Dry-type air-core connecting reactor for slcc hybrid dc power transmission

Abstract

This invention discloses a dry-type hollow-connected reactor for SLCC hybrid DC transmission, comprising a reactor coil, a rain cap, a side bird guard, an upper hanger, a lower hanger, a transition seat, an insulator, fiberglass legs, a foundation, and a surge arrester. The foundation is located at the bottom. One end of the fiberglass leg is fixedly connected to the foundation, and the other end of the fiberglass leg is connected to one end of the insulator. The other end of the insulator is connected to one end of the transition seat, and the other end of the transition seat is connected to one side of the lower hanger. The other side of the lower hanger is connected to one end of the reactor coil, and the other end of the reactor coil is connected to one side of the upper hanger. The rain cap is fixedly connected to the other side of the upper hanger. The upper end of the rain cap has a rain cap corona ring, and the lower end of the rain cap has a side bird guard. The upper hanger is connected to the upper end of the surge arrester, and the lower hanger is connected to the lower end of the surge arrester. This invention fundamentally solves the problem of inter-turn insulation failure in SLCC systems under ultra-high repetitive pulse voltages.

Description

Technical Field

[0001] This invention relates to the field of power system transmission and distribution equipment technology, specifically to a dry-type air-connected reactor for SLCC hybrid DC transmission. Background Technology

[0002] SLCC (Self-adaptation statcom and Line Commutation Converter) transmission system is an advanced hybrid DC transmission technology that cleverly combines the advantages of traditional LCC (Line-Commutated Converter) and SVG (Static Var Generator). It aims to address some pain points in existing transmission systems and is particularly suitable for the needs of new power systems. During operation, the SLCC system's connecting reactors, connected in series with the SVG device, must withstand harmonic content far exceeding that of conventional DC transmission system reactors and continuous high-voltage pulse impacts (peak values ​​above 150kV, occurring four times per 50Hz power frequency cycle). The inter-turn insulation requirements of the windings are also significantly higher than those of traditional reactors. Traditional DC transmission system reactors use conventional imide film-insulated transposed conductors. While these conductors can reduce eddy current losses, they cannot withstand repeated pulse impacts over long periods. Furthermore, traditional reactors cannot achieve dynamic and optimal reactive power compensation or filtering, potentially leading to overcompensation or undercompensation, affecting the system's economic efficiency and safety. Summary of the Invention

[0003] The technical problem to be solved by this invention is to address the problem of inter-turn insulation failure under ultra-high repetitive pulse voltage in the prior art, and to provide a dry-type air-core connected reactor for SLCC hybrid DC transmission, thereby improving the inter-turn insulation level of the product.

[0004] To solve the above technical problems, the present invention adopts the following technical solution:

[0005] A dry-type hollow-connected reactor for SLCC hybrid DC transmission includes a reactor coil, a rain cap, a side bird guard, an upper hanger, a lower hanger, a corona ring, a transition seat, an insulator, fiberglass legs, a foundation, and a surge arrester.

[0006] The foundation is located at the bottom. One end of the fiberglass support leg is fixedly connected to the foundation with anchor bolts. The other end of the fiberglass support leg is connected to one end of the insulator. The other end of the insulator is connected to one end of the transition seat. The other end of the transition seat is connected to one side of the lower hanger. The other side of the lower hanger is connected to one end of the reactor coil. The other end of the reactor coil is connected to one side of the upper hanger. The rain cap is fixedly connected to the other side of the upper hanger through multiple support rods. The upper end of the rain cap is equipped with a rain cap corona ring, and the lower end of the rain cap is equipped with a side bird guard.

[0007] Both the upper and lower hangers are equipped with corona rings; the upper hanger is connected to the upper end of the surge arrester, and the lower hanger is connected to the lower end of the surge arrester.

[0008] Furthermore, there are two sets of reactor coils, and the terminals of the two sets of reactor coils are symmetrically connected through a parallel connection board to reduce the circulating current between parallel branches, and they are arranged horizontally in parallel in space.

[0009] The reactance coil is made of mica-imide film transposed wire; the mica-imide film transposed wire includes a transposed core wire, a single wire insulation layer and a mica-imide composite insulation layer.

