Cable discharge positioning device and method based on long-distance analog quantity optical fiber transmission

Abstract

The invention relates to the technical field of insulation states of power equipment, in particular to a cable discharge positioning device and method based on long-distance analog quantity optical fiber transmission. The cable discharge positioning device based on long-distance analog quantity optical fiber transmission comprises a plurality of partial discharge detection modules which are sequentially installed at a cable terminal and an intermediate joint grounding box and are used for detecting a plurality of partial discharge analog quantity electric signals and transmitting the electric signals to an optical signal sending module; the plurality of optical signal sending modules are used for receiving the multi-path partial discharge analog quantity electric signals and converting the multi-path partial discharge analog quantity electric signals into multi-path partial discharge analog quantity optical signals; the plurality of distributed optical fiber modules are used for receiving and transmitting the multi-path partial discharge analog quantity optical signals to the multi-path signal switching acquisition module; the multi-path signal switching acquisition module is used for converting the multi-path partial discharge analog quantity optical signals into two paths of gain-amplified partial discharge digital quantity electric signals; and the control module is used for receiving the two paths of gain-amplified partial discharge digital quantity electric signals and carrying out data post-processing and positioning of a partial discharge source.

Description

Technical Field

[0001] The present invention relates to the technical field of power equipment insulation status, and particularly relates to a cable discharge positioning device and method based on long-distance analog optical fiber transmission. Background Art

[0002] With the continuous advancement of the cableization process of transmission lines, the application ratio of transmission cables in the power grid is continuously increasing. Therefore, it is crucial to ensure the safe and reliable operation of transmission cables, and an effective cable insulation status detection system is essential. Partial discharge, as the inducement and early characterization of cable insulation deterioration, is regarded as an effective parameter for cable insulation status assessment. In the existing online detection technology for cable partial discharge, the distributed detection method has a longer detection distance and higher detection sensitivity compared with the traditional single-end detection method, can accurately locate the partial discharge source, shorten the time cost of defect investigation and cable replacement and maintenance, and gradually becomes a popular research direction. However, the existing distributed partial discharge detection system for transmission cables needs to install high-speed sampling units at each detected cable terminal and intermediate joint, and the high cost hinders its further popularization and use; at the same time, the existing number of distributed detection nodes can no longer meet the increasing detection requirements of transmission cables. Therefore, to solve the above problems, it is necessary to improve on the basis of the original distributed detection system. Summary of the Invention

[0003] The purpose of the present invention is to provide a cable discharge positioning device based on long-distance analog optical fiber transmission to solve the problem of high cost of the distributed detection system in the prior art.

[0004] To solve the above problems, the technical solution of the cable discharge positioning device based on long-distance analog optical fiber transmission of the present invention is as follows: A cable discharge positioning device based on long-distance analog optical fiber transmission, comprising: A control module, a multi-channel signal switching and acquisition module, a plurality of partial discharge detection modules, a plurality of optical signal transmission modules, and a plurality of distributed optical fiber modules; The plurality of partial discharge detection modules are sequentially installed at two cable terminals and a plurality of intermediate joints of the cable, and are respectively connected to a plurality of optical signal transmission modules, and are used for detecting multi-channel partial discharge analog electrical signals and transmitting the multi-channel partial discharge analog electrical signals to the plurality of optical signal transmission modules; The plurality of optical signal transmission modules are respectively connected to a plurality of distributed optical fiber modules, and are used for receiving the multi-channel partial discharge analog electrical signals, converting them into multi-channel partial discharge analog optical signals, and transmitting them to the plurality of distributed optical fiber modules; The plurality of distributed optical fiber modules are connected to the multi-channel signal switching and acquisition module, and are used for receiving and transmitting the multi-channel partial discharge analog optical signals to the multi-channel signal switching and acquisition module; The multi-channel signal switching and acquisition module is connected to the control module and is used to convert multi-channel partial discharge analog optical signals into two-channel amplified partial discharge digital electrical signals and transmit them to the control module; The control module is used to receive two-channel amplified partial discharge digital electrical signals and perform post-processing of the amplified partial discharge digital electrical signals and positioning of the partial discharge source.

