Device and method for detecting cable fracture position in expressway

Abstract

The invention, which belongs to the technical field of cable fault detection, discloses a detection apparatus and method for a cable fracture position in an expressway, the detection apparatus comprises an audio oscillator, a buffer, a high-pass filter, an output amplifier, a detector, an earphone, a data processing module and a user interface, the audio oscillator, the buffer, the high-pass filter and the output amplifier are sequentially connected, the input ends of the detector and the earphone are respectively connected with the output amplifier, the output ends of the detector and the earphone are both connected with the data processing module, and the data processing module is connected with the user interface. According to the device for detecting the fracture position of the cable in the expressway, a detection signal is applied to the exterior of the cable, so that damage to an insulating layer of the cable by a traditional method is avoided, and non-contact detection is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of cable fault detection, and in particular to a device and method for detecting a cable break position in a highway. Background Art

[0002] With the increasing demand for information communication, traffic management and industrial automation in modern society, cables are increasingly used in various fields, especially in key infrastructure such as transportation technology, ships and offshore equipment, submarine cables, mines and distribution networks. The performance of cables is directly related to the stability of communication, power supply and equipment operation. However, cable breakage is a common and serious form of failure, especially in cables used over long distances, with heavy loads and in harsh environments. The breakage problem will seriously affect the overall reliability and safety of the system.

[0003] At present, the commonly used technologies for detecting the cable break position include pulse echo method, bridge method, etc. These methods have certain detection accuracy, but have the following shortcomings in practical applications: (1) Signal attenuation and noise interference: Over long distances or in complex environments, the signals of these technologies are greatly attenuated and are easily interfered by environmental noise, which affects the detection accuracy.

[0004] (2) Damage to the cable insulation layer: Some detection methods require direct contact with the conductor part of the cable, which will inevitably damage the insulation layer of the cable, resulting in additional maintenance costs and safety hazards. Summary of the invention

[0005] The object of the present invention is to provide a device and method for detecting the break position of a cable in a highway, so as to solve the problems mentioned in the background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides a detection device for the cable break position in a highway, comprising an audio oscillator, a buffer, a high-pass filter, an output amplifier, a detector, a headset, a data processing module and a user interface. The audio oscillator, the buffer, the high-pass filter and the output amplifier are connected in sequence, the input ends of the detector and the headset are respectively connected to the output amplifier, the output ends of the detector and the headset are both connected to the data processing module, and the data processing module is connected to the user interface.

[0007] Preferably, the audio oscillator is composed of a low-power 555 timer and its peripheral component 1, the low-power 555 timer is configured to generate a rectangular wave signal in an astable mode, the rectangular wave frequency is 890 Hz, and the peripheral component 1 includes resistors R1 and R2, capacitor C2, and a protection resistor R3.

[0008] Preferably, the buffer adopts a common-phase buffer to receive and transmit the audio signal, and the input impedance is adjusted to 10M ohms by using the input bias resistor R6.

[0009] Preferably, the high-pass filter is composed of a plurality of RC filters in cascade, with a cut-off frequency of about 765 Hz, producing an attenuation of 80 dB at 50 Hz.

[0010] Preferably, the output amplifier is composed of a common-mode amplifier circuit and a second peripheral component thereof, and the second peripheral component includes resistors R12 and R13 and a capacitor C9.

[0011] Preferably, one end of the lead of the detector generates an audio signal and is connected to one end of the cable to be tested, and the other end acts as a plate of a coupling capacitor and moves along the cable to be tested, receives a starting audio signal emitted from the audio signal end, and transmits the audio signal to the data processing module.

[0012] Preferably, the earphone is used to receive and monitor changes in signal strength, and transmit the received reflected audio signal to the data processing module.

[0013] Preferably, the data processing module includes a timer, uses an edge detection algorithm to determine the starting point of the reflected signal, and measures the time difference from the starting audio signal to the receipt of the reflected audio signal, and calculates the break point position in the cable to be tested based on the relationship between the time difference and the signal speed.

[0014] Preferably, the user interface includes an LCD display screen, operation buttons and indicator lights.

