A novel ultra-high voltage reactor resistant to low temperatures

Abstract

A novel low-temperature resistant ultra-high voltage reactor, relating to the field of reactor equipment technology, includes a reactor core installed between two sets of conductive star frames. The reactor core comprises multiple layers of spaced-apart encapsulation bodies, each arranged in a ring. Each encapsulation body includes an inner encapsulation with a conductive coil wound around its outer side, the two ends of which are connected to the two sets of conductive star frames. An outer encapsulation is also wound around the outer side of the conductive coil. The radial thickness of the inner encapsulation is greater than that of the outer encapsulation. After the conductive coil is wound, a sealant compound layer is applied to its outer surface. This enhances the crack resistance of the inner layer, adapting to the reactor's high-load, continuous heating conditions. Simultaneously, the sealant compound layer fills the gaps in the coil winding, improving the overall structural density and water-tightness, alleviating structural deformation stress caused by significant temperature differences, and greatly reducing problems such as insulation cracking and moisture penetration.

Description

Technical Field

[0001] This invention relates to the field of reactor equipment technology, specifically to a novel ultra-high voltage reactor resistant to low temperatures. Background Technology

[0002] Currently, conventional UHV dry-type air-core reactors still use traditional electromagnetic wire winding and standard thickness insulation encapsulation processes, relying on a single epoxy resin encapsulation for insulation protection. This can meet the basic operational needs of UHV sites in temperate climate zones. However, many UHV transmission lines traverse cold and high-altitude areas in the north, where extreme winter temperatures can drop below -50°C. UHV reactors, operating under long-term high loads, continuously generate significant heat, creating a huge temperature difference between the equipment's own temperature rise and the extremely low external temperatures. The insulation encapsulation is frequently subjected to significant alternating stresses due to thermal expansion and contraction. Existing UHV reactors lack specific low-temperature reinforcement designs, resulting in weak tensile and crack resistance, making them highly susceptible to encapsulation cracking and damage. Furthermore, the traditional winding process has numerous gaps at the joints, leading to poor overall sealing performance. In low-temperature environments, moisture easily penetrates the encapsulation, causing rapid deterioration of the coil insulation under UHV conditions, potentially leading to partial discharge, insulation breakdown, and other major power grid safety hazards. Summary of the Invention

[0003] To address the problems of poor low-temperature resistance and low tensile strength of the encapsulation surface in existing reactors, this invention provides a novel ultra-high voltage reactor with low-temperature resistance.

[0004] The technical solution of this invention is as follows: A novel ultra-high voltage reactor resistant to low temperatures includes a reactor core, which is installed between two sets of conductive star frames; The reactor core comprises multiple layers of encapsulated bodies spaced apart, each layer arranged in a ring shape; The encapsulation body includes an inner encapsulation, on the outside of which a conductive coil is wound, and the two ends of the conductive coil are respectively connected to two sets of conductive star frames. An outer encapsulation is wound on the outside of the conductive coil. The radial thickness of the inner encapsulation is greater than that of the outer encapsulation, and after the conductive coil is wound, a filler compound layer is applied to its outer surface.

[0005] To further enhance the overall insulation and protection capabilities of the inner and outer encapsulations, reduce the direct erosion of the encapsulation substrate and conductive coils by external low-temperature moisture and frost, and improve the low-temperature aging resistance of the encapsulation surface, both the inner and outer surfaces of the inner and outer encapsulations are coated with an insulating layer.

[0006] In order to reduce the tensile stress caused by thermal expansion and contraction in low-temperature environments and improve the overall crack resistance, multiple glass fiber layers are wound around the outer surface of the insulation layer of both the inner and outer encapsulation.

[0007] To ensure that the glass fiber layer is evenly stressed and to avoid local stress concentration, the glass fiber layer is provided with 8-12 glass fibers, which are obliquely wound along the inner or outer encapsulation.

[0008] In order to form a closed-loop, all-round winding reinforcement structure that covers all weak stress areas of the encapsulation sidewalls, top, and bottom, and to make up for the crack resistance shortcomings of the upper and lower end faces of the annular encapsulation, the glass fiber layer is set by diagonally pulling upwards from the inner or outer encapsulation side, passing over the top, and then diagonally pulling downwards to pass over the bottom.

[0009] In order to further enhance the overall tensile strength of the glass fiber layer, form a multi-layer composite protective tensile mesh, distribute the alternating cold and heat stress step by step, and adapt to the ultra-large temperature difference working conditions in high-altitude and extremely cold regions, the glass fiber layer is wound with at least three layers along the inner or outer encapsulation.

