A transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection system

Abstract

The application provides a transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection system, which comprises an adjustable laser source configured to emit laser signals of different wavelengths according to settings; a light splitter configured to divide one laser signal emitted by the adjustable laser source into N laser signals, N >= 2; an optical fiber micro-water sensor arranged in a transformer bushing and configured to receive the laser signal output by the light splitter to detect the micro-water content in the insulating oil in the transformer bushing; and an optical fiber partial discharge ultrasonic sensor arranged on the surface of an insulating capacitor core in the transformer bushing and configured to receive the laser signal output by the light splitter to detect the partial discharge condition of the insulating capacitor core in the transformer bushing. The application can realize online detection of at least one of micro-water and / or partial discharge of a transformer high-voltage bushing with a voltage of 110 kV or above; and can realize micro-water and / or partial discharge detection of multiple points in the transformer bushing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transformer detection, and particularly relates to a transformer bushing multi-array optical fiber micro-water and ultrasonic partial discharge combined detection system. BACKGROUND

[0002] The high-voltage bushing is an important component of the outgoing line device of the super-high voltage transformer, and plays an important role in the safe operation of the super-high voltage transformer. The capacitor core of the high-voltage bushing has the characteristics of long axial insulation, thick radial insulation, and many built-in aluminum foil poles, and the on-line monitoring of the insulation state has always been a difficult problem in the industry. At present, the insulation monitoring of the high-voltage bushing mostly depends on offline preventive experiments in the actual operation and maintenance process, especially for the operation and maintenance of higher voltage grade bushings, there is a lack of real-time data monitoring, resulting in the operation state and insulation degradation degree of the high-voltage grade bushing being in an unknown state, and the operation and maintenance strategy lacking online monitoring data support.

[0003] The existing internal micro-water state monitoring of the bushing mainly relies on offline oil sample testing. For the detection of micro-water in the transformer bushing, the transformer oil is sampled, and the sampled sample is detected in the laboratory using chromatographic analysis method, Karl Fischer reagent method or coulomb method. These methods have high detection precision, and the detection lower limit can reach one part per million, but they do not have the ability to monitor the transformer bushing in real time.

[0004] The existing monitoring of the internal discharge state of the transformer bushing mostly relies on offline oil chromatographic monitoring. The online bushing end screen current monitoring changes the structure of the end screen directly grounded, and is easily affected by electromagnetic interference. The online monitoring of the internal discharge state of the bushing is not mature.

[0005] Several technologies for online monitoring of transformer bushings have been developed, particularly those based on fiber optic sensing. For example, patent application number 202210883056.0 discloses a fiber optic ultrasonic sensor for partial discharge of transformer bushings and a vibration and noise suppression system. This system includes a fiber optic ultrasonic sensor for partial discharge of transformer bushings mounted on a raised platform, a vibration and noise measuring device for transformer bushings, and a vibration compensation signal conversion and output device. The vibration and noise measuring device is connected to the vibration compensation signal conversion and output device, which is connected to the compensation signal generation layer of the fiber optic ultrasonic sensor for partial discharge of transformer bushings. The fiber optic ultrasonic sensor for partial discharge of transformer bushings and the vibration and noise suppression system provided by this invention induce reverse vibration, canceling out vibration and noise. This prevents the fiber optic ultrasonic sensor from acquiring local ultrasonic signals that are not aliased by noise signals, improving the signal-to-noise ratio and lowering the ultrasonic detection limit. The aforementioned existing technology can realize online monitoring of transformer bushing faults based on fiber optic sensing technology. However, due to the limitation of the laser's output wavelength, it can only monitor one type of fault signal and cannot simultaneously monitor partial discharge and micro-water. Summary of the Invention

[0006] To address at least one of the above technical problems, this invention provides a multi-element fiber optic micro-water and ultrasonic partial discharge joint detection system and method for transformer bushings, which can perform online detection of micro-water and partial discharge on bushings of high-voltage transformers above 110kV.

[0007] The first aspect of the present invention provides a multi-element fiber optic micro-water and ultrasonic partial discharge joint detection system for transformer bushings, comprising:

[0008] An adjustable laser source, which is configured to emit laser signals of different wavelengths according to settings;

[0009] A beam splitter is configured to split a single laser signal emitted by the tunable laser source into N laser signals, where N ≥ 2.