[0005] Further, the multi-channel signal switching and acquisition module includes an optoelectronic conversion expansion module, a switching switch module, and a dual-channel high-speed sampling module; The optoelectronic conversion expansion module is connected to a plurality of distributed optical fiber modules and connected to the switching switch module, and is used to convert multi-channel partial discharge analog optical signals into multi-channel amplified partial discharge analog electrical signals; The switching switch module is connected to the dual-channel high-speed sampling module and is used to select two-channel amplified partial discharge analog electrical signals from the multi-channel amplified partial discharge analog electrical signals and transmit them to the dual-channel high-speed sampling module; The dual-channel high-speed sampling module is connected to the control module and is used to convert two-channel amplified partial discharge analog electrical signals into two-channel amplified partial discharge digital electrical signals and transmit them to the control module.

[0006] Further, the switching switch module and the dual-channel high-speed sampling module are connected through a first sampling channel and a second sampling channel, the dual-channel high-speed sampling module and the control module are connected through a sampling data channel, the two-channel amplified partial discharge analog electrical signals are respectively input into the dual-channel high-speed sampling module through the first sampling channel and the second sampling channel, and the dual-channel high-speed sampling module converts them into amplified partial discharge digital electrical signals and inputs them into the control module through the sampling data channel.

[0007] Further, the switching switch module includes a first multi-channel switch module and a second multi-channel switch module. The first multi-channel switch module includes a plurality of first signal input ends and a first signal output end connected to them uniformly. The plurality of first signal input ends are respectively connected to the multi-channel amplified partial discharge analog electrical signals, the first signal output end is connected to the first sampling channel, and the first multi-channel switch module is used to conduct the selected first signal input end and output the corresponding amplified partial discharge analog electrical signal through the first signal output end.

[0008] Further, the second multiplexer module includes multiple second signal input terminals and a second signal output terminal connected thereto in a unified manner. The multiple second signal input terminals are respectively connected to multiple amplified partial discharge analog electrical signals, and the second signal output terminal is connected to the second sampling channel. The second multiplexer module is used to conduct a selected second signal input terminal and output the corresponding amplified partial discharge analog electrical signal through the second signal output terminal.

[0009] Further, the switching module is also connected to the control module, and is used to conduct the first signal input terminal and the second signal input terminal to be detected according to the control module, so as to realize the time-division multiplexing of the dual-channel high-speed sampling module.

[0010] Further, the optoelectronic conversion and expansion module includes multiple optoelectronic conversion modules and multiple conditioning and amplification modules; The multiple optoelectronic conversion modules are respectively connected to multiple distributed optical fiber modules and connected to multiple conditioning and amplification modules, and are used to convert multiple partial discharge analog optical signals into multiple partial discharge analog electrical signals; The multiple conditioning and amplification modules are connected to the switching module, and are used to convert multiple partial discharge analog electrical signals into multiple amplified partial discharge analog electrical signals.

[0011] Further, the optical signal transmission module includes a signal conditioning module and an electro-optic conversion module; The signal conditioning module is connected to the partial discharge detection module and connected to the electro-optic conversion module, and is used to receive the partial discharge analog electrical signal and perform denoising processing on it; The electro-optic conversion module is connected to the signal conditioning module and connected to the distributed optical fiber module, and is used to convert the denoised partial discharge analog electrical signal into a local analog optical signal.

[0012] Further, the partial discharge detection module is a high-frequency current transformer. The high-frequency current transformer includes a circular coupling unit and an integration circuit connected thereto. The coupling unit is used to collect the partial discharge analog electrical signals of the cable terminal and the intermediate joint, and the integration circuit is used to output the partial discharge analog electrical signal.

[0013] The present invention also provides a cable discharge positioning method based on long-distance analog optical fiber transmission. Based on the above-mentioned cable discharge positioning device based on long-distance analog optical fiber transmission, the technical solution adopted is: The cable discharge positioning method based on long-distance analog optical fiber transmission includes the following steps: S1, multiple partial discharge detection modules detect multiple partial discharge analog electrical signals at two cable terminals and multiple intermediate joints of the cable, and convert them into multiple partial discharge analog optical signals through multiple optical signal transmission modules; S2. Use multiple distributed optical fiber modules to transmit multiple partial discharge analog optical signals to a multi-channel signal switching and acquisition module; S3. The multi-channel signal switching and acquisition module converts the multiple partial discharge analog optical signals into two amplified partial discharge digital electrical signals and transmits them to the control module; S4. The control module receives the two amplified partial discharge digital electrical signals and performs post-processing on the amplified partial discharge digital electrical signals and locates the partial discharge source.

