Terahertz scanning detection system and method for measuring moisture content of transformer insulation structure

Abstract

The invention discloses a terahertz scanning detection system and method for measuring the moisture content of a transformer insulation structure, and relates to the field of power system detection, and in the system, a terahertz detection probe is fixedly installed on an end effector of a scanning mechanical arm; the scanning controller is deployed in the terahertz spectrometer and communicates with the scanning mechanical arm and the terahertz spectrometer; the scanning controller determines a scanning path according to the geometrical characteristics of the target insulation structure and measurement requirements, and sends a motion control instruction to the scanning mechanical arm according to the scanning path; the scanning mechanical arm drives the terahertz detection probe to scan according to the motion control instruction; the scanning controller determines a moisture content value of each spatial position point on the surface of the target insulation structure based on the response signal, a spatial position coordinate corresponding to the scanning path and a terahertz nondestructive moisture assessment curve, and generates a moisture two-dimensional distribution map; according to the invention, stable, omnibearing and automatic scanning of the transformer insulation structure can be realized.

Description

Technical Field

[0001] This application relates to the field of power system testing, and in particular to a terahertz scanning testing system and method for measuring the moisture content of transformer insulation. Background Technology

[0002] Oil-filled equipment is a crucial component of power systems, making the study of its internal insulation state and failure processes extremely important. Moisture, as a polar substance, not only reduces the electrical performance of insulation but also accelerates its aging. Therefore, the moisture content of the insulation system is a critical parameter to monitor during both manufacturing and maintenance phases of oil-filled equipment. Terahertz technology, due to its non-destructive, rapid, and highly sensitive moisture detection capabilities, has become a novel sensing technology for oil-paper insulation, applicable to laboratory measurements of moisture content in typical transformer insulation samples. However, applying terahertz technology to field insulation testing requires expanding the research object from single sheet samples to more complex insulation structures, such as thin insulating paper wrapped around copper windings, screens isolating oil channels, and thick insulating pads. Since the probe cannot be placed inside the structure, field insulation moisture testing of transformers often requires handheld scanning. This handheld measurement method limits scanning accuracy, easily leads to incomplete coverage and data loss, and also inconveniences field scanning personnel.

[0003] Therefore, in order to solve the technical problems of incomplete coverage, low accuracy and inconvenient operation of handheld measurements on site, there is an urgent need to provide a scanning system for measuring the moisture content of transformer insulation structure. Summary of the Invention

[0004] The purpose of this application is to provide a terahertz scanning detection system and method for measuring the moisture content of transformer insulation structure, which can achieve stable, all-round, and automated scanning of transformer insulation structure.

[0005] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a terahertz scanning detection system for measuring the moisture content of transformer insulation structure. The terahertz scanning detection system for measuring the moisture content of transformer insulation structure includes: a terahertz spectrometer, a terahertz detection probe, a scanning robotic arm, and a scanning controller. The terahertz spectrometer is connected to the terahertz detection probe via an optical fiber; the terahertz detection probe is fixedly mounted on the end effector of the scanning robotic arm; the scanning controller is deployed inside the terahertz spectrometer and communicates with the scanning robotic arm and the terahertz spectrometer. The scanning controller is used to determine the scanning path of the end effector of the scanning robot arm based on the geometric features of the target insulation structure and the measurement requirements, and to send motion control commands to the scanning robot arm according to the scanning path; the scanning robot arm drives the terahertz detection probe to scan according to the motion control commands; the scanning path adopts a two-dimensional gridded scanning mode for planar structures or curved insulation structures; the motion control commands include: scan start coordinates, end coordinates, step size, and scanning path; The scanning controller is also used to associate and store the response signal of the target insulation structure in the terahertz band received by the terahertz spectrometer with the spatial coordinates corresponding to the scanning path; and based on the response signal, the spatial coordinates corresponding to the scanning path, and the terahertz non-destructive assessment curve of moisture, to determine the moisture content value at each spatial point on the surface of the target insulation structure and generate a two-dimensional moisture distribution map; the terahertz non-destructive assessment curve of moisture is a calibration curve of absorption coefficient and actual moisture.