[0010] In order to ensure that the inner layer can withstand the main alternating stress and play a core anti-cracking buffer role, while avoiding the heat dissipation obstruction caused by the redundancy of the outer encapsulation thickness, and to balance the low temperature resistance, equipment weight and coil heat dissipation effect, the radial thickness of the outer encapsulation is 1 / 2 to 4 / 5 of the radial thickness of the inner encapsulation.

[0011] To ensure a stable heat dissipation channel between the multiple layers of encapsulation, promptly remove the heat generated during coil operation, reduce the temperature difference between the inside and outside of the equipment, reduce alternating stress due to thermal expansion and contraction from the source, and at the same time ensure that the interlayer insulation distance meets the standard and avoid the risk of interlayer discharge, the thickness of the inner encapsulation is 2.5mm-4.5mm, and the spacing between the outer encapsulation and the inner encapsulation is 4-5 times the thickness of the inner encapsulation.

[0012] To improve the overall thermal uniformity of the coil and reduce the local temperature difference of the coil, the conductive coil includes multiple turns of electromagnetic wire wrapped in an inner enclosure, and the wires are arranged closely from the inner enclosure to the outer enclosure.

[0013] To ensure the stability of the compound under high and low temperature differences, reduce shrinkage cracking and moisture absorption problems, permanently seal the gaps in coil winding, effectively prevent water vapor penetration, and ensure insulation stability under thermal expansion and contraction conditions, the filling compound layer uses a single-component epoxy resin paste. The volume shrinkage rate is no more than 2% and the mass loss is no more than 0.5% after being placed at 100℃ for T hours, and the water absorption rate is no more than 0.5% after being placed at room temperature for T hours.

[0014] The beneficial effects of this invention are as follows: This invention is a novel ultra-high voltage reactor resistant to low temperatures. Unlike traditional reactors that rely solely on a single layer of standard epoxy resin encapsulation for insulation protection, this solution adopts a double-layer encapsulation layout with a thicker inner layer and a thinner outer layer. The thicker inner encapsulation bears the main alternating temperature difference stress, improving the crack resistance of the inner layer. At the same time, it limits the reasonable thickness ratio between the outer and inner encapsulations and the safe spacing between layers, taking into account both insulation performance and heat dissipation requirements. It is suitable for reactors operating under high load and continuous heating conditions. In addition, a special sealant compound layer is used to fill the gaps in the coil winding, improving the overall structural density and sealing and water-proofing capabilities, alleviating the structural deformation stress caused by large temperature differences, greatly reducing problems such as insulation encapsulation cracking and moisture infiltration, effectively slowing down the rate of coil insulation deterioration in cold environments, and ensuring the long-term stable, safe and reliable operation of the ultra-high voltage transmission system. Attached Figure Description

[0015] The solutions and advantages of this application will become clear to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0016] In the attached diagram: Figure 1 This is a cross-sectional view of the main body of the package; Figure 2 This is a schematic diagram of the reactor core structure; The components represented by the various reference numerals in the diagram are: 1. Encapsulation body; 11. Inner encapsulation; 12. Conductive coil; 13. Outer encapsulation; 14. Sealant compound layer; 15. Glass fiber layer. Detailed Implementation

[0017] Exemplary embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. It should be noted that these embodiments are provided to enable a more thorough understanding of this disclosure and to fully convey the scope of this disclosure to those skilled in the art. This disclosure can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0018] Example This embodiment discloses a novel ultra-high voltage reactor resistant to low temperatures, belonging to the technical field of ultra-high voltage power grid transmission and transformation equipment. It is suitable for long-term operation and use at ultra-high temperature transmission stations in northern regions with extreme cold. The design optimizes the technical defects of existing conventional ultra-high voltage dry-type hollow reactors.

[0019] Existing reactors only use a single standard thickness epoxy resin insulation enclosure for protection, without low-temperature crack resistance or sealing reinforcement structure design. In extreme low-temperature environments below -50℃ in cold regions, the internal temperature rise generated by the reactor's high-load operation and the extremely low external temperature create a huge temperature difference. The insulation enclosure is subjected to high-frequency and large-amplitude alternating stress of thermal expansion and contraction for a long time. The overall tensile and crack resistance of the equipment is insufficient, and the insulation enclosure is prone to cracking and damage. This solution effectively improves the overall tensile and fatigue crack resistance of the insulation enclosure through an overall structural design that combines a differentiated thickness double-layer enclosure structure and multiple layers of inclined glass fiber 15 winding, thereby offsetting the alternating stress generated by high and low temperature alternation.