[0015] The present invention also provides a method for detecting a cable break position in a highway, and the specific steps are as follows: The audio oscillator generates a high-frequency audio signal, the buffer receives the audio signal and transmits the audio signal to the high-pass filter, and the audio signal is filtered in multiple stages by the high-pass filter to remove low-frequency and high-frequency noise; The filtered audio signal is amplified by the output amplifier, the a end of the detector is connected to one end of the cable to be tested, and the b end moves along the cable to be tested to receive the starting audio signal emitted from the audio signal end, and then transmits the audio signal to the data processing module; Monitor signal strength changes through headphones and transmit received reflected audio signals to a data processing module; The data processing module uses an edge detection algorithm to determine the starting point of the reflected audio signal, and then measures the time difference from the starting audio signal to the receipt of the reflected audio signal through a timer in the data processing module. Finally, based on the relationship between the time difference and the signal speed, the position of the breaking point in the cable to be tested is calculated, wherein the signal speed is determined according to the dielectric constant of the cable.

[0016] Therefore, the present invention adopts the above-mentioned device and method for detecting the cable break position in a highway, which has the following beneficial effects: (1) Non-contact detection: The present invention adopts coupling capacitor technology to apply a detection signal outside the cable, thereby avoiding the damage to the cable insulation layer by traditional methods and realizing non-contact detection.

[0017] (2) Efficient positioning and practicality: The detection device has a simple structure and is easy to operate. It can quickly and accurately locate the cable break point without the need for expensive equipment. It is particularly suitable for large-scale and widely distributed cable monitoring scenarios such as highways.

[0018] (3) Multi-scenario application: The present invention is particularly suitable for laying cables in highways to monitor the collapse of highways. When the cable breaks or becomes abnormal, an alarm signal can be issued in time. Combined with functions such as remote notification and Internet of Things linkage, more comprehensive safety protection can be provided.

[0019] (4) The use of multi-stage filtering and high-precision amplification circuits enables accurate detection in complex electromagnetic environments.

[0020] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of an embodiment of the present invention; Figure 2 A block diagram of the monitoring principle of an embodiment of the present invention; Figure 3 is a circuit diagram of an audio oscillator according to an embodiment of the present invention; Figure 4 is a buffer circuit diagram of an embodiment of the present invention; Figure 5 A high-pass filter circuit diagram according to an embodiment of the present invention; Figure 6 is a circuit diagram of an output amplifier according to an embodiment of the present invention; Figure 7 A schematic diagram of a user interface according to an embodiment of the present invention; Figure 8 This is a user interface layout diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0024] like Figure 1-8 As shown, the present invention provides a detection device for the cable break position in a highway, comprising an audio oscillator, a buffer, a high-pass filter, an output amplifier, a detector, an earphone, a data processing module and a user interface. The audio oscillator, the buffer, the high-pass filter and the output amplifier are connected in sequence, the input ends of the detector and the earphone are respectively connected to the output amplifier, the output ends of the detector and the earphone are both connected to the data processing module, and the data processing module is connected to the user interface.

[0025] In the circuit design, the audio oscillator part uses precision resistors and capacitors to ensure the stability of the oscillation frequency and avoid frequency drift caused by environmental factors. The high-pass filter uses multi-stage RC filtering to form a steep cutoff frequency response curve and improve anti-interference ability. The output amplifier part uses a broadband amplifier to ensure that the amplified signal is distortion-free and suitable for long-distance application scenarios such as highways.

[0026] The audio oscillator consists of a low-power 555 timer (IC1) and its peripheral components. The low-power 555 timer is configured to generate a rectangular wave signal in an astable mode with a rectangular wave frequency of 890Hz. Peripheral components include resistors R1 and R2, capacitor C2, and protection resistor R3. The functions of each structure in the peripheral components are as follows: resistors R1 and R2 are used to adjust the charge and discharge time of capacitor C2; capacitor C2 together with resistors R1 and R2 determine the frequency of the oscillator; protection resistor R3 is connected in series with the output signal to limit the current and protect the circuit.

