CN116026444A - Vibration characteristic monitoring method and system for overhead transmission line - Google Patents
Vibration characteristic monitoring method and system for overhead transmission line Download PDFInfo
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- CN116026444A CN116026444A CN202211579307.2A CN202211579307A CN116026444A CN 116026444 A CN116026444 A CN 116026444A CN 202211579307 A CN202211579307 A CN 202211579307A CN 116026444 A CN116026444 A CN 116026444A
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Abstract
The invention discloses a method and a system for monitoring vibration characteristics of an overhead transmission line, wherein the method comprises the following steps: placing sensing optical fibers in a ground wire of an overhead transmission line, and installing tension sensors between a tension tower and a tension string insulator and between a tangent tower and a suspension string insulator of the overhead transmission line; a laser and a modulator with linewidth and frequency shift characteristics meeting preset standards generate pulse light, and the pulse light passes through the sensing optical fiber after being amplified; after separating the optical fiber signals in the sensing optical fiber through a circulator, identifying the optical fiber signals by using a photoelectric detector; and acquiring the measured values of the tension sensor and the photoelectric detector in real time to obtain real-time amplitude and real-time frequency. By adopting the invention, the vibration characteristics can be monitored in real time by slightly changing the original overhead transmission line, and the early warning can be realized for the vibration with larger harm.
Description
Technical Field
The invention relates to the technical field of overhead transmission line monitoring, in particular to a method and a system for monitoring vibration characteristics of an overhead transmission line.
Background
Nowadays, various voltage classes of overhead transmission lines are more and more, and overhead transmission is performed. The daily safety maintenance of the electric circuit relates to the quality and operation safety of the electric power system. The circuit amplitude characteristic is an important evaluation index for the operation of the overhead transmission line.
However, the existing overhead transmission line state detection principle is complex and has high cost, and the real-time vibration amplitude and frequency of the transmission line cannot be monitored according to the existing transmission line sensor.
Disclosure of Invention
The embodiment of the invention provides a method and a system for monitoring vibration characteristics of an overhead transmission line, which are used for respectively acquiring real-time vibration amplitude and frequency of the overhead transmission line in two different modes.
To achieve the above object, a first aspect of an embodiment of the present application provides a method for monitoring vibration characteristics of an overhead transmission line, including:
placing sensing optical fibers in a ground wire of an overhead transmission line, and installing tension sensors between a tension tower and a tension string insulator and between a tangent tower and a suspension string insulator of the overhead transmission line;
a laser and a modulator with linewidth and frequency shift characteristics meeting preset standards generate pulse light, and the pulse light passes through the sensing optical fiber after being amplified;
after separating the optical fiber signals in the sensing optical fiber through a circulator, identifying the optical fiber signals by using a photoelectric detector;
and acquiring the measured values of the tension sensor and the photoelectric detector in real time to obtain real-time amplitude and real-time frequency.
In a possible implementation manner of the first aspect, the preset criteria of the laser are specifically:
the linewidth value of the laser is lower than a narrow line threshold and the frequency shift value of the laser under the influence of noise is lower than a frequency shift threshold.
In a possible implementation manner of the first aspect, the amplifying the pulsed light and passing the pulsed light through the sensing optical fiber specifically includes:
the laser is used as a light source, the light is changed into pulse light after being acted by the modulator, and the pulse light is amplified by the erbium-doped optical fiber amplifier and then is transmitted into the sensing optical fiber.
In a possible implementation manner of the first aspect, the measurement error of the tension sensor is not greater than an error threshold value, and the measurement frequency of the tension sensor is greater than a frequency measurement threshold value.
In a possible implementation manner of the first aspect, the acquiring, in real time, the measured values of the tension sensor and the photodetector, to obtain a real-time amplitude and a real-time frequency specifically includes:
acquiring the real-time frequency according to the indication change of the tension sensor, drawing a real-time frequency indication-time image, and sampling the real-time frequency at equal time distance;
and drawing a real-time amplitude-time image in real time according to the indication change of the photoelectric detector, and sampling the real-time amplitude at equal time distances.