[0014] Compared with the prior art, the cable discharge positioning device and method based on long-distance analog optical fiber transmission of the present application convert multiple partial discharge analog electrical signals detected by multiple partial discharge detection modules into multiple partial discharge analog optical signals through multiple optical signal transmission modules, and directly transmit the multiple partial discharge analog optical signals over a long distance through multiple distributed optical fiber modules. The multi-channel signal switching and acquisition module is used to convert the multiple partial discharge analog optical signals into two amplified partial discharge digital electrical signals. Finally, only the control module performs post-processing on the received amplified partial discharge digital electrical signals, realizing low-cost and simplified partial discharge source positioning. Compared with the existing distributed partial discharge detection and positioning system, the cable discharge positioning device based on long-distance analog optical fiber transmission of the present application avoids the cost problem caused by the need to install high-speed acquisition units at each detection node, promotes the popularization and application of the distributed partial discharge detection system, and has important engineering practical value.

[0015] The multi-channel signal switching and acquisition module includes an optoelectronic conversion and expansion module, a switching switch module, and a dual-channel high-speed sampling module; The optoelectronic conversion and expansion module is connected to multiple distributed optical fiber modules and connected to the switching switch module, and is used to convert multiple partial discharge analog optical signals into multiple amplified partial discharge analog electrical signals; The switching switch module is connected to the dual-channel high-speed sampling module, and is used to select two amplified partial discharge analog electrical signals from the multiple amplified partial discharge analog electrical signals and transmit them to the dual-channel high-speed sampling module; The dual-channel high-speed sampling module is connected to the control module, and is used to convert the two amplified partial discharge analog electrical signals into two amplified partial discharge digital electrical signals and transmit them to the control module to realize time-division multiplexing of the multi-channel signal switching and acquisition module, and the partial discharge analog signals at the cable terminal or intermediate joint that need to be accessed can be selected according to the actual detection process.

[0016] The switching switch module is also connected to the control module, and is used to turn on the first signal input terminal and the second signal input terminal to be detected according to the control module, so as to realize the time-division multiplexing of the multi-channel signal switching acquisition module, and facilitate the selection of the partial discharge analog signal at the cable terminal or the intermediate joint to be accessed according to the actual detection process.

[0017] The optoelectronic conversion and expansion module includes a plurality of optoelectronic conversion modules and a plurality of conditioning and amplification modules; The plurality of optoelectronic conversion modules are respectively connected to the distributed optical fiber module and connected to the plurality of conditioning and amplification modules, and are used to convert the multi-channel partial discharge analog optical signals into multi-channel partial discharge analog electrical signals; The plurality of conditioning and amplification modules are connected to the switching switch module, and are used to convert the multi-channel partial discharge analog electrical signals into multi-channel gain-amplified partial discharge analog electrical signals, so as to compensate for the attenuation of the partial discharge analog optical signals during long-distance transmission.

[0018] The optical signal transmitting module includes a signal conditioning module and an electro-optic conversion module; The signal conditioning module is connected to the partial discharge detection module and connected to the electro-optic conversion module, and is used to receive the partial discharge analog electrical signal and perform denoising processing on it; The electro-optic conversion module is connected to the signal conditioning module and connected to the distributed optical fiber module, and is used to convert the denoised partial discharge analog electrical signal into a local analog optical signal, so as to facilitate transmission through the optical fiber. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of a cable discharge positioning device based on long-distance analog optical fiber transmission according to an embodiment of the present invention; Figure 2 is a schematic structural diagram of an optical signal transmitting module in a cable discharge positioning device based on long-distance analog optical fiber transmission according to an embodiment of the present invention; Figure 3 is a schematic structural diagram of a multi-channel signal switching acquisition module in a cable discharge positioning device based on long-distance analog optical fiber transmission according to an embodiment of the present invention; Figure 4 is a schematic structural diagram of a high-frequency current transformer in a cable discharge positioning device based on long-distance analog optical fiber transmission according to an embodiment of the present invention.

