Isolation medium window and detection system

Abstract

This utility model discloses an isolation medium window, relating to the technical field of auxiliary components for transformer testing. It includes an insulating cover and a metal base, with the insulating cover fixedly connected to the metal base. The insulating cover has a cylindrical structure. One end of the metal base, away from the insulating cover, is fixedly connected to a mounting base on the transformer tank. The other end of the insulating cover, away from the metal base, can extend into an opening on the transformer tank. A detection sensor is fixedly mounted on the end of the insulating cover away from the metal base. This utility model also discloses a detection system, including a detection sensor and the isolation medium window described above. This utility model enables the sensor to have high detection sensitivity and a large detection coverage angle.

Description

Technical Field

[0001] This utility model relates to the technical field of auxiliary components for transformer testing, and in particular to an isolation medium window and a testing system. Background Technology

[0002] Power transformers are core equipment in power systems, and their operational reliability directly affects the safety and stability of the power system. Partial discharge is an important sign of transformer insulation degradation, and timely and accurate detection of partial discharge is crucial for ensuring the safe operation of transformers. Ultra-high frequency (UHF) detection and ultrasonic detection are two effective methods for detecting partial discharge in transformers. Built-in UHF and ultrasonic sensors directly acquire UHF and ultrasonic signals from inside the transformer, shielding it from external electromagnetic waves and sound interference, thus improving detection sensitivity and anti-interference capabilities.

[0003] Installing a built-in partial discharge sensor requires drilling holes in the side or top of the transformer tank to prepare a mounting base. After installation, poorly designed sealing structures can easily lead to oil leakage, allowing external moisture and humidity to penetrate the transformer and damage the insulation. Furthermore, the sensor consists of multiple components, and long-term operation under high temperature and vibration poses a risk of component detachment, especially at the top of the tank where unprotected components could fall directly into the transformer, creating a significant safety hazard. One current solution involves installing a flat insulating dielectric window on top of the sensor, fixing it to a pre-installed mounting base in the transformer tank, and then using the window to secure the sensor. However, this method results in the dielectric window being flush with the outer surface of the mounting base, creating a gap of over 50mm between the sensor's detection surface and the inner wall of the transformer tank. This significant distance reduces the sensor's detection sensitivity and coverage angle. Therefore, a more sophisticated insulating dielectric window and detection system are urgently needed to address these technical problems. Utility Model Content

[0004] The purpose of this invention is to provide an isolation medium window and a detection system to solve the problems existing in the prior art, thereby enabling the sensor to have higher detection sensitivity and a larger detection coverage angle.

[0005] To achieve the above objectives, this utility model provides the following solution:

[0006] This utility model provides an isolation medium window, including an insulating cover and a metal base. The insulating cover is fixedly connected to the metal base. The insulating cover has a cylindrical structure. One end of the metal base away from the insulating cover is used to be fixedly connected to a mounting base on a transformer oil tank. The other end of the insulating cover away from the metal base can extend into an opening on the transformer oil tank. A detection sensor is fixedly installed at the end of the insulating cover away from the metal base.

[0007] In some embodiments, the insulating cover has a tapered hole at the end away from the metal base, and the larger end of the tapered hole is used to extend into the opening, while the smaller end of the tapered hole is positioned close to the detection sensor.

[0008] In some embodiments, the metal base includes a fixedly connected annular portion and an extension portion, the annular portion being fixedly connected to the insulating cover, and the extension portion being disposed at one end of the annular portion away from the insulating cover and extending outward.

[0009] In some embodiments, the end of the insulating cover near the metal base is provided with a protrusion, and the end of the annular portion near the insulating cover is provided with a groove, the protrusion being fixedly connected to the groove.

[0010] In some embodiments, a pull rod is vertically fixedly disposed in the groove, and the two ends of the pull rod are respectively fixedly connected to the metal base and the insulating cover.

[0011] In some embodiments, the detection sensor includes an ultrasonic sensor and an ultra-high frequency partial discharge sensor. The ultrasonic sensor is disposed against the inner wall of the insulating cover, and the ultra-high frequency partial discharge sensor is fixedly disposed inside the insulating cover. The end of the ultra-high frequency partial discharge sensor can extend into the opening and is flush with the inner edge of the side wall of the transformer tank.