[0027] The formula for deriving the frequency of a rectangular wave is: T1=R2×C×In2=220k×3300pF×ln2=0.005032s; T2=(R2+R1)×C×In2=(51k+220k)×3300pF×ln2=0.0061988s; T=T1+T2=0.005032+0.0061988=0.0112310s; F=1 / T=1.443 / (R1+2×R2)=889.7588HZ; The buffer uses a common-phase buffer to receive and transmit audio signals, and uses the input bias resistor R6 to adjust the input impedance to 10M ohms. Since the impedance from the cable to be tested to the detector is very high at the operating frequency of the audio oscillator, a high-impedance buffer stage is used at the input end of the circuit to generate an input impedance of 10M ohms, that is, the input impedance is adjusted to 10M ohms through R6.

[0028] The high-pass filter is composed of multiple RC filters (including resistors R4 and R5) in cascade, with a cut-off frequency of about 765Hz, which can filter out low-frequency noise signals below 1kHz and produce 80dB attenuation at 50Hz to avoid low-frequency noise from interfering with the detection results. Resistors R4 and R5 are components of the filter circuit and can adjust the filtering effect of the signal.

[0029] Principle of high-pass filter: Generally, for a single-stage RC filter, the transition from passband to stopband is slow. If a fast transition is required, multiple RC filters can be combined together to form a more ideal RC high-pass filter. In this way, the transition from passband to stopband is accelerated, but the voltage attenuation increases by 6dB for each additional stage. Due to the high sensitivity of the circuit, the detector is susceptible to 50Hz AC hum, so a high-pass filter is used to attenuate signals below 1kHz, producing 80dB attenuation at 50Hz, improving the sensitivity of the detector. Its cutoff frequency is f=1 / 6.28RC, and the calculated result is approximately 1kHz.

[0030] The output amplifier is composed of a common-mode amplifier circuit (IC3-2) and its peripheral component 2, which can amplify the filtered audio signal. The peripheral component 2 includes resistors R12, R13 and capacitor C9. The voltage gain of the amplifier is adjusted to just below 50 by the voltage divider R12 and R13. The value of R12 is 100K, the value of R13 is 2K, and the capacitor C9 plays a filtering role. In order to monitor the size of the injected signal to determine the location of the fault, the signal output from pin (7) of IC3-2 (i.e. the amplified signal) is coupled to the headphone socket XSP using C9.

[0031] The voltage gain is calculated as: A=(R12+R13) / R13=(100+2) / 251=51; One end of the detector lead (end a) generates an audio signal and connects to one end of the cable to be tested. The other end (end b) moves along the cable to be tested as a plate of a coupling capacitor to receive the starting audio signal from the audio signal end and transmit the audio signal to the data processing module. When the detector end b receives the signal coupled from end a, the earphone emits a uniform and delicate sound; when the detector end b moves to the cable break, the audio signal received by the coupling capacitor is weakened, and the sound at the earphone end is significantly weakened.

[0032] The earphone is used to receive and monitor the changes in signal strength, and transmit the received reflected audio signal to the data processing module to determine the break position of the cable under test. When the detector detects that the cable under test is not broken, the earphone emits a uniform and delicate sound; when the cable under test is broken, the sound in the earphone is significantly weakened, which is convenient for quickly locating the break point.

[0033] The data processing module includes a high-precision timer, which uses an edge detection algorithm to determine the starting point of the reflected signal, and then measures the time difference from the starting audio signal to the reception of the reflected audio signal (i.e., the signal propagation time). Finally, based on the relationship between the signal propagation time and the signal speed, the position of the break point in the cable to be tested is calculated using the following formula: Distance = (signal propagation time × signal speed) / 2; The signal propagation time is measured using a high-precision timer, and the signal speed is determined based on the dielectric constant of the cable to be tested.

[0034] The user interface includes an LCD display, operation buttons, and indicator lights. LCD display: used to display measurement results and device status in real time; operation buttons: used to start and stop detection operations; indicator lights: used to display the working status of the device (for example, standby, testing, fault).

[0035] Working principle: First, the audio oscillator outputs a rectangular wave signal with a frequency of 890Hz, which is coupled to the input end of the buffer and is limited by the series protection resistor R3 as the input signal of the buffer; the output signal of the buffer is fed into the four-stage high-pass filter composed of IC2-1 for filtering, and the signal output from the output end of the filter has no interference from AC hum. The output end of the filter only has a high-frequency signal with a frequency higher than the lower cutoff frequency of the high-pass filter of 1kHz.

