Speed measuring system based on sliding rail type optical fiber sensor

Abstract

The invention relates to the technical field of rapid high-voltage circuit breaker opening and closing motion detection, in particular to a speed measurement system based on a sliding rail type optical fiber sensor. The system selects a butterfly-shaped laser as a light source and is sequentially connected with a sliding rail type optical fiber speed sensor, a photoelectric converter and a single chip microcomputer, an optical fiber sensing structure is composed of a single-mode optical cable and a sliding rail, the two ends of the single-mode optical cable in the optical fiber sensing structure are plugged into a hard thin tube, certain stretching adjustment is carried out, and the optical fiber speed sensor is obtained. And the middle part of the final optical fiber is of a U-shaped structure, is left on one side of the hard thin tube, and is synchronously compressed and stretched along with the sliding rail. According to the invention, the single-mode optical cable is bent, so that the middle part of the optical fiber is of a U-shaped structure and is fixed on the sliding rail to form a sensing structure, thereby enabling the variation of an optical signal of the optical fiber sensing structure to reflect the displacement of the switching-on and switching-off actions, and further accurately calculating the speed of the switching-on and switching-off actions of the high-speed high-voltage circuit breaker.

Description

Technical Field

[0001] The present invention relates to the technical field of rapid high-voltage circuit breaker opening and closing action detection, and in particular to a speed measurement system based on a slide rail type optical fiber sensor. Background Art

[0002] High-voltage vacuum circuit breakers are an important part of the power system, so the detection of the opening and closing speed of high-voltage vacuum circuit breakers is also crucial. The speed of the opening and closing action of the high-voltage vacuum circuit breaker is directly related to the contact time of its internal moving contact and the length of the arc extinguishing time. Only by ensuring the appropriate opening and closing speed can its performance be fully utilized. When the arc extinguishing time of the high-voltage vacuum circuit breaker is too long, it will cause harm. Therefore, in order to ensure the safe and stable operation of equipment and power grids, it is necessary to measure and control the opening and closing speed of the high-voltage vacuum circuit breaker to ensure that it operates within a safe and reliable range. Since there is no space inside the high-voltage vacuum circuit breaker device to install a sensor, a displacement conversion device is specially designed to connect the sensor to the moving contact to indirectly obtain the circuit breaker speed characteristics.

[0003] At present, some institutions use image recognition to measure speed. They use cameras to shoot the movement process of the detection object linked to the moving contacts of the high-voltage circuit breaker, repair the captured video to eliminate lens distortion, restore the real coordinates, and obtain the displacement time data of the moving parts. When calculating and analyzing the opening and closing speed of the high-voltage circuit breaker, due to its short opening and closing movement stroke, if conventional detection methods are used, it is easy to produce errors due to shooting. Although the use of high-precision cameras can circumvent this problem, it faces the dilemma of excessively high equipment costs.

[0004] A spring-type fiber optic speed sensor is a commonly used mechanical device with few components and high reliability. A synchronization rod is fixed to the outer surface of the drive shaft, which is linked to the opening and closing operation. A spring-type fiber optic speed sensor and a mounting plate are attached to the synchronization rod in sequence. This sensor, along with a laser emitter and a signal processing module, forms a signal detection system. The laser emitter emits a tunable narrowband beam, which is modulated by the sensor and then fed into the signal processing module. During opening and closing operations, the drive shaft drives the synchronization rod to produce linear displacement, which, through the mounting plate, causes elastic deformation of the return spring. The signal processing module then collects the power attenuation signal of the narrowband beam in real time. Based on a precalibrated power loss-displacement mapping curve, the system analyzes the loss signal in real time and calculates the instantaneous speed of the drive shaft using a differential algorithm. This speed value is directly correlated to the circuit breaker's opening and closing speed. However, because this technology wraps the optical fiber around the return spring, the impact of high-voltage circuit breaker opening and closing forces can damage the optical fiber structure. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention proposes a speed measurement system based on a slide-type optical fiber sensor. This system can indirectly measure the displacement of the opening and closing actions, thereby accurately calculating the speed parameters.