[0010] A fiber optic micro-water sensor, installed inside a transformer bushing, is configured to receive the laser signal output by the beam splitter to detect the micro-water content in the insulating oil inside the transformer bushing.

[0011] An optical fiber partial discharge ultrasonic sensor is disposed on the surface of the insulating capacitor core inside the transformer bushing and is configured to receive the laser signal output by the beam splitter to detect the discharge condition along the surface of the insulating capacitor core inside the transformer bushing.

[0012] Preferably, at least two fiber optic micro-water sensors are provided, which are disposed between the inner wall of the transformer bushing and the surface of the insulating capacitor core.

[0013] Preferably, in any of the above solutions, the optical fiber micro-water sensors are uniformly distributed about the transformer bushing axis.

[0014] Preferably, in any of the above solutions, the optical fiber partial discharge ultrasonic sensors are provided in at least two, and are arranged on the surface of the insulating capacitor core in the transformer bushing.

[0015] Preferably, in any of the above solutions, the optical fiber partial discharge ultrasonic sensors are arranged in an array on the surface of the insulating capacitor core in the transformer bushing.

[0016] Preferably, in any of the above solutions, the system further comprises an optical fiber feedthrough provided at the flange position of the transformer bushing, configured to transmit the laser signals split by the optical splitter from outside the transformer bushing to inside the transformer bushing, and / or transmit the reflected light signals of the optical fiber micro-water sensors and / or the reflected light signals of the optical fiber partial discharge ultrasonic sensors from inside the transformer bushing to outside the transformer bushing.

[0017] Preferably, in any of the above solutions, the transformer bushing is provided with a plurality of optical fibers, one end of each optical fiber is connected to one channel of the optical fiber feedthrough, and the other end is connected to an optical fiber micro-water sensor or an optical fiber partial discharge ultrasonic sensor.

[0018] Preferably, in any of the above solutions, the plurality of optical fibers are spirally arranged on the inner wall of the transformer bushing.

[0019] Preferably, in any of the above solutions, the system further comprises a coupler, an input end of the coupler is connected to the optical fiber micro-water sensors and the optical fiber partial discharge ultrasonic sensors through the feedthrough.

[0020] Preferably, in any of the above solutions, the system further comprises a photodetector, an input end of the photodetector is connected to an output end of the coupler, for converting the reflected light signals of the optical fiber micro-water sensors and / or the reflected light signals of the optical fiber partial discharge ultrasonic sensors into electrical signals and amplifying to a range that can be collected.

[0021] Preferably, in any of the above solutions, the adjustable laser source, the optical splitter, the optical fiber feedthrough, the optical fiber micro-water sensors and the optical fiber partial discharge ultrasonic sensors, the coupler, and the photodetector are sequentially connected through optical fibers.

[0022] Preferably, in any of the above solutions, the system further comprises a collection card, an input end of the collection card is connected to an output end of the photodetector, for collecting the amplified electrical signals of the photodetector.

[0023] Preferably, the system further comprises a processor connected to the output of the acquisition card, configured to receive the electrical signal acquired by the acquisition card and process the electrical signal to obtain a detection result.

[0024] Preferably, the processor is further configured to set the wavelength of the laser signal emitted by the adjustable laser source.

[0025] The second aspect of the present application provides a transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection method, which is realized by a transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection system, and comprises the following steps:

[0026] Step 1: set a working mode;

[0027] Step 2: according to the set working mode, the adjustable laser source emits a laser signal in a corresponding wavelength range to drive at least one of the optical fiber micro-water sensor and the optical fiber partial discharge ultrasonic sensor to work;

[0028] Step 3: process the signal fed back by the optical fiber micro-water sensor and / or the optical fiber partial discharge ultrasonic sensor to obtain a detection result.