[0010] The reactor coil has multiple encapsulation layers, and a ventilation strip is provided between each encapsulation layer. The ventilation strip is T-shaped.

[0011] Furthermore, the mica-imide composite insulation layer is a composite structure of polyimide film and mica film, bonded together using H-grade heat-resistant insulating adhesive.

[0012] Furthermore, the upper suspension frame includes a first central hub, a first horizontal binding strap, an upper lifting arm, and a reinforcing plate. The upper lifting arm includes a long upper lifting arm and a short upper lifting arm. One end of multiple radially arranged upper lifting arms is welded to the first central hub, and the adjacent upper lifting arms are bound together with the first horizontal binding strap. The reinforcing plate is welded to the first central hub.

[0013] The lower hanger includes a second center hub, a second horizontal tie-down strap, and a lower boom. The lower boom includes a long lower boom and a short lower boom. One end of each of the multiple radially arranged lower booms is welded to the second center hub, and the adjacent lower booms are tied together with the second horizontal tie-down strap.

[0014] Vertical binding straps are used to bind the upper and lower booms, which are on the same vertical plane.

[0015] Furthermore, both the upper and lower booms are equipped with terminal blocks at their ends, which are used to connect to external equipment.

[0016] Furthermore, the side bird guard includes a side partition and a bird guard; the side partition is a ring-shaped structure spliced ​​together by multiple arc segments with the frame bent outward at 90°, the upper 90° bend of the side partition is connected to the outer edge of the rain cap, and the lower 90° bend of the side partition is connected to the bird guard.

[0017] Furthermore, there is a gap between the corona ring and the outer surface of the reactor. The corona ring includes a multi-layered arc-shaped corona ring unit, all of which are located on the same horizontal plane, and there is a set spacing between two adjacent corona ring units.

[0018] The corona ring unit is an arc-shaped hollow tube structure made of aluminum alloy.

[0019] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0020] This invention uses transposed wires made of mica-imide film to wind two identical reactor coils connected in parallel to form a single-phase reactor. This reduces the amount of wire used and lowers costs. Increasing the number of turns in the reactor coil reduces the pulse voltage that each turn of wire needs to withstand, thus improving the safety and reliability of the reactor. Attached Figure Description

[0021] Figure 1 This is an overall structural diagram of the present invention.

[0022] Figure 2 This is a top view of the present invention.

[0023] Figure 3 This is a top view of the rain cap in this invention.

[0024] Figure 4 This is the left view of the present invention.

[0025] Figure 5 This is a structural diagram of the mica imide film transposition wire in this invention.

[0026] Figure 6 This is a front view of the bird guard on the side of the rain cap in this invention.

[0027] Figure 7 This is a top view of the side bird guardrail in this invention.

[0028] Figure 8 This is a top view of the bottom bird guardrail in this invention.

[0029] Figure 9 This is a top view of the upper suspension bracket in this invention.

[0030] Figure 10 This is a top view of the lower hanger in this invention.

[0031] Figure 11This is a top view of the corona ring unit in this invention.

[0032] Figure 12 This is a cross-sectional view of the corona ring unit in this invention.

[0033] Figure 13 This is a structural diagram of the ventilation strip in this invention.

[0034] Figure 14 This is a physical image of the present invention.

[0035] Figure 15 This is a waveform diagram of the end-to-end lightning full-wave impulse test of the first group of reactor coils in this embodiment of the invention.

[0036] Figure 16 This is a waveform diagram of the end-to-end lightning full-wave impulse test of the second group of reactor coils in this embodiment of the invention.

[0037] Figure 17 This is a waveform diagram of the end-to-end lightning chopped wave impact test of the first group of reactor coils in this embodiment of the invention.

[0038] Figure 18 This is a waveform diagram of the end-to-end lightning chopped wave impact test of the second group of reactor coils in this embodiment of the invention.

[0039] Figure 19 This is a waveform diagram of the inter-turn insulation test of the reactance coil in an embodiment of the present invention.

[0040] Figure 20 This is a waveform diagram of the end-to-ground lightning full-wave impact test in an embodiment of the present invention.

[0041] Figure 21 This is a waveform diagram of the ground-to-ground lightning interception wave impact test in an embodiment of the present invention.