[0006] The slide-rail fiber optic sensor utilizes the mechanical properties of the slide rail structure. The sensor body utilizes a single-mode optical cable, which offers strong mechanical strength and low cost. The movement of the slider inside the slide rail changes the bending radius of the U-shaped single-mode optical cable, causing changes in bending loss and, consequently, optical power. This changes the corresponding voltage value after photoelectric conversion, enabling displacement demodulation. The sensing system utilizes a DFB butterfly laser and a photoelectric converter, resulting in a simple structure and high operability. It is designed to address the engineering challenge of measuring the opening and closing speed of high-voltage vacuum circuit breakers.

[0007] The technical solutions of the present invention are as follows:

[0008] Speed ​​measurement system based on slide-type optical fiber sensor, such as Figure 1 As shown, the system uses a butterfly laser as the light source, which is connected in sequence to a sliding-rail optical fiber sensor and a signal processing unit.

[0009] The slide rail type optical fiber sensor consists of a slide rail and an optical fiber sensing structure, and the optical fiber sensing structure uses a single-mode optical cable, such as Figure 2 As shown, the ends of the single-mode optical fiber cable in the fiber optic sensing structure are inserted into a rigid capillary tube. The fiber is stretched and adjusted to form a "U" shape in the middle, with the inner slider's travel end located on one side of the capillary tube. Since the slide rail contains two freely sliding sliders, to prevent interference from the other slider, 502 glue is used to secure silent ball bearings between the innermost and outer sliders. This allows the slide rail to only slide between the inner slider and the outer housing. The capillary tube is placed on the slider but not glued to it. Instead, it is secured to the outer housing to maintain its position during movement. Tape is then wrapped around the lower portion of the capillary tube to thicken it, making the radius larger than the tube. This section is then used to stop the slider when it moves upward, marking the end of its travel. Finally, the fiber pigtails are attached to the slider. The slider is then moved up and down, allowing the bending radius of the "U"-shaped SMF on one side of the capillary tube to change accordingly. From a structural point of view, the movement of the slider is the same as the displacement of the opening and closing actions. Figure 3 As shown, a high-speed high-voltage circuit breaker has a vacuum interrupter chamber. A stationary contact is fixed to the top of the chamber, and a moving contact and a drive shaft connected to the moving contact are arranged on the bottom wall. The moving contact, stationary contact, and drive shaft are all arranged vertically. The lower end of the drive shaft is located in the bracket of the high-speed high-voltage circuit breaker. The up and down movement of the drive shaft causes the L-shaped steel plate to move up and down with it.

[0010] The method of using the speed measurement system based on the slide rail optical fiber sensor is as follows:

[0011] Step 1: Fix the drive shaft to the L-shaped steel plate so that the drive shaft drives the L-shaped steel plate to move up and down;

[0012] Step 2: Fix the inner slider of the optical fiber sensor on the L-shaped steel plate, and fix the outer casing of the optical fiber sensor on the bracket of the high-voltage vacuum circuit breaker with a fixing clamp. That is, when the inner slider of the optical fiber sensor moves with the transmission shaft, the outer casing of the optical fiber sensor remains stationary.

[0013] Step 3: The sliding-rail optical fiber sensor, butterfly laser, and photoelectric converter form a signal detection system. The butterfly laser emits light, which passes through the sliding-rail optical fiber sensor and then enters the photoelectric converter.

[0014] Step 4: During the opening and closing operation, the transmission shaft drives the L-shaped steel plate to move, causing the internal slider of the slide-type optical fiber sensor to move, thereby causing the bending loss of the single-mode optical cable to change accordingly;

[0015] Step 5: Because the bending loss of the single-mode optical cable changes, the voltage signal passing through the optical-to-electrical converter will change;

[0016] Step 6: Based on the negative correlation between the voltage signal and the transmission shaft displacement, calculate the speed of the transmission shaft movement.

[0017] Furthermore, the corresponding relationship between the voltage signal and the transmission shaft displacement is a negative correlation.

[0018] The signal processing unit includes a photoelectric converter and a single-chip microcontroller. The photoelectric converter converts the optical signal output by the slide-type fiber optic speed sensor into a voltage signal, which is then transmitted to the single-chip microcontroller. The single-chip microcontroller detects the first rising or falling edge of the voltage waveform to determine the starting point of the drive shaft's displacement. Based on the time difference, it calculates the speed parameters of the opening and closing operations.

[0019] Next, place the rigid tubing on the slider, but don't glue it to the slider. Instead, secure it to the outer casing of the rail to keep it in place during movement. Then, tape the lower portion of the tubing to make it thicker, making the radius of this portion larger than the tubing. This way, when the slider slides upward, it stops at this point, marking the end of its travel. Finally, glue the fiber pigtails on both ends of the optical fiber to the slider.