[0006] Optionally, the scanning robotic arm includes: a base, an arm body, and an end effector; The arm includes a single-axis servo motor for pitching and a dual-axis servo motor for horizontal rotation; the end effector rigidly fixes the terahertz detection probe with screws.

[0007] Optionally, the base includes: a counterweight gimbal and a servo control board; The counterweight gimbal is used to lower the center of gravity of the scanning robotic arm; The servo control board integrates an Arduino core board and an expansion board; the Arduino core board is used to send PWM signals generated according to motion control commands to the single-axis and dual-axis servos of the scanning robotic arm; the single-axis and dual-axis servos rotate at corresponding angles according to the PWM signals, driving the terahertz detection probe to move; the expansion board integrates a power supply and a buzzer.

[0008] Optionally, the scanning controller communicates with the scanning robotic arm via an Arduino core board.

[0009] Optionally, the scanning controller is also used to control the terahertz detection probe to stay at each scanning point on the scanning path for a fixed duration.

[0010] Secondly, this application provides a terahertz scanning detection method for measuring the moisture content of transformer insulation structure, applied to the aforementioned terahertz scanning detection system for measuring the moisture content of transformer insulation structure. The terahertz scanning detection method for measuring the moisture content of transformer insulation structure includes: Obtain the geometric features of the target insulation structure and the measurement requirements; The scanning path of the end effector of the scanning robot arm is determined based on the geometric features of the target insulation structure and the measurement requirements. Send motion control commands to the scanning robotic arm according to the scanning path; A scanning robotic arm drives a terahertz detection probe to perform scanning according to motion control commands; The response signal of the target insulating structure in the terahertz band was obtained using a terahertz spectrometer. Based on the spatial coordinates of the response signal and the scanning path, as well as the terahertz non-destructive assessment curve for moisture, the moisture content at each spatial location on the surface of the target insulation structure is determined, and a two-dimensional moisture distribution map is generated.

[0011] Optionally, the step of using a scanning robotic arm to drive the terahertz detection probe to perform scanning according to motion control commands specifically includes: When the target insulation structure is planar, the entire scanning area is divided into multiple equally spaced scanning points in a Cartesian coordinate system according to the motion control command, and each scanning point is matched with a corresponding spatial coordinate. During scanning, the device first moves along the X-axis from the starting coordinate to the ending coordinate to complete one line of scanning, and then moves along the Y-axis by one unit according to the step size, and reverses along the X-axis to complete the next line of scanning. This process is repeated until the entire target area is covered. When the target insulation structure is a curved surface, the entire scanning area is divided into a number of equally spaced scanning points in the cylindrical coordinate system according to the motion control command, and each point is matched with a corresponding spatial coordinate. During scanning, the scanning robot arm is first at the starting coordinate, the electric rotary table rotates one revolution according to the step size, and the scanning robot arm moves one unit along the Z-axis according to the step size. This process is repeated until the entire target area is covered.

[0012] Optionally, the step of using a scanning robotic arm to drive the terahertz detection probe to perform scanning according to motion control commands further includes: The PWM signal generated by the motion control command; The PWM signal is sent to the Arduino core board of the scanning robotic arm via USB serial port; The Arduino core board sends the processed PWM signal to the single-axis and dual-axis servos of the scanning robotic arm. Single-axis and dual-axis servos rotate at corresponding angles according to PWM signals, thereby driving the terahertz detection probe to move.