[0042] Figure 22 This is a waveform diagram of the end-to-ground (wet) operation impact test in an embodiment of the present invention.

[0043] Figure 23 This is a schematic diagram of a reactor obtained by finite element modeling in an embodiment of the present invention.

[0044] Figure 24 This is a standard response spectrum curve under short-term combined loading in an embodiment of the present invention.

[0045] Figure 25 This is a diagram showing the result of applying wind load under short-term combined load in an embodiment of the present invention.

[0046] Figure 26 This is a diagram showing the result of applying ice and snow loads under short-term combined loads in an embodiment of the present invention.

[0047] Figure 27 This is the natural frequency diagram of the reactor obtained by finite element modeling in an embodiment of the present invention.

[0048] Figure 28 This is a diagram showing the reactor displacement results under short-term combined load in an embodiment of the present invention.

[0049] Figure 29 This is a stress diagram of the entire supporting structure under short-term combined load in an embodiment of the present invention.

[0050] Figure 30 This is a stress diagram of the boom under short-term combined load in an embodiment of the present invention.

[0051] Figure 31 This is a stress diagram of the transition seat under short-term combined load in an embodiment of the present invention.

[0052] Figure 32 This is a stress diagram of an insulator under short-term combined load in an embodiment of the present invention.

[0053] Figure 33 This is a stress diagram of the high-leg crossbeam under short-term combined load in an embodiment of the present invention.

[0054] Figure 34 This is a stress diagram of the fiberglass support leg under short-term combined load in an embodiment of the present invention.

[0055] Figure 35 This is a stress diagram of the FRP (fiberglass reinforced plastic) support flange under short-term combined load in an embodiment of the present invention.

[0056] Reference numerals: 1. Reactor coil; 2. Rain cap; 3. Side bird guard; 31. Side partition; 32. Bird guard; 4. Upper hanger; 41. First center hub; 42. First horizontal binding strap; 43. Upper long boom; 44. Upper short boom; 45. Reinforcing plate; 5. Lower hanger; 51. Second center hub; 52. Second horizontal binding strap; 53. Lower long boom; 54. Lower short boom; 6. Corona ring; 61. Corona ring 7. Unit; 8. Transition seat; 9. Insulator; 10. Fiberglass support leg; 11. Parallel connection plate; 12. Foundation; 13. Surge arrester; 14. Mica-imide film transposed conductor; 15. Transposed core wire; 16. Single conductor insulation layer; 17. Mica-imide composite insulation layer; 18. Bottom bird guard; 19. Bottom center hub bird guard; 10. Bottom arc-shaped bird guard; 11. Terminal block; 12. Ventilation strip. Detailed Implementation

[0057] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0058] To achieve the above objectives, this invention proposes a dry-type air-core connected reactor for SLCC hybrid DC transmission, such as... Figure 1 , Figure 2 , Figure 3 As shown, the details are as follows:

[0059] It includes a reactor coil 1, a rain cap 2, a side bird guard 3, an upper hanger 4, a lower hanger 5, a corona ring 6, a transition seat 7, an insulator 8, a fiberglass support leg 9, a foundation 11, and a surge arrester 12.

[0060] The foundation 11 is located at the bottom. One end of the fiberglass support leg 9 is fixedly connected to the foundation 11 by anchor bolts. The other end of the fiberglass support leg 9 is connected to one end of the insulator 8. The other end of the insulator 8 is connected to one end of the transition seat 7. The other end of the transition seat 7 is connected to one side of the lower hanger 5. The other side of the lower hanger 5 is connected to one end of the reactor coil 1. The other end of the reactor coil 1 is connected to one side of the upper hanger 4. The rain cap 2 is fixedly connected to the other side of the upper hanger 4 by multiple support rods. The upper end of the rain cap 2 is provided with a rain cap corona ring, and the lower end of the rain cap 2 is provided with a side bird guard 3.

[0061] like Figure 4 As shown, both the upper hanger 4 and the lower hanger 5 are equipped with corona rings 6; the upper hanger 4 is connected to the upper end of the surge arrester 12, and the lower hanger 5 is connected to the lower end of the surge arrester 12.