In a possible implementation manner of the first aspect, after the acquiring, in real time, the measurement values of the tension sensor and the photodetector, obtaining a real-time amplitude and a real-time frequency, the method further includes:
and if the root mean square value of the real-time amplitude is larger than the early warning amplitude and the root mean square value of the real-time frequency is equal to the natural frequency, early warning is carried out on a system where the overhead transmission line is located.
In a possible implementation manner of the first aspect, the root mean square value of the real-time amplitude is a magnitude of a root mean square value of a frequency of a sampling point in a unit time in the real-time amplitude-time image.
In a possible implementation manner of the first aspect, the root mean square value according to the real-time frequency is a magnitude of a root mean square value of a frequency of a sampling point per unit time in the real-time frequency readout-time image.
A second aspect of embodiments of the present application provides an overhead transmission line vibration characteristic monitoring system, including: the device comprises a sensing optical fiber, a ground wire, a strain tower, a strain insulator string insulator, a tangent tower, a suspension string insulator, a laser module, a separation module and a measurement module;
the sensing optical fiber is placed in a ground wire of the overhead transmission line, and tension sensors are arranged between a tension tower and a tension string insulator and between a tangent tower and a suspension string insulator of the overhead transmission line; the strain tower is connected with the tangent tower through sensing optical fibers;
the laser module is used for generating pulse light through a laser and a modulator with linewidth and frequency shift characteristics meeting preset standards, and enabling the pulse light to pass through the sensing optical fiber after being amplified;
the separation module is used for identifying the optical fiber signals by using a photoelectric detector after the optical fiber signals in the sensing optical fibers are separated by the circulator;
and the measuring module is used for acquiring the measured values of the tension sensor and the photoelectric detector in real time to obtain real-time amplitude and real-time frequency.
Compared with the prior art, the method and the system for monitoring the vibration characteristics of the overhead transmission line provided by the embodiment of the invention have the advantages that the laser and the modulator with the linewidth and the frequency shift characteristics meeting the preset standard generate pulse light, the pulse light passes through the sensing optical fiber after being amplified, and then the optical fiber signals in the sensing optical fiber are separated through the circulator, and then the optical fiber signals are identified by the photoelectric detector to obtain real-time amplitude values; the real-time frequency is obtained by installing tension sensors between a tension tower and a tension string insulator and between a tangent tower and a suspension string insulator of the overhead transmission line, and the vibration with larger harm is early warned. The implementation method of the embodiment is simple to realize, the vibration characteristics can be monitored in real time by slightly changing the original overhead transmission line, and the early warning can be realized for the vibration with larger harm.
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Fig. 1 is a flow chart of a method for calculating regional ionosphere electron density according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, an embodiment of the present invention provides a method for monitoring vibration characteristics of an overhead transmission line, including:
s10, placing the sensing optical fiber in a ground wire of an overhead transmission line, and installing tension sensors between a tension tower and a tension string insulator and between a tangent tower and a suspension string insulator of the overhead transmission line.
S11, enabling a laser and a modulator with line width and frequency shift characteristics meeting preset standards to generate pulse light, and enabling the pulse light to pass through the sensing optical fiber after being amplified.
S12, after the optical fiber signals in the sensing optical fibers are separated through the circulator, the optical fiber signals are identified through the photoelectric detector.
S13, acquiring measured values of the tension sensor and the photoelectric detector in real time to obtain real-time amplitude and real-time frequency.
The overhead transmission line in this embodiment is an OPGW optical cable, optical Fiber Composite Overhead Ground Wire (also referred to as an optical fiber composite overhead ground wire). The lightning protection wire has 2 functions, namely, the lightning protection wire is used as a lightning protection wire of a power transmission line, and shielding protection is provided for lightning discharge resistance of the power transmission wire; and secondly, an optical fiber compounded in a ground wire is used as a medium for transmitting optical signals, and audio, video, data and various control signals can be transmitted to form a multipath broadband communication network. The optical fiber composite ground wire is a carrier of phi-OTDR. The phi-OTDR comprises an erbium-doped optical fiber amplifier which is used for amplifying pulses to be introduced into the sensing optical fiber, and a photoelectric detector is used for collecting a return signal and then processing the return signal. Here, the optical signals returned from the optical fiber, audio, video, data, various control signals, etc., and the signal processing is to separate the optical signals from the optical signals caused by vibration.