[0012] This invention also provides a detection system, including a detection sensor and an isolation medium window as described above.

[0013] In some embodiments, an adapter flange is also included, wherein an extension is provided at one end of the metal base away from the insulating cover, the extension being disposed between the adapter flange and the mounting base, and the adapter flange being able to be fixedly connected to the mounting base.

[0014] In some embodiments, a first sealing groove is provided circumferentially on the side of the extension away from the mounting base, and a second sealing groove is provided circumferentially on the side of the mounting base near the extension. A first sealing gasket is provided in the first sealing groove, and a second sealing gasket is provided in the second sealing groove.

[0015] In some embodiments, an adapter gasket is also included, which is disposed between the adapter flange and the mounting base. The adapter gasket has a stepped structure, including a first part and a second part. The thickness of the first part is less than the thickness of the second part. The extension is fitted to the first part. The adapter flange has a third sealing groove along its circumference, and a third sealing gasket is disposed in the third sealing groove. The adapter flange and the adapter gasket are sealed together.

[0016] The present invention achieves the following technical advantages over the prior art:

[0017] The insulating cover of the isolation medium window provided by this utility model can extend into the transformer's oil tank. A detection sensor is installed inside the insulating cover, positioned closer to the oil tank. The closer the sensor is to the object being detected, the less attenuation the received signal (such as temperature, pressure, insulation status, etc.), allowing for more accurate capture of subtle changes and significantly improving detection sensitivity. This enables timely detection of potential faults or anomalies and ensures high detection sensitivity. Furthermore, because the detection sensor is closer to the oil tank, it covers a wider detection angle, reducing blind spots and providing more comprehensive monitoring of the oil tank's internal state, thus improving the overall control over the transformer's operation. The insulating cover is made of insulating material and has a cylindrical structure, achieving electrical isolation between the sensor and external metal components (such as the metal base and oil tank shell), meeting the transformer's insulation requirements, and providing a stable installation space for the sensor. The insulating cover is fixedly connected to the metal base, which in turn is fixed to the oil tank mounting base. The overall structure has good sealing performance, effectively preventing oil leakage from the oil tank and blocking external dust, moisture, and other impurities from entering, ensuring a stable internal environment for the transformer. The metal base provides a solid support for the overall structure, ensuring that the insulation cover and sensors remain stable during transformer operation (which may involve vibration, temperature changes, etc.), reducing detection errors or component damage caused by shaking. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is an external view of the isolation medium window in some embodiments of this utility model;

[0020] Figure 2 This is a schematic diagram of the structure of the isolation medium window in some embodiments of this utility model;

[0021] Figure 3 This is a schematic diagram of the structure of the isolation medium window installed on the transformer tank wall in some embodiments of this utility model.

[0022] In the figure: 1-Insulating cover; 2-Metal base; 21-Annular part; 22-Extension part; 3-Conical hole; 4-Pull rod; 5-Protrusion; 6-Groove; 7-First sealing groove; 8-Mounting base; 9-Transfer flange; 10-Transformer oil tank; 11-Ultra-high frequency partial discharge sensor; 12-Ultra-high frequency partial discharge sensor; 13-Transfer gasket; 15-Second sealing groove; 16-Third sealing groove. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] The purpose of this invention is to provide an isolation medium window and a detection system to solve the problems existing in the prior art, thereby enabling the sensor to have higher detection sensitivity and a larger detection coverage angle.

