the initial quaternion q0=1, q2=q3=q4=0, the quaternion at time t+∆t can be obtained from the gyroscope data.

[0097] The following conversion formula is obtained by converting quaternions and Euler angles:

[0098] (4);

[0099] Substituting equation (4) into equation (1), we obtain the equivalent attitude transformation matrix in quaternion representation, as follows:

[0100] (5).

[0101] The attitude transformation matrix established based on the Euler angle algorithm or the equivalent attitude transformation matrix represented by quaternions can transform the three-axis acceleration data of the tower collected by the IMU in the carrier coordinate system to the inertial navigation coordinate system. Then, the transformed acceleration data is subjected to a second integral operation to calculate the displacement of the tower at the corresponding time.

[0102] To improve positioning accuracy, optionally, a rotary encoder can be used to periodically compensate and calibrate the error accumulated during the integration process, ultimately achieving accurate detection of the attitude of the tower under test.

[0103] The tower screw loosening measurement module is used to collect real-time time-domain vibration signals of the tower screws under test. The microprocessor unit converts the time-domain vibration signals into frequency-domain signals and extracts spectral features, and determines the working state of the screws based on the spectral features.

[0104] Furthermore, the output terminal of the tower screw loosening measurement module is connected to the input I / O port of the microprocessor unit.

[0105] The tower bolt loosening measurement module includes a PVDF piezoelectric film sensor and a dual-T type 50Hz notch filter circuit.

[0106] When the tower screws become loose, they will vibrate and make noise under the action of wind. Therefore, the PVDF piezoelectric film sensor collects the real-time time-domain vibration signal of the tower screw under test. The microprocessor unit converts the time-domain vibration signal into a frequency-domain signal through the DFT (Discrete Fourier Transform) algorithm based on FFT and extracts the spectral features. Based on the spectral features, the working state of the screw is determined. By analyzing the components of each harmonic in the spectrum, it is possible to intuitively determine whether the screw is in an abnormal state.

[0107] Reference Figure 6 By observing the changing trends in the frequency domain of the spectrum, for example, when the screw is tightened, the spectrum should mainly contain low-frequency components with fewer high-frequency components; while when the screw is loose, the high-frequency components in the spectrum increase. Therefore, the problem of loose screws can be judged based on the magnitude of each harmonic component in the spectrum.

[0108] The output terminal of the PVDF piezoelectric film sensor is connected to the input terminal of the dual-T 50Hz notch filter circuit, which is used to filter out power frequency interference.

[0109] In the actual process of acquiring vibration signals, 50Hz power frequency interference is unavoidable. Therefore, the spectrum obtained in each acquisition will always contain 50Hz harmonic components. A dual-T type 50Hz notch filter is used to filter out power frequency interference, such as... Figure 5 As shown.

[0110] Furthermore, judging the condition of screws based on vibration spectrum analysis requires experimental data. By analyzing the measured data, the changing trend of the screw's spectral characteristics over time can be determined, thereby predicting the gradual deterioration of screw performance and achieving early prediction of screw loosening failures. The Prophet time series prediction model is selected for data analysis, such as... Figure 7 The figure shown is a trend graph of the Prophet model's predictions over time.

[0111] The tower temperature measurement module converts the acquired temperature signal of the tower under test into an oscillation frequency signal. The microprocessor unit obtains the temperature measurement value based on the oscillation frequency signal. Converting the temperature signal into an oscillation frequency signal enables temperature measurement while improving resistance to strong electromagnetic interference. Since metal screws exhibit thermal expansion and contraction, considering the influence of the tower's temperature while monitoring for screw loosening further enhances the reliability of the judgment.

[0112] Furthermore, the output terminal of the tower temperature measurement module is connected to the input I / O port of the microprocessor unit.

[0113] To improve the accuracy of temperature measurement, enhance interference resistance, and reduce the impact of harsh electromagnetic environments on temperature sensors installed on towers, the tower temperature measurement module includes a thermistor and a 555 multivibrator circuit. The thermistor serves as the control element of the 555 multivibrator circuit, converting the temperature signal into an oscillation frequency signal for output. The microprocessor unit is optically isolated from the 555 multivibrator circuit and acquires the oscillation frequency signal.

[0114] By using an NTC thermistor in conjunction with a 555 multivibrator circuit, temperature changes are converted into frequency changes, and further isolated by optocouplers, the anti-interference capability of the temperature measurement circuit can be greatly improved.