[0020] In the figure, 1 is a cable, 11 is an intermediate joint, 12 is a cable terminal, 2 is a high-frequency current transformer, 21 is a coupling unit, 22 is an integrating circuit, 3 is an optical signal transmitting module, 31 is a signal conditioning module, 32 is an electro-optical conversion module, 4 is a distributed optical fiber module, 5 is a multi-channel signal switching and acquisition module, 51 is an opto-electronic conversion expansion module, 511 is an opto-electronic conversion module, 512 is a conditioning and amplification module, 52 is a switching module, 53 is a two-channel high-speed sampling module, and 6 is a computer. Specific embodiments

[0021] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application.

[0022] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0023] Next, in combination with Figure 1 , the cable discharge positioning device based on long-distance analog optical fiber transmission provided by the present application will be described in detail. Figure 1 It is a schematic structural diagram of the cable discharge positioning device based on long-distance analog optical fiber transmission according to an embodiment of the present application.

[0024] In this embodiment, as Figure 1As shown in the figure, the present invention provides a cable discharge positioning device based on long-distance analog fiber optic transmission, which includes a control module, a multi-channel signal switching and acquisition module 5, a plurality of partial discharge detection modules, a plurality of optical signal transmission modules 3, and a plurality of distributed fiber optic modules 4. The plurality of partial discharge detection modules are sequentially installed on two cable terminals 12 and a plurality of intermediate joints 11 of the cable 1 along the length of the cable 1, and are respectively connected to the plurality of optical signal transmission modules 3, and are used for detecting multi-channel partial discharge analog electrical signals and transmitting the multi-channel partial discharge analog electrical signals to the plurality of optical signal transmission modules 3. Among them, the partial discharge detection module is a high-frequency current transformer 2, and the bandwidth of the high-frequency current transformer 2 is 0.1-30 MHz, and the sensitivity is 5 mV / mA.

[0025] Specifically, as Figure 4 shown, the high-frequency current transformer 2 includes a circular coupling unit 21 and an integration circuit 22 connected thereto. The coupling unit 21 is used for collecting multi-channel partial discharge analog electrical signals of the cable terminal 12 and the intermediate joint 11, and the integration circuit 22 is used for outputting multi-channel partial discharge analog electrical signals. Here, the input of the high-frequency current transformer 2 is connected or voltage-coupled to the cable 1 to be detected. The coupling unit 21 includes two semi-circular structures and a transmission coil. The transmission coil is wound on one of the semi-circular structures, and the integration circuit 22 is connected to both ends of the transmission coil. Specifically: the multi-channel partial discharge analog electrical signals of the cable terminal 12 and the intermediate joint 11 collected by the coupling unit 21 are coupled into the transmission coil and transmitted to the integration circuit 22. Among them, the integration circuit 22 is composed of a capacitor C and an integration resistor R; the two semi-circular structures are made of manganese-zinc materials.

[0026] The plurality of optical signal transmission modules 3 are respectively connected to the plurality of distributed fiber optic modules 4, and are used for receiving multi-channel partial discharge analog electrical signals, converting them into multi-channel partial discharge analog optical signals, and transmitting them to the plurality of distributed fiber optic modules 4. Among them, as Figure 2 shown, the optical signal transmission module 3 includes a signal conditioning module 31 and an electro-optical conversion module 32. The signal conditioning module 31 is connected to the partial discharge detection module and connected to the electro-optical conversion module 32, and is used for receiving the partial discharge analog electrical signal and performing denoising processing on it. Here, the signal conditioning module 31 uses a three-channel bandwidth 30M signal conditioning.

[0027] The electro-optical conversion module 32 is connected to the signal conditioning module 31 and connected to the distributed fiber optic module 4, and is used for converting the denoised partial discharge analog electrical signal into a partial discharge analog optical signal. Here, the strength of the partial discharge analog optical signal is in a proportional relationship with the magnitude of the partial discharge analog electrical signal.

[0028] The plurality of distributed fiber optic modules 4 are connected to the multi-channel signal switching and acquisition module 5, and are used for receiving and transmitting multi-channel partial discharge analog optical signals to the multi-channel signal switching and acquisition module 5.

[0029] The multi-channel signal switching and acquisition module 5 is connected to the control module and is used to convert multi-channel partial discharge analog optical signals into two-channel amplified partial discharge digital electrical signals and transmit them to the control module.

