A cable trunking cable online monitoring system

Abstract

The present invention provides an online monitoring system for a cable trough, which relates to the field of circuit monitoring technology, and includes: a sensing module, which is arranged on the surface of the cable trough, and is used to detect the temperature and vibration of the cable trough; a signal processing module, which is electrically connected to the sensing module, and is used to receive and process the temperature and vibration signals collected by the sensing module; a communication module, which is connected to the signal processing module, and is used to transmit the processed temperature and vibration signals to a monitoring center; the monitoring center is used to receive and display the temperature and vibration signals, and to issue an alarm when the signal exceeds a preset threshold; wherein the signal processing module is integrated in a connector at one end of the cable trough. The present invention can continuously monitor the key parameters of the cable trough, such as temperature and vibration, to achieve early warning of cable faults, and to ensure the safe and stable operation of the power grid.

Description

Technical Field

[0001] The invention relates to the technical field of circuit monitoring, and in particular to an online monitoring system for cable ducts. Background Art

[0002] As the demand for cables in power systems continues to grow, the operating status of cable trunking cables, as an important component of the power system, directly affects the safe and stable operation of the power grid. During long-term use, cable trunking cables will increase in temperature due to factors such as overload, short circuit, and moisture, which may cause the cables to burn out and break in severe cases. At the same time, cable trunking cables also face problems such as mechanical damage, corrosion, and aging. Therefore, it is very necessary to monitor and warn the status of cable trunking cables in real time.

[0003] At present, some cable trunking cable status monitoring mostly adopts manual inspection, which has few monitoring points and long monitoring time intervals, and cannot achieve all-weather and all-round monitoring of cable trunking cables. There are monitoring blind spots, which is not conducive to the timely discovery of cable faults. In recent years, some new online monitoring systems have begun to be applied to cable trunking cable monitoring, such as systems based on distributed optical fiber sensing technology, but such systems are expensive and require modifications to the cable trunking cables themselves, affecting the normal use of the cables. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an online monitoring system for cable ducts, which can continuously monitor key parameters of cable ducts such as temperature and vibration, realize early warning of cable faults, and ensure the safe and stable operation of the power grid.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0006] A cable trough online monitoring system, comprising:

[0007] A sensing module is arranged on the surface of the cable in the cable trough and is used to detect the temperature and vibration of the cable in the cable trough;

[0008] A signal processing module, electrically connected to the sensing module, and configured to receive and process the temperature and vibration signals collected by the sensing module;

[0009] A communication module, connected to the signal processing module, for transmitting the processed temperature and vibration signals to a monitoring center;

[0010] The monitoring center is used to receive and display the temperature and vibration signals and issue an alarm when the signal exceeds a preset threshold; wherein the signal processing module is integrated in the connector at one end of the cable trough.

[0011] Furthermore, the sensing module includes:

[0012] A temperature sensor module is arranged on the surface of the cable in the cable trough and is used to detect the temperature of the cable in the cable trough;

[0013] A vibration sensor module is arranged on the surface of the cable in the cable trough and is used to detect vibration of the cable in the cable trough;

[0014] The signal amplification module is connected to the temperature sensor module and the vibration sensor module and is used to amplify the temperature and vibration signals.

[0015] Furthermore, the temperature sensor module includes:

[0016] A first sensitive element, used to detect temperature changes;

[0017] A temperature measuring circuit, connected to the first sensitive element, for converting temperature changes into electrical signals;

[0018] A compensation circuit, connected to the temperature measurement circuit, for performing temperature compensation on the temperature sensor;

[0019] The calibration circuit is connected to the compensation circuit and is used to calibrate the temperature sensor.

[0020] Furthermore, the vibration sensor module includes:

[0021] A second sensitive element, used to detect vibration and generate a corresponding electrical signal;

[0022] A preamplifier, connected to the second sensitive element, for pre-amplifying the electrical signal;

[0023] A bandpass filter, connected to the preamplifier, for filtering out noise;

[0024] an amplifying and conditioning circuit, connected to the bandpass filter, for amplifying and conditioning the signal;

[0025] The analog-to-digital converter is connected to the amplifying and conditioning circuit and is used for converting the analog signal into a digital signal.

[0026] Furthermore, the signal amplification module includes:

[0027] A temperature signal pre-amplification module, connected to the temperature sensor module, and used to pre-amplify the temperature signal to obtain a first temperature signal;

[0028] a temperature signal amplifying module, connected to the temperature signal pre-amplifying module, and configured to amplify the first temperature signal to obtain a second temperature signal;

[0029] A vibration signal pre-amplification module, connected to the vibration sensor module, and used to pre-amplify the vibration signal to obtain a first vibration signal;

[0030] The vibration signal amplifying module is connected to the vibration signal pre-amplifying module and is used to amplify the first vibration signal to obtain a second vibration signal.

[0031] Furthermore, the signal processing module includes:

[0032] A filtering module, connected to the temperature signal amplifying module and the vibration signal amplifying module, and used to filter out noise in the signal to generate an analog signal;

[0033] An analog-to-digital conversion module, connected to the filtering module, and used to convert an analog signal into a digital signal;

[0034] The microprocessor module is connected to the analog-to-digital conversion module and is used for processing digital signals.

