A fiber-optic temperature measurement structure for a converter transformer

Abstract

The utility model relates to a kind of converter transformer optical fiber temperature measurement structure, including valve side winding, hot spot optical fiber and oil channel optical fiber, wherein valve side winding upper end is equipped with fixed pad block A and fixed pad block B, and the temperature measurement probe of hot spot optical fiber is fixed at the hottest line cake of valve side winding first end by corresponding fixed pad block A, and the temperature measurement probe of oil channel optical fiber is fixed at the top first oil channel of valve side winding by corresponding fixed pad block B;Valve side winding upper end is equipped with multiple layers of angle ring, and optical fiber limiting pad block is equipped between adjacent layers of angle ring, and the optical fiber limiting slot for optical fiber cable to pass through is equipped on the optical fiber limiting pad block;Hot spot optical fiber and oil channel optical fiber pass through corresponding optical fiber limiting pad block and each layer of angle ring in sequence, then are led out by the gap between the two angle rings of the uppermost layer.The utility model can meet the technical requirements of stable temperature measurement of converter transformer valve side winding under alternating current and direct current superimposed electric field by arranging optical fiber leading point reasonably and controlling deviation of optical fiber cable path.

Description

Technical Field

[0001] This utility model relates to the field of converter transformer temperature control, specifically a fiber optic temperature measurement structure for converter transformers. Background Technology

[0002] Transformer lifespan is related to winding temperature (the rate of insulation aging doubles for every 6°C increase). Traditional oil temperature monitoring or infrared thermography can only reflect the overall or surface temperature of the transformer. These methods cannot capture the temperature of the hottest spots inside the windings in real time, thus failing to accurately adjust the operating load to improve operational stability and lifespan. Embedding optical fibers inside the windings allows for direct measurement of the true temperature of the hottest spots, thereby avoiding overload risks caused by temperature calculation errors and improving equipment safety and operating efficiency.

[0003] However, the aforementioned fiber optic temperature measurement method has not yet been applied to converter transformers. This is because converter transformers are at the core of the AC-DC conversion process, working with converter valves to achieve this conversion. The valve-side windings of converter transformers simultaneously withstand both AC and DC voltages. Compared to ordinary AC products, their insulation tests include additional tests such as long-term DC withstand voltage, DC polarity reversal, and long-term AC external application, making the insulation structure of converter transformers more complex. In converter transformers, the AC electric field is capacitively distributed and inversely proportional to the dielectric constant of the material, resulting in a higher field strength in oil. Conversely, the DC electric field is resistively distributed and directly proportional to the resistivity of the material. Fiber optics, being insulating materials, will withstand very high field strengths under DC fields. Therefore, how to arrange fiber optics on the valve-side windings of converter transformers while ensuring that the fiber optic insulation performance meets requirements and that the temperature deviation at different points does not exceed 2K and the signal strength is not less than 80% remains a problem that needs to be solved.

[0004] Patent CN120597491A discloses a method for calculating the oil flow temperature rise of the valve-side winding of a converter transformer based on PCA-FCNN, but the design purpose of this method is to improve the calculation speed of the valve-side winding temperature rise. Patent CN208225692U discloses a device for monitoring overheating faults of the valve-side bushing of a converter transformer, but this device monitors the valve-side bushing and does not detect the internal temperature of the winding. Patent CN201562556U discloses a terminal ring structure for an ultra-high voltage converter transformer, but this structure mainly aims to match the shape of the pad with the curvature of the corner ring to ensure insulation distance, etc. Utility Model Content

[0005] The purpose of this invention is to provide a fiber optic temperature measurement structure for converter transformers. By rationally arranging fiber optic lead-out points and using fiber optic limiting pads in each layer to control the deviation of the fiber optic cable path, it can meet the technical requirements for stable temperature measurement of the valve-side winding of the converter transformer under AC and DC superimposed electric fields.

[0006] The objective of this utility model is achieved through the following technical solution: A fiber optic temperature measurement structure for a converter transformer includes a valve-side winding, a hot spot fiber, and an oil channel fiber. The valve-side winding has a fixing block A and a fixing block B at its upper end. The temperature probe of the hot spot fiber is fixed to the hottest coil at the beginning of the valve-side winding via the corresponding fixing block A. The temperature probe of the oil channel fiber is fixed to the first oil channel at the top of the valve-side winding via the corresponding fixing block B. The valve-side winding has multiple layers of corner rings at its upper end, with fiber optic limiting blocks between adjacent layers. Each fiber optic limiting block has a fiber optic limiting groove for the fiber optic cable to pass through. The hot spot fiber and the oil channel fiber pass sequentially through the corresponding fiber optic limiting blocks and corner rings of each layer, and then exit through the gap between the two uppermost corner rings.