[0029] Preferably, the working mode comprises a full detection mode, a micro-water detection mode, a partial discharge detection mode and a specific channel detection mode; in the full detection mode, the micro-water of the insulating oil in the transformer bushing and the surface discharge of the insulating capacitor core in the transformer bushing are detected simultaneously; in the micro-water detection mode, only the micro-water of the insulating oil in the transformer bushing is detected; in the partial discharge detection mode, only the surface discharge of the insulating capacitor core in the transformer bushing is detected; in the specific channel detection mode, only the optical fiber micro-water sensor and / or the optical fiber partial discharge ultrasonic sensor of the corresponding channel work to detect the micro-water of the insulating oil in the transformer bushing and / or the surface discharge of the insulating capacitor core in the transformer bushing.

[0030] Preferably, in the full detection mode, the wavelength range of the laser signal emitted by the adjustable laser source is a wavelength range that can make the optical fiber micro-water sensor and the optical fiber partial discharge ultrasonic sensor work simultaneously.

[0031] Preferably, in the micro-water detection mode, the wavelength range of the laser signal emitted by the adjustable laser source is a wavelength range that can only make the optical fiber micro-water sensor work.

[0032] Preferably, in the partial discharge detection mode, the wavelength range of the laser signal emitted by the adjustable laser source is a wavelength range that can only make the optical fiber partial discharge ultrasonic sensor work.

[0033] Preferably, in the specific channel detection mode, the wavelength range of the laser signal emitted by the adjustable laser source is a wavelength range that can enable the optical fiber micro-water sensor and / or the optical fiber partial discharge ultrasonic sensor of the corresponding channel to work.

[0034] Preferably, in step 3, the processing of the feedback signal includes separately processing the feedback signal of each optical fiber micro-water sensor and / or each optical fiber partial discharge ultrasonic sensor to obtain the detection result.

[0035] Preferably, in step 3, the processing of the feedback signal includes differentially processing the feedback signal of the optical fiber micro-water sensor.

[0036] Preferably, in step 3, the processing of the feedback signal includes differentially processing the feedback signal of the optical fiber partial discharge ultrasonic sensor.

[0037] The transformer bushing multi-array optical fiber micro-water and ultrasonic partial discharge combined detection system and the corresponding detection method have the following beneficial effects:

[0038] 1. By setting the working mode, at least one of the micro-water and / or partial discharge of the bushing of the high-voltage transformer above 110kV can be detected online. At the same time, the online detection of a specific channel can also be realized.

[0039] 2. The arrayed distributed optical fiber micro-water sensor and the optical fiber partial discharge ultrasonic sensor can realize the micro-water and / or partial discharge detection of multiple points in the transformer bushing.

[0040] 3. It is conducive to improving the operation and maintenance level of the transformer bushing and ensuring the safe and stable operation of the transformer bushing. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of a preferred embodiment of the transformer bushing multi-array optical fiber micro-water and ultrasonic partial discharge combined detection system according to the present application.

[0042] Figure 2 It is a sensor installation schematic diagram of the embodiment of the transformer bushing multi-array optical fiber micro-water and ultrasonic partial discharge combined detection system according to the present application. Figure 1

[0043] Figure 3 It is a fiber feedthrough installation schematic diagram of the embodiment of the transformer bushing multi-array optical fiber micro-water and ultrasonic partial discharge combined detection system according to the present application. Figure 1

[0044] Figure 4 ​​Figure 1 is a schematic diagram of the installation of the fiber feedthrough according to another embodiment of the multi-array optical fiber micro-water and ultrasonic partial discharge combined detection system for transformer bushings according to the present application.

[0045] Figure 5 Figure 2 is a schematic diagram of the installation of the sensor according to the embodiment of the multi-array optical fiber micro-water and ultrasonic partial discharge combined detection system for transformer bushings according to the present application. Figure 4

[0046] Figure 6 Figure 3 is a schematic diagram of the workflow of a preferred embodiment of the multi-array optical fiber micro-water and ultrasonic partial discharge combined detection method for transformer bushings according to the present application. DETAILED DESCRIPTION

[0047] In order to better understand the present application, the present application will be described in detail below in conjunction with specific embodiments.