[0115] Optionally, an NTC 10k thermistor with a constant of 3950 is selected as the temperature sensing element. The temperature acquisition circuit schematic is shown below. Figure 8 As shown. When the temperature of the thermistor changes, its resistance changes, and the frequency f of the INT_K1 output terminal of the 555 multivibrator circuit also changes. When the output terminal OUT of the 555 multivibrator circuit is high, the transistor... When the output terminal INT_K1 is low, the optocoupler is turned on. Conversely, when the output terminal INT_K1 is low, the optocoupler is turned off. This causes the optocoupler to switch once for each oscillation of the oscillator. The microprocessor unit obtains the number of optocoupler switching through interrupt technology to obtain the oscillation frequency and thus obtain the temperature measurement value.

[0116] Reference Figure 9 Based on the known table of temperature and resistance values ​​for NTC10k thermistors and the formula for calculating the frequency of oscillation circuits, the corresponding oscillation frequencies for different resistance values ​​can be calculated, thus obtaining the corresponding oscillation frequencies at different temperatures. The curve relationship between oscillation frequency and temperature can be plotted using Matlab with polynomial fitting.

[0117] Furthermore, based on Figure 9 The oscillation frequency exhibits a highly nonlinear relationship with temperature. Although curve fitting and neural networks can effectively improve the accuracy of temperature calculations, microprocessors have limited accuracy in floating-point calculations, making it difficult to handle high-order fitting equations and neural network calculations. Therefore, the frequency-temperature curve is divided into several frequency intervals based on its derivative. A linear equation between frequency and temperature can be established within each interval, thus creating a piecewise frequency-temperature function. The temperature is then calculated from the frequency obtained by the microprocessor unit according to the frequency-temperature equation within its respective frequency interval. Figure 8 The calculation formula is expressed as follows:

[0118] ;

[0119] Specifically, the online monitoring device also includes a clock module, a communication module, and an address selection module that are electrically connected to the microprocessor unit.

[0120] The clock module uses a DS1302 chip to record the time when the integrated monitoring unit performs online monitoring.

[0121] The address selection module uses a 10-bit DIP switch to set the device address, making it easy to distinguish which measuring device it is.

[0122] The communication module uses an isolated serial-to-RS485 communication circuit to transmit data. A π122U31 digital isolator digitally isolates the microcontroller's serial port signal, preventing external interference to the main control chip during operation. The π122U31 digital isolator has a 1.5kV rms isolation withstand voltage rating and a maximum signal transmission rate of 600Mbps, supporting high-speed isolated serial data transmission. Its hardware circuitry is as follows... Figure 11 As shown.

[0123] To convert isolated serial port data into RS485 communication circuitry, the SP3485EN is used as the serial-to-RS485 communication chip. An automatic RS485 transceiver circuit enables automatic switching between RS485 data transmission and reception modes. During data transmission, when the 485_TX pin sends a low level, the transistor is cut off, and the SP3485EN chip enters data transmission mode, transmitting the low level on DI to the AB line for output. When the 485_TX pin sends a high level, the transistor is turned on, and the AB pins enter a high-impedance state. Pull-up resistor R8 pulls the A line of the RS485 high, and pull-down resistor R9 pulls the B line of the RS485 low, thus transmitting a high level on the AB line. During data reception, the 485_TX pin is in a default high-level state, and the SP3485EN chip enters data reception mode. The RO pin of the SP3485EN chip receives the data transmitted from the AB signal lines. The circuit diagram is shown below. Figure 12 As shown.

[0124] It also includes a power module, which uses a 24V solar cell and a rechargeable lithium battery. A wide-range (18VDC-36VDC) isolated regulated DC-DC module, XRE12 / 24S-12W, is used to convert the lithium battery output voltage into a stable 12V DC power supply, providing a stable operating power for the online monitoring device for the comprehensive performance of high-voltage towers based on multi-sensor technology. The specific hardware circuit implementation scheme is as follows... Figure 13 As shown.

[0125] The online monitoring device uses a 5V power supply to power the various measurement modules, sensors, and chips. If an LDO chip such as the LM7805 is used for direct voltage reduction, the large input-output voltage difference will cause severe overheating during prolonged operation. Furthermore, considering the device needs to be used through cable conduits, the overall power supply size needs to be sufficiently small. Therefore, the XL1509 from Shanghai Chipone Technology Co., Ltd. was selected as the 12V to 5V Buck converter chip, with a rated maximum output current of 2A. Its hardware circuit is as follows... Figure 14 As shown.