[0007] The fiber optic limiting pads located on the same layer are arranged along the circumference of the valve-side winding, while the fiber optic limiting pads of each layer are sequentially connected along the circumference of the valve-side winding.

[0008] The valve-side winding is provided with an electrostatic ring at its upper end, and the electrostatic ring is provided with multiple corner rings on its upper side. The hot spot fiber and the oil channel fiber are introduced through the gap between the two electrostatic rings, and then pass through the corresponding fiber limiting pads and corner rings of each layer in sequence.

[0009] The fixing pad A is provided with a first probe fixing groove and a first optical fiber lead-out groove, and the temperature measuring probe of the hot spot optical fiber is fixed in the first probe fixing groove.

[0010] The fixing pad B is provided with a second probe fixing groove and a second optical fiber lead-out groove, and the temperature measuring probe of the oil channel optical fiber is fixed in the second probe fixing groove.

[0011] The fixing pad B has an upper slot that communicates with the second probe fixing slot, and the position of the upper slot corresponds to the center line of each second probe fixing slot.

[0012] The hot spot fiber and the oil channel fiber are led out from the gap between the uppermost corner rings and extend outward along the radial direction of the valve side winding to the fiber optic through disk.

[0013] The advantages and positive effects of this utility model are as follows: 1. This utility model achieves the technical requirement of stable temperature measurement of the valve-side winding of the converter transformer under AC and DC superimposed electric fields by reasonably arranging the optical fiber lead-out points and using optical fiber limiting pads in each layer to control the deviation of the optical fiber cable path.

[0014] 2. This utility model uses fixing pads to fix the hot spot fiber and the oil channel fiber for probe fixation. Then, the hot spot fiber and the oil channel fiber are led out from the upper end of the valve side winding. At the same time, the fiber limiting pads in each layer of the upper end of the valve side winding limit the fiber path. The above structure has almost no impact on the overall structure of the valve side winding, and also facilitates fiber installation and modification of existing equipment. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model. Figure 2 for Figure 1 Enlarged view of point A in the image. Figure 3 for Figure 2 Top view of fixed pad A in the middle. Figure 4 for Figure 3 Front view of fixed pad A in the middle. Figure 5 for Figure 2 Top view of fixed pad B in the middle. Figure 6 Bit Figure 5 Front view of fixed pad B in the middle. Figure 7 for Figure 1 A cross-sectional view of the upper end of the valve-side winding. Figure 8 for Figure 7 A schematic diagram of the distribution of fiber optic limiting pads at point I. Figure 9 for Figure 7 A schematic diagram of the distribution of fiber optic limiting pads at point K. Figure 10 for Figure 7 A schematic diagram of the distribution of fiber optic limiting pads at point J. Figure 11 This is a schematic diagram showing the result of software calculation of the position of the hottest temperature disc in the valve-side winding during the fiber optic path design of this utility model. Figure 12 This is a schematic diagram of the transformer system simulation model established during the fiber optic path design of this utility model. Figure 13 This is a schematic diagram illustrating the three-dimensional temperature and fluid field simulation analysis of the valve-side winding during fiber optic path design in this invention. Figure 14This is a schematic diagram of the fiber optic path simulation obtained during the fiber optic path design of this utility model. Figure 15 This is a schematic diagram of the AC electric field intensity distribution at the upper end of the valve-side winding, obtained during the fiber optic path design for this invention. Figure 16 A schematic diagram of the DC electric field intensity distribution at the upper end of the valve-side winding obtained during the fiber optic path design for this utility model.

[0016] Wherein, 1 is a fixing pad A, 101 is the first temperature probe, 1011 is the first optical fiber cable, 102 is the second temperature probe, 1021 is the second optical fiber cable, 2 is a fixing pad B, 201 is the third temperature probe, 2011 is the third optical fiber cable, 202 is the fourth temperature probe, 2021 is the fourth optical fiber cable, 3 is the optical fiber path, 4 is the optical fiber through plate, 5 is the valve side winding, 601 is the first probe fixing slot, 701 is the first optical fiber lead-out slot, 602 is the second probe fixing slot, 702 is the second optical fiber lead-out slot, 8 is the upper slot, 9 is the optical fiber limiting pad, 901 is the optical fiber limiting slot, 10 is the corner ring, and 11 is the electrostatic ring. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings.