[0020] Beneficial effects of the present invention:

[0021] The present invention bends a single-mode optical cable so that the middle part of the optical fiber presents a "U"-shaped structure and is fixed on a slide rail to form a sensing structure. The change in the optical signal of the optical fiber sensing structure reflects the displacement of the opening and closing action, thereby accurately calculating the opening and closing speed of the fast high-voltage circuit breaker. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the system block diagram;

[0023] Figure 2 This is the packaging method of the single-mode optical cable on the slide rail in the present invention;

[0024] Figure 3 Schematic diagram of the overall structure of the high-voltage circuit breaker;

[0025] Figure 4 is an operational flow chart of the present invention;

[0026] Figure 5 Block diagram of the system for measuring optical fiber bending loss;

[0027] Figure 6 is the relationship curve between voltage and displacement;

[0028] In the figure: 1 slider; 2 "U"-shaped structure; 3 hard capillary; 4 end point of the slider's travel; 5 adhesive tape; 6 silent ball bearing; 7 slide rail housing; 8 vacuum circuit breaker housing; 9 static contact; 10 moving contact; 11 vacuum interrupter; 12 transmission shaft; 13 bracket; 14 slide rail optical fiber sensor; 15 L-shaped steel plate; 16 fixing clamp. DETAILED DESCRIPTION

[0029] Speed ​​measurement system based on slide-type optical fiber sensor, such as Figure 1 As shown, the system uses a butterfly laser as a light source, which is sequentially connected to a slide-type optical fiber sensor 14 and a signal processing unit.

[0030] The slide rail type optical fiber sensor 14 is composed of a slide rail and an optical fiber sensing structure, and the optical fiber sensing structure adopts a single-mode optical cable, such as Figure 2As shown, the ends of the single-mode optical cable in the fiber optic sensing structure are inserted into a rigid capillary tube 3. After stretching and adjustment, the fiber optic cable forms a "U"-shaped structure 2 in the middle. The end point 4 of the internal slider's travel is located on one side of the capillary tube 3. Since the slide rail contains two freely sliding sliders, to prevent interference from the other slider, 502 glue is used to attach silent ball bearings 6 between the innermost and outer sliders. This allows the slide rail to slide only between the inner slider 1 and the rail housing 7. The capillary tube 3 is placed on the slider 1 but not glued to it. Instead, it is fixed to the rail housing 7 to maintain its position during movement. Next, tape 5 is wrapped around the lower portion of the capillary tube 3 to thicken it, making the radius of this portion larger than that of the capillary tube 3. This allows the slider 1 to stop at this point when sliding upwards, marking the end point 4 of the slider's travel. Finally, the fiber pigtails are attached to the slider. At this time, the slider 1 is pushed up and down, so that the bending radius of the "U"-shaped SMF on one side of the hard tube 3 can change accordingly with the up and down movement of the slider 1. From a structural point of view, the movement amount of the slider 1 is the same as the displacement amount of the opening and closing action. Figure 3 As shown, the high-speed high-voltage circuit breaker has a vacuum interrupter 11. A static contact 9 is fixed to the top surface of the vacuum interrupter 11. A moving contact 10 and a drive shaft 12, which is linked to the moving contact 10, are arranged on the bottom wall. The moving contact 10, the static contact 9, and the drive shaft 12 are all arranged vertically. The lower end of the drive shaft 12 is located in the bracket 13 of the high-speed high-voltage circuit breaker. The up and down movement of the drive shaft 12 causes the L-shaped steel plate 15 to move up and down with it.