[0025] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1

[0027] like Figures 1-3As shown, this utility model provides an isolation medium window, including an insulating cover 1 and a metal base 2. The insulating cover 1 is fixedly connected to the metal base 2. One end of the metal base 2 is fixedly connected to the transformer oil tank, and the other end is fixedly connected to the insulating cover. The insulating cover 1 has a cylindrical structure. The end of the metal base 2 away from the insulating cover 1 is used to be fixedly connected to the mounting base 8 on the transformer oil tank 10. The end of the insulating cover 1 away from the metal base 2 can extend into the opening on the transformer oil tank 10. The detection sensor is fixedly installed at the end of the insulating cover 1 away from the metal base 2. The insulating cover 1 extends into the transformer's oil tank. A detection sensor is installed inside the insulating cover 1, positioned closer to the oil tank. The closer the sensor is to the object being detected, the less attenuation the received signal (such as temperature, pressure, insulation status, etc.), allowing for more accurate capture of subtle changes and significantly improving detection sensitivity. This enables timely detection of potential faults or anomalies and ensures high detection sensitivity. Furthermore, because the sensor is closer to the oil tank, it can cover a wider detection angle inside the tank, reducing blind spots and providing more comprehensive monitoring of the tank's internal condition, thus improving the overall control over the transformer's operation. The insulating cover 1 is made of insulating material and has a cylindrical structure, achieving electrical isolation between the sensor and external metal components (such as the metal base 2 and the oil tank shell), meeting the transformer's insulation requirements, and providing a stable installation space for the sensor. Moreover, the insulating material of the insulating cover ensures that it does not interfere with the detection of UHF (Ultra High Frequency) electromagnetic waves. The insulating cover 1 is fixedly connected to the metal base 2, which in turn is fixed to the oil tank mounting base 8. The overall structure has good sealing performance, which can effectively prevent oil leakage from the oil tank and block external dust, moisture and other impurities from entering, ensuring the stability of the transformer's internal environment. The metal base 2 provides a solid support for the overall structure, ensuring that the insulating cover 1 and the sensor remain stable during transformer operation (which may be subject to vibration, temperature changes, etc.), reducing detection errors or component damage caused by shaking.

[0028] In some embodiments, a tapered hole 3 is provided at the end of the insulating cover 1 away from the metal base 2. The larger end of the tapered hole 3 is used to extend into the opening of the transformer tank, and the smaller end of the tapered hole 3 is positioned close to the detection sensor. The function of the tapered hole 3 is to collect and converge the signal. The tapered hole 3 is located on the top of the high-strength insulating cover 1, opposite the internal detection sensor (including the ultrasonic sensor 11), and uses a horn-shaped structure to focus the signal for receiving the ultrasonic signal of partial discharge inside the transformer. The structure of the larger end of the tapered hole 3 extending into the tank opening and the smaller end close to the sensor creates a horn-like sound-gathering effect: the ultrasonic signal generated by partial discharge inside the tank is reflected and guided by the inner wall of the tapered hole 3 during propagation, converging towards the sensor at the smaller end. This reduces the diffusion and attenuation of the ultrasonic signal, allowing more signal energy to be concentrated on the sensor, significantly improving the ability to capture weak signals, and is especially suitable for detecting early and weak partial discharges (at which time the ultrasonic signal strength is low and easily masked by background noise). The small end of the tapered hole 3 is close to the sensor used for detection (especially the ultrasonic sensor 11), so that the converged signal can directly act on the sensor's sensitive surface, shortening the signal propagation distance inside the insulating cover 1 and further reducing attenuation.

[0029] In some embodiments, the metal base 2 includes a fixedly connected annular portion 21 and an extension portion 22. The extension portion 22 is fixedly connected to the edge of the annular portion 21 and extends outward. The annular portion 21 is fixedly connected to the insulating cover 1. The extension portion 22 is located at the end of the annular portion 21 away from the insulating cover 1 and extends outward. The diameter of the annular portion 21 is the same as the diameter of the insulating cover 1. The outward extension of the extension portion 22 increases the contact area between the metal base 2 and the transformer tank 10 mounting base 8. Multi-point fixing (such as multiple bolt holes along the circumference of the extension portion 22) further improves the stability of the overall structure and reduces tilting or displacement caused by external forces (such as installation deviation or equipment vibration), providing a more stable detection environment for the sensor. The larger contact surface between the extension portion 22 and the tank mounting base 8 allows for improved sealing by adding sealing gaskets (such as rubber gaskets or metal bellows).

[0030] In some embodiments, a protrusion 5 is provided at the end of the insulating cover 1 near the metal base 2, and a groove 6 is provided at the end of the annular portion 21 near the insulating cover 1. The protrusion 5 and the groove 6 are fixedly connected. The protrusion 5 and the groove 6 adopt an embedded fit to form a mechanical interlocking structure similar to a mortise and tenon joint. Compared with planar contact connection, it can effectively resist the stress generated by vibration, impact or thermal expansion and contraction during transformer operation, and reduce the risk of loosening of the connection.