[0035] Furthermore, the communication module includes:

[0036] An encoding module, connected to the microprocessor module, for encoding digital signals;

[0037] A modulation module, connected to the encoding module, for modulating the encoded digital signal;

[0038] A radio frequency module, connected to the modulation module, and configured to up-convert the modulated signal into a radio frequency signal;

[0039] A power amplification module, connected to the radio frequency module, for amplifying the transmission power of the radio frequency signal;

[0040] An antenna, connected to the power amplifier module, for transmitting radio frequency signals;

[0041] A signal receiving module, used for receiving radio frequency signals;

[0042] A demodulation module, connected to the signal receiving module, for demodulating the received radio frequency signal;

[0043] The decoding module is connected to the demodulation module and is used to decode the demodulated signal.

[0044] Furthermore, the monitoring center includes:

[0045] A signal interface module, used for receiving a digital signal from a decoding module;

[0046] A signal conditioning module, connected to the signal interface module, for processing the received digital signal;

[0047] A storage module, connected to the signal conditioning module, for storing digital signals and processing results;

[0048] A display module, connected to the signal conditioning module, for displaying temperature and vibration parameter curves;

[0049] An alarm module, connected to the signal conditioning module, for alarming abnormal temperature and vibration;

[0050] The printing module is connected to the signal conditioning module and is used for printing temperature and vibration reports.

[0051] Furthermore, the temperature measurement circuit includes:

[0052] A reference power supply, used for providing a reference voltage;

[0053] A bridge arm circuit, which forms a bridge balancing circuit for temperature detection with the first sensitive element;

[0054] The differential amplifier is connected to the bridge arm circuit and is used to amplify the voltage across the balanced bridge.

[0055] Furthermore, the compensation circuit includes:

[0056] The temperature sensing module is used to detect the ambient temperature to obtain a temperature signal;

[0057] An operational amplifier, used for amplifying the temperature signal to obtain an analog temperature signal;

[0058] A / D converter, used to convert analog temperature signal into digital signal;

[0059] a microprocessor for calculating a compensation value according to the digital signal;

[0060] A DAC converter is used to convert the compensation value into an analog signal.

[0061] The above solution of the present invention includes at least the following beneficial effects:

[0062] The above scheme of the present invention realizes real-time online monitoring of the temperature and vibration of the cable in the cable trough, and can monitor the operating status of the cable trough cable in all directions around the clock, greatly improving the continuity and coverage of monitoring; the use of non-contact monitoring will not affect the cable trough cable itself, so that the cable trough cable can maintain normal use, and can timely feedback the abnormal temperature rise and vibration of the cable trough cable, realize early warning of cable failure, improve the reliability and safety of the power system, and can conveniently select different sensors according to needs to expand the monitoring function of the system to meet different application requirements, realize remote wireless monitoring function, and monitor data can be transmitted remotely, expanding the scope of use of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 It is a schematic diagram of an online monitoring system for cable ducts provided by an embodiment of the present invention.

[0064] Figure 2 It is a schematic diagram of a sensing module of a cable trough online monitoring system provided by an embodiment of the present invention.

[0065] Figure 3 It is a schematic diagram of a temperature sensor module of a cable duct online monitoring system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0066] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0067] like Figure 1 As shown, an embodiment of the present invention provides an online monitoring system for cable ducts, comprising:

[0068] The sensing module 10 is arranged on the surface of the cable in the cable trough and is used to detect the temperature and vibration of the cable in the cable trough;

[0069] A signal processing module 20, electrically connected to the sensing module, for receiving and processing the temperature and vibration signals collected by the sensing module;

[0070] A communication module 30, connected to the signal processing module, for transmitting the processed temperature and vibration signals to a monitoring center;

[0071] The monitoring center 40 is used to receive and display the temperature and vibration signals and to issue an alarm when the signals exceed a preset threshold; wherein the signal processing module is integrated in a connector at one end of the cable duct.

[0072] In the embodiment of the present invention, the present invention realizes real-time online monitoring of the temperature and vibration of the cable in the cable trough, and can monitor the operating status of the cable trough cable around the clock and in all directions, greatly improving the continuity and coverage of the monitoring; the non-contact monitoring is adopted, which will not affect the cable trough cable itself, so that the cable trough cable can maintain normal use, and can timely feedback the abnormal temperature rise and vibration of the cable trough cable, realize early warning of cable failure, improve the reliability and safety of the power system, and can conveniently select different sensors according to needs to expand the monitoring function of the system to meet different application requirements, realize the remote wireless monitoring function, and the monitoring data can be transmitted remotely, which expands the scope of use of the system.

[0073] like Figure 2 As shown, the sensing module 10 includes:

[0074] The temperature sensor module 101 is arranged on the surface of the cable in the cable trough and is used to detect the temperature of the cable in the cable trough;

[0075] A vibration sensor module 102 is provided on the surface of the cable in the cable trough and is used to detect vibration of the cable in the cable trough;

[0076] The signal amplification module 103 is connected to the temperature sensor module and the vibration sensor module, and is used to amplify the temperature and vibration signals.

[0077] In the embodiment of the present invention, a temperature sensor module and a vibration sensor module are provided, which can simultaneously monitor the temperature and vibration of the cable trough cable, thereby realizing all-round monitoring of the cable status; a modular design is adopted, and the temperature sensor module, the vibration sensor module and the signal amplification module have clear functions, flexible design, and are easy to install and maintain; the signal amplification module amplifies the weak original signal, improves the signal acquisition quality, and lays the foundation for subsequent signal processing; the modular design enables the system to have good compatibility, scalability and upgradeability, and is easy to integrate with other modules to meet different application requirements; the system is low-cost, requires no modification to the cable trough cable itself, is easy to install, and is suitable for status monitoring of various types of cable trough cables; real-time monitoring of the temperature and vibration of the cable trough cable can timely discover hidden dangers of cable faults, give early warning to the cable, improve the reliability of the power system, and is conducive to improving the maintenance methods of the power department, reducing maintenance costs, and making monitoring work more intelligent.