[0030] Among them, as Figure 3 shown, the multi-channel signal switching and acquisition module 5 includes an optoelectronic conversion and expansion module 51, a switching switch module 52, and a dual-channel high-speed sampling module 53. The optoelectronic conversion and expansion module 51 is connected to multiple distributed optical fiber modules 4 and connected to the switching switch module 52, and is used to convert multi-channel partial discharge analog optical signals into multi-channel amplified partial discharge analog electrical signals. Specifically, the optoelectronic conversion and expansion module 51 includes multiple optoelectronic conversion modules 511 and multiple conditioning and amplification modules 512. The multiple optoelectronic conversion modules 511 are respectively connected to multiple distributed optical fiber modules 4 and connected to multiple conditioning and amplification modules 512, and are used to convert multi-channel partial discharge analog optical signals into multi-channel partial discharge analog electrical signals. Here, the magnitude of the partial discharge analog electrical signal is proportional to the intensity of the partial discharge analog optical signal.

[0031] The multiple conditioning and amplification modules 512 are connected to the switching switch module 52 and are used to convert multi-channel partial discharge analog electrical signals into multi-channel amplified partial discharge analog electrical signals. Here, the conditioning and amplification module 512 is a gain amplification circuit with a 30M bandwidth and is used to compensate for the attenuation of the partial discharge analog optical signal during long-distance transmission. The gain amplification multiple is positively correlated with the distance from the corresponding detection node to the control module.

[0032] The switching switch module 52 is connected to the dual-channel high-speed sampling module 53 and is used to select two-channel amplified partial discharge analog electrical signals from the multi-channel amplified partial discharge analog electrical signals and transmit them to the dual-channel high-speed sampling module 53. Among them, the switching switch module 52 and the dual-channel high-speed sampling module 53 are connected through a first sampling channel and a second sampling channel. The dual-channel high-speed sampling module 53 and the control module are connected through a sampling data channel. The two-channel amplified partial discharge analog electrical signals are respectively input into the dual-channel high-speed sampling module 53 through the first sampling channel and the second sampling channel. The dual-channel high-speed sampling module 53 converts them into two-channel amplified partial discharge digital electrical signals and inputs them into the control module through the sampling data channel. Here, the two-channel amplified partial discharge analog electrical signals are two identical amplified partial discharge analog electrical signals.

[0033] The switching switch module 52 includes a first multiplexer module and a second multiplexer module. Here, the first multiplexer module and the second multiplexer module are two sets of multiplexer modules with the same structure. Among them, the first multiplexer module includes multiple first signal input terminals and a first signal output terminal connected to them uniformly. The multiple first signal input terminals are respectively connected to multiple amplified partial discharge analog electrical signals. The first signal output terminal is connected to the first sampling channel. The first multiplexer module is used to conduct one selected first signal input terminal and output the corresponding amplified partial discharge analog electrical signal through the first signal output terminal. The second multiplexer module includes multiple second signal input terminals and a second signal output terminal connected to them uniformly. The multiple second signal input terminals are respectively connected to multiple amplified partial discharge analog electrical signals. The second signal output terminal is connected to the second sampling channel. The second multiplexer module is used to conduct one selected second signal input terminal and output the corresponding amplified partial discharge analog electrical signal through the second signal output terminal. Here, the switching switch module 52 is also connected to the control module and is used to conduct the first signal input terminal and the second signal input terminal to be detected according to the control module, so as to realize the time-division multiplexing of the multi-channel signal switching acquisition module 5.

[0034] The dual-channel high-speed sampling module 53 is connected to the control module and is used to convert two amplified partial discharge analog electrical signals into two amplified partial discharge digital electrical signals and transmit them to the control module. Here, the sampling rate of the dual-channel high-speed sampling module 53 is 125 MHz, the sampling time interval is 8 ns, and the sampling data length is 1 s.

[0035] The control module is used to receive two amplified partial discharge digital electrical signals and perform post-processing on the amplified partial discharge digital electrical signals and locate the partial discharge source. Here, the control module is the computer 6.