[0048] Embodiment 1

[0049] As shown in Figure 1, a multi-array optical fiber micro-water and ultrasonic partial discharge combined detection system for transformer bushings includes: Figures 1 to 3 An adjustable laser source 10 configured to emit laser signals of different wavelengths according to settings;

[0050] A light splitter 11 configured to split one laser signal emitted by the adjustable laser source 10 into N laser signals, N≥2;

[0051] An optical fiber micro-water sensor 13 disposed in the transformer bushing and configured to receive the laser signal output by the light splitter 11 to detect the micro-water content in the insulating oil 21 in the transformer bushing;

[0052] An optical fiber partial discharge ultrasonic sensor 14 disposed on the surface of the insulating capacitor core 20 in the transformer bushing and configured to receive the laser signal output by the light splitter 11 to detect the surface discharge condition of the insulating capacitor core 20 in the transformer bushing.

[0053] The optical fiber micro-water sensor 13 is provided with N1, N1 is at least 2, and is disposed between the inner wall of the transformer bushing and the surface of the insulating capacitor core 20. The optical fiber partial discharge ultrasonic sensor 14 is provided with N2, N2 is at least 2, and is disposed on the surface of the insulating capacitor core 20 in the transformer bushing.

[0054] In this embodiment, as shown in Figure 1, the optical fiber micro-water sensor 13 is provided with four, namely a first optical fiber micro-water sensor 131, a second optical fiber micro-water sensor 132, a third optical fiber micro-water sensor 133, and a fourth optical fiber micro-water sensor 134 (see Figure 2).

[0055] Figure 2 In this embodiment, as shown in Figure 1, the optical fiber micro-water sensor 13 is provided with four, namely a first optical fiber micro-water sensor 131, a second optical fiber micro-water sensor 132, a third optical fiber micro-water sensor 133, and a fourth optical fiber micro-water sensor 134 (see Figure 2). Figure 2 ​​(Not shown in the image) Four fiber optic micro-water sensors are set at the tail end of the transformer bushing, between the inner wall of the transformer bushing and the surface of the insulating capacitor core 20, and the four fiber optic micro-water sensors are evenly distributed about the axis of the transformer bushing to detect the water deposited in the insulating oil 21 at the tail end of the transformer bushing.

[0056] In this embodiment, it is preferred that, as Figure 2 As shown, the fiber optic partial discharge ultrasonic sensor 14 is equipped with 9 ( Figure 2 The diagram shows a first fiber optic partial discharge ultrasonic sensor 141, a second fiber optic partial discharge ultrasonic sensor 142, a third fiber optic partial discharge ultrasonic sensor 143, a fourth fiber optic partial discharge ultrasonic sensor 144, a fifth fiber optic partial discharge ultrasonic sensor 145, and a sixth fiber optic partial discharge ultrasonic sensor 146. These nine fiber optic partial discharge ultrasonic sensors are arrayed along the surface of the insulating capacitor core 20 inside the transformer bushing. In this embodiment, every three fiber optic partial discharge ultrasonic sensors form a group, and they are uniformly arranged around a cross-section of the insulating capacitor core 20. In other embodiments, the fiber optic partial discharge ultrasonic sensors 14 can be arranged in other ways as needed, such as being placed at locations where partial discharge is likely to occur.

[0057] Preferably, in this embodiment, the system further includes an optical fiber feeder 12, such as... Figure 2 and Figure 3 As shown, the fiber optic feedthrough 12 is mounted on the flange 22 of the transformer bushing, penetrating both the inside and outside of the bushing. It is configured to transmit the laser signal split by the beam splitter 11 from the outside of the bushing to the inside, and / or to transmit the reflected light signal from the fiber optic micro-water sensor 13 and / or the reflected light signal from the fiber optic partial discharge ultrasonic sensor 14 from the inside of the bushing to the outside. Several optical fibers are spirally arranged on the inner wall of the bushing. One end of each spirally arranged fiber is connected to a channel of the fiber optic feedthrough 12, and the other end is connected to either a fiber optic micro-water sensor 13 or a fiber optic partial discharge ultrasonic sensor 14. Two fiber optic feedthroughs 12 are provided, symmetrically arranged on the flange 22 of the transformer bushing. Each fiber optic feedthrough 12 has multiple channels, which can be connected to one end of multiple optical fibers inside the bushing.

