A monitoring system based on fusion optical fiber sensing technology

Abstract

The present invention provides a monitoring system based on fusion optical fiber sensing technology, which senses the environmental parameters of the measurement range parameter changes and feeds back to the fusion unit in the form of optical signals, and finally obtains the environmental parameters. It realizes the simultaneous perception of multi-state parameters; at the same time, a wavelength division multiplexer is used to suppress the crosstalk of different sensing methods; the present invention realizes the one-core, multi-parameter, and all-round intelligent monitoring of overhead power transmission lines, and can obtain line state parameters in real time to ensure the safe and stable operation of the line.

Description

Technical Field

[0001] The present invention relates to the field of fiber grating applications, and in particular to a monitoring system based on fusion fiber optic sensing technology. Background Art

[0002] The power optical cable network is an important infrastructure of the smart grid. Usually, the design life of the power optical cable is 25 years. At present, some power backbone optical cables have been in operation for more than 10 years, and it is necessary to strengthen the status monitoring of the power optical cable. In order to effectively support communication security and major event security in complex environments, many new requirements have been put forward in the aspects of multi-parameter monitoring, ultra-long distance monitoring, measurement control, diagnosis and analysis of the power optical cable network. Therefore, multi-parameter distributed optical fiber sensing mechanism and intelligent measurement and control technology are very necessary in terms of technology and economy.

[0003] However, the current monitoring methods for power optical cable networks are mainly limited to optical power monitoring, optical time domain reflectometry, etc., especially with the construction of smart distribution networks, the number of power optical cables in distribution communication networks has increased rapidly, and they are relatively weak in multi-parameter measurement and intelligent means. The level of automation urgently needs to be improved, especially for real-time monitoring of multiple parameters, and there is a lack of corresponding solutions. Summary of the invention

[0004] The purpose of the present invention is to provide a monitoring system based on fusion optical fiber sensing technology, which can solve at least one of the above-mentioned technical problems. The specific solution is as follows:

[0005] Fusion unit, distributed sensing fiber, fiber grating sensing unit and display;

[0006] The fusion unit is used to perform multi-parameter fusion measurement;

[0007] The distributed sensing optical fiber is used to sense the changes of the first group of environmental parameters that cause the changes of the first measurement range parameters of the fusion unit, and feed back to the fusion unit in the form of optical signals;

[0008] The fiber grating sensing unit is used to sense the changes of the second group of environmental parameters that cause the changes of the second measurement range parameters of the fusion unit, and feed back to the fusion unit in the form of optical signals;

[0009] Wherein, the first measurement range parameter includes: a first measurement parameter and a second measurement parameter; the second measurement range parameter includes: a third measurement parameter; the first group of environmental parameters includes: a first environmental parameter and a second environmental parameter; the second group of environmental parameters includes: a third environmental parameter;

[0010] The display is used to display the multi-parameter fusion measurement results of the fusion unit.

[0011] Optionally, the fusion unit includes: a fiber optic sensing light source processing unit, a sensing distributed unit, and a fiber optic Bragg grating monitoring unit;

[0012] The optical fiber sensing light source processing unit is used to provide monitoring laser for the distributed sensing optical fiber and the optical fiber grating sensing unit, and process monitoring information;

[0013] The distributed sensing unit is used to demodulate the parameter value after the parameter of the first measurement range changes;

[0014] The fiber grating monitoring unit is used to demodulate the parameter value after the parameter in the second measurement range changes.

[0015] Optionally, it is characterized in that the fusion unit further includes: a first wavelength division multiplexer,

[0016] The first wavelength division multiplexer divides the monitoring laser into at least two paths with different wavelength ranges, one path transmits light in the first wavelength range to the distributed sensing unit; the other path transmits light in the second wavelength range to the fiber grating monitoring unit.

[0017] Optionally, the fusion unit further includes: an optical switch,

[0018] The optical switch is used to control the passage of the monitoring laser in the sensing distributed unit so that the light in the first wavelength range passes through with a single wavelength.

[0019] Optionally, the fusion unit further includes: a second wavelength division multiplexer,

[0020] The second wavelength division multiplexer is used to transmit the light in the first wavelength range to the distributed sensing optical fiber, and transmit the monitoring laser in the second wavelength range to the fiber grating sensing unit.