[0031] In some embodiments, a pull rod 4 is vertically fixedly disposed within the groove 6. Both ends of the pull rod 4 are fixedly connected to the metal base 2 and the insulating cover 1, respectively. Specifically, the pull rod 4 can be threaded, welded, or integrally formed with the metal base 2. As a rigid connecting component, the pull rod 4 provides additional axial tensile or supporting force based on the embedded fit between the protrusion 5 and the groove 6, rigidly connecting the insulating cover 1 and the metal base 2. This dual connection method, combining the embedded fit with the fastening pull rod 4, effectively resists axial or radial loads generated by vibration, impact, and temperature changes (thermal expansion and contraction) during transformer operation, preventing the connection from loosening or separating due to long-term stress. The axial tensile force of the pull rod 4 allows the protrusion 5 of the insulating cover 1 to fit more tightly with the groove 6 of the metal base 2, reducing gaps between them and effectively preventing oil leakage from the tank or intrusion of external impurities.

[0032] It should be noted that the insulating cover 1 is cast from high-temperature resistant polyurethane resin, but other resin materials such as epoxy resin can also be used. The metal base 2 is made of stainless steel, but other metal materials such as carbon steel can also be used. During manufacturing, the pull rod 4 is fixedly installed on the metal base 2. Then, the resin material is liquefied at a high temperature of 260 degrees Celsius, and then the resin material is cast and fixed to the metal base 2. This integrated casting method gives the insulating medium window the advantages of high strength and small difference in thermal expansion coefficient, enabling long-term operation over a wide temperature range. It can work reliably for a long time within the range of -25℃ to 120℃ and can withstand a pressure difference of two atmospheres.

[0033] In some embodiments, the detection sensor includes an ultrasonic sensor 11 and a UHF partial discharge sensor 12. The ultrasonic sensor 11 is fitted to the inner wall of the insulating cover 1, and the UHF partial discharge sensor 12 is fixedly disposed inside the insulating cover 1. The end of the UHF partial discharge sensor 12 can extend into the opening and is flush with the inner edge of the side wall of the transformer tank 10, maximizing the detection sensitivity and detection angle of the UHF sensor. Partial discharge generates both ultrasonic signals (mechanical vibration waves) and UHF electromagnetic signals (300MHz to 3GHz), but the intensity of the two signals differs depending on the type of discharge (such as corona discharge, surface discharge, air gap discharge, etc.). The ultrasonic sensor 11 is good at capturing discharge signals related to mechanical vibration and is sensitive to discharges in oil or inside solid insulation; the UHF sensor is more sensitive to the high-frequency electromagnetic radiation generated by discharge and is suitable for detecting discharges in air gaps or on the surface of high-voltage components. The combination of the two can cover a wider range of discharge types, reduce the detection blind zone of a single sensor, and achieve dual verification. The ultrasonic sensor 11 is attached to the inner wall of the insulating cover 1, and the end of the insulating cover 1 is provided with a conical hole 3 (flare structure). The conical hole 3 can concentrate the ultrasonic wave and guide the signal to the inner wall. The close mounting of the sensor can maximize the reception of the focused ultrasonic energy, reduce the reflection or attenuation of the signal inside the insulating cover 1, and significantly improve the ability to capture weak ultrasonic signals (especially suitable for the detection of early partial discharge). UHF signals are easily absorbed or reflected by metals, insulating media, etc. during propagation, and attenuate quickly. The end of the UHF sensor extends into the opening and is flush with the inner edge of the side wall of the transformer tank 10, which means that its detection end is almost close to the discharge point inside the tank. This can minimize the signal propagation path, reduce signal loss caused by insulating materials, air and other media, and improve the detection sensitivity of weak UHF signals.

[0034] Example 2

[0035] This embodiment also provides a detection system, including a detection sensor and the isolation medium window in Embodiment 1. The detection system also includes a transition flange 9. An extension 22 is provided at the end of the metal base 2 away from the insulating cover 1. The extension 22 here refers to the same extension 22 mentioned above. The extension 22 is disposed between the transition flange 9 and the mounting base 8. The transition flange 9 can be fixedly connected to the mounting base 8. The transition flange 9 and the mounting base 8 are fixedly connected, and the extension 22 is clamped in the middle to fix the relative position of the metal base 2 and the mounting base 8.