[0058] It should be noted that the spiral arranged optical fiber in the transformer bushing and the optical fiber micro water sensor 13 and the optical fiber partial discharge ultrasonic sensor 14 need to be pre-embedded, wherein the spiral arrangement of the optical fiber in the transformer bushing can effectively avoid the bending of the optical fiber and ensure the reliability of the optical fiber. The optical splitter 11 can divide one laser signal emitted by the adjustable laser source 10 into 2, 4, 8, 16, 32 or 64 laser signals according to the setting. Taking the above sensor setting mode as an example, the optical splitter 11 divides one laser signal into 16 laser signals, and 13 of them are selected to be connected with the pre-embedded optical fiber in the transformer bushing through the optical fiber feedthrough 12. It should be understood that the optical fiber feedthrough 12 should have at least 13 channels in total, and 13 optical fibers should be pre-embedded in the transformer bushing, each pre-embedded optical fiber connects one channel of the optical fiber feedthrough 12 with one optical fiber micro water sensor or one optical fiber partial discharge ultrasonic sensor. It should be understood that the number N of laser signals divided by the optical splitter should be greater than the sum of N1 and N2, and the number of the optical fiber feedthrough 12 should also be greater than the sum of N1 and N2.

[0059] In the embodiment, it is preferred that the system further comprises a coupler 15, an input end of the coupler 15 being connected with the optical fiber micro water sensor 13 and the optical fiber partial discharge ultrasonic sensor 14 through the feedthrough 12. The system further comprises a photodetector 16, an input end of the photodetector 16 being connected with an output end of the coupler 15, for converting the reflected light signal of the optical fiber micro water sensor 13 and / or the reflected light signal of the optical fiber partial discharge ultrasonic sensor 14 into an electrical signal and amplifying it to a range that can be collected.

[0060] It should be understood that the adjustable laser source 10, the optical splitter 11, the optical fiber feedthrough 12, the optical fiber micro water sensor 13 or the optical fiber partial discharge ultrasonic sensor 14, the coupler 15 and the photodetector 16 are sequentially connected through optical fibers.

[0061] In the embodiment, it is preferred that the system further comprises a collection card 17, an input end of the collection card 17 being connected with an output end of the photodetector 16, for collecting the electrical signal amplified by the photodetector 16. The system further comprises a processor 18, the processor 18 being connected with an output end of the collection card 17, for receiving the electrical signal collected by the collection card 17 and processing the electrical signal to obtain a detection result. The processor 18 is also used for setting the wavelength of the laser signal emitted by the adjustable laser source 1.

[0062] The processor 18 can be a general computer, industrial computer, server, etc. In the embodiment, preferably, the processor 18 is a general computer with Labview interface, and has functions of channel setting, acquisition setting, trigger setting, buffer and data transmission setting, waveform display, data storage, etc.

[0063] It should be noted that, Figure 2 and Figure 3 Only the parts of the transformer bushing related to the present application are shown in the drawings, and for the parts not shown, the specific structure of the transformer bushing in the prior art can be referred to for understanding.

[0064] Embodiment 2

[0065] The embodiment is similar to Embodiment 1, except that in the embodiment, preferably, as shown in Figure 4 and Figure 5 four fiber feedthroughs are symmetrically arranged on the flange 22, which are, in clockwise direction, a first fiber feedthrough 121, a second fiber feedthrough 122, a third fiber feedthrough 123 and a fourth fiber feedthrough 124. The first fiber feedthrough 121 and the third fiber feedthrough 123 are each provided with two channels, and the second fiber feedthrough 122 and the fourth fiber feedthrough 124 are each provided with only one channel. A first fiber micro-water sensor 131 is connected to the first channel of the first fiber feedthrough 121 and arranged at a position close to the flange 22; a second fiber micro-water sensor 132 is connected to the second channel of the first fiber feedthrough 121 and arranged at a position at the tail end of the transformer bushing; a third fiber micro-water sensor 133 is connected to the first channel of the third fiber feedthrough 123 and arranged at a position close to the flange 22; and a fourth fiber micro-water sensor 134 is connected to the second channel of the third fiber feedthrough 123 and arranged at a position at the tail end of the transformer bushing. The fiber partial discharge ultrasonic sensor 14 is provided with two, which are a first fiber partial discharge ultrasonic sensor 141 and a second fiber partial discharge ultrasonic sensor 142. The first fiber partial discharge ultrasonic sensor 141 is connected to the channel of the second fiber feedthrough 122 and arranged at a position close to the flange 22, and the second fiber partial discharge ultrasonic sensor 142 is connected to the channel of the fourth fiber feedthrough 124 and arranged at a position close to the flange 22.