[0021] Optionally, the distributed sensing unit includes: a Brillouin distributed monitoring unit and a distributed vibration monitoring unit.

[0022] The Brillouin distributed monitoring unit is connected to the first wavelength division multiplexer at one end and to the optical switch at the other end, and is used to transmit the monitoring laser of the first sub-wavelength to the distributed sensing optical fiber through the second wavelength division multiplexer under the control of the optical switch;

[0023] The distributed vibration monitoring unit is connected to the first wavelength division multiplexer at one end and to the optical switch at the other end, and is used to transmit the monitoring laser of the second sub-wavelength to the distributed sensing optical fiber through the second wavelength division multiplexer under the control of the optical switch;

[0024] The first sub-wavelength and the second sub-wavelength belong to the first wavelength range.

[0025] Optionally, the optical fiber sensing light source processing unit processes the monitoring information, including:

[0026] The Brillouin distributed monitoring unit receives a first feedback signal from the distributed sensing optical fiber, and demodulates a parameter value of the first measurement parameter after the first feedback signal is changed;

[0027] The distributed vibration monitoring unit demodulates the second feedback signal of the distributed sensing optical fiber to obtain a parameter value after the second measurement parameter is changed through the second feedback signal;

[0028] The fiber Bragg grating monitoring unit receives the third feedback signal, and demodulates the parameter value of the third measurement parameter after the change through the third feedback signal;

[0029] The optical fiber sensing light source processing unit receives the first feedback signal, the parameter value after the first measurement parameter changes, the second feedback signal, the parameter value after the second measurement parameter changes, the third feedback signal, and the parameter value after the third measurement parameter changes, and calculates the first environmental parameter through the relationship between the parameter value after the first measurement parameter changes and the first feedback signal, calculates the second environmental parameter through the relationship between the parameter value after the second measurement parameter changes and the second feedback signal, and calculates the third environmental parameter through the relationship between the parameter value after the third measurement parameter changes and the third feedback signal; wherein the first feedback signal and the second feedback signal belong to the first group of feedback signals.

[0030] Optionally, the first environmental parameter satisfies the following relationship:

[0031] ν B (ε,T)=ν B (ε0,T0)+C ε (ε-ε0)+C T (T-T0)

[0032] Among them, ν B (ε0, T0) is the initial Brillouin frequency shift in the optical fiber, T0 and ε0 are the initial temperature and strain value, T and ε are the changed temperature and strain value, C ε is the strain linear coefficient of the Brillouin frequency shift, C T is the temperature linear coefficient of the Brillouin frequency shift.

[0033] Optionally, the second environmental parameter satisfies the following relationship:

[0034]

[0035] Where f is the frequency, w is the pulse width, e r (t) is the backscattered Rayleigh light obtained at the optical fiber input end, a i and t i are the amplitude and time delay of the i-th scattering point, respectively, and N is the number of scattering centers set; when (tt i ) / w≤1, rectangular function rect[(tt i ) / w]=1, otherwise 0; time delay t i and the fiber length l from the input to the i-th scatterer i The relationship is t i =(2n f l i ) / C, where C is the speed of light in a vacuum, n f is the refractive index of the optical fiber.

[0036] Optionally, the third environmental parameter satisfies the following relationship:

[0037]

[0038] Among them, Δλ B is the change in the grating center wavelength, λ B is the grating Bragg wavelength, ε is the external stress, ΔT is the temperature change, ρ e , α, ξ are fixed parameters of optical fiber.

[0039] The present invention senses the environmental parameters of the changes in the measurement range parameters and feeds them back to the fusion unit in the form of optical signals, and finally obtains the environmental parameters, thereby achieving the beneficial effects of simultaneously sensing multi-state parameters and accurately calculating the environmental parameters.

[0040] At the same time, the wavelength division multiplexer is used to effectively suppress the crosstalk of different sensing methods;

[0041] The present invention realizes the single-core, multi-parameter, and all-round intelligent monitoring of overhead power transmission lines, and can obtain line status parameters in real time to ensure safe and stable operation of the lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings herein are incorporated into and constitute a part of the specification, showing embodiments consistent with the present invention, and together with the specification, are used to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0043] Figure 1 A schematic diagram of a monitoring system based on fusion optical fiber sensing technology according to an embodiment of the present invention is shown;

[0044] Figure 2 A schematic diagram of a monitoring system based on fusion optical fiber sensing technology according to another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0047] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0048] It should be understood that although the terms first, second, third, etc. may be used to describe ... in the embodiments of the present invention, these ... should not be limited to these terms. These terms are only used to distinguish .... For example, without departing from the scope of the embodiments of the present invention, the first ... may also be referred to as the second ..., and similarly, the second ... may also be referred to as the first ....

