CN111238573A - An optical fiber type multi-parameter cable terminal detection system - Google Patents

Abstract

An optical fiber type multi-parameter cable terminal detection system provides a synchronous signal to a data acquisition unit while a sawtooth wave driver drives an adjustable laser, the output optical signal of the adjustable laser passes through the optical isolator, the optical circulator and the optical splitter to reach the fiber grating sensor laid at the cable terminal, the wavelength signal reflected by the fiber grating sensor returns to pass through the optical splitter and the optical circulator respectively, then the photoelectric detector converts the optical signal into an electric signal, and then the electric signal is sent to the data acquisition unit, the data acquisition unit transmits the acquired digital signal to the central processing unit, the central processing unit compares and analyzes the voltage signal generated by the current group of sawtooth wave signals with the voltage signal generated by the next group of sawtooth wave signals, and then sends the detection data to the terminal equipment through the communication module. The invention effectively solves the problems of power supply on the installation site and remote sensing and transmission, and has higher detection sensitivity.

Description

An optical fiber type multi-parameter cable terminal detection system

technical field

The invention relates to the field of safety monitoring, in particular to an optical fiber type multi-parameter cable terminal detection system.

Background technique

With the in-depth development of the urban network reconstruction project, in order to facilitate the construction, reduce the area of the line corridor, and improve the reliability of the power supply, the 10KV line outlet section of the substation, the incoming section of the 10KV power supply line for customers in the industrial park, and the urban 10KV distribution line, box Type transformer 10KV power supply input line, etc., are designed and selected YJLV22 ~ 8.7/15KV rubber insulated power cable for power supply. The cable terminal is equipped with heat-shrinkable terminal in the early stage and cold-shrinkable terminal in the later stage, but after the cable line is put into operation for 3 to 5 years, the cable terminal has failed many times every year, causing the substation or line section switch to trip. It directly affects the reliability of the 10KV city grid power supply.

The cable terminals installed outdoors are affected by wind, rain, snow, lightning and temperature all the year round. After many years of operation, they will be damaged due to insulation aging. Moreover, the outdoor cable terminal on the pole is at the first section of the cable line, which is easily attacked by lightning overvoltage. When the lightning rod is discharged, the lightning current flows into the earth through the grounding device of the ground wire, which will cause a voltage drop on the resistance of the grounding device. The resistance of the grounding device is greater than 10Ω, resulting in a large voltage drop. In addition, the residual voltage of the arrester will be added to the insulator between the cable core wire and the terminal head, which will cause the phase wire insulation discharge to break down. Once the above-mentioned failures occur, most of them are small-scale and will not affect the entire system; but there are very few avalanche-type cascading failures, that is, starting from a very simple failure, a series of chain reactions are triggered, resulting in large network failures. Parts or even the entire system is paralyzed. Therefore, the ability to accurately evaluate various health parameters of cable terminals in real time is of great significance to engineering construction and medium and long-term planning.

At present, the detection of cable terminations can only rely on the traditional manual detection method, and there is no online detection method, especially the method of measuring cable terminations through optical fiber sensors.

SUMMARY OF THE INVENTION

The invention mainly solves the problem of online detection of the above-mentioned cable terminal, avoids the damage of the cable terminal, which causes a power failure accident, causes losses to production, and affects life. Therefore, an optical fiber-type multi-parameter cable terminal detection system is proposed. , The fiber grating sensor based on the cable terminal, uses the principle of grating reflection to effectively detect and analyze the state of the cable terminal in real time, uses the optical cable as the transmission and sensing element, relies on the optical fiber for signal sensing, does not require power supply, and is immune to electromagnetic Influence, corrosion resistance, suitable for various complex installation environments, effectively solve the problems of installation site power supply and long-distance sensing and transmission, the optical signal detection sensitivity is higher, and the accuracy of the alarm signal is improved.