[0020] The overall structure of this novel low-temperature resistant ultra-high voltage reactor includes a reactor core and two sets of conductive star frames symmetrically arranged at both ends of the reactor core. The reactor core is assembled and fixed between the two sets of conductive star frames. The conductive star frames are used to achieve conductive wiring and end fixing support, ensuring the stability of the overall installation structure of the reactor and meeting the mechanical vibration resistance and electrical connection requirements under ultra-high voltage conditions. The form of the conductive star frames and their connection with the reactor core can be achieved using existing technologies, such as the star-shaped support in the interchangeable assembly structure dry hollow reactor disclosed in patent number CN209708801U. The figure in this scheme shows the cross-sectional structure of the single-layer encapsulated main body 1. Other existing equipment and connections will not be described in detail.

[0021] Specifically, combining 1 and Figure 2 The reactor core includes multiple layers of annularly spaced encapsulated bodies 1. Each encapsulated body 1 is an annular structure. The multiple annular encapsulations cooperate with each other to form an overall layered insulation and protection system, dispersing the overall stress caused by high and low temperature alternation.

[0022] Based on the above structure, the single-unit encapsulation body 1 includes an inner encapsulation 11 and an outer encapsulation 13. A conductive coil 12 is wound between the two. The conductive coil 12 is tightly wound and fixed on the outer circumferential side of the inner encapsulation 11. The two ends of the conductive coil 12 are respectively connected to the conductive star frame on both sides to realize the conduction of electrical energy and the operation of electromagnetic induction. The outer encapsulation 13 is then wound around the outside of the conductive coil 12. The inner and outer double encapsulation forms an all-round insulating and protective package for the middle conductive coil 12. The double-layer split encapsulation can offset the thermal expansion and contraction stress in layers and improve the overall crack resistance.

[0023] In addition, combined Figure 1This design specifies a differentiated thickness design for the inner and outer encapsulations 13. The radial thickness of the inner encapsulation 11 is greater than that of the outer encapsulation 13, with the radial thickness of the outer encapsulation 13 ranging from 1 / 2 to 4 / 5 of the radial thickness of the inner encapsulation 11. This creates a gradient protection structure with a thicker inner wall and a thinner outer wall. The thicker inner wall of the inner encapsulation 11 can withstand the internal thermal stress generated by the coil's heating, while the thinner outer wall of the outer encapsulation 13 adapts to the shrinkage deformation caused by the extremely low temperature environment. The internal and external deformations compensate for each other, effectively reducing the concentration of alternating stress and improving the overall strength of the encapsulation structure. Specifically, the radial thickness of the inner encapsulation 11 is controlled within the range of 2.5mm to 4.5mm, and a safety insulation gap is reserved between the inner and outer encapsulations 13. This gap is 4 to 5 times the thickness of the inner encapsulation 11. The reasonable interlayer spacing further buffers the temperature deformation difference while ensuring that the insulation safety distance between the two encapsulations meets the standard, reducing the risk of interlayer discharge.

[0024] In this embodiment, the conductive coil 12 is tightly wound with multiple turns of electromagnetic wire, and all the electromagnetic wires are wound in a ring around the outer circumference of the inner enclosure 11, and are arranged in a tight and orderly manner from the inner enclosure 11 toward the outer enclosure 13. At the same time, the traditional coil winding process has gaps at the joints, and the overall airtightness of the equipment is poor. In low-temperature environments, moisture in the air can easily seep into the interior of the insulation enclosure along the gaps at the joints, causing the coil insulation layer to age and deteriorate rapidly, which in turn can lead to serious power grid operation safety accidents such as partial discharge and insulation breakdown. After the conductive coil 12 is wound, a layer of filler compound 14 is uniformly applied to the outer surface to fill the tiny joints, inter-turn gaps and gaps at the joints between the coil and the inner and outer enclosures 13. In this embodiment, the sealant layer 14 is a single-component epoxy resin paste, which is blue in appearance. After being placed at a constant temperature of 100°C for a preset time T hours, the volume shrinkage rate of this material is no more than 2%, and the mass loss is no more than 0.5%. Under high temperature conditions, its deformation is minimal and its performance is stable. At the same time, when placed at room temperature for the same time T hours (T is usually 24 hours), the overall water absorption rate is no more than 0.5%, which has extremely low water absorption and air permeability. Even when in a low temperature and high humidity environment for a long time, it can effectively prevent water vapor from entering the coil and maintain the long-term stability of the coil's insulation performance.