The embodiment can realize real-time monitoring of the real-time vibration amplitude and vibration frequency of the power transmission line according to the existing tension sensor and phi-OTDR. The method provided by the embodiment of the invention is simple to realize, can realize real-time monitoring and can realize early warning on vibration with larger harm, so that the applicability is strong and the effectiveness is high.
Illustratively, the preset criteria of the laser are specifically:
the linewidth value of the laser is lower than a narrow line threshold and the frequency shift value of the laser under the influence of noise is lower than a frequency shift threshold.
Narrow linewidth, low frequency shift lasers have many advantages over other lasers, such as: the narrow linewidth low frequency shift laser has good quality, good monochromaticity, directivity and stability; the narrow linewidth and low frequency shift laser is not only a gain medium of laser, but also a waveguide medium of light, has large light intensity and small fiber core diameter, and is easy to form high power density in the optical fiber.
Illustratively, the amplifying the pulse light and passing the pulse light through the sensing optical fiber specifically includes:
the laser is used as a light source, the light is changed into pulse light after being acted by the modulator, and the pulse light is amplified by the erbium-doped optical fiber amplifier and then is transmitted into the sensing optical fiber.
Bait doped fiber amplifiers are typically obtained by installing phi-OTDR in overhead transmission lines.
Illustratively, the measurement error of the tension sensor is not greater than an error threshold, and the measurement frequency of the tension sensor is greater than a frequency measurement threshold.
In practical applications, the required tension sensor needs to meet the following conditions: 1) The error is not more than +/-0.5%. 2) The measurement frequency needs to be greater than 300HZ.
Illustratively, the acquiring, in real time, the measurement values of the tension sensor and the photodetector to obtain a real-time amplitude and a real-time frequency specifically includes:
acquiring the real-time frequency according to the indication change of the tension sensor, drawing a real-time frequency indication-time image, and sampling the real-time frequency at equal time distance;
and drawing a real-time amplitude-time image in real time according to the indication change of the photoelectric detector, and sampling the real-time amplitude at equal time distances.
Since the instantaneous value of the vibration is continuously changed with time, as a representative of the magnitude of such vibration change, a real-time amplitude of a signal after signal processing is acquired, a real-time amplitude-time image is drawn, and the real-time amplitude is sampled at equal time distances { ki } (i=1, 2, 3, 4, 5, 6 … … n), respectively.
Since the instantaneous value of the vibration frequency is continuously changed with time, the real-time frequency is obtained through the reading change rule of the tension sensor, the real-time frequency reading-time image is drawn, and the real-time frequency is sampled with the same time distance as { fi } (i=1, 2, 3, 4, 5, 6 … … n).
Illustratively, after the obtaining the measurement values of the tension sensor and the photodetector in real time, obtaining a real-time amplitude and a real-time frequency, the method further includes:
and if the root mean square value of the real-time amplitude is larger than the early warning amplitude and the root mean square value of the real-time frequency is equal to the natural frequency, early warning is carried out on a system where the overhead transmission line is located.
And setting an early warning amplitude Kmax and a natural frequency FT of the system, and when the root mean square value of the vibration amplitude is larger than the early warning amplitude and the root mean square value of the frequency is equal to the natural frequency, namely KR > Kmax and FR=FT. Early warning is carried out in the system.
Illustratively, the root mean square value of the real-time amplitude is the magnitude of the root mean square value of the frequency of the sampling point per unit time in the real-time amplitude-time image.
Illustratively, the root mean square value according to the real-time frequency is the magnitude of the root mean square value of the frequency of the sampling point per unit time in the real-time frequency index-time image.
Evaluation index K of amplitude R The root mean square value of the frequency of all sampling points within one minute. Namely:
Evaluation index F of frequency R The root mean square value of the frequency of all sampling points within one minute. Namely:
In particular, the whole implementation is described with a 110kV overhead transmission line:
step 1: and selecting an optical fiber composite overhead ground wire in the ground wire type selection of the 110kV overhead transmission line.