The technical scheme of the present invention is as follows:

An optical fiber type multi-parameter cable terminal detection system disclosed in the present invention includes an optical fiber sensing module and a processing module. The optical fiber sensing module includes a sawtooth wave driver, a tunable laser, an optical isolator, an optical circulator, and an optical fiber branch. The sawtooth wave driver provides a sawtooth wave signal for the tunable laser to scan from short wavelength to long wavelength. The output wavelength of the tunable laser is between 1525 and 1605 nm. The sawtooth wave driver sends out Each sawtooth wave produces a set of spectra from 1525 to 1605 nm. The output end of the tunable laser is connected to the input end of the optical isolator, the output end of the optical isolator is connected to the optical circulator, the optical circulator is connected to the optical fiber splitter, and the optical circulator controls the optical It can be input from the optical isolator, but cannot be returned, so as not to damage the tunable laser. Several fiber grating sensors are connected behind the optical fiber splitter, and the fiber grating sensors are laid on each cable terminal.

The processing module includes a photodetector, a data collector and a central processing unit, the photodetector is connected to the optical circulator, and the reflected wavelength spectrum of the fiber grating sensor passes through the optical fiber splitter and the optical circulator in turn after reflection, and then Into the photodetector, the photodetector demodulates the optical signal into an electrical signal, and then sends the electrical signal to the data collector, the data collector collects the electrical signal transmitted by the photodetector, at the same time, the sawtooth When the wave driver provides the sawtooth wave signal to the tunable laser, it also provides a synchronization signal to the data collector, the data collector transmits the collected digital signal to the central processing unit, and the central processing unit will The voltage signal generated by the sawtooth wave signal is then compared and analyzed with the voltage signal generated by the next group of sawtooth wave signals.

In the above-mentioned optical fiber type multi-parameter cable termination detection system, the optical fiber splitter includes several output ports.

In the fiber-optic multi-parameter cable termination detection system described above, the fiber grating sensor includes a fiber grating temperature sensor, a fiber grating vibration sensor, a fiber grating strain sensor, and a fiber grating displacement sensor, which can simultaneously measure multiple parameters of the cable termination.

Wherein, the fiber grating vibration sensor can detect whether the connection of the cable terminal is vibrated.

The fiber grating temperature sensor can detect the temperature of the cable terminal, and if the temperature is high, it means that the operation is abnormal and can play an early warning role.

The fiber grating strain sensor can detect whether the cable terminal is thermally expanded and deformed.

The fiber grating displacement sensor can detect the relative displacement between the cable terminal and the installation base, and can warn in advance to avoid the cable from the cable terminal from falling off.

Further, the wavelength range of the fiber grating sensor is between 1525 and 1605 nm, and the wavelengths of the fiber grating sensors do not coincide with each other.

In the above-mentioned fiber-optic multi-parameter cable terminal detection system, a communication module is connected behind the central processing unit, and the detection data is sent to a terminal device, such as a computer in a monitoring room, through the communication module.

The beneficial effects of the present invention are:

1. The optical fiber type multi-parameter cable terminal detection system of the present invention is different from the traditional detection method for the entire cable. The fiber grating sensor is only set at the cable terminal head, and the state of the cable terminal head is effectively detected in real time by using the principle of grating reflection. Analysis, using optical cable as transmission and sensing element, relying on optical fiber for signal induction, no power supply, no electromagnetic influence, corrosion resistance, suitable for various complex installation environments, effectively solving the problem of installation site power supply and long-distance sensing, transmission The problem.

2. The optical fiber type multi-parameter cable terminal detection system of the present invention has higher optical signal detection sensitivity and improves the accuracy of the alarm signal.

3. The optical fiber type multi-parameter cable terminal detection system of the present invention can be easily expanded by increasing the number of optical fiber splitters, realize real-time online safety monitoring and alarm of multiple cable terminal heads, can accurately distinguish the position of the alarm cable terminal head, and improve the alarm Validity and accuracy of location.

Description of drawings

The aspects and advantages of the present application will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are for the purpose of illustrating preferred embodiments only and are not to be considered limiting of the invention.