[0049] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0050] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0051] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0052] Example 1

[0053] like Figure 1 As shown, according to a specific embodiment of the present invention, the present invention provides a monitoring system based on fusion optical fiber sensing technology, comprising:

[0054] Fusion unit 100, distributed sensing optical fiber 101, fiber Bragg grating sensing unit 102 and display 103; fusion unit 100 is connected to distributed sensing optical fiber 101, fiber Bragg grating sensing unit 102 and display 103 respectively.

[0055] The fusion unit 100 includes: a fiber sensing light source processing unit 1001, a first wavelength division multiplexer 1002, a sensor distributed unit 1003, a fiber Bragg grating monitoring unit 1004, an optical switch 1005 and a second wavelength division multiplexer 1006; the fiber sensing light source processing unit 1001, the first wavelength division multiplexer 1002, the sensor distributed unit 1003, the optical switch 1005 and the second wavelength division multiplexer 1006 are connected in sequence. The fiber sensing light source processing unit 1001, the first wavelength division multiplexer 1002, the fiber Bragg grating monitoring unit 1004 and the second wavelength division multiplexer 1006 are connected in sequence.

[0056] The optical fiber sensing light source processing unit 1001 provides monitoring laser for the distributed sensing optical fiber 101 and the optical fiber grating sensing unit 102, and then processes the monitoring information to obtain monitoring data. Finally, the display 103 displays the multi-parameter measurement results processed by the optical fiber sensing light source processing unit 1001.

[0057] The monitoring laser emitted by the optical fiber sensing light source processing unit 1001 undergoes threshold processing to form a monitoring laser that meets the monitoring conditions. The monitoring laser has pulse width and power requirements, wherein the pulse width should be less than 10um and the power should be greater than 1W. For the monitoring laser within the threshold range, an accurate feedback signal can be obtained. When the monitoring laser passes through the first wavelength division multiplexer 1002, the first wavelength division multiplexer 1002 divides the monitoring laser into two paths with different wavelength ranges. The first path transmits the light of the first wavelength range to the sensing distributed unit 1003; the second path transmits the light of the second wavelength range to the optical fiber grating monitoring unit 1004. For example, the first wavelength range is 1500nm-1800nm. The second wavelength range is 1000nm-1400nm.

[0058] The first monitoring laser is controlled by the optical switch 1005, so that the monitoring laser output by the distributed sensing unit 1003 passes through with a single wavelength, for example, only the monitoring laser of 1650nm can pass through. After the single wavelength monitoring laser passes through the optical switch 1005, it is transmitted to the distributed sensing optical fiber 101 by the second wavelength division multiplexer 1006. After the second monitoring laser is output from the fiber grating monitoring unit 1004, for example, the monitoring laser of 1300nm is transmitted to the fiber grating sensing unit 102 by the second wavelength division multiplexer 1006.

[0059] The second wavelength division multiplexer 1006 can suppress crosstalk between different sensing modes.

[0060] The optical switch uses time division multiplexing to avoid crosstalk between different distributed optical fiber sensors. Time division multiplexing, or TDM, is the use of the same physical connection at different time periods to transmit different signals, and can also achieve the purpose of multi-channel transmission.

[0061] When the distributed sensing optical fiber 101 causes the first monitoring laser parameter to change due to factors such as temperature, strain, and vibration, it is returned to the sensing distributed unit 1003 in the form of an optical signal. The sensing distributed unit 1003 demodulates the parameter value of the first monitoring laser parameter after the change based on the feedback signal, such as the frequency shift value, phase value, etc.

[0062] When the fiber grating sensing unit 102 causes the second monitoring laser parameter to change due to factors such as stress and temperature, it is returned to the fiber grating monitoring unit 1004 in the form of an optical signal. The fiber grating monitoring unit 1004 demodulates the parameter value of the second monitoring laser parameter after the change, such as the wavelength value, based on the feedback signal.

