An ultrasonic sensor and an ultrasonic detection device

Abstract

The application discloses an ultrasonic sensor and an ultrasonic detection device, wherein the ultrasonic sensor comprises a flange body, an annular groove, a single-mode optical fiber, an optical fiber channel, a protection ring and a plurality of bolt holes; the annular groove is arranged on the flange body, the single-mode optical fiber is uniformly wound in the annular groove to form a sensing optical fiber ring; the protection ring is detachably arranged at a groove opening of the annular groove; the plurality of bolt holes are arranged at the periphery of the flange body and used for fixing the flange body on a transformer by cooperating with fixing bolts; one end of the optical fiber channel is communicated with the annular groove, and the other end of the optical fiber channel extends outside the flange body, and the optical fiber channel is used for leading a section of the single-mode optical fiber in the sensing optical fiber ring in the annular groove out of the flange body. The protection ring is detachably arranged at the groove opening of the annular groove, so that the convenience of replacing the sensing optical fiber can be effectively improved, and the maintenance difficulty of the ultrasonic sensor is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power systems, in particular to an ultrasonic sensor and an ultrasonic detection device. BACKGROUND

[0002] The transformer in the power grid bears the function of power conversion and transmission, is the key node supporting the power grid, and plays a very important role in the operation of the power grid. Large power transformers are mostly oil-immersed power transformers, and their insulation structure is mainly a solid-oil insulation structure composed of oil, paper, paperboard and other solid insulations. The high-voltage outlet position of the transformer is relatively weak in insulation due to the large field strength, and the connection between the winding outlet and the bushing is relatively weak in insulation. Under the action of the electric field, this area is prone to partial discharge, which seriously affects the safe and stable operation of the transformer. Accurate detection of the partial discharge condition of the high-voltage outlet position of the transformer can timely discover potential insulation defects and other faults inside the transformer, realize fault early warning, and improve the stability of the transformer operation. Ultrasonic signals are generated during the partial discharge process, and the measurement of transformer partial discharge by using an ultrasonic sensor has strong anti-electromagnetic interference capability.

[0003] The existing ultrasonic sensor needs to open the transformer body for replacement of the sensing optical fiber when replacing the sensing optical fiber, resulting in difficult maintenance of the existing ultrasonic sensor. SUMMARY

[0004] The present application provides an ultrasonic sensor and an ultrasonic detection device to solve the technical problem that the existing ultrasonic sensor needs to open the transformer body for replacement of the sensing optical fiber when replacing the sensing optical fiber, resulting in difficult maintenance of the existing ultrasonic sensor.

[0005] One embodiment of the present application provides an ultrasonic sensor, comprising:

[0006] a flange body, an annular groove, a single-mode optical fiber, an optical fiber channel, a protective ring and a plurality of bolt holes;

[0007] The annular groove is arranged on the flange body, and the single-mode optical fibers are uniformly wound in the annular groove to form a sensing optical fiber ring;

[0008] The protective ring is detachably arranged at the slot opening of the annular groove;

[0009] The plurality of bolt holes are arranged at the periphery of the flange body and used for fixing the flange body on the transformer by cooperating with fixing bolts;

[0010] One end of the optical fiber channel is in communication with the annular groove, and the other end of the optical fiber channel extends out of the flange body, and the optical fiber channel is used for leading a section of single-mode optical fiber of the sensing optical fiber ring in the annular groove out of the flange body.

[0011] Further, the ultrasonic sensor further comprises a fiber joint and a fiber protection cover.

[0012] The fiber joint is arranged at one end of the fiber channel extending outside the flange body, the fiber protection cover is sleeved on the fiber joint, and one end of the single-mode optical fiber extending out of the sensing fiber ring is fused on the fiber joint.

[0013] Further, the upper part of the annular groove is provided with an internal thread, and the outer part of the fiber protection cover is provided with an external thread for rotationally fixing the internal thread.

[0014] Further, the sensing fiber ring and the protection ring are filled with an ultrasonic coupling agent.

[0015] Further, the single-mode optical fiber wound in the annular groove is bonded by using an ultrasonic coupling glue to form the sensing fiber ring.