[0062] There are two sets of reactor coils 1. The terminals of the two sets of reactor coils 1 are symmetrically connected through parallel connecting plate 10 and arranged horizontally in parallel in space.

[0063] like Figure 5 As shown, the reactance coil 1 is made of mica-imide film transposed wire 13; the mica-imide film transposed wire 13 includes transposed core wire 131, single wire insulation layer 132 and mica-imide composite insulation layer 133.

[0064] The mica-imide composite insulation layer 133 is a composite structure of polyimide film and mica film, bonded together with H-grade heat-resistant insulating adhesive.

[0065] like Figure 6 , Figure 7 As shown, the side bird guardrail 3 includes a side partition 31 and a bird guardrail 32; the side partition 31 is a ring-shaped structure spliced ​​together by multiple arc segments with the edges bent outward at 90°, the upper 90° bend of the side partition 31 is connected to the outer edge of the rain cap 2, and the lower 90° bend of the side partition 31 is connected to the bird guardrail 32.

[0066] like Figure 8As shown, the bottom of the hollow part in the middle of the reactor coil 1 is provided with a bottom bird guard 14, which is connected to the upper part of the lower boom by bolts using a stainless steel support plate.

[0067] The bottom bird guard 14 is a circular structure formed by splicing the bottom center hub bird guard 141 and the bottom arc-shaped bird guard 142, with a mesh inside.

[0068] like Figure 9 As shown, the upper hanger 4 includes a first central hub 41, a first horizontal binding strap 42, an upper hanger arm, and a reinforcing plate 45. The upper hanger arm includes an upper long hanger arm 43 and an upper short hanger arm 44. One end of a plurality of radially arranged upper hanger arms is welded to the first central hub 41, and the adjacent upper hanger arms are bound together with the first horizontal binding strap 42. The reinforcing plate 45 is welded to the first central hub 41.

[0069] like Figure 10 As shown, the lower hanger 5 includes a second central hub 51, a second horizontal binding strap 52, and a lower hanger arm. The lower hanger arm includes a lower long hanger arm 53 and a lower short hanger arm 54. One end of each of the multiple radially arranged lower hanger arms is welded to the second central hub 51, and the adjacent lower hanger arms are bound together with the second horizontal binding strap 52.

[0070] Vertical binding straps are used to bind the upper and lower booms, which are on the same vertical plane.

[0071] Both the upper boom 43 and the lower boom 53 are equipped with terminal blocks 15 at their ends, which are used to connect to external equipment.

[0072] like Figure 11 , Figure 12 As shown, the corona ring 6 includes a multi-layered arc-shaped corona ring unit 61, all of which are located on the same horizontal plane, and there is a gap between two adjacent corona ring units 61.

[0073] The corona ring unit 61 is an arc-shaped hollow tube structure made of aluminum alloy.

[0074] like Figure 13 As shown, the reactor coil 1 has multiple encapsulation layers, and a ventilation strip 16 is provided between each encapsulation layer. The ventilation strip 16 is T-shaped.

[0075] The transition seat 7 is a stainless steel transition seat, the insulator 8 is a high bending resistance insulator, and the fiberglass support leg 9 is an epoxy fiberglass support leg. The number of transition seats 7, insulators 8, and fiberglass support legs 9 is the same as that of the lower boom. All transition seats 7, insulators 8, and fiberglass support legs 9 are arranged parallel to each other and evenly at the other end of the lower boom.

[0076] The dry-type air-core connected reactor proposed in this invention for SLCC hybrid DC transmission is suitable for SLCC systems with voltage levels of 220kV and above and other scenarios with high inter-turn insulation requirements.

[0077] Based on the above operating conditions, the insulation level between the turns of the reactor coil is a crucial parameter in reactor design. Insufficient inter-turn insulation can easily lead to inter-turn breakdown discharge, causing reactor damage. To avoid this problem, a single-phase, two-unit parallel installation method is adopted. This increases the inductance of each unit and the number of turns in the reactor coil, reducing the impulse withstand voltage that each turn of the reactor coil needs to withstand and improving operational safety. Using mica-imide film transposed conductors to wind the reactor coil improves the conductor's long-term voltage withstand level and corona (micro-discharge) resistance.

