Transformer winding temperature on-line monitoring device based on optical fiber temperature measurement

Abstract

This utility model discloses an online monitoring device for transformer winding temperature based on fiber optic temperature measurement, belonging to the field of temperature monitoring technology. It includes a temperature probe, a fiber optic transmission assembly, a control box, and a display panel. The temperature probe is composed of a quartz optical fiber coated with a high-temperature resistant polyimide coating. A europium-doped yttrium aluminum garnet crystal temperature sensor is fused to the end of the fiber. The temperature sensor is covered with an alumina ceramic protective layer. The temperature probe is embedded in the interlayer gap of the transformer winding conductors. The fiber optic transmission assembly uses a double-armored composite optical cable, with both ends connected via fiber optic connectors. The control box includes a metal heat sink, a detection circuit housed within the casing, and a microcontroller. The display panel is integrated onto the surface of the control box and electrically connected to the microcontroller. The display panel also includes a dual-color LED alarm light group and a miniature buzzer. This utility model can accurately and stably measure the temperature of transformer windings and achieve online monitoring.

Description

Technical Field

[0001] This utility model belongs to the field of temperature monitoring technology, and specifically relates to an online monitoring device for transformer winding temperature based on fiber optic temperature measurement. Background Technology

[0002] Transformer winding temperature is a crucial indicator in transformer operation monitoring. Overheating of the windings directly impacts transformer lifespan and can potentially lead to serious accidents. Therefore, accurate monitoring and timely understanding of transformer winding temperature are essential. Currently, power generation companies commonly use traditional oil-immersed transformer winding temperature monitoring devices, typically calculating hot spot temperatures by combining oil surface temperature with electrical load data, or employing insertion-type electrical temperature sensors. These traditional methods suffer from significant response lag, limited measurement accuracy, and insufficient safety and reliability. With the expansion of power grids and increasingly stringent requirements for equipment operational safety and reliability, the shortcomings of existing temperature measurement technologies in terms of accuracy and real-time performance are becoming increasingly apparent. Therefore, it is necessary to propose a novel online transformer winding temperature monitoring device to achieve real-time and accurate monitoring of transformer winding hot spot temperatures, thereby improving equipment operational safety and reliability. Utility Model Content

[0003] The purpose of this invention is to overcome the above-mentioned defects and propose an online monitoring device for transformer winding temperature based on fiber optic temperature measurement. This device can solve the problems of measurement lag and insufficient accuracy of existing transformer winding temperature monitoring devices, which make it difficult to monitor the hot spot temperature of transformer windings in real time and accurately.

[0004] The specific technical solution is as follows:

[0005] An online monitoring device for transformer winding temperature based on fiber optic temperature measurement includes a temperature probe, a fiber optic transmission assembly, a control box, and a display panel. The temperature probe is characterized by: a quartz optical fiber coated with a high-temperature resistant polyimide coating, with a europium-doped yttrium aluminum garnet crystal temperature sensor fused to the fiber end; the temperature sensor is covered with an alumina ceramic protective layer; and the temperature probe is embedded in the interlayer gap of the transformer winding conductors. The fiber optic transmission assembly uses a double-armored composite optical cable, with both ends connected via fiber optic connectors. The control box includes a metal heat dissipation shell, a detection circuit housed within the shell, and a microcontroller. The display panel is integrated onto the surface of the control box and electrically connected to the microcontroller. The display panel also features a dual-color LED alarm light group and a miniature buzzer, and an SD card expansion slot on its side.

[0006] Furthermore, the above-mentioned scheme includes a central communication optical fiber and three surrounding temperature measuring optical fibers, each optical fiber is covered with an armored protective layer, and a flame-retardant silicone rubber buffer layer is filled between the armored protective layer and the optical fiber.

[0007] Furthermore, the armored protective layer comprises an inner thin aramid layer and an outer stainless steel wire interwoven layer, with a silicone rubber shock-absorbing layer between the two layers.

[0008] Furthermore, the detection circuit in the above scheme includes a temperature-compensated semiconductor laser, a collimating lens group, an avalanche photodiode, and a transimpedance amplifier.

[0009] Furthermore, the alumina ceramic protective layer is coated with an epoxy resin adhesive, and a dome-shaped sensitive layer with a thickness of 0.5 mm is formed at the end of the optical fiber.

[0010] Furthermore, in the above scheme, a set of temperature measuring probes is set at each end of each phase winding, and each set contains three temperature measuring probes evenly distributed along the circumference at 120°, with a distance of not less than 20mm between adjacent probes.

[0011] Furthermore, the outer casing surface is provided with U-shaped protruding heat dissipation fins, and the bottom has honeycomb convection holes with a diameter of 8mm.

[0012] Furthermore, the control box is equipped with a communication module, which is connected to an external monitoring platform.

[0013] Furthermore, in the above scheme, an aerogel insulation layer is attached to the inner wall of the metal heat dissipation shell, and a fire-retardant coating is sprayed on the outer surface.

[0014] Furthermore, in the above scheme, the temperature probe is fixed in the interlayer gap of the winding conductor inside the transformer by a ceramic bracket. The ceramic bracket is provided with a positioning slot, and the positioning slot is lined with a silicone shock-absorbing pad.