[0078] like Figure 3 As shown, the temperature sensor module 101 includes:

[0079] A first sensitive element 1011, used to detect temperature changes;

[0080] A temperature measuring circuit 1012, connected to the first sensitive element, for converting temperature changes into electrical signals;

[0081] A compensation circuit 1013, connected to the temperature measurement circuit, for performing temperature compensation on the temperature sensor;

[0082] The calibration circuit 1014 is connected to the compensation circuit and is used to calibrate the temperature sensor.

[0083] In the embodiment of the present invention, by setting a first sensitive element, the change of the surface temperature of the cable in the cable trough can be accurately detected to meet the temperature measurement requirements; the temperature measurement circuit converts the temperature change into a standard electrical signal, laying the foundation for subsequent circuit processing; the compensation circuit compensates for the zero drift and sensitivity drift of the temperature sensor, thereby improving the temperature measurement accuracy and stability; the calibration circuit facilitates regular calibration of the sensor to ensure the accuracy of long-term measurement; the modular design has clear functions of each circuit, flexible design, and is easy to debug and maintain. The temperature sensor module has high accuracy, fast response speed, and strong anti-interference ability. It can accurately reflect the temperature changes of the cable trough cable, has good compatibility with the cable trough cable, does not affect the normal operation of the cable, is easy to install and use, has a low power consumption design, can work continuously for a long time, meets the needs of online monitoring, is low cost, is easy to mass produce, and has good economy.

[0084] In a preferred embodiment of the present invention, the vibration sensor module comprises:

[0085] A second sensitive element, used to detect vibration and generate a corresponding electrical signal;

[0086] A preamplifier, connected to the second sensitive element, for pre-amplifying the electrical signal;

[0087] A bandpass filter, connected to the preamplifier, for filtering out noise;

[0088] an amplifying and conditioning circuit, connected to the bandpass filter, for amplifying and conditioning the signal;

[0089] The analog-to-digital converter is connected to the amplifying and conditioning circuit and is used for converting the analog signal into a digital signal.

[0090] In the embodiment of the present invention, by setting a second sensitive element, the vibration signal of the cable trough can be accurately detected to meet the vibration measurement requirements, the preamplifier amplifies the weak vibration signal and improves the signal acquisition quality; the bandpass filter filters out unnecessary noise and improves the signal-to-noise ratio of the signal; the amplification and conditioning circuit further amplifies and conditions the signal to prepare for analog-to-digital conversion; the analog-to-digital conversion converts the analog signal into a digital signal to facilitate subsequent digital processing; modular design, each circuit has clear functions, flexible design, and is easy to debug and maintain; the vibration sensor has high sensitivity and a wide frequency response range, and can accurately detect various mechanical vibrations of the cable trough cable; it has strong anti-interference ability and high reliability, can adapt to use in harsh environments, has low cost, simple mass production, good economy, easy installation, no effect on the cable trough cable, and good compatibility with the cable trough cable.

[0091] In another preferred embodiment of the present invention, in the second sensitive element, by The linear acceleration a of the vibration can be detected, where a is the linear acceleration, k is the stiffness coefficient of the cantilever beam, x0 is the static offset, m is the mass block mass, and x is the moving distance of the mass block. m = ρw2t2l2, E is the Young's modulus of the cantilever beam (Pa), w1 is the width of the cantilever beam, t1 is the thickness of the cantilever beam, l1 is the length of the cantilever beam, ε0 is the vacuum dielectric constant, S is the area of ​​the capacitor plate, d is the gap between the capacitor plate and the substrate, ρ is the density of the mass block, w2 is the width of the mass block, t2 is the thickness of the mass block, and l2 is the length of the mass block; Detect the angular velocity of vibration, where w3 is the angular velocity, Δf is the frequency deviation caused by the Coriolis effect, and S1 is the gyroscope sensitivity. It can amplify the angular velocity and linear acceleration, effectively suppress the influence of environmental noise on the signal, detect the signal amplitude and adjust the gain in real time. out is the output voltage, A is the differential amplifier gain, V + and V - is the input voltage, w4 is the signal frequency, τ is the amplifier time constant, where, Among them, R f is the feedback resistor of the preamplifier; R gr is the resistance of the preamplifier loop; τ is the time constant of the amplifier, R i is the input resistance, C i is the input capacitance, G m is the mutual impedance of the tube, j is an imaginary unit, indicating that the signal is an AC signal. Extract weak useful signals, where H(z) is the filter transfer function, b i is the filter coefficient, N is the filter order; in the amplification and conditioning circuit, V out =a i V in +b i Amplify the vibration signal, where V in ∈ interval i, V out is the output voltage, V in is the input voltage, a i and b i is the amplification factor of interval i. In the analog-to-digital converter, the analog signal is converted into a digital signal by Y(z)=X(z)H(z)+Q(z), where Y(z) represents the digital output signal, X(z) is the input signal, H(z) is the modulator transfer function, and Q(z) is the quantization noise; z is the z-transform, where

[0092] In a preferred embodiment of the present invention, the signal amplification module comprises:

[0093] A temperature signal pre-amplification module, connected to the temperature sensor module, and used to pre-amplify the temperature signal to obtain a first temperature signal;

[0094] a temperature signal amplifying module, connected to the temperature signal pre-amplifying module, and configured to amplify the first temperature signal to obtain a second temperature signal;

[0095] A vibration signal pre-amplification module, connected to the vibration sensor module, and used to pre-amplify the vibration signal to obtain a first vibration signal;

[0096] The vibration signal amplifying module is connected to the vibration signal pre-amplifying module and is used to amplify the first vibration signal to obtain a second vibration signal.

