Optical fiber ultrasonic sensor for GIS partial discharge monitoring

Abstract

The utility model belongs to the technical field of GIS partial discharge detection, and particularly relates to an optical fiber ultrasonic sensor for GIS partial discharge monitoring, which comprises a GIS cover plate, the GIS cover plate comprises a first end face and a second end face, the first end face is provided with an annular groove, and an ultrasonic sensing optical fiber is fixed in the annular groove. The two ends of the ultrasonic sensing optical fiber are connected with a first optical fiber connector and a second optical fiber connector respectively, sensibilization elements are arranged between the first optical fiber connector and the end of the ultrasonic sensing optical fiber and between the second optical fiber connector and the end of the ultrasonic sensing optical fiber, the first optical fiber connector and the second optical fiber connector are fixed to a GIS cover plate, and the first optical fiber connector is used for injecting optical signals into the ultrasonic sensing optical fiber. The second optical fiber connector is used for transmitting the optical signal passing through the ultrasonic induction optical fiber to the detection device; the technical problems that an existing ultrasonic sensor is not embedded into a GIS body, the sensitivity is poor, and the partial discharge detection accuracy is low are solved.

Description

Technical Field

[0001] This utility model belongs to the field of GIS partial discharge detection technology, specifically relating to an optical fiber ultrasonic sensor for GIS partial discharge monitoring. Background Technology

[0002] Gas-insulated switchgear (GIS) houses circuit breakers and disconnectors in substations within a metal enclosure, using SF6 gas of a specific concentration as the insulating medium. It boasts significant advantages such as high operational reliability, long maintenance cycles, and small footprint, making it widely used in modern power systems. Despite these advantages, GIS inevitably suffers from insulation defects during manufacturing, storage and logistics, installation, and natural degradation. These defects can lead to excessively high electric field strengths in certain areas, exceeding the breakdown field strength of the insulating medium, resulting in partial discharge. Partial discharge is both a characteristic quantity of GIS insulation condition and a major cause of insulation degradation. Detecting partial discharge allows for the timely detection of insulation defects within GIS equipment, preventing sudden insulation breakdown accidents. This is crucial for ensuring the safe and stable operation of GIS equipment.

[0003] Among various methods for detecting partial discharge defects, ultrasonic testing has the advantage of strong resistance to electromagnetic interference, making it highly suitable for detecting partial discharge signals in GIS equipment. Its basic principle is to detect the ultrasonic signals generated by partial discharge defects to reflect the internal discharge situation of the GIS equipment. Traditional ultrasonic testing mainly uses piezoelectric transducers (PZT) sensors. These sensors have low sensitivity, and are typically attached to the metal casing of the GIS during detection. Due to the complex internal structure of GIS equipment, the ultrasonic signals detected by the piezoelectric transducers propagate from the partial discharge source through the gas medium to the metal casing. However, the insulating SF6 gas has a high absorption rate for sound waves, resulting in severe sound wave attenuation. The ultrasonic signal intensity transmitted to the metal casing is often very low, leading to low accuracy in partial discharge detection. Utility Model Content

[0004] The purpose of this invention is to provide a fiber optic ultrasonic sensor for GIS partial discharge monitoring, so as to solve the technical problems of poor sensitivity and low accuracy of partial discharge detection in existing sensors.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0006] A fiber optic ultrasonic sensor for partial discharge monitoring in GIS includes a GIS cover plate. The GIS cover plate has a first end face and a second end face. An annular groove is provided on the first end face, and an ultrasonic sensing fiber is fixed in the annular groove. The two ends of the ultrasonic sensing fiber are respectively connected to a first fiber connector and a second fiber connector. A sensitivity-enhancing element is provided between the first fiber connector, the second fiber connector and the end of the ultrasonic sensing fiber. The first fiber connector and the second fiber connector are fixed on the GIS cover plate. The first fiber connector is used to inject an optical signal into the ultrasonic sensing fiber, and the second fiber connector is used to transmit the optical signal passing through the ultrasonic sensing fiber to a detection device.

[0007] Furthermore, the first end face of the GIS cover plate is also provided with a cable outlet box, and a bracket is provided inside the cable outlet box, with the first optical fiber connector and the second optical fiber connector fixed on the bracket.

[0008] Furthermore, the ultrasonic sensing fiber is made of 100 meters of ordinary single-mode fiber or special multi-core fiber that is not sensitive to bending and is tightly wound in a ring, and is fixed in the ring groove by casting epoxy resin.

[0009] Furthermore, a sealing protrusion is provided on the second end face of the GIS cover plate, and the outer edge of the sealing protrusion fits tightly with the hand hole of the GIS equipment.

[0010] Furthermore, the GIS cover plate is provided with a flange, which is used to fix the GIS cover plate to the handhole of the GIS equipment.

[0011] Compared with the prior art, the present invention has the following beneficial technical effects:

[0012] This invention integrates an ultrasonic sensing fiber onto a GIS cover plate using epoxy resin casting. Compared to piezoelectric ceramic sensors, the fiber optic ultrasonic sensor offers higher sensitivity, effectively improving the reliability of partial discharge detection in GIS equipment. Furthermore, this invention connects the fiber optic ultrasonic sensor to the GIS equipment as a whole via a flange, which, compared to commonly used adhesive sensors, effectively reduces ultrasonic signal loss and improves detection accuracy and reliability.

[0013] This invention embeds ultrasonic sensing fiber optic cable into a GIS cover plate, enabling real-time online monitoring of ultrasonic signals generated by partial discharge during GIS equipment operation. It features simple structure, compact size, convenient installation, and can be operated under power. It also boasts advantages such as strong anti-electromagnetic interference capability, safety and reliability, and high detection sensitivity. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model;

[0015] Figure 2This is a cross-sectional view of the present invention.