[0036] The present invention also provides a method for detecting the position of a cable break in a highway, which detects the position of the cable in the highway based on a coupling capacitance method, and the specific steps are as follows: The audio oscillator generates a high-frequency audio signal, the buffer receives the audio signal and transmits the audio signal to the high-pass filter, and the audio signal is filtered in multiple stages by the high-pass filter to remove low-frequency and high-frequency noise; The filtered audio signal is amplified by the output amplifier, the a end of the detector is connected to one end of the cable to be tested, and the b end moves along the cable to be tested to receive the starting audio signal emitted from the audio signal end, and then transmits the audio signal to the data processing module; Monitor signal strength changes through headphones and transmit received reflected audio signals to a data processing module; The data processing module uses an edge detection algorithm to determine the starting point of the reflected audio signal, and then measures the time difference from the starting audio signal to the receipt of the reflected audio signal through a timer in the data processing module. Finally, based on the relationship between the time difference and the signal speed, the position of the breaking point in the cable to be tested is calculated, wherein the signal speed is determined according to the dielectric constant of the cable.

[0037] Comparative Example 1 Multimeter to detect cable faults Detection principle: Remove both ends of the faulty cable with an open circuit or short circuit, separate the inner and outer conductors of the cable. If the cable has a short circuit fault, the needle will point to zero. When the cable is open, short-circuit the other end of the cable and check with a multimeter. If the needle still does not swing, it proves that the cable is disconnected.

[0038] Disadvantages: significant damage to the cable insulation layer; huge cost.

[0039] Comparative Example 2 Reflection Method for Finding Low-Resistance Faults Detection principle: Reflection method, also called pulse echo method, uses the principle of evaluating the point where the wave impedance changes, such as the high-frequency pulse generated at the fault point, to detect the fault.

[0040] Advantages: It can intuitively determine the location and type of cable fault; the measurement is simple and accurate, and the operation is very simple.

[0041] Disadvantages: The measuring instrument is relatively expensive; the pulse wave is easily affected by obstacles, resulting in measurement errors or mistakes; the pulse wave reflection method is not suitable for long-distance detection; it can simultaneously detect the breaks of wires of various thicknesses; the transmission signal frequency is adjustable to minimize power frequency interference in different environments.

[0042] Example 1 Detecting breaks in long distance communications cables The cable type to be tested is coaxial cable and the length is 1 km.

[0043] The above detection method and steps are used for measurement. The measured signal speed of the cable is 200 m / μs and the time difference is 8 μs. The distance between the break point and the transmitting end is calculated as follows: Distance = (8us × 200m) / 2 = 800m; Then, the measurement results are displayed in real time on the LCD screen, and the break point is 800 meters. Finally, the results are verified: by measuring the actual break point, the detection accuracy and reliability of the device are verified, and the error is within 1 meter, which meets the expected requirements.

[0044] Example 2 Detecting breaks in medium-distance power cables The cable type to be tested is a power cable, and its length is 500 meters. The above detection method and steps are used for measurement, and the signal speed of the cable is measured to be 200 meters / microseconds, and the time difference is 3 microseconds. The position of the break point from the transmitter is calculated as follows: Distance = (3us × 200m) / 2 = 300m; Then, the measurement results are displayed on the LCD screen, and the break point is 300 meters. Finally, the results are verified: the break point is verified on site to confirm the detection results of the device. The error is within 0.5 meters, and the performance meets the requirements.

[0045] Example 3 Detecting breaks in short-distance sensor cables The cable type to be tested is a sensor cable, and its length is 100 meters. The above detection method and steps are used for measurement, and the signal speed of the cable is measured to be 200 meters / microseconds, and the time difference is 2 microseconds. The position of the breakpoint from the transmitter is calculated using the formula: Distance = (1us×200m) / 2=100m; Then, the measurement result is displayed on the LCD screen, that is, the breaking point is 100 meters. Finally, the result is verified: the actual breaking point is checked and the device detection result is verified. The error is within 0.2 meters, which meets the short-distance precise detection requirements.

[0046] The advantages of this detection method: it can continuously and indirectly detect the cable connection status, and the detection cable length is not limited; it saves time and money; it can directly detect the cable without causing any damage to the original cable before testing; it can detect the cable break position in just one time; it can detect the breakage of wires of various thicknesses at the same time; the transmission signal frequency is adjustable to minimize power frequency interference in different environments.