[0097] In an embodiment of the present invention, the temperature signal pre-amplification module pre-amplifies the temperature signal, which can improve the input dynamic range of the subsequent amplifier circuit, provide the subsequent amplifier circuit with an input signal of suitable amplitude, and avoid error amplification caused by too small amplitude of the temperature signal; the temperature signal amplification module further amplifies the pre-amplified temperature signal to obtain a temperature output signal with moderate amplitude to meet the processing requirements of the subsequent circuit, and the graded amplification can better control the amplification factor of the signal to improve the amplification accuracy; the vibration signal pre-amplification module pre-amplifies the vibration signal, which can increase the amplitude of the tiny vibration signal to make it higher than the minimum recognizable input requirement of the subsequent circuit, and avoid the small signal being buried in the noise; the vibration signal amplification module accurately amplifies the pre-amplified vibration signal to obtain a large-amplitude vibration output signal, which is convenient for the subsequent circuit to process the vibration information, and at the same time, the signal amplitude can be controlled by adjusting the amplification factor to prevent the vibration signal from being distorted; the graded pre-amplification and amplification can more accurately control the amplification factor of the signal, improve the flexibility of amplification, and obtain a high-quality output signal.

[0098] In another preferred embodiment of the present invention, the temperature signal pre-amplification module adopts a low bias current CMOS operational amplifier with an input bias current less than 10pA, which can greatly reduce drift. An automatic bias current calibration circuit is set internally, and a digital potentiometer is used to detect the bias current in real time, and the output voltage of the bias power supply is adjusted in a feedback manner to keep the bias current at an accurate set value. A three-stage low-pass RC filter is designed, with a first-stage cutoff frequency of 100Hz, a second-stage cutoff frequency of 10Hz, and a third-stage cutoff frequency of 1Hz, which is used to filter out high-frequency noise, and a digital signal processing unit based on STM32 is set to perform temperature The signal is digitally filtered and smoothed, and the temperature sensor is corrected for nonlinearity to compensate for its nonlinear error. The pre-amplifier circuit adopts a four-layer PCB design, and the ground and power layers are carefully laid out to reduce the impact of parasitic parameters on the signal. The key analog components use 0.1% accuracy non-biased components to improve circuit accuracy. The temperature sensor accuracy reaches 0.01℃. The entire pre-amplifier circuit is encapsulated in a metal shell for shielding and heat insulation to improve anti-interference. The frequency response range of the pre-amplifier circuit is 0.1Hz to 10Hz, the amplification factor is adjustable, up to 1000 times, and the output signal-to-noise ratio is greater than 80dB. The temperature signal amplification module adopts a low-noise dual-rail operational amplifier as the basic amplifier for three-stage amplification. The first-stage amplification factor is set to 10 times, the second-stage amplification factor is set to 30 times, and the third-stage variable gain range is 10 times to 100 times. A second-order Butterworth low-pass filter is set between each stage of amplification, and the cut-off frequency is adjustable to eliminate high-frequency noise. A digital signal processing unit based on STM32 is set to digitally filter the amplified temperature signal to achieve a temperature resolution of 0.001°C. A digital automatic gain control circuit is used to detect the amplitude of the temperature signal and adjust the third-stage gain in real time. An overload protection circuit is added to each stage of the amplification circuit to prevent strong signals from causing amplifier saturation distortion. A DC shielding capacitor is set to remove the DC component in the signal to improve the amplification quality. The digital correction unit based on DSP can detect and compensate for the parameter drift of each stage of the amplifier in real time to ensure long-term stability. The amplification circuit adopts a four-layer PCB board design, and the copper cladding area of ​​the power layer and the ground layer is maximized.

[0099] In another preferred embodiment of the present invention, the vibration signal pre-amplification module adopts a low-noise industrial frequency differential amplifier with an internally integrated digital amplitude stabilization control circuit, which can detect the amplitude of the amplifier output signal in real time and feedback-adjust the bias current so that the amplifier gain is stabilized at 100 times, the center frequency range is 10Hz-500Hz, and the bandwidth is adjustable for filtering out interference noise. The temperature compensation system based on STM32 can detect changes in ambient temperature and introduce compensation to make the amplifier parameters change very little with temperature. The amplifier circuit adopts low-drift thin-film resistors with a time drift of less than 50ppm / ℃; the capacitance temperature coefficient is less than 100ppm / ℃, and a four-layer PCB board design is adopted. The copper covering area of ​​the power layer and the ground layer is maximized to reduce noise interference. The bandwidth range of the pre-amplification circuit is 1Hz-1000Hz, the gain accuracy is ±0.1%, and the output signal-to-noise ratio is greater than 85dB. The entire circuit is encapsulated in a metal shell for shielding to improve anti-interference performance.