[0015] Compared with existing technologies, the beneficial effects of this utility model are as follows:

[0016] This invention employs a composite protection structure combining an alumina ceramic protective layer and armored optical cable, enabling the probe to maintain a temperature measurement accuracy of 0.5℃ even in the strong electromagnetic field environment of a transformer. The combination of U-shaped heat dissipation fins and honeycomb convection holes controls the internal temperature of the enclosure, preventing performance drift of electronic components. The orthogonal arrangement of three probes with a 120° circumferential distribution eliminates the blind spots of traditional single-point temperature measurement, allowing for early warning in actual measurements. The communication module supports simultaneous uploading of transformer temperature data, and combined with local storage on an SD card, forms dual data backup. This invention shortens the response time for transformer winding temperature monitoring and significantly improves spatial resolution compared to traditional resistance temperature detectors (RTD) solutions.

[0017] This invention achieves strong mechanical protection, accurate temperature measurement, and strong environmental adaptability (temperature resistance, electromagnetic insulation, and insulation compatibility) in transformer winding monitoring, while also having communication functions, providing reliable support for winding safety monitoring. Attached Figure Description

[0018] Figure 1 This is a functional module block diagram of this utility model;

[0019] Figure 2 This is a schematic diagram of the cross-sectional structure of an optical fiber transmission component.

[0020] 1-Central communication optical fiber, 2-Temperature measurement optical fiber, 3-Armored protective layer, 4-Flame-retardant silicone rubber buffer layer. Detailed Implementation

[0021] The embodiments of the utility model are further described in detail below with reference to the accompanying drawings, so that the purpose, technical solution and technical effect of the utility model can be more clearly presented.

[0022] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] This utility model discloses an online monitoring device for transformer winding temperature based on fiber optic temperature measurement, including a temperature probe, a fiber optic transmission component, a control box, and a display panel.

[0024] The temperature probe uses quartz optical fiber as the substrate, with its surface uniformly coated with a high-temperature resistant polyimide coating to improve heat resistance. The fiber end is connected to a europium-doped yttrium aluminum garnet crystal temperature sensor. An alumina ceramic protective layer is formed on the outer surface of this temperature sensor using a vapor deposition process. This protective layer is further coated with epoxy resin adhesive to form a 0.5mm thick dome-shaped sensitive layer structure. To enhance temperature measurement accuracy, the probe is embedded in the interlayer gap of the transformer winding conductors, with two sets of orthogonally wound temperature probes symmetrically arranged within a single winding interval. Specifically, one set of probes is placed at each end of each phase winding, with each set containing three temperature measurement points uniformly distributed 120° circumferentially, and the distance between adjacent probes is strictly maintained at no less than 20mm.

[0025] The fiber optic transmission assembly employs a double-armored composite optical cable, primarily consisting of a central communication fiber 1 and three surrounding temperature-sensing fibers 2. Each fiber is covered by a composite armored protective layer 3, which features a dual structure consisting of an inner thin aramid layer and an outer stainless steel wire interwoven layer. The cable is internally filled with a flame-retardant silicone rubber buffer layer 4 to enhance its resistance to compression. Both ends are connected quickly and reliably via precision-ground fiber optic connectors. This dual structure combines high strength and flexibility, withstanding winding vibration, compression, and installation stress, ensuring long-term fiber stability. Optimized heat transfer design effectively reduces the thermal resistance impact of the dual protective layers.

[0026] The control enclosure features a cast aluminum alloy metal heat dissipation shell with an inner wall lined with a nano-aerogel insulation layer and an outer surface coated with fire-retardant paint. The shell surface is designed with a U-shaped array of raised heat dissipation fins, and the bottom has 8mm diameter honeycomb convection holes to enhance heat dissipation. Inside the enclosure is a detection circuit consisting of a temperature-compensated semiconductor laser, a collimating lens group, an avalanche photodiode, and a transimpedance amplifier to ensure accurate signal conversion. The core control unit uses an STM32F407 microprocessor and integrates a 4G communication module for data interaction with a remote monitoring platform.

[0027] The display panel is integrated into the front of the control box and uses an industrial-grade capacitive touchscreen, directly connected to the microcontroller via an FPC cable. A dual-color LED alarm light group and a miniature buzzer are embedded in the upper right corner of the panel, automatically triggering an audible and visual alarm when the detected temperature exceeds a set threshold. A standard SD card expansion slot is located on the side of the panel for local data storage, and a built-in FAT32 file system enables continuous cyclic recording of temperature data.

[0028] During installation, the temperature probe is fixed between the transformer winding layers using a ceramic bracket. The bracket has positioning slots and is lined with silicone shock-absorbing pads to ensure a constant contact pressure between the probe and the winding conductors. Testing shows that the device can monitor winding temperature changes in real time when the transformer is running at full load, with a measurement accuracy of ±0.5℃ and an alarm response time of less than 100ms, effectively preventing transformer overheating faults. An external monitoring platform allows for centralized management and historical trend analysis of temperature data from multiple transformers, significantly improving the operation and maintenance efficiency of power equipment.