[0013] Optionally, determining the moisture content value at each spatial location point on the surface of the target insulation structure based on the spatial coordinates corresponding to the response signal and the scanning path, and the terahertz non-destructive assessment curve for moisture, specifically includes: Based on Fresnel's formula and the propagation factor of terahertz waves in a medium, the complex refractive index of the insulating paper is determined by the ratio of the sample signal to the reference signal. The absorption coefficient is determined based on the complex refractive index of the insulating paper; A calibration curve was established based on the absorption coefficient and the moisture content determined by the Karl Fischer method; and the calibration curve was used as the curve for non-destructive terahertz assessment of moisture content. Based on the spatial coordinates of the response signal and the scanning path, as well as the terahertz non-destructive assessment curve for moisture, the moisture content values ​​at each spatial location on the surface of the target insulation structure are inverted.

[0014] Optionally, the step of generating a two-dimensional moisture distribution map further includes: Visualize the two-dimensional distribution map of moisture.

[0015] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a terahertz scanning detection system and method for measuring the moisture content of transformer insulation structures. Leveraging the non-destructive, rapid, and highly sensitive moisture-sensing advantages of terahertz technology, the terahertz detection probe is fixed to the end effector of a scanning robotic arm. Combined with customized scanning path planning and automated control, a comprehensive scan of the transformer insulation structure is achieved. Compared to traditional handheld probe measurement methods, this application avoids the limited scanning accuracy caused by manual operation, solves the pain points of incomplete coverage and missing data in transformer insulation structure scanning, and reduces the operational difficulty for on-site measurement personnel. It achieves stable, efficient, and fully covered automated detection of insulation moisture in oil-filled equipment. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a terahertz scanning detection system for measuring the moisture content of transformer insulation structure according to an embodiment of this application; Figure 2 A schematic diagram of a terahertz wave passing through a copper winding structure; Figure 3 A schematic diagram of terahertz waves passing through the screen structure; Figure 4 This is an image. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] In one exemplary embodiment, such as Figure 1 As shown, a terahertz scanning detection system for measuring the moisture content of transformer insulation structure is provided. The system includes: a terahertz spectrometer, a terahertz detection probe, a scanning robotic arm, and a scanning controller. The terahertz spectrometer is connected to the terahertz detection probe via an optical fiber; the terahertz detection probe is fixedly mounted on the end effector of the scanning robotic arm; the scanning controller is deployed inside the terahertz spectrometer and communicates with the scanning robotic arm and the terahertz spectrometer. The scanning controller is used to determine the scanning path of the end effector of the scanning robot arm based on the geometric features of the target insulation structure and the measurement requirements, and to send motion control commands to the scanning robot arm according to the scanning path; the scanning robot arm drives the terahertz detection probe to scan according to the motion control commands; the motion control commands include: scan start coordinates, end coordinates, step size and scanning path; The scanning controller is also used to associate and store the response signal of the target insulation structure in the terahertz band received by the terahertz spectrometer with the spatial coordinates corresponding to the scanning path, so as to realize synchronous data acquisition and processing; and based on the response signal, the spatial coordinates corresponding to the scanning path and the curve of terahertz non-destructive assessment of moisture, to determine the moisture content value of each spatial point on the surface of the target insulation structure and generate a two-dimensional moisture distribution map; the curve of terahertz non-destructive assessment of moisture is a calibration curve of absorption coefficient and actual moisture content.

[0021] As a specific example, the terahertz spectrometer (an integration of a computer and a spectrometer) is connected to the scanning robotic arm via a USB serial port to achieve communication between the two. As a specific embodiment, the scanning path adopts a two-dimensional rasterized scanning mode for planar structures or curved insulating structures; the specific scanning process is as follows: (1) For planar structures, scanning is completed by controlling the scanning robotic arm to move back, forth, left, and right within the same plane. Therefore, a planar rectangular coordinate system is established, and the dimensions of the target insulation structure are measured. The scanning controller generates a "matrix-like" scanning path (grid path instruction sequence) by controlling the starting coordinates (X0, Y0) and ending coordinates (X1, Y1) of the scanning area, and the step size of the terahertz detection probe. The entire scanning area is divided into several equally spaced scanning points, and each point is matched with a corresponding spatial coordinate. During scanning, the robot first moves along the X-axis from the starting coordinate to the ending coordinate to complete one line of scanning. Then, it moves along the Y-axis one unit according to the preset step size, and reverses along the X-axis to complete the next line of scanning. This cycle continues until the entire target area is covered.