[0016] One embodiment of the present application provides an ultrasonic detection device, comprising:

[0017] a first coupler, a reference optical fiber, a second coupler, a photodetector, a laser and the above ultrasonic sensor;

[0018] The output end of the laser is connected with the input end of the first coupler, the first output end of the first coupler is connected with the input end of the sensing fiber ring, the second output end of the first coupler is connected with the input end of the second coupler, the output end of the sensing fiber ring is connected with the input end of the second coupler, and the output end of the second coupler is connected with the input end of the photodetector.

[0019] Further, the photodetector is provided with a liquid nitrogen circulating cooling system, which is used for ensuring that the photosensitive element in the photodetector is in a preset temperature range.

[0020] The protection ring is detachably arranged at the slot of the annular groove, and the protection ring can encapsulate and protect the sensing fiber ring in the annular groove, so that the ultrasonic sensor can work normally without the pollution of external pollutants along the optical fiber, and the sensing fiber ring in the annular groove can be conveniently taken out and replaced by detaching the protection ring when the sensing fiber ring is replaced, so that the convenience of replacing the sensing fiber can be effectively improved, and the maintenance difficulty of the ultrasonic sensor can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic view of an ultrasonic sensor provided by the embodiment of the present application;

[0022] Figure 2 This is another structural schematic diagram of an ultrasonic sensor provided in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of an ultrasonic testing device provided in an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more.

[0026] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0027] Please see Figures 1-2 One embodiment of the present invention provides an ultrasonic sensor, comprising:

[0028] Flange body 101, annular groove 105, single-mode optical fiber, optical fiber channel 106, protective ring 104 and several bolt holes 102;

[0029] An annular groove 105 is provided on the flange body 101, and a single-mode optical fiber is uniformly wound in the annular groove 105 to form a sensing optical fiber ring 103.

[0030] In this embodiment of the invention, the annular groove 105 is used to place a uniformly wound single-mode optical fiber, so that the single-mode optical fiber forms a sensing fiber ring 103 in the annular groove 105.

[0031] In a specific embodiment, a single-mode optical fiber with a length of 700 m is uniformly wound in the annular groove 105 with a groove depth of 15 mm and a groove width of 15 mm to form the sensing optical fiber ring 103. It can be understood that the length of the single-mode optical fiber can be selected according to actual needs, and the groove depth and groove width of the annular groove 105 can be set. In the process of winding the single-mode optical fiber, the ultrasonic coupling agent is used to bond the single-mode optical fiber. The specific winding method is: winding layer by layer from the inner circle to the outer circle, and 0.5 mm thick ultrasonic coupling agent is applied after each layer is wound. After the formed sensing optical fiber ring 103 structure is stably maintained in a ring shape without external force, the ultrasonic coupling agent is filled into the gap between the annular groove 105 and the sensing optical fiber ring 103, and the filling coupling of the ultrasonic coupling agent is 2.3 mm.

[0032] The protective ring 104 is detachably arranged at the groove opening of the annular groove 105;

[0033] After the filling of the ultrasonic coupling agent is completed, the protective ring 104 is detachably arranged at the groove opening of the annular groove 105. The protective ring 104 can encapsulate and protect the sensing optical fiber ring 103 inside the annular groove 105, which can effectively prevent external pollutants from entering the ultrasonic sensor along the optical fiber to cause the ultrasonic sensor to malfunction. When the sensing optical fiber ring 103 is replaced, the sensing optical fiber ring inside the annular groove 105 can be conveniently taken out and replaced by detaching the protective ring 104, thereby effectively improving the convenience of replacing the sensing optical fiber and facilitating the maintenance difficulty of the ultrasonic sensor. In the embodiment of the present application, the ultrasonic coupling agent inside the annular groove 105 is a semi-liquid oily preparation without adhesive ability, but has a strong ultrasonic coupling coefficient, good adhesion and insulation performance, which can effectively avoid affecting the insulation performance of the transformer when the ultrasonic sensor is used for ultrasonic detection of the transformer, and also can prevent the flange body 101 and the retainer ring in contact with the ultrasonic coupling agent from electrochemical corrosion, thereby effectively improving the working stability of the ultrasonic sensor.

[0034] A plurality of bolt holes 102 are arranged on the periphery of the flange body 101 for fixing the flange body 101 on the transformer by cooperating with the fixing bolts;

[0035] In the embodiment of the present application, eight screw holes are arranged on the periphery of the flange body 101. The diameter of each bolt hole 102 can be 10 mm. The bolt hole 102 cooperates with the fixing bolt to mount the flange body 101 to the transformer body, thereby enabling ultrasonic detection of the transformer.