[0078] Example:

[0079] Figure 14 This is a physical diagram of the dry-type hollow-connected reactor for SLCC hybrid DC transmission proposed in this invention. The reactor was tested for performance, and the specific test items and results are shown in Table 1.

[0080] Table 1 Test Items and Results of Reactors

[0081]

[0082] As can be seen from Table 1, all tests of the reactor proposed in this invention meet the requirements of the technical parameters, indicating that the reactor is a qualified product.

[0083] For the end-to-end full-wave impulse test, the test voltage was 440kV with negative polarity. The obtained waveform is shown below. Figure 15 , Figure 16 As shown. Figure 15 (a) is the lightning impulse waveform at the first end of the first group of reactor coils. It can be seen that the T1 wavefront time is 1.79μs, the T2 half-peak time is 43.07μs, the Upk peak voltage is -446.55kV, and the maximum current passing through is 2.04kA and -3.27kA (the positive and negative signs of the current indicate different current directions). Figure 15 (b) shows the lightning impulse waveform at the end of the first group of reactance coils. It can be seen that the T1 wavefront time is 1.87 μs, the T2 half-peak time is 43.74 μs, the Upk peak voltage is -442.8 kV, and the maximum currents are 3.62 kA and -3.22 kA. Therefore, from... Figure 15 It can be seen from this that the lightning impulse test of the first group of reactor coils was qualified. Figure 16(a) is the lightning impulse waveform at the first end of the second group of reactor coils. It can be seen that the T1 wavefront time is 1.77μs, the T2 half-peak time is 43.63μs, the Upk peak voltage is -444.25kV, and the maximum current passing through is 1.99kA and -3.26kA. Figure 16 (b) shows the lightning impulse waveform at the end of the second group of reactance coils. It can be seen that the T1 wavefront time is 1.9 μs, the T2 half-peak time is 43.54 μs, the Upk peak voltage is -441.25 kV, and the maximum currents are 3.39 kA and -3.84 kA. Therefore, from... Figure 16 It can be seen from this that the lightning impulse test of the second group of reactor coils was qualified.

[0084] For the end-to-end lightning impulse test, the test voltage was 484kV with negative polarity. The obtained waveform is shown below. Figure 17 , Figure 18 As shown. Figure 17 (a) is the lightning truncated waveform at the first end of the first group of reactor coils. It can be seen that the T1 wavefront time is 1.71μs, the Tc cutoff time is 3.74μs, the Upk peak voltage is -484.01kV, the Oz zero-crossing coefficient is 0.00, and the maximum current passing through is 6.89kA and -7.93kA. Figure 17 (b) shows the lightning truncated waveform at the end of the first group of reactor coils. It can be seen that the T1 wavefront time is 1.71 μs, the Tc cutoff time is 3.76 μs, the Upk peak voltage is -491.94 kV, the Oz zero-crossing coefficient is 0.00, and the maximum currents passing through are 12.28 kA and -13.2 kA. Therefore, from... Figure 17 It can be seen from this that the lightning chopped wave impact test of the first group of reactor coils is qualified. Figure 18 (a) is the lightning truncated waveform at the first end of the second group of reactor coils. It can be seen that the T1 wavefront time is 1.74μs, the Tc cutoff time is 3.79μs, the Upk peak voltage is -490.36kV, the Oz zero-crossing coefficient is 0.00, and the maximum current passing through is 6.5kA and -8.02kA. Figure 18 (b) shows the lightning truncated waveform at the end of the second group of reactor coils. It can be seen that the T1 wavefront time is 1.68 μs, the Tc cutoff time is 3.63 μs, the Upk peak voltage is -487.9 kV, the Oz zero-crossing coefficient is 0.00, and the maximum currents passing through are 16.23 kA and -16.87 kA. Therefore, from... Figure 18 It can be seen from this that the lightning chopped wave impact test of the second group of reactor coils is qualified.