[0022] (2) For curved structures (such as copper windings and screens), the scanning of the curved surface is completed by simultaneously controlling the up and down movement of the scanning robotic arm and the 360° rotation of the copper winding (or screen) driven by the electric rotary table. Therefore, a cylindrical coordinate system is established, the dimensions of the target insulation structure are measured, and the starting coordinates of the scanning area are used to determine the dimensions of the target insulation structure. ), Termination coordinates ( Simultaneously, the step size for the terahertz detection probe movement is set (unfolding the cylindrical coordinate system is essentially a two-dimensional plane, therefore surface scanning also belongs to two-dimensional rasterized scanning of the plane), generating a "matrix-like" raster path command sequence, dividing the entire scanning area into several equally spaced scanning points, and matching each point with corresponding spatial coordinates. During scanning, the scanning robotic arm is initially at the starting coordinate Z0. Each time the electric rotary table completes one revolution according to the set step size, the scanning robotic arm advances one unit along the Z-axis according to the preset step size, repeating this cycle until the entire target area is covered; where, Z represents the angle through which the electric rotary table has rotated, and Z represents the height of the scanning position of the robotic arm.

[0023] The scanning path planning allows for customized programming for complex heterogeneous structures such as thin insulating paper and insulating pads on the winding surface, to adapt to different field measurement environments and ensure the integrity of scanning coverage and measurement efficiency.

[0024] The scanning robotic arm includes: a base, an arm body, and an end effector; The arm includes a single-axis servo motor for pitching and a dual-axis servo motor for horizontal rotation; the end effector rigidly fixes the terahertz detection probe with screws.

[0025] Specifically, the base includes: a counterweight gimbal and a servo control board; The counterweight gimbal is used to lower the center of gravity of the scanning robotic arm; The servo control board integrates an Arduino core board and an expansion board. The Arduino core board sends PWM signals generated according to motion control commands to the single-axis and dual-axis servos of the scanning robotic arm. The single-axis and dual-axis servos rotate at corresponding angles according to the PWM signals, thereby achieving arm twisting and driving the terahertz detection probe at the end of the scanning robotic arm to scan. During the scanning process, the terahertz detection probe stays at each grid point for a fixed duration (e.g., 1 second) to ensure sufficient acquisition of terahertz signals and achieve uniform full coverage of planar or curved insulating structures. The expansion board integrates a power supply and a buzzer.

[0026] As a specific embodiment, the scanning controller communicates with the scanning robotic arm via an Arduino core board.

[0027] As a specific embodiment, in a traditional robotic arm, the gripper is located at the very top of the device and is the end effector of the scanning robotic arm. However, due to the large size of the probe, the gripper cannot completely hold the probe. For safety and stability considerations, the gripper was modified: a [missing information - likely a design feature] was created in the non-working area of ​​the terahertz detection probe. The hole is just big enough for the screw to pass through (without interfering with the normal use of the probe), and the original hole used to fix the claw is now in place. The screw is passed through the hole just drilled for the probe, and the screw is tightened to fix the probe to the end of the robotic arm, replacing the claw.