[0031] Slider 1: enables the slide rail to slide between the internal slider and the outer shell; "U"-shaped structure 2: when the internal slider is pushed up and down, the bending radius of the optical fiber in the "U"-shaped structure can change accordingly with the up and down movement of the slider; Hard capillary 3: insert the two ends of the single-mode optical cable in the optical fiber sensing structure into a hard capillary to form a "U"-shaped structure; The end point of the internal slider's travel 4: stops when the slider slides upward; Adhesive tape 5: sticks the optical fiber pigtails at both ends to the slider, and moves up and down with the internal slider; Silent ball 6: enables the slide rail to only slide between the internal slider and the outer shell; Slide rail outer shell 7: enables the slide rail to slide between the internal slider and the outer shell, and is fixed to the external bracket of the vacuum circuit breaker with a fixing clamp; Vacuum circuit breaker outer shell 8: plays a role in protecting and insulating the vacuum circuit breaker; Static contact 9: separates from the moving contact and maintains insulation when opening the switch; Moving contact Head 10: Separated from the static contact and maintained insulated when opening; Vacuum interrupter 11: Uses a high vacuum environment to extinguish the arc, providing an insulating medium for contact disconnection, ensuring that the arc is quickly extinguished and not easily reignited when opening, while ensuring that the circuit is reliably conductive when closing; Drive shaft 12: Used to transmit the mechanical power of the operating mechanism, and transmit the power of the opening and closing operation to the moving contact system, to achieve accurate opening and closing of the contacts, and ensure the normal operation of the circuit breaker; Bracket 13: Used to provide the power required for opening and closing, realize the opening and closing of the contacts through mechanical transmission, and maintain the corresponding state after opening or closing, to ensure that the circuit breaker reliably executes the circuit on-off operation according to instructions; Slide-type optical fiber sensor 14: A measuring device for measuring the opening and closing speed; L-shaped steel plate 15: The drive shaft drives the L-shaped steel plate to move, so that the internal slider of the slide-type optical fiber speed sensor moves, thereby measuring the speed.

[0032] Combine Figure 4 As shown in the figure, the method of using the speed measurement system based on the sliding rail optical fiber sensor is as follows:

[0033] Step 1: Fix the transmission shaft 12 and the L-shaped steel plate 15 so that the transmission shaft 12 drives the L-shaped steel plate 15 to move up and down;

[0034] Step 2: Fix the inner slider 1 of the slide rail type optical fiber sensor 14 on the L-shaped steel plate 15, and fix the slide rail housing 7 to the bracket 13 of the high-voltage vacuum circuit breaker with a fixing clamp 16. That is, when the inner slider 1 of the slide rail type optical fiber sensor 14 moves with the transmission shaft 12, the slide rail housing 7 of the slide rail type optical fiber sensor 14 is always in a stationary state;

[0035] Step 3: The slide-type optical fiber sensor 14, the butterfly laser, and the photoelectric converter form a signal detection system. The butterfly laser emits light, which passes through the slide-type optical fiber sensor 14 and then enters the photoelectric converter.

[0036] Step 4: During the opening and closing operation, the transmission shaft 12 drives the L-shaped steel plate 15 to move, causing the inner slider 1 of the slide rail type optical fiber sensor 14 to move, thereby causing the bending loss of the single-mode optical cable to change accordingly;

[0037] Step 5: Because the bending loss of the single-mode optical cable changes, the voltage signal passing through the optical-to-electrical converter will change;

[0038] Step 6: Calculate the speed of the transmission shaft 12 based on the negative correlation between the voltage signal and the displacement of the transmission shaft 12.

[0039] The experimental process of the present invention is as follows:

[0040] like Figure 2 As shown, the two ends of the single-mode optical cable in the optical fiber sensing structure are stuffed into a rigid capillary tube 3, and a certain stretching adjustment is performed so that the middle part of the optical fiber finally presents a "U"-shaped structure 2 and remains on one side of the rigid capillary tube 3; after the two ends of the single-mode optical cable are led out from the slide rail, they are respectively fused with the jumper wires to complete the production of the optical fiber sensing structure.

[0041] Combine Figure 5 As shown, one end of the prepared slide rail optical fiber sensor 14 is then connected to a butterfly laser, and a light source with a stable emission center wavelength of 1550nm is selected; the other end of the sensor is connected to an oscilloscope via a photoelectric converter. The sensor is then fixed on a micro-displacement platform, connected to the butterfly laser, and the initial displacement of the sensor and the initial reading of the oscilloscope are recorded. Finally, through the micro-displacement platform, the relationship between the sensor's opening displacement and the voltage value is as follows: Figure 6 As shown. Data fitting yields the formula: s = -12.05u + 14.87; where s represents displacement and u represents voltage. When the high-voltage circuit breaker is closed, waveforms captured by the microcontroller and processed reveal a voltage drop of 0.24V, corresponding to a displacement of 11.98mm. The rise time from steady state to the first peak is 0.022s. With v = s / t = 0.012 / 0.022 = 0.54m / s, the closing speed of the high-voltage switch is 0.54m / s.