[0036] In some embodiments, the side of the extension 22 away from the mounting base 8 is provided with a first sealing groove 7 along the circumferential direction, and the side of the mounting base 8 near the extension 22 is provided with a second sealing groove 15 along the circumferential direction. A first sealing gasket is provided in the first sealing groove 7, and a second sealing gasket is provided in the second sealing groove 15. The detection system also includes an adapter gasket 13, which is disposed between the adapter flange 9 and the mounting base 8. The adapter gasket 13 has a stepped structure, including a first part and a second part. The thickness of the first part is less than the thickness of the second part. The extension 22 is fitted to the first part. The adapter flange 9 is provided with a third sealing groove 16 along the circumferential direction, and a third sealing gasket is provided in the third sealing groove 16. The adapter flange 9 and the adapter gasket 13 are sealed together. The first and second gaskets primarily block the direct leakage path of oil from the inside of the tank to the outside. The third gasket prevents external moisture and dust from entering the interior through the gap between the transition flange 9 and the transition gasket 13 (especially preventing impurities from contaminating the sealing surface or corroding metal parts), while further intercepting trace amounts of oil that might bypass the first two seals. These three seals work in a progressive manner; even if one seal experiences minor failure due to aging or wear, the other two can still maintain their sealing function, significantly improving the system's sealing reliability for long-term operation.

[0037] This utility model uses specific examples to illustrate its principles and implementation methods. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the idea of ​​this utility model. In summary, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. An isolation dielectric window characterized by: It includes an insulating cover and a metal base. One end of the insulating cover is fixedly connected to one end of the metal base. The insulating cover has a cylindrical structure. The end of the metal base away from the insulating cover is used to be fixedly connected to a mounting base on a transformer tank. The end of the insulating cover away from the metal base can extend into an opening on the transformer tank. A detection sensor is fixedly installed at the end of the insulating cover away from the metal base.

2. The isolation dielectric window of claim 1, wherein: The insulating cover has a tapered hole at the end away from the metal base, with the larger end of the tapered hole used to extend into the opening, and the smaller end of the tapered hole positioned close to the detection sensor.

3. The isolation dielectric window of claim 1, wherein: The metal base includes a fixedly connected annular portion and an extension portion. The annular portion is fixedly connected to the insulating cover, and the extension portion is located at the end of the annular portion away from the insulating cover and extends outward.

4. The isolation dielectric window of claim 3, wherein: The insulating cover has a protrusion at the end near the metal base, and the annular portion has a groove at the end near the insulating cover. The protrusion is fixedly connected to the groove.

5. The isolation dielectric window of claim 4, wherein: A pull rod is vertically fixed inside the groove, and the two ends of the pull rod are fixedly connected to the metal base and the insulating cover, respectively.

6. The isolation dielectric window of claim 1, wherein: The detection sensors include an ultrasonic sensor and an ultra-high frequency partial discharge sensor. The ultrasonic sensor is attached to the inner wall of the insulating cover, and the ultra-high frequency partial discharge sensor is fixedly installed inside the insulating cover. The end of the ultra-high frequency partial discharge sensor can extend into the opening and is flush with the inner edge of the side wall of the transformer tank.

7. A detection system characterized by: It includes a detection sensor and an isolation medium window as described in any one of claims 1-6.

8. The detection system of claim 7, wherein: It also includes an adapter flange, wherein the metal base has an extension at one end away from the insulating cover, the extension being disposed between the adapter flange and the mounting base, and the adapter flange being able to be fixedly connected to the mounting base.

9. The detection system of claim 8, wherein: The extension portion has a first sealing groove along its circumference on the side away from the mounting base, and the mounting base has a second sealing groove along its circumference on the side near the extension portion. A first sealing gasket is disposed in the first sealing groove, and a second sealing gasket is disposed in the second sealing groove.

10. The detection system of claim 9, wherein: It also includes an adapter gasket, which is disposed between the adapter flange and the mounting base. The adapter gasket has a stepped structure, including a first part and a second part. The thickness of the first part is less than the thickness of the second part. The extension is fitted to the first part. The adapter flange has a third sealing groove along its circumference, and a third sealing gasket is disposed in the third sealing groove. The adapter flange and the adapter gasket are sealed together.

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