[0028] The robotic arm is divided into an upper arm, a middle arm, and a lower arm, and is constructed from five digital servos (two TBS-K20 single-axis servos and three TBD-K20 dual-axis servos) fixed to a U-shaped bracket via metal servo discs and screws. The upper arm and the gripper are hinged together via a single-axis digital servo (TBS-K20) No. 1, with the servo's output shaft fixed to the transmission hole of the upper arm, allowing the upper arm to achieve ±90° pitch rotation. The middle arm has three dual-axis digital servos (Nos. 2, 3, and 4), which are the key force-generating sections for driving the robotic arm's up-and-down scanning. Precise measurements show the probe weighs 617g, and the arm length (distance from the lowest servo in the middle arm to the gripper) is 37.8cm. To easily lift the probe, the robotic arm was further modified: the three servos in the middle arm section with torque... The dual-axis digital servo motor (TBD-K20) was replaced with one of the same specifications but with a torque of [missing information]. The dual-axis digital servo motor (TBD-K30) enhances the load-bearing capacity of the robotic arm. The lower arm section is hinged to the base via digital servo motor No. 5, which can drive the entire arm to achieve 360° circular rotation on the horizontal plane.

[0029] The base provides stable bottom support for the entire device and transmits control signals to the servos. It consists of a counterweight gimbal and a servo control board. The counterweight gimbal lowers the device's center of gravity, preventing it from tipping over when the arm is fully extended. The servo control board includes an Arduino core board and an expansion board. The Arduino core board acts as the "command center," receiving scanning path commands from the terahertz spectrometer via USB serial port, parsing them, and sending them to each servo to precisely control the angle and rotation speed of the arm's five digital servos (the servo angle is represented by PWM values; if the servo is not turned, the default PWM value is 1500; the servo's PWM value will be between 500 and 2500, where 500 corresponds to 0° and 2500 corresponds to an actual 270°, so all servos are controllable at 270°). The expansion board mainly contains a power supply and a buzzer. The power supply has a 5V supply voltage, meeting the drive power requirements of the five digital servos; the buzzer sounds once and automatically triggers a reset every time the robotic arm connects to the terahertz spectrometer via USB cable, indicating a successful connection.

[0030] Taking the scanning robotic arm and electric rotary stage in conjunction with scanning a copper winding as an example, the electric rotary stage is secured to a custom-drilled circular plate with screws, thereby increasing its bearing surface to support the copper winding's rotation. Both the electric rotary stage and the scanning robotic arm are connected to the terahertz spectrometer via USB serial port. The movement of both the electric rotary stage and the scanning robotic arm can be controlled simultaneously by adjusting input parameters on the terahertz spectrometer software. The electric rotary stage, carrying the transformer sample, rotates 360 degrees in the horizontal plane, while the robotic arm, carrying the probe, moves up and down for scanning. Together, they achieve omnidirectional scanning imaging of the moisture content distribution of the copper winding.

[0031] Based on the same inventive concept, this application also provides a terahertz scanning detection method for measuring the moisture content of transformer insulation structure, including: S101, Obtain the geometric features of the target insulation structure and measurement requirements; S102, determine the scanning path of the end effector of the scanning robot arm based on the geometric features of the target insulation structure and the measurement requirements; S103, Send motion control commands to the scanning robotic arm according to the scanning path; S104, using a scanning robotic arm to drive the terahertz detection probe to perform scanning according to motion control commands; When the target insulation structure is planar, the entire scanning area is divided into multiple equally spaced scanning points in a Cartesian coordinate system according to the motion control command, and each scanning point is matched with a corresponding spatial coordinate. During scanning, the device first moves along the X-axis from the starting coordinate to the ending coordinate to complete one line of scanning, and then moves along the Y-axis by one unit according to the step size, and reverses along the X-axis to complete the next line of scanning. This process is repeated until the entire target area is covered. When the target insulation structure is a curved surface, the entire scanning area is divided into a number of equally spaced scanning points in the cylindrical coordinate system according to the motion control command, and each point is matched with a corresponding spatial coordinate. During scanning, the scanning robot arm is first at the starting coordinate, the electric rotary table rotates one revolution according to the step size, and the scanning robot arm moves one unit along the Z-axis according to the step size. This process is repeated until the entire target area is covered.

