Hydropower station backbone optical cable monitoring device and monitoring system

Abstract

The utility model provides a hydropower station backbone optical cable monitoring device and monitoring system, the monitoring device comprises a pulse laser, a circulator, an optical filter, a multi-parameter monitoring unit, a first analyzer, a first detector and an acquisition card, the multi-parameter monitoring unit is used for at least obtaining a first signal and a second signal, the first signal is used for calculating distributed vibration information of the to-be-monitored hydroelectric optical cable, and the second signal is used for calculating temperature information of the to-be-monitored hydroelectric optical cable; the input end of the first polarization analyzer is used for being connected with an outlet of a hydroelectric optical cable to be monitored, and the output end of the first polarization analyzer is connected with the first detector. According to the utility model, a plurality of monitoring means are organically integrated, and the measurement of distributed vibration, distributed temperature and high-frequency vibration of the hydroelectric optical fiber is realized by only using one pulse laser and combining a plurality of polarization analyzers and detectors, so that various threat events faced by the hydroelectric optical cable are responded, and the monitoring level of the backbone optical cable of a hydropower station is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of hydropower station monitoring, and particularly relates to a monitoring device and a monitoring system for backbone optical cables of hydropower stations. Background Art

[0002] The backbone optical cable of a hydropower station is the foundation of the communication system of the hydropower station. If the optical cable is damaged or destroyed, it will seriously affect the operation of the hydropower station. At present, the backbone optical cable of a hydropower station is mainly monitored by an optical time domain reflectometer (OTDR). The OTDR can measure the loss of the optical cable and issue an alarm when the optical cable is broken or the loss is too large. However, due to the harsh operating environment of the optical cable in the hydropower station, it is vulnerable to threats such as wildfires, strong winds, lightning strikes, and damage caused by human and animal intrusion. For these monitoring requirements, the OTDR can only monitor the change in its loss and cannot simultaneously sense multiple events such as wildfires, strong winds, lightning strikes, and damage caused by human and animal intrusion, resulting in the problem of missed alarms.

[0003] In view of this, overcoming the defects of the existing technology is an urgent problem to be solved in this technical field. Summary of the Utility Model

[0004] In view of the above problems, it is necessary to propose a monitoring device for the backbone optical cable of a hydropower station to solve or partially solve the above problems, which can respond to various threat events faced by the hydropower optical cable and improve the monitoring level of the backbone optical cable of the hydropower station. The technical solution proposed by the utility model is as follows:

[0005] In a first aspect, the utility model provides a monitoring device for the backbone optical cable of a hydropower station, including a pulsed laser 10, a circulator 20, an optical filter 30, a multi-parameter monitoring unit 40, a first polarization analyzer 50, a first detector 60, and a data acquisition card, wherein:

[0006] The first port of the circulator 20 is connected to the output end of the pulsed laser 10, the second port is connected to the entrance of the hydropower optical cable to be monitored, and the third port is connected to the input end of the optical filter 30;

[0007] The output port of the optical filter 30 is connected to the multi-parameter monitoring unit 40, and the multi-parameter monitoring unit 40 is used to obtain at least a first signal and a second signal. Among them, the first signal is used to calculate the distributed vibration information of the hydropower optical cable to be monitored, and the second signal is used to calculate the temperature information of the hydropower optical cable to be monitored;

[0008] The input end of the first polarization analyzer 50 is used to be connected to the exit of the hydropower optical cable to be monitored, and the output end of the first polarization analyzer 50 is connected to the first detector 60;

[0009] The input end of the acquisition card is connected to the output ends of the first detector 60 and the multi-parameter monitoring unit 40. The output end of the acquisition card is used to be connected to an external controller to convert the first signal, the second signal output by the multi-parameter monitoring unit 40, and the signal output by the first detector 60 into digital signals and send them to the external controller for processing.

[0010] Preferably, the multi-parameter monitoring unit 40 includes a second polarization analyzer 41, a second detector 42, a third detector 43, and a fourth detector 44, where:

[0011] The input end of the second polarization analyzer 41 is connected to the first output port of the optical filter 30, and the output end of the second polarization analyzer 41 is connected to the second detector 42;

[0012] The input end of the third detector 43 is connected to the second output port of the optical filter 30; the input end of the fourth detector 44 is connected to the third output port of the optical filter 30;

[0013] The output ends of the second detector 42, the third detector 43, and the fourth detector 44 are respectively connected to the acquisition card.