[0063] The optical fiber sensing light source processing unit 1001 processes the monitoring information, specifically including:

[0064] The optical fiber sensing light source processing unit 1001 receives the first feedback signal, the demodulated frequency shift, the phase change value, and the second feedback signal, the demodulated wavelength change value, and then calculates and obtains environmental parameters such as temperature, phase, stress, and vibration.

[0065] Specifically, according to the first feedback signal, the demodulated frequency shift, the phase change value, etc., the strain and temperature obtained satisfy the following calculation relationship:

[0066] ν B (ε,T)=ν B (ε0,T0)+C ε (ε-ε0)+C T (T-T0)

[0067] Among them, ν B (ε0, T0) is the initial Brillouin frequency shift in the optical fiber, T0 and ε0 are the initial temperature and strain value, T and ε are the changed temperature and strain value, C ε is the strain linear coefficient of the Brillouin frequency shift, C T is the temperature linear coefficient of the Brillouin frequency shift.

[0068] When the change of strain ε is not considered, that is, ε=ε0, C ε (ε-ε0)=0, after multiple measurements, the temperature parameter T can be obtained; when the change of temperature T is not considered, C T (T-T0)=0, the strain parameter ε can be calculated.

[0069] According to the first feedback signal, the demodulated frequency shift, the phase change value, etc., the obtained vibration physical quantity satisfies the following calculation relationship:

[0070]

[0071] Where f is the frequency, w is the pulse width, e r (t) is the backscattered Rayleigh light obtained at the optical fiber input end, a i and t i are the amplitude and time delay of the i-th scattering point, respectively, and N is the number of scattering centers. i ) / w≤1, rectangular function rect[(tt i ) / w]=1, otherwise it is 0. Time delay t i and the fiber length l from the input to the i-th scatterer i The relationship is t i =(2n f l i ) / C, where C is the speed of light in a vacuum, n f is the refractive index of the optical fiber.

[0072] According to the second feedback signal, the demodulated wavelength change value, etc., the obtained temperature and stress satisfy the following calculation relationship:

[0073]

[0074] Among them, Δλ B is the change in the grating center wavelength, λ B is the grating Bragg wavelength, ε is the external stress, ΔT is the temperature change, ρ e , α, ξ are fixed parameters of optical fiber.

[0075] When the change of strain ε is not considered, that is, ε is a constant, the temperature change ΔT can be obtained through the change of the grating center wavelength; when the change of temperature T is not considered, ΔT=0, the strain parameter ε can be calculated through the change of the grating center wavelength.

[0076] Finally, the display 103 displays the multi-parameter real-time measurement results processed by the optical fiber sensing light source processing unit 1001. The operator monitors in real time according to the displayed results and makes precise adjustments to the monitoring laser.

[0077] The present invention senses the environmental parameters of the changes in the measurement range parameters and feeds them back to the fusion unit in the form of optical signals, and finally obtains the environmental parameters, thereby achieving the beneficial effects of simultaneously sensing multi-state parameters and accurately calculating the environmental parameters.

[0078] At the same time, the wavelength division multiplexer is used to effectively suppress the crosstalk of different sensing methods;

[0079] The present invention realizes the single-core, multi-parameter, and all-round intelligent monitoring of overhead power transmission lines, and can obtain line status parameters in real time to ensure safe and stable operation of the lines.

[0080] Example 2

[0081] like Figure 2 As shown, according to a specific embodiment of the present invention, the present invention provides another monitoring system based on fusion optical fiber sensing technology, comprising:

[0082] Fusion unit 200, distributed sensing optical fiber 201, fiber Bragg grating sensing unit 202 and display 203; fusion unit 200 is connected to distributed sensing optical fiber 201, fiber Bragg grating sensing unit 202 and display 203 respectively.

[0083] Wherein, the fusion unit 200 comprises: an optical fiber sensing light source processing unit 2001, a first wavelength division multiplexer 2002, a Brillouin distributed monitoring unit 2003 and a distributed vibration monitoring unit 2004, a fiber grating monitoring unit 2005, an optical switch 2006 and a second wavelength division multiplexer 2007; the optical fiber sensing light source processing unit 2001, the first wavelength division multiplexer 2002, the Brillouin distributed monitoring unit 2003, the distributed vibration monitoring unit 2004, the optical switch 2006 and the second wavelength division multiplexer 2007 are connected in sequence, wherein, after the Brillouin distributed monitoring unit 2003 and the distributed vibration monitoring unit 2004 are connected in parallel, the optical fiber sensing light source processing unit 2001, the first wavelength division multiplexer 2002, the fiber grating monitoring unit 2005 and the second wavelength division multiplexer 2007 are connected in sequence.