[0032] S104 specifically includes: S41 generates the PWM signal from the motion control command; S42 sends PWM signals to the Arduino core board of the scanning robot via USB serial port; S43, the Arduino core board sends the processed PWM signal to the single-axis servo and dual-axis servo of the scanning robotic arm; S44, the single-axis servo and the dual-axis servo rotate at the corresponding angle according to the PWM signal, driving the terahertz detection probe to move.

[0033] S105, using a terahertz spectrometer to obtain the response signal of the target insulation structure in the terahertz band; S106. Based on the spatial coordinates of the response signal and the scanning path, as well as the terahertz non-destructive assessment curve for moisture, determine the moisture content value at each spatial location point on the surface of the target insulation structure; and generate a two-dimensional moisture distribution map.

[0034] S106 specifically includes: S61. Based on Fresnel's formula and the propagation factor of terahertz waves in the medium, the complex refractive index of the insulating paper is determined by the ratio of the sample signal to the reference signal. S62, the absorption coefficient is determined based on the complex refractive index of the insulating paper; S63, establish a calibration curve based on the absorption coefficient and the moisture content determined by the Karl Fischer method; and use the calibration curve as the curve for non-destructive terahertz assessment of moisture. As a specific example, the moisture content analysis is described in detail below: Terahertz radiation sources are linearly polarized, possessing only one polarization component, spatially defined as p-polarized. According to Fresnel's formula, where... Let be the angle of incidence, with For the angle of refraction, Indicates the transmission coefficient. Represents the reflection coefficient. Represents the refractive index of the incident medium (medium 1). Let represent the refractive index of the transmission medium (medium 2). Then, the formulas for the transmission coefficient and reflection coefficient from medium 1 to medium 2 are: (1) (2) Electromagnetic waves in a medium (refractive index) propagation factors in ) for: (3) in, This represents the angular frequency of the terahertz wave. It represents the path length of an electromagnetic wave in a medium. The speed of light in a vacuum. denoted as the refractive index of the medium.

[0035] For real oil-filled equipment, solid insulation structures can be mainly divided into three types: copper windings containing metal conductors, shielding, and thick insulating blocks. This section mainly introduces copper winding and shielding structures.

[0036] Figure 2 The basic structure of a copper winding can be expressed as follows, based on the formulas (1), (2), and (3) derived above: (4) (5) in, This represents the reflected electric field intensity on the upper surface (air-insulating paper interface) of the copper winding insulation structure. This represents the electric field strength of the incident signal of the terahertz wave. This represents the signal electric field intensity reflected from the lower surface of the copper winding insulation structure (insulating paper-copper conductor interface) and then transmitted back to the air. That is, the propagation factor of terahertz waves in the air path. That is, the propagation factor of terahertz waves in insulating paper. This represents the reflectance at the air-insulating paper interface. This represents the transmittance at the air-insulating paper interface. This represents the reflection coefficient at the interface between the insulating paper and the copper conductor. This represents the transmittance coefficient at the insulating paper-air interface.

[0037] by For reference signal, If the sample signal is the reference signal, then the ratio of the reference signal to the sample signal is: (6) Substituting Fresnel's reflection formula into the above formula, we can obtain: (7) Specifically, ; (8) (9) in, Let be the refractive index (real part) of the insulating paper. This is the extinction coefficient (imaginary part) of the insulating paper. is the complex refractive index of the insulating paper.

[0038] Since the insulating paper is a weakly polar material, and its n >> k, formulas (8) and (9) can be simplified to: ; ; Then, by using the relationship between the absorption coefficient and the extinction coefficient, the expression for the absorption coefficient can be obtained as follows: Figure 3 As shown: ; Following the same derivation logic, when terahertz measurements are performed on oil-filled equipment that is not immersed in oil or after the oil has been drained, the enclosure structure is similar to a combination of insulating cardboard and air. This structure can still be solved using a self-reference method.