[0014] Preferably, the first output port of the optical filter 30 is used to separate Rayleigh scattered light, the second output port is used to separate anti-Stokes Raman scattered light, and the third output port is used to separate Stokes Raman scattered light.

[0015] Preferably, the multi-parameter monitoring unit 40 includes an optical switch 41’, a third polarization analyzer 42’, a sixth detector 43’, a seventh detector 44’, an eighth detector 45’, and a fifth detector 46’, where:

[0016] The input end of the optical switch 41’ is connected to the first output port of the optical filter 30. The output end of the optical switch 41’ is used to be respectively connected to the sixth detector 43’ or the third polarization analyzer 42’. The control port of the optical switch 41’ is used to be connected to an external controller and is used to receive the control of the controller to be respectively connected to the sixth detector 43’ or the third polarization analyzer 42’;

[0017] The output end of the third polarization analyzer 42’ is further connected to the seventh detector 44’;

[0018] The input end of the seventh detector 44’ is connected to the second output port of the optical filter 30; the input end of the eighth detector 45’ is connected to the third output port of the optical filter 30;

[0019] The output ends of the sixth detector 43’, the seventh detector 44’, the eighth detector 45’, and the fifth detector 46’ are respectively connected to the acquisition card.

[0020] Preferably, the first output port of the optical filter 30 is used to separate Rayleigh scattered light, the second output port is used to separate anti-Stokes Raman scattered light, and the third output port is used to separate Stokes Raman scattered light.

[0021] Preferably, the pulsed laser 10 operates at a wavelength of 1550 nm.

[0022] In a second aspect, the present invention provides a monitoring system for a backbone optical cable of a hydropower station, including the monitoring device for the backbone optical cable of a hydropower station as described in the first aspect and a controller, and the controller is connected to the acquisition card.

[0023] Preferably, the monitoring system further includes a display unit, and / or a sound unit, and / or a communication unit connected to the controller.

[0024] In a third aspect, the present invention provides a monitoring system for a backbone optical cable of a hydropower station, including the monitoring device for the backbone optical cable of a hydropower station as described in the first aspect and a controller, and the controller is connected to the acquisition card and the optical switch 41'.

[0025] Preferably, the monitoring system further includes a display unit, and / or a sound unit, and / or a communication unit connected to the controller.

[0026] Based on the above technical solutions, the beneficial effects of the present invention compared with the prior art are as follows:

[0027] The present invention provides a monitoring device for a backbone optical cable of a hydropower station, including a pulsed laser, a circulator, an optical filter, a multi-parameter monitoring unit, a first polarization analyzer, a first detector, and an acquisition card. Among them: the multi-parameter monitoring unit is used to obtain at least a first signal and a second signal. Among them, the first signal is used to calculate the distributed vibration information of the hydropower optical cable to be monitored, and the second signal is used to calculate the temperature information of the hydropower optical cable to be monitored; the input end of the first polarization analyzer is used to be connected to the outlet of the hydropower optical cable to be monitored, and the output end of the first polarization analyzer is connected to the first detector; the input end of the acquisition card is connected to the output ends of the first detector and the multi-parameter monitoring unit, and the output end of the acquisition card is used to be connected to an external controller to convert the first signal, the second signal output by the multi-parameter monitoring unit and the signal output by the first detector into digital signals and send them to the external controller for processing.

[0028] The multi-parameter monitoring device for the backbone optical cable of a hydropower station proposed by the present invention organically integrates a variety of monitoring means, and only uses one pulsed laser, combined with several polarization analyzers and detectors to achieve the measurement of distributed vibration, distributed temperature and high-frequency vibration of hydropower optical fibers, so as to respond to various threat events faced by hydropower optical cables and improve the monitoring level of backbone optical cables of hydropower stations. Description of the Drawings

[0029] To more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the attached drawings required for use in the embodiments of the present utility model. Obviously, the attached drawings described below are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other attached drawings can also be obtained based on these attached drawings.