[0126] exist Figure 14In the diagram, C5 is a decoupling capacitor, providing a fast discharge path for high-frequency noise; C4 and C6 are energy storage and filtering capacitors to smooth low-frequency ripple; D1 is a 1N5820 high-power Schottky diode; and L1 is a power inductor. When selecting the inductance value, a margin should be allowed, typically at least 25% larger than the inductor's rated value.

[0127] To achieve maximum power supply efficiency, the rated inductance value can be calculated based on the chip's internal switching frequency and input / output voltage. The calculation formula is as follows:

[0128] ;

[0129] In the formula, V IN V is the input voltage. OUT For output voltage, For ripple current, f osc The internal switching frequency of the chip is 150kHz. The calculated rated value of L is 50uH. However, in practical applications, considering temperature and load variations, a 68uH power inductor is selected.

[0130] This invention selects the AMS1117 LDO power supply chip to convert 5VDC to 3.3VDC to power the microprocessor chip, and its circuit is as follows. Figure 15 As shown in the diagram. An isolated 3.3V voltage is generated by the isolated DC-DC module B0303_1WR3 to power the RS485 isolated communication circuit. The circuit diagram is as follows. Figure 16 As shown.

[0131] Example 2: This example discloses an online monitoring method for the comprehensive performance of high-voltage transmission towers based on multi-sensor technology, using the monitoring device described in Example 1; the method includes the following steps:

[0132] The monitoring unit receives monitoring commands, enabling it to perform online monitoring of the high-voltage tower.

[0133] The grounding resistance measurement module receives a voltage signal from the microprocessor and generates a current, enabling the microprocessor unit to obtain the grounding resistance of the tower under test based on the current and send it to the display unit.

[0134] The tower attitude measurement module monitors the spatial attitude of the tower under test in real time, enabling the microprocessor unit to perform attitude calculation based on the spatial attitude to obtain modeling data for modeling, and then send it to the display unit.

[0135] The tower screw loosening measurement module collects the real-time time-domain vibration signal of the tower screw under test, so that the microprocessor unit converts the time-domain vibration signal into a frequency-domain signal, extracts the spectral features, determines the working state of the screw based on the spectral features, and sends it to the display unit.

[0136] The tower temperature measurement module converts the collected temperature signal of the tower under test into an oscillation frequency signal, enabling the microprocessor unit to obtain the temperature measurement value based on the oscillation frequency signal and send it to the display unit.

[0137] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0138] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and all such equivalent transformations fall within the protection scope of the present invention.

Claims

1. An online monitoring device for the comprehensive performance of high-voltage transmission towers, characterized in that: include: The integrated monitoring unit is configured to acquire monitoring instructions sent by the microprocessor unit to monitor the high-voltage tower. The microprocessor unit processes the various data of the tower under test monitored by the integrated monitoring unit and sends them to the display unit. The integrated monitoring unit includes: The grounding resistance measurement module is used to receive the voltage signal sent by the microprocessor unit and the voltage generation circuit and generate a current. The microprocessor unit obtains the grounding resistance of the tower under test based on the current. The tower attitude measurement module is used to monitor the spatial attitude of the tower under test in real time. The microprocessor unit performs attitude calculation based on the spatial attitude to obtain modeling data for modeling. The tower screw loosening measurement module is used to collect real-time time-domain vibration signals of the tower screws under test. The microprocessor unit converts the time-domain vibration signals into frequency-domain signals and extracts spectral features to determine the working state of the screws based on the spectral features. The tower temperature measurement module is used to convert the collected temperature signal of the tower under test into an oscillation frequency signal, and the microprocessor unit obtains the temperature measurement value based on the oscillation frequency signal.

2. The online monitoring device for the comprehensive performance of high-voltage transmission towers according to claim 1, characterized in that: The grounding resistance measurement module includes a voltage-excited iron core coil and a current-measuring iron core coil. The voltage-excited iron core coil and the current-measuring iron core coil are coaxially arranged and coupled in a stacked manner along the axial direction, so that the grounding resistance lead of the tower under test passes through both the voltage-excited iron core coil and the current-measuring iron core coil at the same time. A shield is provided outside the voltage-excited iron core coil and the current-measuring iron core coil, and the shield is in an open state.

