Gas-insulated non-metal closed power transmission line and basic unit and boundary basic unit of gas-insulated non-metal closed power transmission line

Abstract

The invention belongs to the technical field of power equipment structure design, and discloses a gas insulation nonmetal closed power transmission line and a basic unit and a boundary basic unit thereof, the basic unit comprises a three-phase GIL nonmetal shell, a three-phase single-phase GIL is arranged in the three-phase GIL nonmetal shell in parallel, and a GIL supporting structure used for supporting the three-phase single-phase GIL is fixedly arranged in the three-phase GIL nonmetal shell; a grounding metal bushing is nested in the inner cavity of the three-phase GIL nonmetal shell, and the grounding metal bushing is electrically connected with the GIL supporting structure; each single-phase GIL comprises a single-phase GIL non-metal shell, a GIL current-carrying tubular bus and an insulator used for supporting the GIL current-carrying tubular bus are coaxially arranged in an inner cavity of the single-phase GIL non-metal shell, the single-phase GIL non-metal shell is sleeved with a grounding ring, and the grounding ring is electrically connected with the GIL supporting structure. The three-phase GIL non-metal shell and the single-phase GIL non-metal shell are adopted, so that the electric field distribution from a high-voltage conductor to the shell in the GIL can be effectively reduced, and the probability of gap discharge or creeping discharge is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power equipment structure design, and in particular relates to a gas-insulated non-metallic enclosed transmission line and a basic unit and a boundary basic unit thereof. Background Art

[0002] High-voltage gas-insulated metal-enclosed transmission lines (GIL) are an important part of power transmission lines in power grids. They are widely used due to their small size, long maintenance cycle, and stable operation. They are now used in special transmission scenarios such as pipe corridors and tunnels. Insulators are key insulating components of GILs and play an important role in supporting the central conductor. At present, discharge accidents of insulators often occur. The outer shell of conventional GILs is grounded metal. Once the GIL gap discharge or the insulator surface discharge occurs, the entire line will not work, making it difficult to meet the technical requirements of zero discharge and maintenance-free. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a gas-insulated non-metallic enclosed transmission line and its basic unit and boundary basic unit. The present invention adopts a three-phase GIL non-metallic shell and a single-phase GIL non-metallic shell. Through reasonable structural design, the use of the non-metallic shell (i.e., the three-phase GIL non-metallic shell and the single-phase GIL non-metallic shell) in the present invention can effectively reduce the electric field distribution from the high-voltage conductor to the shell in the GIL, and reduce the probability of gap discharge or surface discharge.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] A basic unit of a gas-insulated non-metallic enclosed transmission line comprises a three-phase GIL non-metallic shell, a three-phase single-phase GIL is arranged in parallel inside the three-phase GIL non-metallic shell, a GIL support structure for supporting the three-phase single-phase GIL is fixed inside the three-phase GIL non-metallic shell, a grounded metal liner is nested in the inner cavity of the three-phase GIL non-metallic shell, and the grounded metal liner is electrically connected to the GIL support structure;

[0006] Each single-phase GIL includes a single-phase GIL non-metallic shell, the inner cavity of the single-phase GIL non-metallic shell is coaxially provided with a GIL current-carrying tube mother, the inner cavity of the single-phase GIL non-metallic shell is also provided with an insulator for supporting the GIL current-carrying tube mother, and the single-phase GIL non-metallic shell is sleeved with a grounding ring, which is electrically connected to the GIL support structure.

[0007] Preferably, the insulator adopts at least one of a three-pillar insulator and a pot-type insulator; the pot-type insulator includes at least one of an air-separated pot-type insulator and an air-through pot-type insulator.