[0016] In the diagram: 1. GIS cover plate; 2. Annular groove; 3. Outlet box; 4. Bracket; 5. Ultrasonic sensing fiber optic cable; 6. First fiber optic connector; 7. Second fiber optic connector; 8. Sealing protrusion; 9. Flange. Detailed Implementation

[0017] The following detailed description illustrates the specific implementation method:

[0018] Example

[0019] like Figure 1-2 As shown, a fiber optic ultrasonic sensor for partial discharge monitoring in GIS includes a GIS cover plate 1. The GIS cover plate 1 has a first end face and a second end face. An annular groove 2 and a junction box 3 are provided on the first end face of the GIS cover plate 1. An ultrasonic sensing fiber 5 is fixed inside the annular groove 2. A bracket 4 is fixed inside the junction box 3. A first fiber optic connector 6 and a second fiber optic connector 7 are mounted on the bracket 4. The two ends of the ultrasonic sensing fiber 5 are respectively connected to the first fiber optic connector 6 and the second fiber optic connector 7. A sensitivity-enhancing element is installed between the first fiber optic connector 6 and the second fiber optic connector 7 and the ends of the ultrasonic sensing fiber 5. The sensitivity-enhancing element is used to identify and amplify the optical signal in the ultrasonic sensing fiber 5. Fiber optic connector 6 is used to inject external optical signals into the ultrasonic sensing fiber 5, and second fiber optic connector 7 is used to transmit the optical signals passing through the ultrasonic sensing fiber 5 to the external detection device. The ultrasonic sensing fiber 5 is made of 100 meters of ordinary single-mode fiber or special multi-core fiber that is not sensitive to bending and is tightly wound in a ring, and is fixed in the annular groove 2 by casting epoxy resin. An annular sealing protrusion 8 is formed on the second end face of the GIS cover plate 1. The outer edge of the sealing protrusion 8 fits tightly with the hand hole of the GIS equipment to improve the sealing performance of the GIS equipment. A flange 9 is also formed on the GIS cover plate 1, which can fix the GIS cover plate 1 to the hand hole of the GIS equipment.

[0020] The detection principle of this utility model is as follows:

[0021] The present invention is connected to the GIS equipment via flange 9 to form a whole. An optical signal is injected into the ultrasonic sensing fiber 5 through the first optical fiber connector 6. The optical signal is transmitted to the external detection device through the ultrasonic sensing fiber 5 and the second optical fiber connector 7. When the GIS equipment generates partial discharge, the discharge energy will cause the surrounding medium to vibrate. This vibration is further converted into an ultrasonic signal. When the ultrasonic signal propagates to the vicinity of the ultrasonic sensing fiber 5, it will cause a slight vibration of the ultrasonic sensing fiber 5, thereby changing the phase, frequency or intensity of the optical signal in the ultrasonic sensing fiber 5. By measuring the changes in these parameters by the external detection device, it can be determined whether an ultrasonic signal exists, thus realizing the detection of partial discharge in the GIS equipment.

[0022] In this embodiment, the ultrasonic sensing fiber optic cable 5 is embedded in the GIS cover plate 1 and fixed with epoxy resin casting. This enables real-time online monitoring of ultrasonic signals generated by partial discharge during the operation of the GIS equipment. It features a simple structure, compact size, and the ability to operate under power. Furthermore, the fiber optic ultrasonic sensor of this invention is connected to the GIS equipment as a whole through a flange, which not only facilitates installation and operation but also effectively reduces the loss of ultrasonic signals during transmission. It has good detection accuracy and reliability. Utilizing optical fiber to detect ultrasonic signals also provides higher sensitivity, strong resistance to electromagnetic interference, and safety and reliability.

[0023] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A fiber optic ultrasonic sensor for partial discharge monitoring in GIS, characterized in that: The GIS cover plate (1) includes a first end face and a second end face. An annular groove (2) is provided on the first end face. An ultrasonic sensing fiber (5) is fixed in the annular groove (2). A first fiber connector (6) and a second fiber connector (7) are respectively connected to the two ends of the ultrasonic sensing fiber (5). A sensitivity enhancement element is provided between the first fiber connector (6) and the second fiber connector (7) and the end of the ultrasonic sensing fiber (5). The first fiber connector (6) and the second fiber connector (7) are fixed on the GIS cover plate (1). The first fiber connector (6) is used to inject the optical signal into the ultrasonic sensing fiber (5). The second fiber connector (7) is used to transmit the optical signal passing through the ultrasonic sensing fiber (5) to the detection device.

2. The fiber optic ultrasonic sensor for partial discharge monitoring in GIS according to claim 1, characterized in that: The first end face of the GIS cover plate (1) is also provided with a cable outlet box (3), and a bracket (4) is provided inside the cable outlet box (3). The first fiber optic connector (6) and the second fiber optic connector (7) are fixed on the bracket (4).

3. The fiber optic ultrasonic sensor for partial discharge monitoring in GIS according to claim 1 or 2, characterized in that: The ultrasonic sensing fiber (5) is made of 100 meters of ordinary single-mode fiber or special multi-core fiber that is not sensitive to bending and is tightly wound in a ring, and is fixed in the annular groove (2) by casting epoxy resin.

4. The fiber optic ultrasonic sensor for partial discharge monitoring in GIS according to claim 3, characterized in that: The second end face of the GIS cover plate (1) is provided with a sealing protrusion (8), and the outer edge of the sealing protrusion (8) is tightly fitted with the hand hole of the GIS equipment.

5. The fiber optic ultrasonic sensor for partial discharge monitoring in GIS according to claim 4, characterized in that: The GIS cover plate (1) is provided with a flange (9), which is used to fix the GIS cover plate (1) to the hand hole of the GIS equipment.

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