[0084] Among them, the distributed vibration monitoring unit is also called the DAS vibration monitoring module, and the full spelling of DAS is Distributedfiber Acoustic Sensing.

[0085] The optical fiber sensing light source processing unit 2001 provides monitoring laser for the distributed sensing optical fiber 201 and the optical fiber grating sensing unit 202, and then processes the monitoring information to obtain monitoring data. Finally, the display 203 displays the multi-parameter measurement results processed by the optical fiber sensing light source processing unit 2001.

[0086] The monitoring laser emitted by the optical fiber sensing light source processing unit 2001 undergoes threshold processing to form a monitoring laser that meets the monitoring conditions. The monitoring laser has pulse width and power requirements, wherein the pulse width should be less than 10um and the power should be greater than 1W. For the monitoring laser within the threshold range, an accurate feedback signal can be obtained. When the monitoring laser passes through the first wavelength division multiplexer 2002, the first wavelength division multiplexer 2002 divides the monitoring laser into three paths with different wavelength ranges. The first path transmits the light of the first sub-length to the Brillouin distributed monitoring unit 2003; the second path transmits the light of the second sub-length to the distributed vibration monitoring unit 2004; and the third path transmits the light of the second wavelength range to the fiber grating monitoring unit 2005.

[0087] The first sub-wavelength and the second sub-wavelength belong to the first wavelength range, wherein, for example, the first wavelength range is 1500nm-1800nm, the first sub-wavelength is 1500nm, the second sub-wavelength is 1550nm, and the second wavelength range is 1000nm-1400nm.

[0088] Under the control of the optical switch 2006, the Brillouin distributed monitoring unit 2003 and the distributed vibration monitoring unit 2004 work alternately, and light of a single wavelength passes through, for example, only a monitoring laser of 1550 nm can pass through, and the single wavelength monitoring laser passes through the optical switch 2006 and then is transmitted to the distributed sensing optical fiber 201 by the second wavelength division multiplexer 2007;

[0089] After the third monitoring laser is output from the FBG monitoring unit 2005, for example, the 1300nm monitoring laser is transmitted to the FBG sensing unit 202 via the second WDM 2007. The second WDM 2007 transmits the light in the second wavelength range to the FBG sensing unit 202.

[0090] The second wavelength division multiplexer 2007 can suppress crosstalk between different sensing modes.

[0091] The optical switch uses time division multiplexing to avoid crosstalk between different distributed optical fiber sensors. Time division multiplexing, or TDM, is the use of the same physical connection at different time periods to transmit different signals, and can also achieve the purpose of multi-channel transmission.

[0092] When the distributed sensing optical fiber 201 causes the first monitoring laser parameter to change due to factors such as temperature and strain, it is returned to the Brillouin distributed monitoring unit 2003 in the form of an optical signal. The Brillouin distributed monitoring unit 2003 demodulates the parameter value of the first monitoring laser parameter after the change, such as the frequency shift value, based on the feedback signal.

[0093] When the distributed sensing optical fiber 201 causes the second monitoring laser parameter to change due to vibration factors, it is returned to the distributed vibration monitoring unit 2004 in the form of an optical signal. The distributed vibration monitoring unit 2004 demodulates the parameter value of the second monitoring laser parameter after the change, such as the phase value, based on the feedback signal.

[0094] When the fiber grating sensing unit 202 causes the third monitoring laser parameter to change due to factors such as stress and temperature, it is returned to the fiber grating monitoring unit 2005 in the form of an optical signal. The fiber grating monitoring unit 2005 demodulates the parameter value of the third monitoring laser parameter after the change, such as the wavelength change value, based on the feedback signal.

[0095] Then, the optical fiber sensing light source processing unit 2001 processes the monitoring information, specifically including:

[0096] The optical fiber sensing light source processing unit 2001 receives the frequency shift change value demodulated from the first feedback signal, the phase change value demodulated from the second feedback signal, and the wavelength change value demodulated from the third feedback signal, and then calculates and obtains environmental parameters such as temperature, phase, stress, and vibration.