[0008] Preferably, the three-pillar insulator comprises a three-pillar insulator body made of epoxy composite material, the center of the three-pillar insulator body is sleeved on the outside of the GIL current-carrying tube mother, and the outer edge of the three-pillar insulator body is evenly provided with a first pillar, a second pillar and a third pillar made of epoxy composite material;

[0009] When the GIL current-carrying tube mother supporting the three-leg insulator is connected, the outer ends of the first leg, the second leg and the third leg are in contact with the inner wall surface of the single-phase GIL non-metallic shell.

[0010] Preferably, when the insulator adopts a pot-type insulator, the two ends of the center of the pot-type insulator are fixed and connected to the GIL current-carrying tube mother using a pot-type insulator plug-in structure, a fixing flange is provided on the single-phase GIL non-metallic shell, the outer edge of the pot-type insulator is sealed and connected to the fixing flange, a shielding cover is provided on the outside of the fixing flange, and a voltage-equalizing shielding ring is provided on the inside of the outer edge of the pot-type insulator.

[0011] Preferably, the insulator adopts at least one air-spaced basin insulator.

[0012] Preferably, the grounding ring is a metal ring, which is sleeved on the outside of the three-phase GIL non-metallic shell. Voltage-equalizing rings are provided on the outside of both ends of the metal ring, and the metal ring is electrically connected to the GIL support structure.

[0013] Preferably, two three-phase GILs are arranged in the basic unit of the gas-insulated non-metallic enclosed transmission line, and the two three-phase GILs are symmetrical about the longitudinal plane passing through the center line of the three-phase GIL non-metallic shell; in the circumferential direction of the three-phase GIL non-metallic shell, the three-phase single-phase GILs located on the same side of the three-phase GIL non-metallic shell are located on the same circumference of the axis.

[0014] Preferably, in the circumferential direction of the three-phase GIL non-metallic shell, in the three-phase single-phase GIL located on the same side of the three-phase GIL non-metallic shell, the insulators in adjacent single-phase GILs are located on different vertical planes, which are the vertical planes in the single-phase GIL that are perpendicular to the central axis of the single-phase GIL non-metallic shell.

[0015] The present invention also provides a boundary basic unit of a gas-insulated non-metallic enclosed transmission line, which includes a gas-insulated basin-type insulator and the basic unit of the present invention as described above, wherein the gas-insulated basin-type insulator is installed at the end of one end on the same side of each single-phase GIL non-metallic shell of the basic unit.

[0016] The present invention also provides a gas-insulated non-metallic enclosed transmission line, comprising the boundary basic unit of the present invention as described above, and a plurality of the basic units as described above, wherein the plurality of basic units are sequentially connected to form an integral structure, and the two ends of the integral structure are respectively connected to the boundary basic units;

[0017] in:

[0018] When a plurality of basic units are sequentially connected to form the overall structure, for adjacent basic units, the GIL current-carrying tube mothers of the same phase are correspondingly connected, and the single-phase GIL non-metallic shells are connected through pot-type insulators, or share a section of the single-phase GIL non-metallic shell (3-1); the three-phase GIL non-metallic shells are connected to each other, or share a section of the three-phase GIL non-metallic shell;