In the attached image:

Fig. 1 is the frame diagram of the optical fiber type multi-parameter cable terminal detection system of the present embodiment 1;

FIG. 2 is a spectral distribution diagram of the fiber grating sensor of the present embodiment 1;

Fig. 3 is the laying structure diagram of the fiber grating sensor in the cable terminal of the present embodiment 1;

The components represented by each reference number in the figure are:

61, fiber grating temperature sensor, 62, fiber grating vibration sensor, 63, fiber grating strain sensor, 64, fiber grating displacement sensor.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. It should be noted that 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. The present disclosure can be implemented in various forms, and should not be described herein. Implementation restrictions.

Example 1

Referring to FIG. 1, FIG. 1 is a frame diagram of an optical fiber type multi-parameter cable terminal detection system according to the present embodiment, including an optical fiber sensing module and a processing module, and the optical fiber sensing module includes a sawtooth wave driver, a tunable laser, an optical isolation The sawtooth wave driver provides a sawtooth wave signal to scan the tunable laser from short wavelength to long wavelength, and the output wavelength of the tunable laser is between 1525 and 1605 nm. In the meantime, each sawtooth wave sent out by the sawtooth wave driver will generate a set of spectrums from 1525 to 1605 nm. The output end of the tunable laser is connected to the input end of the optical isolator, and by adding the optical isolator, the signal reflected from the back optical path can be effectively prevented from returning to the tunable laser, thereby damaging the laser.

Further, the output end of the optical isolator is connected to the optical circulator, the optical circulator is connected to the optical fiber splitter, and the optical circulator controls the light to be input only from the optical isolator, but cannot be returned to avoid damage. Tunable laser. Several fiber grating sensors are connected behind the optical fiber splitter. For wavelength division multiplexing, the signals of a plurality of fiber grating sensors can be connected in series, and the fiber grating sensors are laid at each cable terminal. Preferably, the optical fiber splitter includes several output ports, and each output port is connected to several fiber grating sensors, which can realize the monitoring of multi-channel fiber grating sensors. Figure 1 only shows the state diagram of the fiber grating sensor with a single channel laid on the cable terminal. Only one cable terminal can be installed as a single channel. Of course, the number of cable terminals can also be expanded according to the usage scenario to realize multi-channel optical fiber. The monitoring of the grating sensor has strong expansibility and is not limited here.

Further, the fiber grating sensor in this embodiment includes a fiber grating temperature sensor 61 , a fiber grating vibration sensor 62 , a fiber grating strain sensor 63 and a fiber grating displacement sensor 64 . See FIG. Through the setting of each fiber grating sensor, multiple parameters of the cable terminal can be measured simultaneously.

Wherein, the fiber grating vibration sensor 62 can detect whether the connection of the cable terminal is subjected to vibration.

The fiber grating temperature sensor 61 can detect the temperature of the cable terminal, and if the temperature is high, it means that the operation is abnormal and can play an early warning role.

The fiber grating strain sensor 63 can detect whether the cable terminal is thermally expanded and deformed.

The fiber grating displacement sensor 64 can detect the relative displacement between the cable terminal and the installation base, and can warn in advance to prevent the cable from the cable terminal from falling off.

Further, the wavelength range of the fiber grating sensor is also between 1525 nm and 1605 nm, see FIG. 2 , which is consistent with the output wavelength of the tunable laser, so that the reflection wavelength of the fiber grating sensor can be displayed in the spectrogram. Also, the wavelengths of the respective fiber grating sensors here do not coincide with each other.

Further, the processing module includes a photodetector, a data collector and a central processing unit, the photodetector is connected to the optical circulator, and the reflected wavelength spectra of the four fiber grating sensors pass through the optical fiber splitter and the optical ring in turn after being reflected. Then it enters into the photodetector that collects the optical signal in real time, the photodetector demodulates the optical signal into an electrical signal, and then sends the electrical signal to the data collector, which collects the data transmitted by the photodetector. At the same time, when the sawtooth wave driver provides the sawtooth wave signal to the adjustable laser, it also provides a synchronization signal to the data collector, and the data collector transmits the collected digital signal to the central processing unit, The central processing unit compares and analyzes the voltage signals generated by the current group of sawtooth wave signals and the voltage signals generated by the next group of sawtooth wave signals, so as to know the signal change of the optical wavelength between each time.