[0025] In addition, combined Figure 1The inner and outer surfaces of both the inner and outer enclosures 11 and 13 are uniformly coated with a special insulating layer to further enhance the basic insulation performance of the double-layer enclosure and strengthen the insulation withstand voltage under ultra-high voltage conditions. After the insulating layer is cured, multiple glass fiber layers 15 are wound around the outer surface of the insulating layer to enhance its toughness. A total of 8-12 glass fibers are wound around the outer side of each enclosure insulation layer. All glass fiber layers 15 are wound obliquely around the annular enclosure body. The oblique winding can form an oblique mesh-like stress structure, which resists radial, axial and circumferential cracking stresses in all directions. The glass fiber layers 15 adopt a circular arrangement path, starting from one side of the enclosure, obliquely going up around the top of the annular enclosure, and then obliquely going down around the bottom of the enclosure, forming a complete closed-loop oblique winding structure with no dead angles. At the same time, the glass fiber layers 15 are continuously wound at least three times along the outer wall of the enclosure. The multiple layers of glass fiber layers 15 are interwoven with each other and form a composite structure with the epoxy resin enclosure matrix, which greatly improves the overall tensile strength and fatigue crack resistance of the insulation enclosure and effectively resists the structural cracking risk caused by repeated high and low temperature alternating stress.

[0026] This reactor abandons the traditional single-thickness epoxy resin encapsulation structure, adopting a double-layer encapsulation with a thicker inner layer and a thinner outer layer, combined with a multi-layer oblique glass fiber layer 15. This effectively improves the insulation encapsulation's resistance to alternating stress and low-temperature cracking, making it suitable for extreme temperature difference conditions in high-altitude and cold regions. The inner encapsulation 11, with its varying thickness angle, can withstand the thermal stress generated by the thermal expansion and contraction of the reactor's inner coils. Combined with a low-shrinkage, low-water-absorption sealant layer 14, it seals the coil winding gaps, significantly reducing insulation faults caused by moisture infiltration. It can operate stably for extended periods in high-altitude and cold-climate ultra-high-voltage transmission scenarios in northern regions, effectively reducing safety hazards such as encapsulation cracking, partial discharge, and insulation breakdown, and improving the operational reliability of ultra-high-voltage power grid lines in cold regions.

Claims

1. A novel ultra-high voltage reactor resistant to low temperatures, characterized in that, Includes the reactor core, which is installed between two sets of conductive star frames; The reactor core includes multiple layers of encapsulated bodies (1) arranged at intervals, each layer being arranged in a ring shape; The encapsulation body (1) includes an inner encapsulation (11), on the outside of which a conductive coil (12) is wound, and the two ends of the conductive coil (12) are respectively connected to two sets of conductive star frames. The outer encapsulation (13) is wound on the outside of the conductive coil (12). The radial thickness of the inner encapsulation (11) is greater than the radial thickness of the outer encapsulation (13), and after the conductive coil (12) is wound, a filler compound layer (14) is applied to its outer surface.

2. The novel ultra-high voltage reactor resistant to low temperatures according to claim 1, characterized in that, The inner and outer surfaces of the inner encapsulation (11) and the outer encapsulation (13) are coated with an insulating layer.

3. The novel ultra-high voltage reactor resistant to low temperatures according to claim 2, characterized in that, Multiple glass fiber layers (15) are wound around the outer surface of the insulating layer of both the inner encapsulation (11) and the outer encapsulation (13).

4. A novel ultra-high voltage reactor resistant to low temperatures according to claim 3, characterized in that, The glass fiber layer (15) is provided with 8-12 glass fibers, which are obliquely wound along the inner enclosure (11) or the outer enclosure (13).

5. A novel ultra-high voltage reactor resistant to low temperatures according to claim 4, characterized in that, The glass fiber layer (15) is set by diagonally pulling upwards from the inner enclosure (11) or the outer enclosure (13) to bypass the top and then diagonally pulling downwards to bypass the bottom.

6. A novel ultra-high voltage reactor resistant to low temperatures according to claim 4, characterized in that, The glass fiber layer (15) is wound in at least three layers along the inner encapsulation (11) or the outer encapsulation (13).

7. A novel ultra-high voltage reactor resistant to low temperatures according to claim 1, characterized in that, The radial thickness of the outer encapsulation (13) is 1 / 2 to 4 / 5 of the radial thickness of the inner encapsulation (11).

8. A novel ultra-high voltage reactor resistant to low temperatures according to claim 7, characterized in that, The thickness of the inner encapsulation (11) is 2.5mm-4.5mm, and the distance between the outer encapsulation (13) and the inner encapsulation (11) is 4-5 times the thickness of the inner encapsulation (11).

9. A novel ultra-high voltage reactor resistant to low temperatures according to claim 1, characterized in that, The conductive coil (12) comprises multiple turns of electromagnetic wire wound around the inner enclosure (11) and arranged closely from the inner enclosure (11) to the outer enclosure (13).

10. A novel ultra-high voltage reactor resistant to low temperatures according to claim 1, characterized in that, The sealant compound layer (14) is made of single-component epoxy resin paste, and its volume shrinkage rate is not greater than 2% and its mass loss is not greater than 0.5% when placed at 100°C for T hours, and its water absorption rate is not greater than 0.5% when placed at room temperature for T hours.

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