Step 2: and installing a tension sensor in the monitored 110kV overhead transmission line.
Step 3: a laser with narrow linewidth and low frequency shift characteristic is used as a light source, the light is changed into pulse light after being acted by a modulator, and the pulse light is amplified by an erbium-doped optical fiber amplifier and then is transmitted into a sensing optical fiber.
Step 4: the optical signal is converted into an electrical signal by a photodetector after separation by a circulator.
Step 5: and acquiring the real-time amplitude of the electric signal of the power transmission line, sampling the real-time amplitude, and solving the root mean square value of each sampling point.
Step 6: the real-time data of the tension sensor is converted into an electric signal through an A/D converter.
Step 7: and analyzing the electric signal, obtaining the real-time frequency of the power transmission line, sampling the real-time frequency, and solving the root mean square value of each sampling point.
Step 8: and carrying out joint evaluation on the real-time amplitude and the real-time frequency.
Compared with the prior art, the vibration characteristic monitoring method for the overhead transmission line provided by the embodiment of the invention has the advantages that the laser and the modulator with the linewidth and the frequency shift characteristics meeting the preset standard generate pulse light, the pulse light passes through the sensing optical fiber after being amplified, and then the optical fiber signals in the sensing optical fiber are separated through the circulator, and then the optical fiber signals are identified by the photoelectric detector to obtain real-time amplitude values; the real-time frequency is obtained by installing tension sensors between a tension tower and a tension string insulator and between a tangent tower and a suspension string insulator of the overhead transmission line, and the vibration with larger harm is early warned. The implementation method of the embodiment is simple to realize, the vibration characteristics can be monitored in real time by slightly changing the original overhead transmission line, and the early warning can be realized for the vibration with larger harm.
An embodiment of the present application provides an overhead transmission line vibration characteristic monitoring system, including: the device comprises a sensing optical fiber, a ground wire, a strain tower, a strain insulator string insulator, a tangent tower, a suspension string insulator, a laser module, a separation module and a measurement module;
the sensing optical fiber is placed in a ground wire of the overhead transmission line, and tension sensors are arranged between a tension tower and a tension string insulator and between a tangent tower and a suspension string insulator of the overhead transmission line; the strain tower is connected with the tangent tower through sensing optical fibers;
the laser module is used for generating pulse light through a laser and a modulator with linewidth and frequency shift characteristics meeting preset standards, and enabling the pulse light to pass through the sensing optical fiber after being amplified;
the separation module is used for identifying the optical fiber signals by using a photoelectric detector after the optical fiber signals in the sensing optical fibers are separated by the circulator;
and the measuring module is used for acquiring the measured values of the tension sensor and the photoelectric detector in real time to obtain real-time amplitude and real-time frequency.
Compared with the traditional overhead transmission line, the phase-sensitive optical time domain reflectometry (phi-OTDR) system based on the phi-OTDR and the tension sensor is added, and the phase-sensitive optical time domain reflectometry system has the advantages of quick response, high sensitivity and the like, so that the vibration amplitude can be detected in a non-contact mode. The technology has great application potential in the directions of structural health monitoring of tunnel bridges, safety detection of petroleum and natural gas pipelines, intrusion detection of border lines and the like.
The tension sensor can obtain the change of the value caused by vibration in real time, and the vibration frequency of the power transmission line can be obtained through the periodical change of the value of the tension sensor.
Compared with the prior art, the vibration characteristic monitoring system for the overhead transmission line provided by the embodiment of the invention has the advantages that the laser and the modulator with the linewidth and the frequency shift characteristics meeting the preset standard generate pulse light, the pulse light passes through the sensing optical fiber after being amplified, and then the optical fiber signals in the sensing optical fiber are separated through the circulator, and then the optical fiber signals are identified by the photoelectric detector to obtain real-time amplitude values; the real-time frequency is obtained by installing tension sensors between a tension tower and a tension string insulator and between a tangent tower and a suspension string insulator of the overhead transmission line, and the vibration with larger harm is early warned. The implementation method of the embodiment is simple to realize, the vibration characteristics can be monitored in real time by slightly changing the original overhead transmission line, and the early warning can be realized for the vibration with larger harm.