[0030] Figure 1 It is a schematic structural diagram of a backbone optical cable monitoring device for a hydropower station in the embodiments of the present utility model;

[0031] Figure 2 It is a schematic structural diagram of a backbone optical cable monitoring device for a hydropower station in another embodiment of the present utility model. Specific embodiments

[0032] In order to make the objectives, technical solutions and advantages of the present utility model clearer and more understandable, the following further details the present utility model in conjunction with the attached drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0033] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted in an open and inclusive sense, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "examples", "specific examples" or "some examples", etc., are intended to indicate that specific features, structures, materials or characteristics related to the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representations of the above terms are not necessarily directed to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner, that is, although they may be carried in the embodiments or examples of the above terms due to reasons such as the order and position of appearance, however, it is not limited that they can be carried by one embodiment or example in a combined manner.

[0034] In the description of the present utility model, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present disclosure, unless otherwise stated, the meaning of "a plurality" is two or more. In addition, for example, in the description, for the same type of nouns, the method of adding "A" and "B" at the end is used to describe them as two independent individuals. In this case, the features defined with "A" and "B" are only used for the purpose of distinguishing similar individuals and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features.

[0035] Embodiment 1:

[0036] This embodiment provides a monitoring device for backbone optical cables of a hydropower station, in combination with Figure 1 As shown, it includes a pulsed laser 10, a circulator 20, an optical filter 30, a multi-parameter monitoring unit 40, a first polarization analyzer 50, a first detector 60, and a data acquisition card (not shown in the figure). Among them:

[0037] The first port a of the circulator 20 is connected to the output end of the pulsed laser 10, the second port b is connected to the entrance of the hydropower optical cable to be monitored, and the third port c is connected to the input end of the optical filter 30.

[0038] The output port of the optical filter 30 is connected to the multi-parameter monitoring unit 40. The multi-parameter monitoring unit is used to obtain at least a first signal and a second signal. Among them, the first signal is used to calculate the distributed vibration information of the hydropower optical cable to be monitored, and the second signal is used to calculate the temperature information of the hydropower optical cable to be monitored.

[0039] The input end of the first polarization analyzer 50 is used to be connected to the exit of the hydropower optical cable to be monitored, and the output end of the first polarization analyzer 50 is connected to the first detector 60.

[0040] The input end of the data acquisition card is connected to the output ends of the first detector 60 and the multi-parameter monitoring unit 40. The output end of the data acquisition card is used to be connected to an external controller to convert the first signal, the second signal output by the multi-parameter monitoring unit 40, and the signal output by the first detector into digital signals and send them to the external controller for processing.

[0041] In some embodiments, the multi-parameter monitoring unit 40 includes a second polarization analyzer 41, a second detector 42, a third detector 43, and a fourth detector 44. Among them:

[0042] The input end of the second polarizer 41 is connected to the first output port of the optical filter 30, and the output end of the second polarizer 41 is connected to the second detector 42. The first output port of the optical filter 30 is used to separate Rayleigh scattered light.

[0043] The input end of the third detector 43 is connected to the second output port of the optical filter; the input end of the fourth detector 44 is connected to the third output port of the optical filter 30. The second output port of the optical filter 30 is used to separate anti-Stokes Raman scattered light, and the third output port of the optical filter 30 is used to separate Stokes Raman scattered light.

[0044] The output ends of the second detector, the third detector, and the fourth detector are respectively connected to the acquisition card.

[0045] Specifically, in some embodiments, the pulsed laser 10 can emit pulsed laser light with its operating wavelength near 1550 nm. The first polarizer 50 and the second polarizer 41 allow light with a specific polarization direction in the incident light to transmit through, and the extinction ratio is greater than 30 dB. The bandwidths of the first detector 60, the second detector 42, the third detector 43, and the fourth detector 44 are greater than 250 MHz. The optical filter 30 can filter out light with wavelengths of 1450 nm, 1550 nm, and 1660 nm, and the extinction ratio is greater than 40 dB. Among them, the first output port is used to separate Rayleigh scattered light (filter out light with a wavelength of 1550 nm), the second output port is used to separate anti-Stokes Raman scattered light (filter out light with a wavelength of 1450 nm), and the third output port is used to separate Stokes Raman scattered light (filter out light with a wavelength of 1450 nm).