3. The online monitoring device for the comprehensive performance of high-voltage transmission towers according to claim 2, characterized in that: Both the voltage-excited iron core coil and the current-measuring iron core coil include an elliptical iron core, and the two iron cores are of the same size. The voltage-excited core coil has a first number of turns wound on its core, and the current-measuring core coil has a second number of turns wound on its core, with the first number of turns being greater than the second number of turns.

4. The online monitoring device for the comprehensive performance of high-voltage transmission towers according to claim 3, characterized in that: The voltage-excited iron core coil is connected to the microprocessor unit, the output terminal of the current-measuring iron core coil is connected to a full-bridge rectifier circuit, the output terminal of the full-bridge rectifier circuit is connected in parallel with a conversion resistor, and the microprocessor unit collects the voltage across the conversion resistor.

5. The online monitoring device for the comprehensive performance of high-voltage transmission towers according to claim 1, characterized in that: The tower attitude measurement module includes a six-axis inertial measurement unit, which is used to collect the three-axis acceleration and three-axis angular velocity data of the tower under test; The microprocessor unit reads triaxial acceleration and triaxial angular velocity data to perform attitude calculation and obtains the spatial attitude parameters of the tower under test. The attitude parameters are quaternions or Euler angles.

6. The online monitoring device for the comprehensive performance of high-voltage transmission towers according to claim 5, characterized in that: The six-axis inertial measurement unit is configured in the carrier coordinate system. All data collected by the six-axis inertial measurement unit is based on the carrier coordinate system, and the origin of the carrier coordinate system coincides with the centroid of the six-axis inertial measurement unit.

7. The online monitoring device for the comprehensive performance of high-voltage transmission towers according to claim 6, characterized in that: The carrier coordinate system is associated with the inertial navigation coordinate system through an attitude transformation matrix; The attitude transformation matrix is ​​either an attitude transformation matrix established based on the Euler angle algorithm or an attitude transformation matrix represented by quaternions.

8. The online monitoring device for comprehensive performance of high-voltage transmission towers according to claim 1, characterized in that: The tower bolt loosening measurement module includes a PVDF piezoelectric film sensor and a dual-T type 50Hz notch filter circuit. The PVDF piezoelectric thin film sensor acquires the real-time time-domain vibration signal of the tower under test. The microprocessor unit converts the time-domain vibration signal into a frequency-domain signal through the DFT algorithm, extracts the spectral features, and determines the working state of the screw based on the spectral features. The output terminal of the PVDF piezoelectric film sensor is connected to the input terminal of the dual-T 50Hz notch filter circuit, which is used to filter out power frequency interference.

9. The online monitoring device for the comprehensive performance of high-voltage transmission towers according to claim 1, characterized in that: The tower temperature measurement module includes a thermistor and a 555 multivibrator circuit. The thermistor serves as the control element of the 555 multivibrator circuit, used to convert the temperature signal into an oscillation frequency signal for output. The microprocessor unit is optically isolated from the 555 multivibrator circuit and acquires the oscillation frequency signal.

10. A method for online monitoring of the comprehensive performance of high-voltage transmission towers, characterized in that: The method, employing the monitoring device as described in any one of claims 1-9, comprises the following steps: The monitoring unit receives monitoring commands, enabling it to perform online monitoring of the high-voltage tower. The grounding resistance measurement module receives voltage signals from the microprocessor and voltage generation circuit, generates current, and enables the microprocessor unit to obtain the grounding resistance of the tower under test based on the current, and sends it to the display unit. The tower attitude measurement module monitors the spatial attitude of the tower under test in real time, enabling the microprocessor unit to perform attitude calculation based on the spatial attitude to obtain modeling data for modeling, and then send it to the display unit. The tower screw loosening measurement module collects the real-time time-domain vibration signal of the tower screw under test, so that the microprocessor unit converts the time-domain vibration signal into a frequency-domain signal, extracts the spectral features, determines the working state of the screw based on the spectral features, and sends it to the display unit. The tower temperature measurement module converts the collected temperature signal of the tower under test into an oscillation frequency signal, enabling the microprocessor unit to obtain the temperature measurement value based on the oscillation frequency signal and send it to the display unit.

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