[0085] For the winding inter-turn insulation test, the test voltage was 430kV with negative polarity, and the obtained waveform diagram is as follows. Figure 19 As shown. Figure 19(a) is the waveform diagram of the inter-turn insulation test of the first group of reactor coils. It can be seen that the wavefront time of T1 is 3362.06μs, the half-peak time of T2 is 3362.06μs, the peak voltage of Upk is -439.1kV, and the maximum current passing through is 309.04kA and -346.73kA. Figure 19 (b) shows the waveform of the inter-turn insulation test of the second group of reactor coils. It can be seen that the T1 wavefront time is 3327.32 μs, the T2 half-peak time is 3170 μs, the Upk peak voltage is -433.1 kV, and the maximum currents are 297.54 kA and -334.77 kA. Therefore, from... Figure 19 It can be seen from this that the inter-turn insulation test of the reactor coil is qualified.

[0086] For the end-to-ground full-wave impulse test, the test voltage was ±1425kV, and the obtained waveform diagram is as follows. Figure 20 As shown. Figure 20 (a) is a waveform diagram of a positive polarity lightning impulse to ground. It can be seen that the wavefront time of T1 is 1.42μs, the half-peak time of T2 is 48.63μs, and the peak voltage of Upk is 1461.56kV. Figure 20 (b) shows the waveform of a negative polarity lightning impulse to ground. It can be seen that the T1 wavefront time is 1.41 μs, the T2 half-peak time is 48.72 μs, and the Upk peak voltage is -1429.13 kV. Therefore, from... Figure 20 It can be seen from the data that the end-to-ground lightning full-wave impulse test was passed.

[0087] For the end-to-ground lightning impulse test, the test voltage was 1567.5kV with negative polarity. The obtained waveform is shown below. Figure 21 As shown, the T1 wavefront time is 1.42 μs, the Tc cutoff time is 3.05 μs, and the Upk peak voltage is -1578.41 kV. Therefore, from... Figure 21 It can be seen from the data that the end-to-ground lightning interception wave impact test was qualified.

[0088] For the end-to-ground (wet) operation impulse test, the test voltage was ±1175kV, and the obtained waveform diagram is as follows. Figure 22 As shown. Figure 22 (a) is the impulse waveform diagram of positive polarity operation to ground. It can be seen that the peak voltage of Upk is 1186.33kV, the wavefront time of Tp is 238.5μs, and the half-peak time of T2 is 2652.47μs. Figure 22 (b) is the waveform diagram of the negative polarity operation impulse to ground. It can be seen that the peak voltage Upk is -1179.37kV, the wavefront time Tp is 228.1μs, and the half-peak time T2 is 2648.86μs. Therefore, from... Figure 22 It can be seen from the results that the end-to-ground (wet) operation impact test was passed.

[0089] The dry-type hollow-connected reactor for SLCC hybrid DC transmission proposed in this invention was applied to a converter station for seismic performance testing of the supporting structure. A single reactor coil weighs approximately 9940 kg, has an outer diameter of approximately 2060 mm, and is fixed to the ground at the bottom by six 2.3-meter fiberglass legs, with a total height of approximately 12.1 meters. Seismic calculations were performed using finite element modeling. A schematic diagram of the model, taking one section of the coil as an example, is shown below. Figure 23 As shown.

[0090] According to the technical documents, the seismic strength calculation of electrical facilities should ensure that the stress value generated at the root or other dangerous sections of the electrical facility is less than the allowable stress value of the facility or materials. In the support structure of this reactor, for insulators, the calculation is performed using the breaking stress, and the safety factor should be greater than 1.67; for ductile metal materials, the yield stress is taken as the allowable stress, and the calculation is performed using the breaking stress, with a safety factor greater than 1.67. The main materials used in the support structure of this reactor are shown in Table 2.

[0091] Table 2 Main materials used in the supporting structure

[0092]

[0093] Based on the calculation methods provided in the technical documents and the requirements outlined in the reactor technical agreement, and using a seismic load input at a seismic fortification intensity of 7° (0.2g), the standard response spectrum curve is as follows: Figure 24 As shown.

[0094] The gravity load is caused by the self-weight of the reactor, and the gravitational acceleration is taken as 9.8 m / s². 2 Based on the environmental parameters provided in the technical documents, an average maximum wind speed of 27.1 m / s was maintained at a height of 10 m above ground for 10 minutes. The wind load values ​​were determined according to the technical documents and applied to each node of the reactor coil. The result of applying the wind load is shown in the diagram below. Figure 25 As shown.