It will be clear to those skilled in the art that for convenience and brevity of description, reference may be made to the corresponding procedure in the foregoing method embodiments for the specific working procedure of the above-described system, which is not further described herein.
While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the invention, such changes and modifications are also intended to be within the scope of the invention.
Claims (9)
1. The method for monitoring the vibration characteristics of the overhead transmission line is characterized by comprising the following steps of:
placing sensing optical fibers in a ground wire of an overhead transmission line, and installing tension sensors between a tension tower and a tension string insulator and between a tangent tower and a suspension string insulator of the overhead transmission line;
a laser and a modulator with linewidth and frequency shift characteristics meeting preset standards generate pulse light, and the pulse light passes through the sensing optical fiber after being amplified;
after separating the optical fiber signals in the sensing optical fiber through a circulator, identifying the optical fiber signals by using a photoelectric detector;
and acquiring the measured values of the tension sensor and the photoelectric detector in real time to obtain real-time amplitude and real-time frequency.
2. The method for monitoring vibration characteristics of overhead transmission line according to claim 1, wherein the preset criteria of the laser are specifically:
the linewidth value of the laser is lower than a narrow line threshold and the frequency shift value of the laser under the influence of noise is lower than a frequency shift threshold.
3. The method for monitoring vibration characteristics of overhead transmission line according to claim 1, wherein the amplifying the pulsed light and passing the amplified pulsed light through the sensing optical fiber specifically comprises:
the laser is used as a light source, the light is changed into pulse light after being acted by the modulator, and the pulse light is amplified by the erbium-doped optical fiber amplifier and then is transmitted into the sensing optical fiber.
4. The method for monitoring vibration characteristics of overhead transmission line according to claim 1, wherein a measurement error of the tension sensor is not greater than an error threshold, and a measurement frequency of the tension sensor is greater than a frequency measurement threshold.
5. The method for monitoring vibration characteristics of overhead transmission line according to claim 1, wherein the step of obtaining the measured values of the tension sensor and the photoelectric detector in real time to obtain real-time amplitude and real-time frequency comprises the following steps:
acquiring the real-time frequency according to the indication change of the tension sensor, drawing a real-time frequency indication-time image, and sampling the real-time frequency at equal time distance;
and drawing a real-time amplitude-time image in real time according to the indication change of the photoelectric detector, and sampling the real-time amplitude at equal time distances.
6. The method for monitoring vibration characteristics of overhead transmission line according to claim 5, further comprising, after said obtaining in real time the measurement values of said tension sensor and said photodetector, obtaining a real-time amplitude and a real-time frequency:
and if the root mean square value of the real-time amplitude is larger than the early warning amplitude and the root mean square value of the real-time frequency is equal to the natural frequency, early warning is carried out on a system where the overhead transmission line is located.
7. The method of claim 6, wherein the root mean square value of the real-time amplitude is the root mean square value of the frequency of the sampling point per unit time in the real-time amplitude-time image.
8. The method of claim 6, wherein the root mean square value according to the real-time frequency is the root mean square value of the frequency of the sampling point per unit time in the real-time frequency reading-time image.
9. An overhead transmission line vibration characteristic monitoring system, comprising: the device comprises a sensing optical fiber, a ground wire, a strain tower, a strain insulator string insulator, a tangent tower, a suspension string insulator, a laser module, a separation module and a measurement module;
the sensing optical fiber is placed in a ground wire of the overhead transmission line, and tension sensors are arranged between a tension tower and a tension string insulator and between a tangent tower and a suspension string insulator of the overhead transmission line; the strain tower is connected with the tangent tower through sensing optical fibers;
the laser module is used for generating pulse light through a laser and a modulator with linewidth and frequency shift characteristics meeting preset standards, and enabling the pulse light to pass through the sensing optical fiber after being amplified;
the separation module is used for identifying the optical fiber signals by using a photoelectric detector after the optical fiber signals in the sensing optical fibers are separated by the circulator;
and the measuring module is used for acquiring the measured values of the tension sensor and the photoelectric detector in real time to obtain real-time amplitude and real-time frequency.
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