[0018] like Figures 1-6 As shown, this utility model includes a valve-side winding 5, a hotspot optical fiber, and an oil passage optical fiber. The upper end of the valve-side winding 5 is provided with a fixing block A1 and a fixing block B2. The temperature probe of the hotspot optical fiber is fixed to the hottest coil at the beginning of the valve-side winding 5 via the corresponding fixing block A1. The temperature probe of the oil passage optical fiber is fixed to the first oil passage at the top of the valve-side winding 5 via the corresponding fixing block B2. Figure 7 As shown, an electrostatic ring 11 is provided at the upper end of the valve-side winding 5, and multiple layers of corner rings 10 are provided on the upper side of the electrostatic ring 11. In addition to the normal support pads, fiber optic limiting pads 9 are also provided between adjacent layers of corner rings 10, such as... Figures 8-10 As shown, each fiber optic limiting pad 9, together with each supporting pad, is evenly arranged along the circumferential direction of the valve-side winding 5. The fiber optic limiting pad 9 is provided with a fiber optic limiting groove 901 for the corresponding fiber optic cable to pass through; as shown... Figure 7 As shown, both the hotspot fiber and the oil channel fiber pass through the gap between the two electrostatic rings 11, and then... Figures 8-10 As shown, the fiber optic cable then passes sequentially through the corresponding fiber optic limiting pads 9 and corner rings 10 of each layer, and finally exits through the gap between the two corner rings 10 of the top layer. Figure 1 As shown, the fiber optic limiting pads 9 of each layer are arranged and connected sequentially along the circumferential direction of the valve-side winding 5, thereby limiting the extension of each fiber optic cable along the set fiber optic path 3.

[0019] like Figures 3-4 As shown, in this embodiment, the fixing pad A1 is provided with a first probe fixing groove 601 and a first optical fiber lead-out groove 701. The temperature measuring probe of the hot spot optical fiber is fixed in the first probe fixing groove 601 of the corresponding pad, and the optical fiber cable is led out along the first optical fiber lead-out groove 701 of the corresponding pad.

[0020] like Figures 5-6 As shown, in this embodiment, the fixing pad B2 is provided with a second probe fixing groove 602 and a second optical fiber lead-out groove 702. The temperature measuring probe of the oil channel optical fiber is fixed in the second probe fixing groove 602 of the corresponding pad, and the optical fiber cable is led out along the second optical fiber lead-out groove 702 of the corresponding pad. In addition, the fixing pad B2 is provided with an upper slot 8 that communicates with the second probe fixing groove 602. Its position corresponds to the center line connecting the various second probe fixing grooves 602. The upper slot 8 facilitates the flow of transformer oil into the second probe fixing groove 602, so that the optical fiber probe and the oil can directly contact each other to monitor the oil temperature.

[0021] like Figure 7 As shown, except for the fiber optic limiting pad 9, the rest of the structure at the upper end of the valve-side winding 5 is all known in the art, as can be seen in patents such as CN201562556U. However, this utility model replaces a portion of the support pads in the prior art with the fiber optic limiting pad 9, thereby achieving the desired effect. Figure 1 The diagram shows the purpose of guiding the optical fiber cable to extend within the set optical fiber path 3 range. The optical fiber path 3 must ensure that the optical fiber cable does not enter the high field strength region, thereby ensuring that the hot spot optical fiber and the oil channel optical fiber can operate reliably in the AC and DC field superposition region at the end of the valve side winding 5. For details, please refer to the design section of the optical fiber path 3 later.

[0022] like Figures 8-10 As shown, on the upper end of the valve-side winding 5, the fiber optic limiting pads 9 between adjacent corner rings 10 are designed in terms of the number and structure of fiber optic limiting grooves 901 in conjunction with the fiber optic path 3, such as... Figure 2 As shown, this embodiment includes two fixing blocks A1 and two fixing blocks B2. One fixing block A1 is provided with a first temperature probe 101, and the other fixing block A1 is provided with a second temperature probe 102. One fixing block B2 is provided with a third temperature probe 201, and the other fixing block B2 is provided with a fourth temperature probe 202.