Further, a communication module is also connected behind the central processing unit, and the detection data is sent to the terminal device through the communication module.

The specific operation process and principle of this system are as follows:

The sawtooth wave driver drives the tunable laser and provides a synchronization signal to the data collector. The output optical signal of the tunable laser passes through the optical isolator, the optical circulator and the optical fiber splitter, and reaches the optical fiber laid on the cable terminal. grating sensor, the fiber grating sensor includes a fiber grating temperature sensor 61, a fiber grating vibration sensor 62, a fiber grating strain sensor 63 and a fiber grating displacement sensor 64, and the wavelength signal reflected by the fiber grating sensor returns again, and passes through the fiber shunt respectively. Then, the optical signal is converted into an electrical signal by a photodetector, and then the electrical signal is sent to the data collector, which transmits the collected digital signal to the central processing unit. The central processing unit compares and analyzes the voltage signal generated by the current group of sawtooth wave signals with the voltage signal generated by the next group of sawtooth wave signals, so as to know the signal change of the optical wavelength between each time, and then the central processing unit Send the detection data to the terminal equipment through the communication module, such as the computer in the monitoring room.

This fiber-optic multi-parameter cable terminal detection system is different from the traditional detection method for the entire cable. Only the fiber grating sensor is set at the cable terminal head. Using the principle of grating reflection, it can effectively detect and analyze the state of the cable terminal head in real time. As a transmission and sensing element, optical cable relies on optical fiber for signal sensing, does not require power supply, is immune to electromagnetic influence, and is resistant to corrosion. The optical signal detection sensitivity is higher, which improves the accuracy of the alarm signal.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Additions, subtractions, and substitutions should all be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (6)

1. An optical fiber type multi-parameter cable terminal detection system is characterized by comprising an optical fiber sensing module and a processing module, wherein the optical fiber sensing module comprises a sawtooth wave driver, a tunable laser, an optical isolator, an optical circulator, an optical fiber branching unit and optical fiber grating sensors, the sawtooth wave driver provides sawtooth wave signals to enable the tunable laser to scan from short wavelength to long wavelength, the output end of the tunable laser is connected with the input end of the optical isolator, the output end of the optical isolator is connected with the optical circulator, the optical circulator is connected with the optical fiber branching unit, the optical circulator controls light to be input from the optical isolator only but not to return, a plurality of optical fiber grating sensors are connected to the rear of the optical fiber branching unit, and the optical fiber grating sensors are laid at each cable terminal;

the processing module comprises a photoelectric detector, a data acquisition unit and a central processing unit, the photoelectric detector is connected with the optical circulator, the reflected wavelength spectrum of the fiber grating sensor is reflected and then sequentially passes through the fiber branching unit and the optical circulator, then the optical signals enter a photoelectric detector, the photoelectric detector demodulates the optical signals into electric signals, the electric signals are sent to a data acquisition unit, the data acquisition unit acquires the electric signals transmitted by the photoelectric detector, meanwhile, the sawtooth wave driver can also provide a synchronous signal to the data acquisition unit when providing the sawtooth wave signal to the tunable laser, the data acquisition unit transmits the acquired digital signals to the central processing unit, and the central processing unit compares and analyzes the voltage signals generated by the current group of sawtooth wave signals with the voltage signals generated by the next group of sawtooth wave signals.

2. The optical fiber type multiparameter cable termination detecting system according to claim 1, wherein an output wavelength of said tunable laser is 1525 to 1605 nm.

3. The fiber optic multiparameter cable termination inspection system of claim 1, wherein the fiber optic splitter includes a plurality of output ports.

4. An optical fiber type multiparameter cable termination detecting system according to claim 2, wherein said fiber grating sensor includes a fiber grating temperature sensor (61), a fiber grating vibration sensor (62), a fiber grating strain sensor (63) and a fiber grating displacement sensor (64).

5. The optical fiber type multiparameter cable termination detection system according to claim 4, wherein the wavelength range of said fiber grating sensor is 1525 to 1605 nm.

6. The system of claim 1, wherein a communication module is connected to the rear of the central processing unit, and the detection data is transmitted to the terminal device through the communication module.

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