[0100] In another preferred embodiment of the present invention, the vibration signal amplification module adopts a low-noise, high-speed operational amplifier to form a three-stage amplification circuit, the first stage has a fixed gain of 100 times, and the latter two stages have a programmable gain range of 10-500 times; a digital automatic gain control circuit is provided to detect the input signal amplitude and adjust the gain of the latter two stages in real time; an overload protection circuit is connected after each stage of the amplification circuit to prevent strong vibration from causing amplifier saturation distortion; FPGA is used for digital signal processing to implement digital filtering, smoothing and other algorithms to optimize signal quality; a DSP-based correction system is provided to detect amplifier parameter drift and introduce feedback compensation in real time; low-drift resistors and capacitors with an accuracy of 0.1% are used to ensure the stable performance of the amplification circuit; the amplification circuit adopts a four-layer PCB design, and the copper cladding area of ​​the power layer and the ground layer is maximized; the bandwidth range of the amplification circuit is 0.5Hz-10000Hz, the maximum amplification factor can reach 100000 times, and the distortion rate is less than 0.1%.

[0101] In another preferred embodiment of the present invention, in the temperature signal pre-amplification module, by The input bias current of the operational amplifier is automatically adjusted according to the feedback voltage to keep it at the target set value, thereby eliminating drift. Where H(s2) is the transfer function, s2 is a complex frequency domain variable, and ω c is the cut-off frequency. The digital signal is processed to perform nonlinear correction of the temperature sensor, where Vout is the output voltage, Vin is the input voltage, and a1, b1, c1 and d1 are correction coefficients. In the temperature signal amplification module, The gain of the amplifier is dynamically adjusted according to the error between the input signal and the reference value, where e(n1) is the error between the input signal and the reference signal; K p is the proportionality coefficient; Ki is the integral coefficient; K d is the differential coefficient; T is the sampling time; n1 is the current sampling point; Gain represents the gain multiple of the amplifier; when the circuit needs to be protected, For overload protection, for example, if the input voltage V in Greater than the maximum value V of the normal input range max , then the output voltage V out Take the saturation voltage V sat ; If the input voltage V in In the normal range, that is, V min and V max The output voltage V out Directly take the input voltage V in Therefore, when the input voltage of the amplifier exceeds the normal range, its output voltage is limited to a fixed saturation voltage value to prevent the amplifier from distortion. Within the normal input range, the amplifier works in a linear amplification state. In this way, through overload protection, it can effectively prevent strong input signals from causing distortion in the amplifier, thereby improving the reliability of the amplifier.

[0102] In a preferred embodiment of the present invention, the signal processing module includes:

[0103] A filtering module, connected to the temperature signal amplifying module and the vibration signal amplifying module, and used to filter out noise in the signal to generate an analog signal;

[0104] An analog-to-digital conversion module, connected to the filtering module, and used to convert an analog signal into a digital signal;

[0105] The microprocessor module is connected to the analog-to-digital conversion module and is used for processing digital signals.

[0106] In an embodiment of the present invention, the filtering module is connected after the temperature signal amplification module and the vibration signal amplification module, and is used to filter the noise components in the two signals, remove unnecessary high-frequency and DC components in the signals, and use low-pass filtering, band-pass filtering and other methods to output clean analog temperature signals and vibration signals. The effect of filtering is to improve the signal-to-noise ratio of the signal and improve the processing quality of the subsequent circuit; the analog-to-digital conversion module converts the temperature signal and vibration signal in the analog domain output by the filtering module into signals in the digital domain, and uses a high-precision analog-to-digital conversion chip to ensure the conversion accuracy. The effect is to achieve a bridge from analog signals to digital signals and prepare for digital signal processing; the microprocessor module uses a microprocessor to process the digital temperature signal and vibration signal after analog-to-digital conversion, and can implement algorithms such as digital filtering, signal analysis, and feature extraction. The effect is to deeply extract signal feature information, provide rich analysis results, and achieve intelligence.

[0107] In another preferred embodiment of the present invention, in the microprocessor module, by The digital temperature signal and the vibration signal after analog-to-digital conversion are filtered to obtain an output signal y[n], wherein h[k1] is a coefficient of the FIR filter, a[k1] is a recursive coefficient of the IIR filter, x[n] is an input signal, y[n] is an output signal, n represents the nth sampling point; N represents the order of the FIR filter, and k1 represents an index variable; x[n-k1] represents the input signal of the filter, n-k1 represents the n-k1th sampling point, M represents the order of the IIR filter, y[n-k1] represents the past output of the filter, and n-k1 represents the n-k1th sampling point;

[0108] In another preferred embodiment of the present invention, by The output signal y[n] is processed, where a4 is the scale factor, b1, b2, …, b n is the n-dimensional translation factor, ψ(t) is the mother wavelet function, x(t1, t2, …, t n ) is the n-dimensional input signal, X(a4,b1,b2,…,b n ) are n-dimensional wavelet coefficients.

[0109] In a preferred embodiment of the present invention, the communication module includes:

[0110] An encoding module, connected to the microprocessor module, for encoding digital signals;

[0111] A modulation module, connected to the encoding module, for modulating the encoded digital signal;

[0112] A radio frequency module, connected to the modulation module, and configured to up-convert the modulated signal into a radio frequency signal;

[0113] A power amplification module, connected to the radio frequency module, for amplifying the transmission power of the radio frequency signal;

[0114] An antenna, connected to the power amplifier module, for transmitting radio frequency signals;

[0115] A signal receiving module, used for receiving radio frequency signals;

[0116] A demodulation module, connected to the signal receiving module, for demodulating the received radio frequency signal;

[0117] The decoding module is connected to the demodulation module and is used to decode the demodulated signal.