[0047] It can be seen that compared with the pulse echo method and the bridge method, the significant advantages of this scheme are: (1) there is no need to destroy the outer structure of the cable, and detection can be performed when the cable is operating normally; (2) it is suitable for various types of cables (including coaxial cables, flat cables, shielded cables, etc.) and has a wide range of applicability; (3) it can maintain stable detection accuracy in high humidity, high temperature, and strong interference environments.

[0048] Therefore, the present invention adopts the above-mentioned device and method for detecting the cable break position in a highway, which has a simple structure and is easy to operate. It can quickly and accurately locate the cable break point without the need for expensive equipment. It is particularly suitable for large-scale and widely distributed cable monitoring scenarios such as highways.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A device for detecting the position of cable breakage in a highway, characterized in that: It includes an audio oscillator, a buffer, a high-pass filter, an output amplifier, a detector, a headset, a data processing module and a user interface. The audio oscillator, the buffer, the high-pass filter and the output amplifier are connected in sequence, the input ends of the detector and the headset are respectively connected to the output amplifier, the output ends of the detector and the headset are both connected to the data processing module, and the data processing module is connected to the user interface.

2. A device for detecting a cable break position in a highway according to claim 1, characterized in that: The audio oscillator is composed of a low power 555 timer and its peripheral components. The low power 555 timer is configured to generate a rectangular wave signal in an astable mode. The rectangular wave frequency is 890 Hz. The peripheral components include resistors R1 and R2, capacitor C2, and protection resistor R3.

3. A device for detecting a cable break position in a highway according to claim 1, characterized in that: The buffer uses a common-phase buffer to receive and transmit audio signals, and the input impedance is adjusted to 10M ohms using the input bias resistor R6.

4. A device for detecting a cable break position in a highway according to claim 1, characterized in that: The high-pass filter is composed of multiple RC filters in cascade, with a cutoff frequency of 765Hz and an attenuation of 80dB at 50Hz.

5. The device for detecting the cable break position in a highway according to claim 1, characterized in that: The output amplifier is composed of a common-mode amplifier circuit and a second peripheral component thereof. The second peripheral component includes resistors R12, R13 and a capacitor C9.

6. A device for detecting cable breakage position in a highway according to claim 1, characterized in that: One end of the detector's lead generates an audio signal and connects to one end of the cable to be tested. The other end acts as a plate of a coupling capacitor and moves along the cable to be tested, receiving a starting audio signal from the audio signal end and transmitting the audio signal to the data processing module.

7. A device for detecting the position of cable breakage in a highway according to claim 6, characterized in that: The earphone is used to receive and monitor the change of signal strength, and transmit the received reflected audio signal to the data processing module.

8. A device for detecting cable breakage position in a highway according to claim 7, characterized in that: The data processing module includes a timer, which uses an edge detection algorithm to determine the starting point of the reflected signal and measures the time difference from the starting audio signal to the reception of the reflected audio signal. According to the relationship between the time difference and the signal speed, the position of the break point in the cable to be tested is calculated.

9. A device for detecting cable breakage position in a highway according to claim 1, characterized in that: The user interface includes an LCD display, operation buttons and indicator lights.

10. A method for detecting a cable break position in a highway, applied to a device for detecting a cable break position in a highway as claimed in any one of claims 1 to 9, characterized in that: The specific steps are as follows: The audio oscillator generates a high-frequency audio signal, the buffer receives the audio signal and transmits the audio signal to the high-pass filter, and the audio signal is filtered in multiple stages by the high-pass filter to remove low-frequency and high-frequency noise; The filtered audio signal is amplified by the output amplifier, the a end of the detector is connected to one end of the cable to be tested, and the b end moves along the cable to be tested to receive the starting audio signal emitted from the audio signal end, and then transmits the audio signal to the data processing module; Monitor signal strength changes through headphones and transmit received reflected audio signals to a data processing module; The data processing module uses an edge detection algorithm to determine the starting point of the reflected audio signal, and then measures the time difference from the starting audio signal to the receipt of the reflected audio signal through a timer in the data processing module. According to the relationship between the time difference and the signal speed, the position of the breaking point in the cable to be tested is calculated, wherein the signal speed is determined according to the dielectric constant of the cable.

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