[0066] In this embodiment, it is preferred that the optical fiber and the optical fiber micro-water sensor 13 and the optical fiber partial discharge ultrasonic sensor 14 inside the transformer bushing are installed in a post-installation manner. During installation, the optical fiber micro-water sensor and the optical fiber partial discharge ultrasonic sensor are first connected to the optical fiber, and then the optical fiber micro-water sensor and the optical fiber partial discharge ultrasonic sensor connected to the optical fiber are passed through the corresponding channels of the optical fiber feedthrough, and the position of the sensor in the transformer bushing is controlled by controlling the length of the optical fiber entering.

[0067] It should be noted that attention must be paid to the sealing of the fiber optic feeder channel to ensure that the insulating oil inside the transformer bushing does not leak and does not change the insulation of the transformer bushing.

[0068] It should be noted that, Figure 4 and Figure 5 Only the components of the transformer bushing relevant to this application are shown. For the parts not shown, please refer to the specific structure of the transformer bushing in the prior art for understanding.

[0069] Example 3

[0070] like Figure 6 As shown, a method for joint detection of micro-water and ultrasonic partial discharge in transformer bushings using multi-element fiber optic cable is implemented through the aforementioned joint detection system, comprising:

[0071] Step 1: Set the working mode;

[0072] Step 2: According to the set working mode, the adjustable laser source emits a laser signal within the corresponding wavelength range to drive at least one of the fiber optic micro water sensor and fiber optic partial discharge ultrasonic sensor to work.

[0073] Step 3: Process the signals fed back by the fiber optic micro-water sensor and / or fiber optic partial discharge ultrasonic sensor to obtain the detection results.

[0074] In this embodiment, preferably, the operating modes include a full detection mode, a micro-water detection mode, a partial discharge detection mode, and a specific channel detection mode. In the full detection mode, micro-water in the insulating oil inside the transformer bushing and surface discharge of the insulating capacitor core inside the transformer bushing are detected simultaneously. In the micro-water detection mode, only micro-water in the insulating oil inside the transformer bushing is detected. In the partial discharge detection mode, only surface discharge of the insulating capacitor core inside the transformer bushing is detected. In the specific channel detection mode, only the fiber optic micro-water sensor and / or fiber optic partial discharge ultrasonic sensor of the corresponding channel works to detect micro-water in the insulating oil inside the transformer bushing and / or surface discharge of the insulating capacitor core inside the transformer bushing.

[0075] In the full detection mode, the wavelength range of the laser signal emitted by the adjustable laser source 10 is a wavelength range that can make the fiber micro-water sensor 13 and the fiber partial discharge ultrasonic sensor 14 work simultaneously. In the micro-water detection mode, the wavelength range of the laser signal emitted by the adjustable laser source 10 is a wavelength range that can only make the fiber micro-water sensor 13 work. In the partial discharge detection mode, the wavelength range of the laser signal emitted by the adjustable laser source 10 is a wavelength range that can only make the fiber partial discharge ultrasonic sensor 14 work. In the specific channel detection mode, the wavelength range of the laser signal emitted by the adjustable laser source 10 is a wavelength range that can make the fiber micro-water sensor 13 and / or the fiber partial discharge ultrasonic sensor 14 of the corresponding channel work.

[0076] For example, if the working wavelength range of the fiber micro-water sensor 13 is 1350nm-1550nm and the working wavelength range of the fiber partial discharge ultrasonic sensor 14 is 1450nm-1650nm, in the full detection mode, the wavelength range of the laser signal emitted by the adjustable laser source 10 is 1450nm-1550nm; in the micro-water detection mode, the wavelength range of the laser signal emitted by the adjustable laser source 10 is 1350nm-1450nm; in the partial discharge detection mode, the wavelength range of the laser signal emitted by the adjustable laser source 10 is 1550nm-1650nm; in the specific channel detection mode, according to the selected channel being connected to the fiber micro-water sensor 13 and / or the fiber partial discharge ultrasonic sensor 14, the wavelength range of the laser signal emitted by the adjustable laser source 10 is determined.