[0118] In an embodiment of the present invention, the encoding module encodes the digital signal to improve the anti-interference ability of the signal. The modulation module modulates the encoded digital signal onto a high-frequency carrier to realize the conversion of the digital signal to the analog signal. The RF module up-converts the baseband modulated signal to the RF signal as a wireless transmission signal. The power amplifier module amplifies the transmission power of the RF signal to expand the transmission distance; the antenna transmits and receives RF electromagnetic waves to realize wireless space transmission; the signal receiving module receives and down-converts the RF signal; the demodulation module demodulates the received RF signal to restore the original encoded digital signal; the decoding module decodes the demodulated digital signal to restore the original digital data.

[0119] In another preferred embodiment of the present invention, by Encode the digital signal to obtain the code word C(x), where m i is an information symbol, p i is the check symbol, n5 is the codeword length, and k4 is the number of information symbols. Modulate the code word C(x) to obtain the modulated complex signal waveform s(t5), where A c is the carrier amplitude, Indicates the complex letter after QAM symbol mapping, is an orthogonal carrier wave, and t5 represents a time variable. rf =f c +f LO +BW / 2 processes the modulated complex signal waveform s(t5) to obtain the RF center frequency f rf , where f c is the baseband signal center frequency, f LO is the local oscillator frequency, BW is the baseband signal bandwidth; The RF center frequency f rf Processing is performed to obtain the decoded information symbol m i , where C1(x) is the received word, g(x) is the generating polynomial, n6 represents the codeword length of the RS code, and k5 represents the number of information symbols of the RS code.

[0120] In a preferred embodiment of the present invention, the monitoring center includes:

[0121] A signal interface module, used for receiving a digital signal from a decoding module;

[0122] A signal conditioning module, connected to the signal interface module, for processing the received digital signal;

[0123] A storage module, connected to the signal conditioning module, for storing digital signals and processing results;

[0124] A display module, connected to the signal conditioning module, for displaying temperature and vibration parameter curves;

[0125] An alarm module, connected to the signal conditioning module, for alarming abnormal temperature and vibration;

[0126] The printing module is connected to the signal conditioning module and is used for printing temperature and vibration reports.

[0127] In an embodiment of the present invention, the signal interface module can receive the digital signal decoded from the communication module to realize the connection between the monitoring center and the communication module; the signal conditioning module can perform digital signal processing to realize filtering, analysis and other functions, thereby improving the availability of the signal; the storage module can save all historical monitoring data for easy query and analysis; the display module can intuitively display temperature, vibration and other curves for easy observation by monitoring personnel; the alarm module can issue an alarm when the temperature and vibration are abnormal, thereby improving the response speed to problems; the printing module can print out the monitoring report to form a monitoring file. The modular design improves the flexibility, compatibility and maintainability of the system, realizes the comprehensive storage, processing, display and output of the monitoring data, facilitates monitoring and analysis, can realize 7×24 hours of continuous monitoring, and quickly respond to faults, thereby improving the reliability of the system.

[0128] In a preferred embodiment of the present invention, the temperature measurement circuit comprises:

[0129] A reference power supply, used for providing a reference voltage;

[0130] A bridge arm circuit, which forms a bridge balancing circuit for temperature detection with the first sensitive element;

[0131] The differential amplifier is connected to the bridge arm circuit and is used to amplify the voltage across the balanced bridge.

[0132] In the embodiment of the present invention, the reference power supply provides a precise reference voltage, which is the basis for precise temperature measurement and can improve the accuracy of measurement. The bridge arm circuit and the sensitive element constitute a bridge balance circuit, which can convert temperature changes into voltage / resistance changes to achieve electrical conversion of temperature. The differential amplifier amplifies the tiny voltage changes at both ends of the bridge to obtain a temperature voltage with a larger amplitude, thereby improving the processing quality of the subsequent circuit. The bridge balance circuit can effectively suppress the influence of ambient temperature changes and power supply voltage fluctuations on the measurement and improve the measurement stability. The modular design has clear circuit functions, is easy to debug and improve, and improves reliability. The temperature measurement circuit has high conversion efficiency, good stability, and high precision, can achieve high-precision temperature acquisition, and provides a reliable basis for temperature monitoring. It has low cost, is easy to mass produce, and has good economy.

[0133] In a preferred embodiment of the present invention, the compensation circuit comprises:

[0134] The temperature sensing module is used to detect the ambient temperature to obtain a temperature signal;

[0135] An operational amplifier, used for amplifying the temperature signal to obtain an analog temperature signal;

[0136] A / D converter, used to convert analog temperature signal into digital signal;

[0137] a microprocessor for calculating a compensation value according to the digital signal;

[0138] A DAC converter is used to convert the compensation value into an analog signal.

[0139] In the embodiment of the present invention, the temperature sensing module detects the ambient temperature and can obtain the temperature information of the working environment of the temperature sensor. The operational amplifier amplifies the temperature signal to improve the processing quality of the subsequent circuit. The A / D converter realizes the analog-to-digital conversion of the temperature, which can facilitate the digital processing of the microprocessor. The microprocessor calculates the compensation value according to the temperature information and is the core of the compensation calculation. The DAC converter completes the digital-to-analog conversion and can obtain the analog compensation amount. The compensation is realized in a digital way, which can increase the flexibility and accuracy of the compensation. The modular design and clear circuit function improve the reliability and maintainability. The compensation circuit can generate the compensation amount in real time according to the temperature change, effectively improving the measurement accuracy and stability of the sensor. It has low cost, is easy to mass produce, and has good economy.