[0036] One end of the fiber channel 106 is communicated with the annular groove 105, and the other end of the fiber channel 106 extends outside the flange body 101, and the fiber channel 106 is used to lead the tail fiber 109 of one end of the sensing fiber ring 103 in the annular groove 105 to outside the flange body 101.

[0037] In the embodiment of the present application, the diameter of the fiber channel 106 is 10 mm, and one end of the fiber channel 106 is communicated with the annular groove 105, and the distance between the communication position and the bottom of the annular groove 105 is 11 mm.

[0038] In one embodiment, the ultrasonic sensor further comprises a fiber joint 108 and a fiber protection cover.

[0039] The fiber joint 108 is arranged at the end of the fiber channel 106 extending outside the flange body 101, the fiber protection cover is sleeved on the fiber joint 108, and the tail fiber 109 extending from the sensing fiber ring 103 is fused to the fiber joint 108.

[0040] In the embodiment of the present application, by sleeving the fiber protection cover on the fiber joint 108, the fiber joint 108 and the single-mode optical fiber connected with the fiber joint 108 can be effectively prevented from being contaminated, thereby effectively improving the reliability of ultrasonic detection.

[0041] In one embodiment, the upper part of the annular groove 105 is provided with an internal thread, and the outer part of the fiber protection cover is provided with an external thread for rotating fixation with the internal thread.

[0042] In the embodiment of the present application, for the annular groove 105 with a diameter of 15 mm, an internal thread with a pitch of 1 μm is arranged at the upper part of 5 mm of the annular groove 105, and the external thread of the fiber protection cover is used to fix the sensing fiber ring 103 inside by screwing, thereby effectively ensuring the good performance of the seal. In the embodiment of the present application, the thickness of the protection ring 104 is 4.8 mm, and the teeth with a depth of 1.5 mm are arranged on the surface of the protection ring 104, so as to facilitate the fastening of the protection ring 104.

[0043] Optionally, before the protection ring 104 is detachably installed in the annular groove 105, the ultrasonic coupling agent with a thickness of 2.3 mm is applied on the top surface of the fiber ring, so as to fill the gap between the sensing fiber ring 103 and the fiber protection ring 104, and stabilize the position of the sensing fiber ring 103 inside the annular groove 105, thereby effectively improving the sensitivity of ultrasonic detection.

[0044] The embodiment of the present application has the following beneficial effects:

[0045] The protective ring 104 is detachably arranged at the slot of the annular groove 105, the protective ring 104 can encapsulate and protect the sensing optical fiber ring 103 inside the annular groove 105, and effectively avoid external pollutants from entering the ultrasonic sensor along the optical fiber, so that the ultrasonic sensor cannot work normally, and when the sensing optical fiber ring 103 is replaced, the sensing optical fiber ring inside the annular groove 105 can be conveniently taken out and replaced by detaching the protective ring 104, so that the convenience of replacing the sensing optical fiber can be effectively improved, and the maintenance difficulty of the ultrasonic sensor is reduced.

[0046] Further, the sensing optical fiber ring is embedded in the flange plate, and the sensing optical fiber ring is solidified and encapsulated by using ultrasonic coupling glue and ultrasonic coupling agent, the ultrasonic detection is performed on the sensing optical fiber ring close to the high-voltage outlet position of the transformer, and the ultrasonic detection sensitivity of the local discharge of the transformer can be effectively improved.

[0047] Please refer to Figure 3 An embodiment of the present application provides an ultrasonic detection device, which comprises:

[0048] The first coupler 111, the reference optical fiber 113, the second coupler 112, the photodetector 114, the laser 110 and the ultrasonic sensor are connected.

[0049] The output end of the laser 110 is connected with the input end of the first coupler 111, the first output end of the first coupler 111 is connected with the input end of the sensing optical fiber ring 103, the second output end of the first coupler 111 is connected with the input end of the second coupler 112, the output end of the sensing optical fiber ring 103 is connected with the input end of the second coupler 112, and the output end of the second coupler 112 is connected with the input end of the photodetector 114.