[0036] Specifically, taking the positions of two cable terminals 12 and multiple intermediate joints 11 of the cable 1 as an example of 10, correspondingly, 10 high-frequency current transformers 2 are respectively connected to the cable terminals 12 and the intermediate joints 11; the 10 high-frequency current transformers 2 are connected to 10 optical signal transmitting modules 3 in one-to-one correspondence, and each optical signal transmitting module 3 includes 1 signal conditioning module 31 and 1 electro-optical conversion module 32; the 10 optical signal transmitting modules 3 are connected to 10 distributed optical fiber modules 4 in one-to-one correspondence; the 10 distributed optical fiber modules 4 are connected to 10 photoelectric conversion modules 511 in one-to-one correspondence, and the 10 photoelectric conversion modules 511 are connected to 10 conditioning and amplification modules 512 in one-to-one correspondence; each of the 10 conditioning and amplification modules 512 is simultaneously connected to 1 first signal input terminal and 1 second signal input terminal, so as to obtain that 10 first signal input terminals are connected to the first signal output terminal, and 10 second signal input terminals are connected to the second signal output terminal; the first signal output terminal and the second signal output terminal are respectively connected to a dual-channel high-speed sampling module 53 through a first sampling channel and a second sampling channel; the dual-channel high-speed sampling module 53 is connected to the control module through a sampling data channel.

[0037] The present invention also proposes a cable discharge positioning method based on long-distance analog optical fiber transmission. Based on the above-mentioned cable discharge positioning device based on long-distance analog optical fiber transmission, it includes the following steps: First, multiple partial discharge detection modules detect multiple paths of partial discharge analog electrical signals on the cable terminals 12 and multiple intermediate joints 11 of the cable 1, and convert them into multiple paths of partial discharge analog optical signals through multiple optical signal transmitting modules 3; Secondly, use multiple distributed optical fiber modules 4 to transmit multiple paths of partial discharge analog optical signals to a multi-channel signal switching and acquisition module 5; Then, the multi-channel signal switching and acquisition module 5 converts multiple paths of partial discharge analog optical signals into two paths of gain-amplified partial discharge digital electrical signals and transmits them to the control module; Finally, the control module receives two paths of gain-amplified partial discharge digital electrical signals, and performs post-processing of the gain-amplified partial discharge digital electrical signals and positioning of the partial discharge source.

[0038] Specifically, taking the detection of any two intermediate joints 11 among the cable terminals 12 and the intermediate joints 11 as an example, in the following description, any two intermediate joints 11 are respectively the intermediate joint A and the intermediate joint B, and the calculation process of the partial discharge source positioning is as follows: Assume that the partial discharge analog electrical signal occurs between the intermediate joint A and the intermediate joint B, and the intermediate joint A is far from the switching switch module 52. At this time, it is considered that the first sampling channel is channel A and the second sampling channel is channel B. Then, the amplified partial discharge analog electrical signal transmitted by channel A is the electrical signal obtained by conditioning and amplifying the partial discharge analog electrical signal detected by the high-frequency current transformer 2 at the intermediate joint A, and the corresponding partial discharge starting time point number is N1; the amplified partial discharge analog electrical signal transmitted by channel B is the electrical signal obtained by conditioning and amplifying the partial discharge analog electrical signal detected by the high-frequency current transformer 2 at the intermediate joint B, and the corresponding partial discharge starting time point number is N2. Assume that the length of the cable 1 between the intermediate joint A and the intermediate joint B is L, the propagation speed of the partial discharge analog electrical signal in the cable 1 is V1, and the propagation speed of the partial discharge analog optical signal in the optical signal transmission module 3 is V2 = 3×10 8 m / s. Then, the time difference T0 between the detection nodes of the intermediate joint A and the intermediate joint B is as shown in Equation 1: T0 = L / V2 Equation 1 In Equation 1, T0 is the time difference between the detection nodes of the intermediate joint A and the intermediate joint B, L is the length of the cable 1 between the intermediate joint A and the intermediate joint B, and V2 is the propagation speed of the partial discharge analog optical signal in the optical signal transmission module 3.

[0039] At this time, the time difference T1 of the partial discharge analog electrical signal propagating to the intermediate joint A and the intermediate joint B is as shown in Equation 2: T1 = (N1×Δt - N2×Δt - T0) Equation 2 In Equation 2, N1 is the partial discharge starting time point number of the partial discharge analog electrical signal detected by the high-frequency current transformer 2 at the intermediate joint A, N2 is the partial discharge starting time point number of the partial discharge analog electrical signal detected by the high-frequency current transformer 2 at the intermediate joint B, Δt is the sampling time interval of the dual-channel high-speed sampling module 53, and T0 is the time difference between the detection nodes of the intermediate joint A and the intermediate joint B.