[0140] In another preferred embodiment of the present invention, by Detect the ambient temperature to obtain the temperature signal T m , where T2 is the actual temperature, P s Sensor self-heating power, R ths is the sensor thermal resistance, G ths is the sensor thermal conductivity, P d is the heat dissipation power, R thd is the heat dissipation thermal resistance, G thd is the heat dissipation thermal conductivity. The temperature signal T m Conditioning is performed, where H(s) is the transfer function, s5 is the complex frequency domain variable, ω n is the natural frequency, ζ is the damping coefficient; The conditioned temperature signal is processed to obtain a digital signal, where D[n6] represents the digital output code of the n6th sampling point, i represents the index of the basis function, N5 represents the total number of basis functions, n6 represents the n6th sampling point, and T s represents the sampling period, b irepresents the weight coefficient of the i-th basis function, φ(t) represents the basis function waveform; according to the digital output code D[n6] of the n6-th sampling point, Calculate the compensation value, where T c (z) is the z-transform of the compensation, M and N are the filter orders, and a i and b i are the filter coefficients; Convert the compensation value into an analog signal V out (t), where sinc(t) = sin(πt) / (πt) represents the zero-order hold impulse response of the DAC, n represents the sampling point index of the digital input code, from 0 to N-1, D[n] represents the digital input code at the nth sampling point, t represents the time variable, T δ represents the sampling period, N represents the total number of digital codes, and sinc(t) represents the sine normalized function.

[0141] In the embodiment of the present invention, a thermal error model of the temperature sensor is established, which can describe the self-heating and heat dissipation characteristics of the sensor, which is conducive to compensating the temperature measurement deviation caused by the thermal error. The temperature signal is conditioned by a second-order low-pass filter, which can effectively suppress high-frequency noise and improve the signal quality. The successive approximation analog-to-digital conversion method is used to improve the conversion accuracy and obtain a high-quality digital temperature signal. The compensation amount is calculated by a digital IIR filter, which can achieve a more accurate and adjustable compensation algorithm and improve the compensation effect. The DAC structure of zero-order hold and impulse response can be used to obtain a smooth and continuous analog compensation amount output. An overall mathematical model from the temperature sensor to the compensation amount output is established, which is conducive to analyzing and optimizing the temperature compensation control system. The performance and accuracy of the temperature compensation are improved by digital and intelligent means, the adaptability of the compensation is enhanced, and the measurement accuracy and long-term stability of the temperature monitoring system are improved as a whole, which is conducive to the accurate judgment of the cable status of the cable duct.