[0046] Taking the optical fiber as the medium, the light emitted by the pulsed laser 10 passes through the first port a of the circulator 30 and enters the hydroelectric cable to be measured through the second port b. The Rayleigh scattering and spontaneous Raman scattering light in the hydroelectric cable return through the second port b of the circulator and enter the optical filter 30 through the third port c. The optical filter 30 separates the Rayleigh scattering light (1550 nm), anti-Stokes Raman scattering light (1450 nm), and Stokes Raman scattering light (1660 nm). Among them, the Rayleigh scattering light passes through the second polarizer 41 and is detected by the second detector 42 (backward Rayleigh scattering light) to obtain the first signal for calculating the distributed vibration information of the hydroelectric cable to be monitored. The anti-Stokes Raman scattering light and Stokes Raman scattering light are detected by the third detector 43 and the fourth detector 44 to obtain the second signal for calculating the temperature information of the hydroelectric cable to be monitored. At the same time, the first polarizer 50 detects the change in the polarization state of the transmitted light passing through the hydroelectric cable and is detected by the first detector 60 to obtain the third signal that can be used to calculate the high-frequency vibration information of the line. The acquisition card converts the first signal, the second signal output by the multi-parameter monitoring unit 40, and the third signal output by the first detector 60 into digital signals and sends them to the external controller for processing. The vibration detection frequency of the second detector 42 is limited by the pulse light repetition frequency, generally in the kHz order of magnitude. The detection frequency of the first detector 60 is only limited by the bandwidth of the detector itself, generally in the MHz order of magnitude.

[0047] In practical applications, the controller will use the first signal, the second signal, and the third signal collected for some processing. The specific processing process of the controller can adopt some conventional technical means in this field, and the present utility model does not limit this.

[0048] Specifically, for example, since the vibration of the optical fiber will cause a change in the polarization of Rayleigh scattering, the first signal obtained by the cooperation of the second polarizer 41 and the second detector 42 can monitor this change. Since pulsed light is emitted, distributed measurement can be achieved.

[0049] For another example, the temperature information of the hydroelectric cable can be obtained by using the second signal. Specifically, the ratio of the anti-Stokes and Stokes signals is used to demodulate the temperature.

[0050]

[0051] In the formula, is the reference optical fiber temperature, is the wave vector, is the Planck constant, represents the Raman frequency shift, is when the optical fiber is at the reference temperature the optical power of the backward anti-Stokes scattering signal light, It is the backscattered anti-Stokes scattered signal optical power in the optical fiber when the optical fiber is at the temperature T to be measured. and is the Stokes scattered optical power at the corresponding temperature. Among them, the Raman frequency shift depends on the characteristics of the material. For silica optical fiber, the Raman frequency shift is approximately 13.2 THz. That is, the Stokes light and anti-Stokes light signals detected by the third detector 43 and the fourth detector 44 in this embodiment can demodulate the temperature information along the line.

[0052] The multi-parameter backbone optical cable monitoring device for hydropower stations proposed by the present utility model organically integrates a variety of monitoring means, and only uses one pulsed laser, combined with several polarization analyzers and detectors to achieve the measurement of distributed vibration, distributed temperature and high-frequency vibration of hydropower optical fibers, so as to respond to various threat events faced by hydropower optical cables and improve the monitoring level of backbone optical cables in hydropower stations.

[0053] In some other embodiments, more monitoring signals can also be obtained through more ingenious designs to further improve the monitoring level of backbone optical cables in hydropower stations. For example, in combination with Figure 2 As shown, it can be achieved by changing the multi-parameter monitoring unit 40. Specifically, the multi-parameter monitoring unit 40 includes an optical switch 41’, a third polarization analyzer 42’, a sixth detector 43’, a seventh detector 44’, an eighth detector 45’, and a fifth detector 46’, where:

[0054] The input end of the optical switch 41’ is connected to the first output port of the optical filter, and the output end of the optical switch 30 is used to be respectively connected to the sixth detector 43’ or the third polarization analyzer 42’. The control port of the optical switch 30 is used to be connected to an external controller for receiving the control of the controller to be respectively connected to the sixth detector 43’ or the third polarization analyzer 42’.

[0055] The input end of the third detector (detector 2) is connected to the second output port of the optical filter; the input end of the fourth detector (detector 3) is connected to the third output port of the optical filter. The output end of the third polarization analyzer 42’ is also connected to the seventh detector 44’. Among them, the first output port of the optical filter 30 is used to separate Rayleigh scattered light (1550 nm), the second output port is used to separate anti-Stokes Raman scattered light (1450 nm), and the third output port is used to separate Stokes Raman scattered light (1660 nm).

[0056] The output ends of the sixth detector 43’, the seventh detector 44’, the eighth detector 45’, and the fifth detector 46’ are respectively connected to the acquisition card.