[0095] Based on the environmental parameters provided in the technical documents, the maximum design ice thickness is 5mm and the maximum snow thickness is 34cm. The ice and snow load values ​​are determined based on the area of ​​the rain cap on top of the reactor and the ice and snow thickness, and are applied to each node of the rain cap. The result of applying the ice and snow load is shown in the diagram below. Figure 26 As shown.

[0096] Short-term combined load The check combination includes dynamic forces caused by earthquakes in the reactor, 28% of the standard value of wind load, 70% of the standard value of snow and ice load, and 120% of its own weight. The calculation formula is as follows:

[0097]

[0098] in, This represents the representative effect of gravity load; This represents the standard value effect of horizontal seismic action, taking into account both horizontal and vertical seismic action. This indicates the standard value effect of wind load; This indicates the standard value effect of ice load.

[0099] A simulation model was established using the finite element analysis method, and the results were obtained as follows: Figure 27 The natural frequency diagram of the model shown is approximately 0.7 Hz.

[0100] The displacement calculation results are obtained under short-term combined load. Figure 28 The diagram shows the displacement results of the reactor proposed in this invention. The maximum displacement is approximately 123.3 mm.

[0101] Under short-term combined load, the stress conditions of the reactor support structure and its various components proposed in this invention are as follows: Figures 29-35 As shown, Figure 29 The stress diagram of the entire support structure under short-term combined load shows that the maximum stress on the entire support structure is approximately 103.8 MPa. Figure 30 The stress diagram of the boom under short-term combined load shows that the maximum stress on the boom is about 27 MPa. Figure 31 The stress diagram of the transition seat under short-term combined load shows that the maximum stress on the transition seat is approximately 103.8 MPa. Figure 32 The stress diagram of the insulator under short-term combined load shows that the maximum stress on the insulator is approximately 65.9 MPa. Figure 33 The stress diagram of the high-leg beam under short-term combined load shows that the maximum stress on the high-leg beam is approximately 69.4 MPa. Figure 34 The stress diagram of the FRP leg under short-term combined load shows that the maximum stress on the FRP leg is approximately 43.1 MPa. Figure 35 The stress diagram of the FRP (fiberglass reinforced plastic) support flange under short-term combined load shows that the maximum stress on the FRP support flange is approximately 30.9 MPa.

[0102] The stress check table under short-term combined load is shown in Table 3.

[0103] Table 3 Stress Check Table under Short-Term Combined Loading

[0104]

[0105] Table 3 uses the destructive stress as the benchmark to check the safety factor. As can be seen from Table 3, the safety factor of each part of the support structure is greater than 1.67, indicating that the support structure can meet the seismic requirements.

[0106] The maximum stress in the support structure occurs on the transition seat, with a value of 103.8 MPa, which is less than its destructive stress of 520 MPa. The safety factor is 5.01 > 1.67, which meets the safety requirements. The stress in the insulator core rod is 65.9 MPa, which is less than its destructive stress of 130 MPa. The safety factor is 1.97 > 1.67, which meets the safety requirements.

[0107] In summary, the dry-type hollow-connected reactor used in a converter station for SLCC hybrid DC transmission meets the seismic performance requirements in the technical documents.

[0108] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A dry-type air-connected reactor for SLCC hybrid DC transmission, characterized in that, It includes a reactor coil (1), a rain cap (2), a side bird fence (3), an upper hanger (4), a lower hanger (5), a corona ring (6), a transition seat (7), an insulator (8), a fiberglass support leg (9), a foundation (11), and a surge arrester (12). The foundation (11) is located at the bottom. One end of the fiberglass support leg (9) is fixedly connected to the foundation (11) by anchor bolts. The other end of the fiberglass support leg (9) is connected to one end of the insulator (8). The other end of the insulator (8) is connected to one end of the transition seat (7). The other end of the transition seat (7) is connected to one side of the lower hanger (5). The other side of the lower hanger (5) is connected to one end of the reactor coil (1). The other end of the reactor coil (1) is connected to one side of the upper hanger (4). The rain cap (2) is fixedly connected to the other side of the upper hanger (4) by multiple support rods. The upper end of the rain cap (2) is provided with a rain cap corona ring. The lower end of the rain cap (2) is provided with a side bird guard (3). Both the upper hanger (4) and the lower hanger (5) are equipped with corona rings (6); the upper hanger (4) is connected to the upper end of the surge arrester (12), and the lower hanger (5) is connected to the lower end of the surge arrester (12); The reactance coil (1) is wound with a mica imide film transposed conductor (13); the mica imide film transposed conductor (13) includes a transposed core wire (131), a single conductor insulation layer (132) and a mica imide composite insulation layer (133).