[0142] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A cable trunking online monitoring system, characterized in that: include: A sensing module is arranged on the surface of the cable in the cable trough and is used to detect the temperature and vibration of the cable in the cable trough; A signal processing module, electrically connected to the sensing module, and configured to receive and process the temperature and vibration signals collected by the sensing module; A communication module, connected to the signal processing module, for transmitting the processed temperature and vibration signals to a monitoring center; A monitoring center, for receiving and displaying the temperature and vibration signals, and issuing an alarm when the signals exceed a preset threshold; wherein the signal processing module is integrated in a connector at one end of the cable in the wire trough; The sensing module includes: a temperature sensor module, which is arranged on the surface of the cable in the wire trough and is used to detect the temperature of the cable in the wire trough; a vibration sensor module, which is arranged on the surface of the cable in the wire trough and is used to detect the vibration of the cable in the wire trough; a signal amplification module, which is connected to the temperature sensor module and the vibration sensor module and is used to amplify the temperature and vibration signals; the signal amplification module includes: a temperature signal pre-amplification module, which is connected to the temperature sensor module and is used to pre-amplify the temperature signal to obtain a first temperature signal; a temperature signal amplification module, which is connected to the temperature signal pre-amplification module and is used to amplify the first temperature signal to obtain a second temperature signal; a vibration signal pre-amplification module, which is connected to the vibration sensor module and is used to pre-amplify the vibration signal to obtain a first vibration signal; a vibration signal amplification module, which is connected to the vibration signal pre-amplification module and is used to amplify the first vibration signal to obtain a second vibration signal; in the temperature signal pre-amplification module, The input bias current of the operational amplifier is automatically adjusted according to the feedback voltage, where H(s2) is the transfer function, s2 is a complex frequency domain variable, and ω c is the cutoff angular frequency; The digital signal is processed to perform nonlinear correction of the temperature sensor, where Vout is the output voltage, Vin is the input voltage; a1, b1, c1 and d1 are correction coefficients; in the temperature signal amplification module, The gain of the amplifier is dynamically adjusted according to the error between the input signal and the reference value, where e(n1) is the error between the input signal and the reference signal; K p is the proportionality coefficient; K i is the integral coefficient; K d is the differential coefficient; T is the sampling time; n1 is the current sampling point; Gain represents the gain multiple of the amplifier; when the circuit needs to be protected, if the input voltage V in Greater than the maximum value V of the normal input range max , then the output voltage V out Take the saturation voltage V sat ; If the input voltage V in In the normal range, that is, V min and V max The output voltage V out Directly take the input voltage V in The value of The temperature sensor module comprises: A first sensitive element, used to detect temperature changes; A temperature measuring circuit, connected to the first sensitive element, for converting temperature changes into electrical signals; A compensation circuit, connected to the temperature measurement circuit, for performing temperature compensation on the temperature sensor; A calibration circuit, connected to the compensation circuit, for calibrating the temperature sensor; The vibration sensor module comprises: A second sensitive element, used to detect vibration and generate a corresponding electrical signal; A preamplifier, connected to the second sensitive element, for pre-amplifying the electrical signal; A bandpass filter, connected to the preamplifier, for filtering out noise; an amplifying and conditioning circuit, connected to the bandpass filter, for amplifying and conditioning the signal; An analog-to-digital converter, connected to the amplifying and conditioning circuit, for converting an analog signal into a digital signal; The signal processing module comprises: A filtering module, connected to the temperature signal amplifying module and the vibration signal amplifying module, and used to filter out noise in the signal to generate an analog signal; An analog-to-digital conversion module, connected to the filtering module, and used to convert an analog signal into a digital signal; A microprocessor module, connected to the analog-to-digital conversion module, for processing digital signals; The communication module comprises: An encoding module, connected to the microprocessor module, for encoding digital signals; A modulation module, connected to the encoding module, for modulating the encoded digital signal; A radio frequency module, connected to the modulation module, and configured to up-convert the modulated signal into a radio frequency signal; A power amplification module, connected to the radio frequency module, for amplifying the transmission power of the radio frequency signal; An antenna, connected to the power amplifier module, for transmitting radio frequency signals; A signal receiving module, used for receiving radio frequency signals; A demodulation module, connected to the signal receiving module, for demodulating the received radio frequency signal; A decoding module, connected to the demodulation module, for decoding the demodulated signal; The monitoring center includes: A signal interface module, used for receiving a digital signal from a decoding module; A signal conditioning module, connected to the signal interface module, for processing the received digital signal; A storage module, connected to the signal conditioning module, for storing digital signals and processing results; A display module, connected to the signal conditioning module, for displaying temperature and vibration parameter curves; An alarm module, connected to the signal conditioning module, for alarming abnormal temperature and vibration; A printing module, connected to the signal conditioning module, for printing temperature and vibration reports; The temperature measurement circuit comprises: A reference power supply, used for providing a reference voltage; A bridge arm circuit, which forms a bridge balancing circuit for temperature detection with the first sensitive element; A differential amplifier, connected to the bridge arm circuit, for amplifying the voltage across the balanced bridge; The compensation circuit comprises: The temperature sensing module is used to detect the ambient temperature to obtain a temperature signal; An operational amplifier, used for amplifying the temperature signal to obtain an analog temperature signal; A / D converter, used to convert analog temperature signal into digital signal; a microprocessor for calculating a compensation value according to the digital signal; A DAC converter for converting the compensation value into an analog signal; In the microprocessor module, by The digital temperature signal and the vibration signal after analog-to-digital conversion are filtered to obtain an output signal y[n], wherein h[k1] is a coefficient of the FIR filter, a[k1] is a recursive coefficient of the IIR filter, x[n] is an input signal, y[n] is an output signal, n represents the nth sampling point; N represents the order of the FIR filter, and k1 represents an index variable; x[n-k1] represents the input signal of the filter, n-k1 represents the n-k1th sampling point, M represents the order of the IIR filter, y[n-k1] represents the past output of the filter, and n-k1 represents the n-k1th sampling point; pass The output signal y[n] is processed, where a4 is the scale factor, b1, b2, …, b n is the n-dimensional translation factor, ψ(t) is the mother wavelet function, x(t1, t2, …, t n ) is the n-dimensional input signal, X(a4,b1,b2,…,b n ) is the n-dimensional wavelet coefficient; pass Encode the digital signal to obtain the code word C(x), where m i is an information symbol, p i is the check symbol, n5 is the codeword length, k4 is the number of information symbols; Modulate the code word C(x) to obtain the modulated complex signal waveform s(t5), where A c is the carrier amplitude, Indicates the complex letter after QAM symbol mapping, is an orthogonal carrier wave, t5 represents the time variable; through f rf =f c +f LO +BW / 2 processes the modulated complex signal waveform s(t5) to obtain the RF center frequency f rf , where f c is the baseband signal center frequency, f LO is the local oscillator frequency, BW is the baseband signal bandwidth; The RF center frequency f rf Processing is performed to obtain the decoded information symbol m i , where C1(x) is the received word, g(x) is the generating polynomial, n6 represents the codeword length of the RS code, and k5 represents the number of information symbols of the RS code; pass The temperature signal T m Conditioning is performed, where H(s) is the transfer function, s5 is the complex frequency domain variable, ω n is the natural frequency, ζ is the damping coefficient; The conditioned temperature signal is processed to obtain a digital signal, where D[n6] represents the digital output code of the n6th sampling point, i represents the index of the basis function, N5 represents the total number of basis functions, n6 represents the n6th sampling point, and T s represents the sampling period, b i represents the weight coefficient of the i-th basis function, φ(t) represents the basis function waveform; according to the digital output code D[n6] of the n6-th sampling point, Calculate the compensation value, where T c (z) is the z-transform of the compensation, M and N are the filter orders, and a i and b i are the filter coefficients; Convert the compensation value into an analog signal V out (t), where sinc(t) = sin(πt) / (πt) represents the zero-order hold impulse response of the DAC, n represents the sampling point index of the digital input code, from 0 to N-1, D[n] represents the digital input code at the nth sampling point, t represents the time variable, T δ represents the sampling period, N represents the total number of digital codes, and sinc(t) represents the sine normalized function.

Images