Claims

1. A speed measurement system based on a slide-type optical fiber sensor, characterized in that: The system uses a butterfly laser as a light source, and sequentially connects a slide-type optical fiber sensor (14) and a signal processing unit; The slide rail type optical fiber sensor (14) is composed of a slide rail and an optical fiber sensing structure, and the optical fiber sensing structure adopts a single-mode optical cable. The two ends of the single-mode optical cable in the optical fiber sensing structure are inserted into a hard thin tube (3), and stretched and adjusted so that the middle of the optical fiber presents a "U"-shaped structure (2), and the end point (4) of the stroke of the internal slider is left on one side of the hard thin tube (3); there are two freely sliding sliders in the slide rail, and the silent ball (6) between the inner slider and the outer slider is glued so that the slide rail can only slide between the inner slider (1) and the slide rail shell (7); the hard thin tube (3) is placed on the slider (1), but is not glued to the slider (1), but is fixed to the slide rail shell (7) and remains fixed when the slider (1) moves; The lower part of the hard capillary (3) is wrapped with tape (5) to make it thicker, so that the radius of this part is larger than the hard capillary (3), so that the slider (1) will stop when it slides upward to this point, which is the end point of the slider's travel (4); the pigtails at both ends of the optical fiber are pasted on the slider; the bending radius of the "U"-shaped SMF on one side of the hard capillary (3) can change accordingly with the up and down movement of the slider (1); the movement amount of the slider (1) is the same as the displacement amount of the opening and closing action; the fast high-voltage disconnection The circuit breaker has a vacuum interrupter (11), a static contact (9) is fixed on the top surface of the vacuum interrupter (11), a moving contact (10) and a transmission shaft (12) linked to the moving contact (10) are arranged on the bottom wall, and the moving contact (10), the static contact (9) and the transmission shaft (12) are all arranged vertically; the lower end of the transmission shaft (12) is located in a bracket (13) of the fast high-voltage circuit breaker, and the up and down movement of the transmission shaft (12) causes the L-shaped steel plate (15) to move up and down accordingly.

2. The speed measurement system based on the sliding rail type optical fiber sensor according to claim 1, characterized in that: The signal processing unit includes a photoelectric converter and a single-chip microcomputer. The function of the photoelectric converter is to convert the optical signal output by the slide-type optical fiber speed sensor into a voltage signal, which is then transmitted to the single-chip microcomputer. The microcontroller determines the displacement starting point of the drive shaft by capturing the first rising or falling edge of the voltage waveform, and then calculates the speed parameters of the opening and closing actions based on the time difference.

3. The method for using the speed measurement system based on the slide rail type optical fiber sensor according to claim 1 or 2, characterized in that: Here are the steps: Step 1: Fix the transmission shaft (12) and the L-shaped steel plate (15) so that the transmission shaft (12) drives the L-shaped steel plate (15) to move up and down; Step 2: Fixing the inner slider (1) of the slide rail type optical fiber sensor (14) on the L-shaped steel plate (15), and fixing the slide rail housing (7) on the bracket (13) of the high-voltage vacuum circuit breaker with a fixing clamp (16), that is, when the inner slider (1) of the slide rail type optical fiber sensor (14) moves with the transmission shaft (12), the slide rail housing (7) of the slide rail type optical fiber sensor (14) is always in a stationary state; Step 3: The slide-type optical fiber sensor (14), the butterfly laser and the photoelectric converter form a signal detection system, the butterfly laser emits light, and the light enters the photoelectric converter after passing through the slide-type optical fiber sensor (14); Step 4: During the opening and closing operation, the transmission shaft (12) drives the L-shaped steel plate (15) to move, thereby moving the inner slider (1) of the slide rail type optical fiber sensor (14), thereby causing the bending loss of the single-mode optical cable to change accordingly; Step 5: Because the bending loss of the single-mode optical cable changes, the voltage signal passing through the optical-to-electrical converter will change; Step 6: Calculate the speed of the transmission shaft (12) based on the negative correlation between the voltage signal and the displacement of the transmission shaft (12).

4. The method for using the speed measurement system based on the slide rail type optical fiber sensor according to claim 3, characterized in that: The corresponding relationship between the voltage signal and the transmission shaft displacement is a negative correlation.

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