[0097] Specifically, according to the first feedback signal and the change value of the demodulated frequency shift, the strain and temperature obtained satisfy the following calculation relationship:

[0098] ν B (ε,T)=ν B (ε0,T0)+C ε (ε-ε0)+C T (T-T0)

[0099] Among them, ν B (ε0, T0) is the initial Brillouin frequency shift in the optical fiber, T0 and ε0 are the known initial temperature and strain values, T and ε are the changed temperature and strain values, C ε is the strain linear coefficient of the Brillouin frequency shift, C T is the temperature linear coefficient of the Brillouin frequency shift.

[0100] When the change of strain ε is not considered, that is, ε=ε0, C ε (ε-ε0)=0, after multiple measurements, the temperature parameter T can be obtained; when the change of temperature T is not considered, C T (T-T0)=0, the strain parameter ε can be calculated.

[0101] According to the second feedback signal and the demodulated frequency shift change value, the obtained vibration physical quantity satisfies the following calculation relationship:

[0102]

[0103] Where f is the frequency, w is the pulse width, e r (t) is the backscattered Rayleigh light obtained at the optical fiber input end, a i and t i are the amplitude and time delay of the i-th scattering point, respectively, and N is the number of scattering centers. i ) / w≤1, rectangular function rect[(tt i ) / w]=1, otherwise it is 0. Time delay t i and the fiber length l from the input to the i-th scatterer i The relationship is t i =(2n f l i ) / C, where C is the speed of light in a vacuum, n f is the refractive index of the optical fiber.

[0104] According to the third feedback signal, the demodulated wavelength change value, etc., the obtained temperature and stress satisfy the following calculation relationship:

[0105]

[0106] When ε is constant, ⊿T can be obtained, and when ⊿T is constant, ε can be obtained.

[0107] Among them, Δλ B is the change in the grating center wavelength, λ B is the grating Bragg wavelength, ε is the external stress, ΔT is the temperature change, ρ e , α, ξ are fixed parameters of optical fiber.

[0108] When the change of strain ε is not considered, that is, ε is a constant, the temperature change ΔT can be obtained through the change of the grating center wavelength; when the change of temperature T is not considered, ΔT=0, the strain parameter ε can be calculated through the change of the grating center wavelength.

[0109] Finally, the display 203 displays the multi-parameter measurement results processed by the optical fiber sensing light source processing unit 2001. The operator monitors in real time according to the displayed results and makes precise adjustments to the monitoring laser.

[0110] The present invention senses the environmental parameters of the changes in the measurement range parameters and feeds them back to the fusion unit in the form of optical signals, and finally obtains the environmental parameters, thereby achieving the beneficial effects of simultaneously sensing multi-state parameters and accurately calculating the environmental parameters.

[0111] At the same time, the wavelength division multiplexer is used to effectively suppress the crosstalk of different sensing methods;