[0039] The derivation process is similar to that of copper windings, and the final calculated refractive index, extinction coefficient, and absorption coefficient are: (11) (12) (13) Finally, the obtained absorption coefficient is correlated with the actual moisture content of the standard sample (obtained by Karl Fischer measurement) to obtain the terahertz non-destructive assessment curve for moisture. Afterwards, only the terahertz spectrum of the sample needs to be detected and substituted into this curve to obtain the sample's moisture content. Once the moisture content is obtained, for each scanning coordinate, different color intensities are used to represent the water content at that coordinate, thus obtaining an image, as shown... Figure 4 As shown.

[0040] S64. Based on the spatial coordinates of the response signal and the scanning path, as well as the terahertz non-destructive evaluation curve of moisture, the moisture content value of each spatial point on the surface of the target insulation structure is inverted.

[0041] Following S1006 are: Visualize the two-dimensional distribution map of moisture.

[0042] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0043] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0044] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0045] In this application, all actions to acquire signals, information, or data are carried out in compliance with the relevant data protection laws and policies of the country where the location is situated, and with the authorization granted by the owner of the relevant device.

[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A terahertz scanning detection system for measuring the moisture content of transformer insulation, characterized in that, The terahertz scanning detection system for measuring the moisture content of transformer insulation structure includes: a terahertz spectrometer, a terahertz detection probe, a scanning robotic arm, and a scanning controller. The terahertz spectrometer is connected to the terahertz detection probe via an optical fiber; the terahertz detection probe is fixedly mounted on the end effector of the scanning robotic arm; the scanning controller is deployed inside the terahertz spectrometer and communicates with the scanning robotic arm and the terahertz spectrometer. The scanning controller is used to determine the scanning path of the end effector of the scanning robot arm based on the geometric features of the target insulation structure and the measurement requirements, and to send motion control commands to the scanning robot arm according to the scanning path; the scanning robot arm drives the terahertz detection probe to scan according to the motion control commands; the scanning path adopts a two-dimensional gridded scanning mode for planar structures or curved insulation structures; the motion control commands include: scan start coordinates, end coordinates, step size, and scanning path; The scanning controller is also used to associate and store the response signal of the target insulation structure in the terahertz band received by the terahertz spectrometer with the spatial coordinates corresponding to the scanning path; and based on the response signal, the spatial coordinates corresponding to the scanning path, and the terahertz non-destructive assessment curve of moisture, to determine the moisture content value at each spatial point on the surface of the target insulation structure and generate a two-dimensional moisture distribution map; the terahertz non-destructive assessment curve of moisture is a calibration curve of absorption coefficient and actual moisture.

2. The terahertz scanning detection system for measuring the moisture content of transformer insulation structure according to claim 1, characterized in that, The scanning robotic arm includes: a base, an arm body, and an end effector; The arm includes a single-axis servo motor for pitching and a dual-axis servo motor for horizontal rotation; the end effector rigidly fixes the terahertz detection probe with screws.

3. The terahertz scanning detection system for measuring the moisture content of transformer insulation structure according to claim 2, characterized in that, The base includes: a counterweight gimbal and a servo control board; The counterweight gimbal is used to lower the center of gravity of the scanning robotic arm; The servo control board integrates an Arduino core board and an expansion board; the Arduino core board is used to send PWM signals generated according to motion control commands to the single-axis and dual-axis servos of the scanning robotic arm; the single-axis and dual-axis servos rotate at corresponding angles according to the PWM signals, driving the terahertz detection probe to move; the expansion board integrates a power supply and a buzzer.

4. The terahertz scanning detection system for measuring the moisture content of transformer insulation structure according to claim 3, characterized in that, The scanning controller communicates with the scanning robotic arm via an Arduino core board.