[0057] Specifically, the pulsed laser 10 can emit pulsed laser light with a working wavelength near 1550 nm. The first polarization analyzer 50 and the third polarization analyzer 42' allow light with a specific polarization direction in the incident light to transmit, and the extinction ratio is greater than 30 dB. The bandwidths of the first detector 60, the sixth detector 43', the seventh detector 44', the eighth detector 45', and the fifth detector 46' are greater than 250 MHz. The optical filter 30 can filter out light with wavelengths of 1450 nm, 1550 nm, and 1660 nm, and the extinction ratio is greater than 40 dB.

[0058] Taking the optical fiber as the medium, the light emitted by the pulsed laser 10 passes through the first port a of the circulator 30 and enters the hydropower optical cable to be measured from the second port b. The Rayleigh scattering and spontaneous Raman scattering light in the hydropower optical cable return through the second port b of the circulator and enter the optical filter 30 from the third port c. The optical filter 30 separates the Rayleigh scattering light (1550 nm), anti-Stokes Raman scattering light (1450 nm), and Stokes Raman scattering light (1660 nm). Among them, the Rayleigh scattering light is controlled by the optical switch 41' and can reach the d path and enter the sixth detector 43' for detection to obtain the fiber distributed loss information (according to the basic principle of OTDR), or reach the e path and be detected by the seventh detector 44' after passing through the third polarization analyzer 42' to obtain the fiber distributed vibration information. The anti-Stokes Raman scattering light and the Stokes Raman scattering light are detected by the eighth detector 45' and the fifth detector 46' to obtain the fiber temperature information. At the same time, the first polarization analyzer 50 detects the change in the polarization state of the transmitted light passing through the hydropower optical cable and is detected by the first detector 60 to obtain the line high-frequency vibration information.

[0059] The process by which the controller calculates the fiber distributed loss, distributed vibration, distributed temperature, and high-frequency vibration information using the signals obtained by the first detector 60, the sixth detector 43', the seventh detector 44', the eighth detector 45', and the fifth detector 46' can sample and use the first signal, the second signal, and the third signal for some processing. The specific processing process of the controller can adopt some conventional technical means in the art, and the present utility model does not limit this. In this embodiment, the optical switch 41' can first work on the d path to detect the loss, temperature, and line high-frequency vibration conditions of the hydropower optical cable. When the overall vibration of the hydropower optical cable is abnormal, the controller switches the optical switch 41' to the e path, and the backward Rayleigh scattering is used to detect the distributed vibration of the optical cable to locate the abnormal vibration.

[0060] The backbone optical cable monitoring device for hydropower stations proposed by the present utility model organically integrates a variety of monitoring means, and realizes fiber distributed loss, distributed vibration, distributed temperature and high-frequency vibration measurement only by using a single pulse laser, combined with several polarization analyzers and detectors. Thus, it can respond to various threat events faced by hydropower optical cables and improve the monitoring level of the backbone optical cables of hydropower stations.

[0061] The present utility model also discloses a backbone optical cable monitoring system for hydropower stations, which includes the above-mentioned backbone optical cable monitoring device for hydropower stations and a controller (not shown), and the controller is connected to an acquisition card and an optical switch 41'. The execution process of the controller is as described in the foregoing embodiments and will not be elaborated herein. In some embodiments, the backbone optical cable monitoring system for hydropower stations further includes a display unit, or / and a sound unit, or / and a communication unit. The display unit, the sound unit and the communication unit are connected to the controller, and the controller can inform the user of the monitoring results through the display unit, the sound unit and the communication unit.

[0062] In the above detailed description, various features are combined in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly recited in each claim. On the contrary, as reflected in the appended claims, the present utility model is in a state with fewer features than all the features of the single disclosed embodiment. Therefore, the appended claims are hereby expressly incorporated into the detailed description, where each claim stands alone as a separate preferred embodiment of the present utility model.

[0063] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for describing the above embodiments, but those of ordinary skill in the art should recognize that each embodiment can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the manner in which this term is covered is similar to the term "including", as interpreted when "including" is used as a transitional word in the claims. In addition, any term "or" used in the claims or the specification is intended to mean "non-exclusive or".