[0050] The embodiment of the present application can be applied to the ultrasonic detection of partial discharge of a transformer by a Mach-Zehnder interference optical path, and the working principle is as follows: the laser 110 emits narrow-band light which is divided into two light signals by the first coupler 111, one of which is transmitted into the sensing optical fiber ring 103, and the other is transmitted into the second coupler 112 through the reference optical fiber 113, and the two light signals are subjected to optical interference in the second coupler 112 after passing through the sensing optical fiber ring 103 and the reference optical fiber 113, and the interference light is converted into an electric signal by the photodetector 114. When the ultrasonic wave of the partial discharge of the transformer acts on the sensing optical fiber ring 103, the phase of the light in the sensing optical fiber is modulated, so that the light phase difference of the sensing optical fiber relative to the reference optical fiber 113 is changed. Since the intensity of the interference signal of the two light beams has a correlation with the phase difference of the two light beams, the change of the intensity of the interference light detected by the photodetector 114 can reflect the phase change, so that the waveform of the ultrasonic signal of the partial discharge is obtained. According to the repetition frequency, amplitude and spectrum of the ultrasonic signal, the intensity and characteristics of the partial discharge of the transformer can be analyzed, so that the ultrasonic detection can be accurately performed.

[0051] In one embodiment, the photodetector 114 is provided with a liquid nitrogen circulating cooling system for ensuring that the photosensitive element in the photodetector 114 is in a preset temperature range.

[0052] The liquid nitrogen circulating cooling system of the embodiment of the present application is used to ensure that the photosensitive element in the photodetector 114 is below 120 DEG C, so that the low-frequency noise introduced by the temperature noise can be eliminated, and the sensitivity and accuracy of the ultrasonic detection are improved.

[0053] The above is the preferred embodiment of the present application, and it should be pointed out that, for those skilled in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements are also regarded as the protection scope of the present application.

Claims

1. An ultrasonic sensor, characterized by It comprises a flange body, an annular groove, single-mode optical fibers, an optical fiber channel, a protective ring, an optical fiber joint, an optical fiber protective cover and a plurality of bolt holes. The annular groove is arranged on the flange body, and the single-mode optical fibers are uniformly wound in the annular groove to form a sensing optical fiber ring; specifically, a single-mode optical fiber with a length of 700 m is uniformly wound in an annular groove with a groove depth of 15 mm and a groove width of 15 mm to form a sensing optical fiber ring. The protective ring is detachably arranged at the groove opening of the annular groove, and the top surface of the sensing optical fiber ring is coated with 2.3 mm thick ultrasonic coupling agent to fill the gap between the sensing optical fiber ring and the protective ring. A plurality of bolt holes are arranged on the periphery of the flange body for fixing the flange body on the transformer by cooperating with fixing bolts. One end of the optical fiber channel is in communication with the annular groove, and the other end of the optical fiber channel extends outside the flange body, and the optical fiber channel is used to lead a section of single-mode optical fiber of the sensing optical fiber ring in the annular groove out of the flange body. The optical fiber joint is arranged at one end of the optical fiber channel extending outside the flange body, the optical fiber protective cover is sleeved on the optical fiber joint, and the single-mode optical fiber extending out of the sensing optical fiber ring is fused to the optical fiber joint. The upper part of the annular groove is provided with an internal thread, and the outer part of the optical fiber protective cover is provided with an external thread for rotating fixation with the internal thread. The sensing optical fiber ring and the protective ring are filled with ultrasonic coupling agent.

2. The ultrasonic sensor of claim 1, wherein, The single-mode optical fibers wound in the annular groove are bonded by ultrasonic coupling agent to form a sensing optical fiber ring.

3. The ultrasonic sensor of claim 1, wherein, It comprises a first coupler, a reference optical fiber, a second coupler, a photodetector, a laser and an ultrasonic sensor as claimed in any one of claims 1-3.

4. An ultrasonic testing apparatus characterized by comprising: The output end of the laser is connected with the input end of the first coupler, the first output end of the first coupler is connected with the input end of the sensing optical fiber ring, the second output end of the first coupler is connected with the input end of the second coupler, the output end of the sensing optical fiber ring is connected with the input end of the second coupler, and the output end of the second coupler is connected with the input end of the photodetector. The photodetector is provided with a liquid nitrogen circulating cooling system for ensuring that the photosensitive element in the photodetector is in a preset temperature range. ​ 5. The ultrasonic testing apparatus of claim 4, wherein, ​

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