[0077] In this embodiment, it is preferred that in step 3, the processing of the feedback signal includes separately processing the feedback signal of each fiber micro-water sensor 13 and / or each fiber partial discharge ultrasonic sensor 14 to obtain a detection result. The detection result includes at least one of whether the insulating oil contains micro-water, the content of the micro-water, the location of the micro-water, whether there is partial discharge, the location of the partial discharge, the degree of the partial discharge, etc.

[0078] Embodiment 4

[0079] This embodiment is similar to Embodiment 1 or 2, except that in this embodiment, it is preferred that the fiber micro-water sensor is not only arranged at the tail of the transformer bushing, but also arranged at other positions where micro-water is prone to occur in the insulating oil to perform micro-water detection at the corresponding positions, including detection of at least one of free water, dissolved water, and emulsified water.

[0080] Embodiment 5

[0081] This embodiment is similar to embodiment 1 or 2, except that, in this embodiment, it is preferred that the fiber optic micro-water sensor is only installed at the flange 22 position to detect micro-water at the corresponding position.

[0082] Example 6

[0083] This embodiment is similar to Embodiment 1 or 2, except that, preferably, several optical fibers, several optical fiber micro-water sensors, and / or several optical fiber partial discharge ultrasonic sensors are pre-embedded inside the transformer bushing. Each optical fiber micro-water sensor and each optical fiber partial discharge ultrasonic sensor is connected to one end of an optical fiber, and the other end of the optical fiber is connected to a channel of an optical fiber feedthrough. Additional channels are reserved on the optical fiber feedthrough for subsequent installation of the optical fiber micro-water sensors and / or optical fiber partial discharge ultrasonic sensors. The positions of the optical fiber micro-water sensors and / or optical fiber partial discharge ultrasonic sensors inside the transformer bushing can be set as needed.

[0084] Example 7

[0085] This embodiment is similar to Embodiment 2, except that, in this embodiment, preferably, the processing of the feedback signal in step 3 includes: differential processing of the signal fed back by the fiber optic micro-water sensor, and / or differential processing of the signal fed back by the fiber optic partial discharge ultrasonic sensor.

[0086] by Figure 2 The sensor setup shown is illustrated below. For a fiber optic micro-water sensor, differential processing is performed on the signals collected by two opposing fiber optic micro-water sensors to obtain the difference between the two signals, thus yielding the detection result. For a fiber optic partial discharge ultrasonic sensor, differential processing is performed on the signals collected by two adjacent fiber optic partial discharge ultrasonic sensors to obtain the detection result. Differential processing can detect minute differences between the two signals, thereby improving the accuracy of the detection results.

[0087] It should be noted that when performing differential processing on the acquired signals, other methods can also be used, such as using one signal as a reference and performing differential processing between the other signals and the reference signal.