[0040] Then, the distance S from the position of the partial discharge source to the intermediate joint A is as shown in Equation 3: S = T1×V1 / 2 + L / 2 Equation 3 In Equation 3, T1 is the time difference of the partial discharge analog electrical signal propagating to the intermediate joint A and the intermediate joint B, V1 is the propagation speed of the partial discharge analog electrical signal in the cable 1, and L is the length of the cable 1 between the intermediate joint A and the intermediate joint B.

[0041] Here, those skilled in the art can understand that the specific operations of each step in the above cable discharge positioning method based on long-distance analog optical fiber transmission have been described above with reference to Figures 1 to 4It has been introduced in detail in the description of the cable discharge positioning device based on long-distance analog optical fiber transmission. Therefore, its repeated description will be omitted.

[0042] As described above, only the preferred embodiments of the present invention are provided, which are not intended to limit the present invention. The patent protection scope of the present invention is subject to the claims. Any equivalent structural changes made by using the content of the specification and drawings of the present invention should, by the same token, be included in the protection scope of the present invention.

Claims

1. A cable discharge positioning device based on long-distance analog optical fiber transmission, characterized in that: include: A control module, a multi-channel signal switching acquisition module (5), a plurality of partial discharge detection modules, a plurality of optical signal sending modules (3) and a plurality of distributed optical fiber modules (4); The plurality of partial discharge detection modules are sequentially mounted on two cable terminals (12) and a plurality of intermediate joints (11) of the cable (1), and are connected to the plurality of optical signal transmission modules (3) in a one-to-one correspondence, and are used to detect multiple partial discharge analog electrical signals, and transmit the multiple partial discharge analog electrical signals to the plurality of optical signal transmission modules (3); The plurality of optical signal sending modules (3) are connected to the plurality of distributed optical fiber modules (4) in a one-to-one correspondence, and are used to receive multiple partial discharge analog electrical signals and convert them into multiple partial discharge analog optical signals, and transmit them to the plurality of distributed optical fiber modules (4); The plurality of distributed optical fiber modules (4) are connected to a multi-channel signal switching and collecting module (5) and are used to receive and transmit a plurality of partial discharge analog optical signals to the multi-channel signal switching and collecting module (5); The multi-channel signal switching acquisition module (5) is connected to the control module and is used to convert the multi-channel partial discharge analog optical signals into two-channel gain-amplified partial discharge digital electrical signals and transmit them to the control module; The control module is used to receive two paths of gain-amplified partial discharge digital electrical signals, and perform post-processing of the gain-amplified partial discharge digital electrical signals and positioning of the partial discharge source.

2. The cable discharge positioning device based on long-distance analog optical fiber transmission according to claim 1 is characterized in that: The multi-channel signal switching acquisition module (5) comprises a photoelectric conversion expansion module (51), a switching switch module (52) and a dual-channel high-speed sampling module (53); The photoelectric conversion extension module (51) is connected to the plurality of distributed optical fiber modules (4) and to the switching switch module (52), and is used for converting multiple partial discharge analog optical signals into multiple gain-amplified partial discharge analog electrical signals; The switching switch module (52) is connected to the dual-channel high-speed sampling module (53) and is used to select two gain-amplified partial discharge analog electrical signals from multiple gain-amplified partial discharge analog electrical signals and transmit them to the dual-channel high-speed sampling module (53); The dual-channel high-speed sampling module (53) is connected to the control module and is used to convert two-channel gain-amplified partial discharge analog electrical signals into two-channel gain-amplified partial discharge digital electrical signals and transmit them to the control module.

3. The cable discharge positioning device based on long-distance analog optical fiber transmission according to claim 2 is characterized in that: The switching switch module (52) is connected to the dual-channel high-speed sampling module (53) via a first sampling channel and a second sampling channel, and the dual-channel high-speed sampling module (53) is connected to the control module via a sampling data channel. The two-channel gain-amplified partial discharge analog electrical signals are input into the dual-channel high-speed sampling module (53) via the first sampling channel and the second sampling channel respectively, and the dual-channel high-speed sampling module (53) converts them into two-channel gain-amplified partial discharge digital electrical signals, and inputs them into the control module via the sampling data channel.