Claims

1. A backbone optical cable monitoring device for a hydropower station, characterized in that: It comprises a pulse laser (10), a circulator (20), an optical filter (30), a multi-parameter monitoring unit (40), a first polarizer (50), a first detector (60) and an acquisition card, wherein: The first port of the circulator (20) is connected to the output end of the pulse laser (10), the second port is connected to the inlet of the water and electricity optical cable to be monitored, and the third port is connected to the input end of the optical filter (30); The output port of the optical filter (30) is connected to the multi-parameter monitoring unit (40), and the multi-parameter monitoring unit (40) is used to obtain at least a first signal and a second signal, wherein the first signal is used to calculate the distributed vibration information of the water and electricity optical cable to be monitored, and the second signal is used to calculate the temperature information of the water and electricity optical cable to be monitored; The input end of the first polarizer (50) is used to be connected to the outlet of the water and electricity optical cable to be monitored, and the output end of the first polarizer (50) is connected to the first detector (60); The input end of the acquisition card is connected to the first detector (60) and the output end of the multi-parameter monitoring unit (40), and the output end of the acquisition card is used to connect to an external controller to convert the first signal output by the multi-parameter monitoring unit (40), the second signal and the signal output by the first detector (60) into digital signals and send them to the external controller for processing.

2. The backbone optical cable monitoring device for a hydropower station according to claim 1, characterized in that: The multi-parameter monitoring unit (40) comprises a second polarizer (41), a second detector (42), a third detector (43), and a fourth detector (44), wherein: An input end of the second polarizer (41) is connected to a first output port of the optical filter (30), and an output end of the second polarizer (41) is connected to a second detector (42); An input end of the third detector (43) is connected to the second output port of the optical filter (30); an input end of the fourth detector (44) is connected to the third output port of the optical filter (30); The output ends of the second detector (42), the third detector (43) and the fourth detector (44) are respectively connected to an acquisition card.

3. The backbone optical cable monitoring device for a hydropower station according to claim 2, characterized in that: The first output port of the optical filter (30) is used to separate Rayleigh scattered light, the second output port is used to separate anti-Stokes Raman scattered light, and the third output port is used to separate Stokes Raman scattered light.

4. The backbone optical cable monitoring device for a hydropower station according to claim 1, characterized in that: The multi-parameter monitoring unit (40) comprises an optical switch (41'), a third polarizer (42'), a sixth detector (43'), a seventh detector (44'), an eighth detector (45'), and a fifth detector (46'), wherein: The input end of the optical switch (41') is connected to the first output port of the optical filter (30), the output end of the optical switch (41') is used to be connected to the sixth detector (43') or the third analyzer (42'), and the control port of the optical switch (41') is used to be connected to an external controller and to be controlled by the controller to be connected to the sixth detector (43') or the third analyzer (42'). The output end of the third polarizer (42') is also connected to the seventh detector (44'); The input end of the seventh detector (44') is connected to the second output port of the optical filter (30); the input end of the eighth detector (45') is connected to the third output port of the optical filter (30); The output ends of the sixth detector (43'), the seventh detector (44'), the eighth detector (45') and the fifth detector (46') are respectively connected to the acquisition card.

5. The backbone optical cable monitoring device for a hydropower station according to claim 4, characterized in that: The first output port of the optical filter (30) is used to separate Rayleigh scattered light, the second output port is used to separate anti-Stokes Raman scattered light, and the third output port is used to separate Stokes Raman scattered light.

6. The backbone optical cable monitoring device for a hydropower station according to claim 1, characterized in that: The pulse laser (10) operates at a wavelength of 1550 nm.

7. A backbone optical cable monitoring system for a hydropower station, characterized in that: It comprises a backbone optical cable monitoring device for a hydropower station as described in any one of claims 1 to 3 and a controller, wherein the controller is connected to the acquisition card.

8. The backbone optical cable monitoring system for a hydropower station according to claim 7 is characterized in that: The monitoring system further comprises a display unit, or / and a sound unit, or / and a communication unit connected to the controller.

9. A backbone optical cable monitoring system for a hydropower station, characterized in that: It comprises the backbone optical cable monitoring device for a hydropower station as claimed in any one of claims 4 or 5 and a controller, wherein the controller is connected to the acquisition card and the optical switch (41').

10. The backbone optical cable monitoring system for a hydropower station according to claim 9, characterized in that: The monitoring system further comprises a display unit, or / and a sound unit, or / and a communication unit connected to the controller.

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