[0088] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the foregoing embodiments have described the present invention in detail, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and these substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection system, comprising: an adjustable laser source configured to emit laser signals of different wavelengths according to a set operating mode; a beam splitter configured to divide one laser signal emitted by the adjustable laser source into N laser signals, N≥2; characterized in that: further comprising: an optical fiber feedthrough configured to transmit the laser signals divided by the beam splitter from outside the transformer bushing to inside the transformer bushing, and to transmit the reflected light signals of the optical fiber micro-water sensor and / or the reflected light signals of the optical fiber partial discharge ultrasonic sensor from inside the transformer bushing to outside the transformer bushing; a plurality of optical fibers are provided inside the transformer bushing, one end of each optical fiber is connected to one channel of the optical fiber feedthrough, and the other end is connected to an optical fiber micro-water sensor or an optical fiber partial discharge ultrasonic sensor, the plurality of optical fibers are spirally arranged on the inner wall of the transformer bushing; an optical fiber micro-water sensor configured to receive the laser signals output by the beam splitter to detect the micro-water content in the insulating oil inside the transformer bushing; an optical fiber partial discharge ultrasonic sensor configured to receive the laser signals output by the beam splitter to detect the partial discharge condition of the insulating capacitor core surface inside the transformer bushing; the operating mode includes a full detection mode, a micro-water detection mode, a partial discharge detection mode, and a specific channel detection mode; in the full detection mode, the wavelength range of the laser signals emitted by the adjustable laser source is a wavelength range that can enable the optical fiber micro-water sensor and the optical fiber partial discharge ultrasonic sensor to work simultaneously; in the micro-water detection mode, the wavelength range of the laser signals emitted by the adjustable laser source is a wavelength range that can only enable the optical fiber micro-water sensor to work; in the partial discharge detection mode, the wavelength range of the laser signals emitted by the adjustable laser source is a wavelength range that can only enable the optical fiber partial discharge ultrasonic sensor to work; in the specific channel detection mode, the wavelength range of the laser signals emitted by the adjustable laser source is a wavelength range that can enable the optical fiber micro-water sensor and / or the optical fiber partial discharge ultrasonic sensor of the corresponding channel to work. The optical fiber micro-water sensor is provided with at least two, which is arranged between the inner wall of the transformer bushing and the insulating capacitor core surface. The optical fiber partial discharge ultrasonic sensor is provided with at least two, which is arranged on the insulating capacitor core surface inside the transformer bushing. Further comprising a coupler and a photodetector, the input end of the coupler is connected with the optical fiber micro-water sensor and the optical fiber partial discharge ultrasonic sensor through the feedthrough; the input end of the photodetector is connected with the output end of the coupler, for converting the reflected light signals of the optical fiber micro-water sensor and / or the reflected light signals of the optical fiber partial discharge ultrasonic sensor into electrical signals and amplifying to a range that can be collected. ​ ​ ​ ​ 2. The transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection system of claim 1, wherein: ​ 3. The transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection system of claim 1, wherein: ​ 4. The transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection system of claim 3, wherein: ​ 5. The transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection system of claim 4, wherein: The tunable laser source, the optical splitter, the fiber feedthrough, the fiber micro-water sensor or the fiber partial discharge ultrasonic sensor, the coupler, and the photodetector are connected in sequence through optical fibers.

6. A transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection method, characterized in that: The transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection system according to any one of claims 1-5 is implemented, comprising: Step 1: setting the working mode; Step 2: according to the set working mode, the tunable laser source emits laser signals in the corresponding wavelength range to drive at least one of the fiber micro-water sensor and the fiber partial discharge ultrasonic sensor to work; Step 3: processing the signals fed back by the fiber micro-water sensor and / or the fiber partial discharge ultrasonic sensor to obtain the detection result; The working mode includes full detection mode, micro-water detection mode, partial discharge detection mode, and specific channel detection mode; in the full detection mode, the wavelength range of the laser signal emitted by the tunable laser source is a wavelength range that can make the fiber micro-water sensor and the fiber partial discharge ultrasonic sensor work simultaneously; in the micro-water detection mode, the wavelength range of the laser signal emitted by the tunable laser source is a wavelength range that can only make the fiber micro-water sensor work; in the partial discharge detection mode, the wavelength range of the laser signal emitted by the tunable laser source is a wavelength range that can only make the fiber partial discharge ultrasonic sensor work; in the specific channel detection mode, the wavelength range of the laser signal emitted by the tunable laser source is a wavelength range that can make the fiber micro-water sensor and / or the fiber partial discharge ultrasonic sensor of the corresponding channel work.

7. The transformer bushing multi-element optical fiber micro-water and ultrasonic partial discharge combined detection method of claim 6, wherein: In the full detection mode, the micro-water of the insulating oil in the transformer bushing and the surface discharge of the insulating capacitor core in the transformer bushing are detected simultaneously; in the micro-water detection mode, only the micro-water of the insulating oil in the transformer bushing is detected; in the partial discharge detection mode, only the surface discharge of the insulating capacitor core in the transformer bushing is detected; in the specific channel detection mode, only the fiber micro-water sensor and / or the fiber partial discharge ultrasonic sensor of the corresponding channel work to detect the micro-water of the insulating oil in the transformer bushing and / or the surface discharge of the insulating capacitor core in the transformer bushing.

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