[0112] The present invention realizes the single-core, multi-parameter, and all-round intelligent monitoring of overhead power transmission lines, and can obtain line status parameters in real time to ensure safe and stable operation of the lines.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A monitoring system based on fusion optical fiber sensing technology, characterized in that: include: Fusion unit, distributed sensing fiber, fiber grating sensing unit and display; The fusion unit is used to perform multi-parameter fusion measurement; The distributed sensing optical fiber is used to sense the changes of the first group of environmental parameters that cause the changes of the first measurement range parameters of the fusion unit, and feed back to the fusion unit in the form of optical signals; The fiber grating sensing unit is used to sense the changes of the second group of environmental parameters that cause the changes of the second measurement range parameters of the fusion unit, and feed back to the fusion unit in the form of optical signals; Wherein, the first measurement range parameter includes: a first measurement parameter and a second measurement parameter; the second measurement range parameter includes: a third measurement parameter; the first group of environmental parameters includes: a first environmental parameter and a second environmental parameter; the second group of environmental parameters includes: a third environmental parameter; The display is used to display the multi-parameter fusion measurement result of the fusion unit; The fusion unit includes: a fiber optic sensing light source processing unit, a sensing distributed unit and a fiber optic Bragg grating monitoring unit; The optical fiber sensing light source processing unit is used to provide monitoring laser for the distributed sensing optical fiber and the optical fiber grating sensing unit, and process monitoring information; The distributed sensing unit is used to demodulate the parameter value after the parameter of the first measurement range changes; The fiber Bragg grating monitoring unit is used to demodulate the parameter value after the parameter of the second measurement range changes; The fusion unit further includes: a first wavelength division multiplexer, The first wavelength division multiplexer divides the monitoring laser into at least two paths with different wavelength ranges, one path transmits light in the first wavelength range to the sensor distributed unit; the other path transmits light in the second wavelength range to the fiber grating monitoring unit; The fusion unit further includes: an optical switch, The optical switch is used to control the passage of the monitoring laser in the sensing distributed unit so that the light in the first wavelength range passes through with a single wavelength; The fusion unit further includes: a second wavelength division multiplexer, The second wavelength division multiplexer is used to transmit the light in the first wavelength range to the distributed sensing optical fiber, and transmit the monitoring laser in the second wavelength range to the fiber grating sensing unit; The first environmental parameter satisfies the following relationship: n B (e,T)=n B (ε0,T0)+C ε (e-e0)+C T (T-T0) Among them, ν B (ε0, T0) is the initial Brillouin frequency shift in the optical fiber, T0 and ε0 are the initial temperature and strain value, T and ε are the changed temperature and strain value, C ε is the strain linear coefficient of the Brillouin frequency shift, C T is the temperature linear coefficient of the Brillouin frequency shift; The second environmental parameter satisfies the following relationship: Where f is the frequency, w is the pulse width, e r (t) is the backscattered Rayleigh light obtained at the optical fiber input end, a i and t i are the amplitude and time delay of the i-th scattering point, respectively, and N is the number of scattering centers set; when (tt i ) / w≤1, rectangular function rect[(tt i ) / w]=1, otherwise 0; time delay t i and the fiber length l from the input to the i-th scatterer i The relationship is t i =(2n f l i ) / C, where C is the speed of light in a vacuum, n f is the fiber refractive index; The third environmental parameter satisfies the following relationship: Among them, Δλ B is the change in the grating center wavelength, λ B is the grating Bragg wavelength, ε is the external stress, ΔT is the temperature change, ρ e , α, ξ are fixed parameters of optical fiber.

2. The system according to claim 1, characterized in that The distributed sensing unit includes: a Brillouin distributed monitoring unit and a distributed vibration monitoring unit. The Brillouin distributed monitoring unit is connected to the first wavelength division multiplexer at one end and to the optical switch at the other end, and is used to transmit the monitoring laser of the first sub-wavelength to the distributed sensing optical fiber through the second wavelength division multiplexer under the control of the optical switch; The distributed vibration monitoring unit is connected to the first wavelength division multiplexer at one end and to the optical switch at the other end, and is used to transmit the monitoring laser of the second sub-wavelength to the distributed sensing optical fiber through the second wavelength division multiplexer under the control of the optical switch; The first sub-wavelength and the second sub-wavelength belong to the first wavelength range.

3. The system according to claim 2, characterized in that The optical fiber sensing light source processing unit processes the monitoring information, including: The Brillouin distributed monitoring unit receives a first feedback signal from the distributed sensing optical fiber, and demodulates a parameter value of the first measurement parameter after the first feedback signal is changed; The distributed vibration monitoring unit receives a second feedback signal from the distributed sensing optical fiber, and demodulates a parameter value of the second measurement parameter after the change through the second feedback signal; The fiber Bragg grating monitoring unit receives a third feedback signal from the fiber Bragg grating monitoring unit, and demodulates a parameter value of the third measurement parameter after the change through the third feedback signal; The optical fiber sensing light source processing unit receives the first feedback signal, the parameter value after the first measurement parameter changes, the second feedback signal, the parameter value after the second measurement parameter changes, the third feedback signal, and the parameter value after the third measurement parameter changes, and calculates the first environmental parameter through the relationship between the parameter value after the first measurement parameter changes and the first feedback signal, calculates the second environmental parameter through the relationship between the parameter value after the second measurement parameter changes and the second feedback signal, and calculates the third environmental parameter through the relationship between the parameter value after the third measurement parameter changes and the third feedback signal.

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