4. The cable discharge positioning device based on long-distance analog optical fiber transmission according to claim 3 is characterized in that: The switching switch module (52) comprises a first multi-way switch module and a second multi-way switch module, the first multi-way switch module comprising a plurality of first signal input terminals and a first signal output terminal connected thereto in a unified manner, the plurality of first signal input terminals being connected one by one to a plurality of gain-amplified partial discharge analog electrical signals, the first signal output terminal being connected to a first sampling channel, the first multi-way switch module being used to conduct a selected first signal input terminal and output a corresponding gain-amplified partial discharge analog electrical signal through the first signal output terminal.

5. The cable discharge positioning device based on long-distance analog optical fiber transmission according to claim 4 is characterized in that: The second multi-way switch module includes multiple second signal input terminals and second signal output terminals uniformly connected thereto, the multiple second signal input terminals are connected one-to-one to multiple gain-amplified partial discharge analog electrical signals, the second signal output terminal is connected to the second sampling channel, and the second multi-way switch module is used to conduct the selected second signal input terminal and output the corresponding gain-amplified partial discharge analog electrical signal through the second signal output terminal.

6. The cable discharge positioning device based on long-distance analog optical fiber transmission according to claim 5 is characterized in that: The switching switch module (52) is also connected to the control module, and is used to realize time-division multiplexing of the multi-channel signal switching acquisition module (5) by switching on the first signal input terminal and the second signal input terminal to be detected according to the control module.

7. The cable discharge positioning device based on long-distance analog optical fiber transmission according to claim 2, characterized in that: The photoelectric conversion extension module (51) comprises a plurality of photoelectric conversion modules (511) and a plurality of conditioning and amplification modules (512); The multiple photoelectric conversion modules (511) are connected to the multiple distributed optical fiber modules (4) and to the multiple conditioning and amplification modules (512) in a one-to-one correspondence, and are used to convert multiple partial discharge analog optical signals into multiple partial discharge analog electrical signals; The plurality of conditioning and amplifying modules (512) are connected to the switching module (52) and are used to convert the multi-channel partial discharge analog electrical signals into multi-channel gain-amplified partial discharge analog electrical signals.

8. The cable discharge positioning device based on long-distance analog optical fiber transmission according to claim 1 is characterized in that: The optical signal sending module (3) comprises a signal conditioning module (31) and an electro-optical conversion module (32); The signal conditioning module (31) is connected to the partial discharge detection module and to the electro-optical conversion module (32), and is used to receive the partial discharge analog electrical signal and perform denoising processing on it; The electro-optical conversion module (32) is connected to the signal conditioning module (31) and to the distributed optical fiber module (4), and is used to convert the de-noised partial discharge analog electrical signal into a local analog optical signal.

9. The cable discharge positioning device based on long-distance analog optical fiber transmission according to claim 1 is characterized in that: The partial discharge detection module is a high-frequency current transformer (2), the high-frequency current transformer (2) comprising a circular coupling unit (21) and an integration circuit (22) connected thereto, the coupling unit (21) being used to collect partial discharge analog electrical signals of the cable terminal (12) and the intermediate joint (11), and the integration circuit (22) being used to output partial discharge analog electrical signals.

10. A cable discharge positioning method based on long-distance analog optical fiber transmission, characterized in that: The cable discharge positioning device based on long-distance analog optical fiber transmission according to any one of claims 1 to 9 comprises the following steps: S1, a plurality of partial discharge detection modules detect multiple partial discharge analog electrical signals on two cable terminals (12) and a plurality of intermediate joints (11) of a cable (1), and convert the signals into multiple partial discharge analog optical signals via a plurality of optical signal sending modules (3); S2, using a plurality of distributed optical fiber modules (4) to transmit a plurality of partial discharge analog optical signals to a multi-channel signal switching and acquisition module (5); S3, the multi-channel signal switching acquisition module (5) converts the multi-channel partial discharge analog optical signals into two-channel gain-amplified partial discharge digital electrical signals, and transmits them to the control module; S4, the control module receives two paths of gain-amplified partial discharge digital electrical signals, and performs post-processing of the gain-amplified partial discharge digital electrical signals and positioning of the partial discharge source.

Images