5. The terahertz scanning detection system for measuring the moisture content of transformer insulation structure according to claim 1, characterized in that, The scanning controller is also used to control the terahertz detection probe to stay at each scanning point on the scanning path for a fixed duration.

6. A terahertz scanning detection method for measuring the moisture content of transformer insulation structure, applied to the terahertz scanning detection system for measuring the moisture content of transformer insulation structure as described in any one of claims 1-5, characterized in that, The terahertz scanning detection method for measuring the moisture content of transformer insulation structure includes: Obtain the geometric features of the target insulation structure and the measurement requirements; The scanning path of the end effector of the scanning robot arm is determined based on the geometric features of the target insulation structure and the measurement requirements. Send motion control commands to the scanning robotic arm according to the scanning path; A scanning robotic arm drives a terahertz detection probe to perform scanning according to motion control commands; The response signal of the target insulating structure in the terahertz band was obtained using a terahertz spectrometer. Based on the spatial coordinates of the response signal and the scanning path, as well as the terahertz non-destructive assessment curve for moisture, the moisture content at each spatial location on the surface of the target insulation structure is determined, and a two-dimensional moisture distribution map is generated.

7. The terahertz scanning detection method for measuring the moisture content of transformer insulation structure according to claim 6, characterized in that, The scanning robotic arm uses motion control commands to drive the terahertz detection probe to perform scanning, specifically including: When the target insulation structure is planar, the entire scanning area is divided into multiple equally spaced scanning points in a Cartesian coordinate system according to the motion control command, and each scanning point is matched with a corresponding spatial coordinate. During scanning, the device first moves along the X-axis from the starting coordinate to the ending coordinate to complete one line of scanning, and then moves along the Y-axis by one unit according to the step size, and reverses along the X-axis to complete the next line of scanning. This process is repeated until the entire target area is covered. When the target insulation structure is a curved surface, the entire scanning area is divided into a number of equally spaced scanning points in the cylindrical coordinate system according to the motion control command, and each point is matched with a corresponding spatial coordinate. During scanning, the scanning robot arm is first at the starting coordinate, the electric rotary table rotates one revolution according to the step size, and the scanning robot arm moves one unit along the Z-axis according to the step size. This process is repeated until the entire target area is covered.

8. The terahertz scanning detection method for measuring the moisture content of transformer insulation structure according to claim 7, characterized in that, The method of using a scanning robotic arm to drive a terahertz detection probe for scanning according to motion control commands specifically includes: The PWM signal generated by the motion control command; The PWM signal is sent to the Arduino core board of the scanning robotic arm via USB serial port; The Arduino core board sends the processed PWM signal to the single-axis and dual-axis servos of the scanning robotic arm. Single-axis and dual-axis servos rotate at corresponding angles according to PWM signals, thereby driving the terahertz detection probe to move.

9. The terahertz scanning detection method for measuring the moisture content of transformer insulation structure according to claim 6, characterized in that, The process of determining the moisture content at various spatial locations on the surface of the target insulation structure based on the spatial coordinates corresponding to the response signal and the scanning path, as well as the terahertz non-destructive testing curve for moisture, specifically includes: Based on Fresnel's formula and the propagation factor of terahertz waves in a medium, the complex refractive index of the insulating paper is determined by the ratio of the sample signal to the reference signal. The absorption coefficient is determined based on the complex refractive index of the insulating paper; A calibration curve was established based on the absorption coefficient and the moisture content determined by the Karl Fischer method; and the calibration curve was used as the curve for non-destructive terahertz assessment of moisture content. Based on the spatial coordinates of the response signal and the scanning path, as well as the terahertz non-destructive assessment curve for moisture, the moisture content values ​​at each spatial location on the surface of the target insulation structure are inverted.

10. The terahertz scanning detection method for measuring the moisture content of transformer insulation structure according to claim 6, characterized in that, The process involves generating a two-dimensional moisture distribution map, followed by: Visualize the two-dimensional distribution map of moisture.

Images