[0029] In the above scheme, a europium-doped yttrium aluminum garnet crystal temperature sensor detects changes in the winding temperature. When the temperature sensor is excited by a laser, its emitted fluorescence lifetime has a definite functional relationship with the temperature. This physical effect is used to convert temperature information into an optical signal. The temperature probe is embedded between the winding layers to achieve distributed temperature field measurement. The three temperature-sensing optical fibers 2 in the double-armored composite optical cable transmit optical signals from different locations, ensuring that the spatial resolution of the measurement data reaches the 15mm level. Here, the semiconductor laser in the detection circuit generates an excitation light source, which is coupled into the optical fiber transmission component through a collimating lens group to excite the temperature sensor to produce fluorescence. The avalanche photodiode receives the returned fluorescence signal and accurately calculates the temperature value by detecting changes in fluorescence lifetime. The STM32F407 microcontroller processes the data from each temperature measurement point in real time and uses a temperature gradient algorithm to identify local hot spots in the winding. The display panel can dynamically display temperature distribution cloud maps and historical curves. When the monitored value exceeds the set threshold, the dual-color LED alarm light group switches between red and yellow according to the temperature difference level, and the buzzer starts a graded alarm.

[0030] Based on the existing fiber optic temperature measurement principle, this invention provides a device suitable for online monitoring of transformer winding temperature, which can accurately and stably measure the temperature of transformer windings and achieve online monitoring.

[0031] The above description is only a preferred embodiment of the present utility model and is not intended to limit the scope of the patent application of the present utility model. All equivalent changes, equivalent substitutions or modifications made within the technical spirit and principles indicated by the present utility model should be included within the scope of patent protection covered by the present utility model.

Claims

1. An online monitoring device for transformer winding temperature based on fiber optic temperature measurement, characterized in that: The device comprises a temperature probe, an optical fiber transmission assembly, a control box, and a display panel. Its features include: the temperature probe is composed of a quartz optical fiber coated with a high-temperature resistant polyimide coating, with a europium-doped yttrium aluminum garnet crystal temperature sensor fused to the end of the fiber; the temperature sensor is covered with an alumina ceramic protective layer; and the temperature probe is embedded in the interlayer gap of the winding conductors within a transformer. The optical fiber transmission assembly uses a double-armored composite optical cable, with both ends connected via optical fiber connectors. The control box includes a metal heat dissipation shell, a detection circuit housed within the shell, and a microcontroller. The display panel is integrated onto the surface of the control box and electrically connected to the microcontroller. The display panel also features a dual-color LED alarm light group and a miniature buzzer, and an SD card expansion slot on its side.

2. The online monitoring device for transformer winding temperature based on fiber optic temperature measurement according to claim 1, characterized in that: The double-armored composite optical cable includes a central communication optical fiber and three temperature-measuring optical fibers arranged around it. Each optical fiber is covered with an armored protective layer, and a flame-retardant silicone rubber buffer layer is filled between the armored protective layer and the optical fiber.

3. The online monitoring device for transformer winding temperature based on fiber optic temperature measurement according to claim 2, characterized in that: The armored protective layer includes an inner thin aramid layer and an outer stainless steel wire interwoven layer, with a silicone rubber shock-absorbing layer between the two layers.

4. The online monitoring device for transformer winding temperature based on fiber optic temperature measurement according to claim 1, characterized in that: The detection circuit includes a temperature-compensated semiconductor laser, a collimating lens group, an avalanche photodiode, and a transimpedance amplifier.

5. The online monitoring device for transformer winding temperature based on fiber optic temperature measurement according to claim 1, characterized in that: The alumina ceramic protective layer is coated with epoxy resin adhesive, and a dome-shaped sensitive layer with a thickness of 0.5 mm is formed at the end of the optical fiber.

6. The online monitoring device for transformer winding temperature based on fiber optic temperature measurement according to claim 1, characterized in that: The temperature probes are set at both ends of each phase winding, and each set contains three temperature probes evenly distributed along the circumference at 120°, with a distance of not less than 20mm between adjacent probes.

7. The online monitoring device for transformer winding temperature based on fiber optic temperature measurement according to claim 1, characterized in that: The outer casing has U-shaped protruding heat dissipation fins on its surface and honeycomb convection holes with a diameter of 8mm at the bottom.

8. The online monitoring device for transformer winding temperature based on fiber optic temperature measurement according to claim 1, characterized in that: The control box is equipped with a communication module, which is connected to an external monitoring platform.

9. The online monitoring device for transformer winding temperature based on fiber optic temperature measurement according to claim 1, characterized in that: The inner wall of the metal heat dissipation shell is covered with an aerogel insulation layer, and the outer surface is sprayed with fire-retardant coating.

10. The online monitoring device for transformer winding temperature based on fiber optic temperature measurement according to claim 1, characterized in that: The temperature probe is secured in the interlayer gap of the winding conductor inside the transformer by a ceramic bracket. The ceramic bracket is provided with a positioning slot, and the positioning slot is lined with a silicone shock-absorbing pad.

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