[0023] Figure 8 As shown Figure 7 The fiber optic limiting pad 9 in the layer indicated by I is relatively densely designed because the various hot spot fibers and oil channel fibers are just introduced through the gap between the two electrostatic rings 11. Figure 8The first optical fiber cable 1011 is connected to the first temperature probe 101, and the second optical fiber cable 1021 is connected to the second temperature probe 102. Both of these are hotspot optical fibers. Additionally... Figure 8 The third optical fiber cable 2011 is connected to the third temperature probe 201, and the fourth optical fiber cable 2021 is connected to the fourth temperature probe 202. All of the above are oil channel optical fibers.

[0024] Figure 9 As shown Figure 7 The fiber optic limiting pad 9 at the middle K layer has a certain degree of expansion due to the extension of the various hot spot fibers and oil channel fibers at this layer. The fiber optic limiting groove 901 is designed to be relatively loose, that is, the distance between the two fiber optic limiting grooves 901 located on the same fiber optic limiting pad 9 is increased.

[0025] Figure 10 As shown Figure 7 The fiber optic limiting pad 9 at point J in the middle layer has a more loose design for the fiber optic limiting groove 901, meaning that each fiber optic limiting pad 9 has only one fiber optic limiting groove 901.

[0026] This utility model, through the combined design of the aforementioned fiber optic limiting pads 9, can achieve the following: Figure 7 As shown, this ensures that the optical fiber can be smoothly led out from inside the valve-side winding 5, and can also be... Figure 1 The diagram shows that each hot spot fiber and oil channel fiber extends within the specified fiber path 3, thereby ensuring that the hot spot fiber and oil channel fiber can operate reliably in the AC and DC electric field superposition region at the end of the valve side winding 5.

[0027] like Figure 1 As shown, the hotspot fiber and the oil channel fiber are led out from the gap between the two uppermost corner rings 10 and extend outward along the radial direction of the valve-side winding 5 to the fiber optic through-hole plate 4, and then connected to the fiber optic temperature measuring device through an external fiber. Both the fiber optic through-hole plate 4 and the fiber optic temperature measuring device are technologies known in the art.

[0028] The working principle of this utility model is as follows: The design of this utility model includes the following steps: Step 1: Establish a simulation model of the converter transformer system.

[0029] like Figure 12 As shown, this embodiment establishes a transformer system simulation model using one-dimensional system simulation software, and then calculates the overall working oil flow rate of the transformer system. The simulation software is a technology known in the art.

[0030] Step Two: Based on Step One, the flow rate of valve-side winding 5 is calculated, and then a three-dimensional temperature and fluid field simulation analysis of transformer valve-side winding 5 is performed using CFD simulation software. The simulation analysis in this embodiment is as follows: Figure 13 As shown. Furthermore, the CFD simulation software described is a technology well-known in the field.

[0031] Step 3: Based on Step 2, the position of the coil with the hottest spot temperature in valve-side winding 5 is calculated using software. The calculation result in this embodiment is as follows: Figure 11 As shown. Furthermore, this embodiment uses TranCalc software for calculation, which is a well-known technique in the field.

[0032] Step 4: Starting from the position of the hottest point on the valve-side winding 5, determine the fiber optic path 3 using transformer electric field calculation software, and ensure that the fiber optic cable can operate reliably in the AC and DC field superposition region at the winding end. The calculation results are as follows: Figure 14 As shown. In this embodiment, the transformer electric field calculation software is TELASZ-2D, which is a well-known technology in the field.

[0033] The specific steps for step four are as follows: Step 4.1: First, based on the actual dimensions and structure of the converter transformer end insulation, preliminarily determine the fiber position and direction in the model, considering the relative position of the fiber and components such as corner ring 10. While ensuring accuracy, unnecessary details can be deleted to improve the mesh generation quality.

[0034] Step 4.2: Define the material parameters of each part of the transformer according to the actual materials used, such as the relative permittivity and resistivity of the cardboard tube, corner ring 10, insulating paper and optical fiber. Among them, the optical fiber material has high insulation performance, and its permittivity and resistivity are different from those of the materials in the transformer. The parameters should be set according to the data provided by the manufacturer.