2. The dry-type air-connected reactor for SLCC hybrid DC transmission according to claim 1, characterized in that, There are two sets of reactor coils (1). The terminals of the two sets of reactor coils (1) are symmetrically connected through parallel connection plate (10) and arranged horizontally in space. The reactor coil (1) has multiple encapsulation layers, and a ventilation strip (16) is provided between each encapsulation layer. The ventilation strip (16) is T-shaped.

3. The dry-type air-connected reactor for SLCC hybrid DC transmission according to claim 2, characterized in that, The mica-imide composite insulation layer (133) is a composite structure of polyimide film and mica film, bonded together with H-grade heat-resistant insulating adhesive.

4. The dry-type air-connected reactor for SLCC hybrid DC transmission according to claim 1, characterized in that, The upper hanger (4) includes a first central hub (41), a first horizontal binding strap (42), an upper hanger arm, and a reinforcing plate (45). The upper hanger arm includes an upper long hanger arm (43) and an upper short hanger arm (44). One end of multiple upper hanger arms arranged radially is welded to the first central hub (41), and the adjacent upper hanger arms are bound together with the first horizontal binding strap (42). The reinforcing plate (45) is welded to the first central hub (41). The lower hanger (5) includes a second center hub (51), a second horizontal tie-down strap (52), and a lower hanger arm. The lower hanger arm includes a lower long hanger arm (53) and a lower short hanger arm (54). One end of the multiple lower hanger arms arranged radially is welded to the second center hub (51), and the adjacent lower hanger arms are tied together with the second horizontal tie-down strap (52). Vertical binding straps are used to bind the upper and lower booms, which are on the same vertical plane.

5. The dry-type air-connected reactor for SLCC hybrid DC transmission according to claim 4, characterized in that, Both the upper long boom (43) and the lower long boom (53) are equipped with terminal blocks (15) at their ends, which are used to connect to external equipment.

6. The dry-type air-connected reactor for SLCC hybrid DC transmission according to claim 1, characterized in that, The side bird guardrail (3) includes a side partition (31) and a bird guardrail (32); the side partition (31) is a ring-shaped structure spliced ​​with multiple arc segments that bend outward at 90°. The upper 90° bend of the side partition (31) is connected to the outer edge of the rain cap (2), and the lower 90° bend of the side partition (31) is connected to the bird guardrail (32).

7. The dry-type air-connected reactor for SLCC hybrid DC transmission according to claim 1, characterized in that, The corona ring (6) includes a multi-layered arc-shaped corona ring unit (61), all of which are located on the same horizontal plane, and there is a set spacing between two adjacent corona ring units (61); The corona ring unit (61) is an arc-shaped hollow tube structure made of aluminum alloy.

8. The dry-type air-connected reactor for SLCC hybrid DC transmission according to claim 4, characterized in that, The bottom of the hollow part of the reactor coil (1) is provided with a bottom bird guard (14), and the bottom bird guard (14) is connected to the upper part of the lower boom by bolts using a stainless steel support plate. The bottom bird guard (14) is a circular structure spliced ​​together from the bottom center hub bird guard (141) and the bottom arc-shaped bird guard (142), with a mesh inside.

9. The dry-type air-connected reactor for SLCC hybrid DC transmission according to claim 4, characterized in that, The transition seat (7) is a stainless steel transition seat, the insulator (8) is a high bending resistance insulator, and the fiberglass support leg (9) is an epoxy fiberglass support leg. The number of transition seats (7), insulators (8), and fiberglass support legs (9) is the same as that of the lower boom. The transition seats (7), insulators (8), and fiberglass support legs (9) are all parallel and evenly arranged at the other end of the lower boom.

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