[0035] Step 4.3: Based on the transformer insulation level and test plan, calculate the AC and DC electric fields after placing the optical fiber, and analyze the electric field distribution characteristics after adding the optical fiber. Pay particular attention to the electric field intensity distribution on the optical fiber under DC voltage and the field strength distribution along the surface. If the electric field intensity on the optical fiber and the field strength along the surface exceed the design specifications, adjust the optical fiber arrangement to ensure that the overall design margin is not reduced after adding the optical fiber. The AC and DC electric field intensity distributions on the upper end of the valve-side winding 5 obtained in this step can be found in [reference needed]. Figure 15 and Figure 16 .

[0036] Finally, based on the above calculation results, this utility model determines that a temperature probe for hot spot optical fiber is placed at the hottest wire cake at the beginning of the valve-side winding 5, and a temperature probe for oil channel optical fiber is placed at the first oil channel at the top of the valve-side winding 5. At the same time, the quantity and structure of each layer of optical fiber limiting pads 9 are designed and processed according to the optical fiber path 3 determined above.

[0037] This invention achieves stable temperature measurement under AC and DC superimposed electric fields by rationally arranging fiber optic lead-out points and using fiber optic limiting pads 9 in each layer to control the deviation of the fiber optic cable path. This ensures that the temperature deviation of each group of fiber optic temperature measurement values ​​is 2K throughout the ten temperature measurement processes, and the fiber optic signal strength at all temperature measurement points is not less than 80%. Furthermore, this invention can ensure the safe and stable operation of the converter transformer equipment and extend its service life by directly, accurately, and in real-time monitoring the temperature inside the winding.

Claims

1. A fiber optic temperature measurement structure for a converter transformer, characterized in that: The device includes a valve-side winding (5), a hot spot fiber, and an oil channel fiber. The valve-side winding (5) is provided with a fixing pad A (1) and a fixing pad B (2) at its upper end. The temperature probe of the hot spot fiber is fixed to the hottest wire at the beginning of the valve-side winding (5) by the corresponding fixing pad A (1). The temperature probe of the oil channel fiber is fixed to the first oil channel at the top of the valve-side winding (5) by the corresponding fixing pad B (2). The valve-side winding (5) is provided with a multi-layer corner ring (10) at its upper end. There is a fiber limiting pad (9) between adjacent corner rings (10). The fiber limiting pad (9) is provided with a fiber limiting groove (901) for the fiber cable to pass through. The hot spot fiber and the oil channel fiber pass through the corresponding fiber limiting pad (9) and corner ring (10) of each layer in sequence, and then are led out from the gap between the two corner rings (10) of the uppermost layer.

2. The fiber optic temperature measurement structure for converter transformers according to claim 1, characterized in that: Each fiber optic limiting pad (9) located on the same layer is arranged along the circumferential direction of the valve-side winding (5), while the fiber optic limiting pads (9) of each layer are sequentially connected along the circumferential direction of the valve-side winding (5).

3. The fiber optic temperature measurement structure for converter transformers according to claim 1, characterized in that: The valve-side winding (5) is provided with an electrostatic ring (11) at the upper end, and the electrostatic ring (11) is provided with a multi-layer corner ring (10) on the upper side. The hot spot fiber and the oil channel fiber are introduced through the gap between the two electrostatic rings (11) and then pass through the corresponding fiber limiting pads (9) and corner rings (10) of each layer in sequence.

4. The fiber optic temperature measurement structure for converter transformers according to claim 1, characterized in that: The fixed pad A (1) is provided with a first probe fixing groove (601) and a first optical fiber lead-out groove (701), and the temperature measuring probe of the hot spot optical fiber is fixed in the first probe fixing groove (601).

5. The fiber optic temperature measurement structure for converter transformers according to claim 1, characterized in that: The fixed pad B (2) is provided with a second probe fixing groove (602) and a second optical fiber lead-out groove (702), and the temperature measuring probe of the oil channel optical fiber is fixed in the second probe fixing groove (602).

6. The fiber optic temperature measurement structure for converter transformers according to claim 5, characterized in that: The fixing pad B (2) has an upper slot (8) that communicates with the second probe fixing slot (602), and the position of the upper slot (8) corresponds to the center line of each second probe fixing slot (602).

7. The fiber optic temperature measurement structure for converter transformers according to claim 1, characterized in that: The hot spot fiber and the oil channel fiber are led out from the gap between the uppermost corner ring (10) and extend outward along the radial direction of the valve side winding (5) to the fiber optic through plate (4).

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