[0019] When the end of the integral structure is connected to the boundary basic unit, one end of each single-phase GIL non-metallic shell on the boundary basic unit where the air-insulated basin insulator is installed is away from the integral structure; for the adjacent ends of the integral structure and the boundary basic unit, the GIL current-carrying tube mothers of the same phase are connected correspondingly, and the single-phase GIL non-metallic shells are connected through basin insulators, or share a section of single-phase GIL non-metallic shell (3-1); the three-phase GIL non-metallic shells are connected to each other, or share a section of three-phase GIL non-metallic shell.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] In the basic unit and boundary basic unit of the gas-insulated non-metallic closed transmission line of the present invention, the three-phase GIL non-metallic shell and the single-phase GIL non-metallic shell are used to replace the three-phase GIL metal shell and the single-phase GIL metal shell. The single-phase GIL non-metallic shell is supported by the GIL support structure, so the single-phase GIL non-metallic shell is suspended and not grounded, the insulation distance between the high-voltage conductor and the grounding is greatly improved, the electric field distribution between the high-voltage conductor and the single-phase GIL non-metallic shell is optimized, and the probability of gap discharge or surface discharge inside the single-phase GIL is greatly reduced. In order to solve the grounding problem, the present invention embeds a grounded metal liner in the inner cavity of the three-phase GIL non-metallic shell, and the grounded metal liner is electrically connected to the grounding ring through the GIL support structure, thereby realizing the grounding of part of the structure in each phase GIL. In summary, the present invention can greatly reduce the probability of discharge accidents in gas-insulated non-metallic closed transmission lines, greatly improve the operating reliability and life of the pipeline corridor transmission GIL, and is one step closer to meeting the technical requirements of zero discharge and maintenance-free pipeline corridor transmission GIL. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a cross-sectional view of a gas-insulated non-metallic enclosed transmission line in an embodiment of the present invention, wherein two three-phase GILs are provided, and the two three-phase GILs are symmetrically distributed about a vertical plane where the central axis of the non-metallic shell of the three-phase GIL is located.

[0023] Figure 2 Schematic diagram of the three-dimensional distribution of the three-phase GIL in the three-phase non-metallic shell in an embodiment of the present invention.

[0024] Figure 3 FIG. 1 is a schematic diagram of the overall structure of the first basic unit of the gas-insulated non-metallic enclosed transmission line according to an embodiment of the present invention. The three-phase GIL is adjusted to the same vertical plane. The actual distribution is as follows: Figure 1 shown.

[0025] Figure 4 FIG. 1 is a schematic diagram of the overall structure of the second basic unit of the gas-insulated non-metallic enclosed transmission line according to an embodiment of the present invention. The three-phase GIL is adjusted to the same vertical plane. The actual distribution is as follows: Figure 1 shown.

[0026] Figure 5 It is a schematic structural diagram of a three-pillar insulator used in an embodiment of the present invention.

[0027] Figure 6 This is a two-dimensional electric field simulation cloud map for the 550kV pipeline transmission GIL in an embodiment of the present invention.

[0028] In the figure: 1-1-single-phase GIL, 1-2-GIL supporting structure, 1-3-three-phase GIL non-metallic shell; 2-2-pot insulator and shielding cover, 2-3-grounding flange and grading ring; 3-1-single-phase GIL non-metallic shell, 3-2-GIL current-carrying tube mother, 3-3-three-pillar insulator, 3-1-1-three-pillar insulator body, 3-1-2-pillar, 3-4-air-insulated pot insulator, 3-5-grounding grading ring, 3-8-grounding ring, 3-8-1-metal ring, 3-4-1-plug-in structure; 4-1-gas-through pot insulator, 4-1-1-through hole, 5-shielding cover, 6-grading shielding ring, 7-fixing flange. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Reference Figure 1-Figure 4The basic unit of the gas-insulated non-metallic enclosed transmission line of this embodiment includes a three-phase GIL non-metallic shell 1-3, a three-phase single-phase GIL is arranged in parallel inside the three-phase GIL non-metallic shell 1-3, a GIL support structure 1-2 for supporting the three-phase single-phase GIL is also fixed inside the three-phase GIL non-metallic shell 1-3, a grounding metal liner is nested in the inner cavity of the three-phase GIL non-metallic shell 1-3, and the grounding metal liner is electrically connected to the GIL support structure 1-2; each phase of the single-phase GIL includes a single-phase GIL non-metallic shell 3-1, a GIL current-carrying tube mother 3-2 is coaxially arranged in the inner cavity of the single-phase GIL non-metallic shell 3-1, an insulator for supporting the GIL current-carrying tube mother 3-2 is also arranged in the inner cavity of the single-phase GIL non-metallic shell 3-1, and a grounding ring 3-8 is sleeved on the outer side of the single-phase GIL non-metallic shell 3-1, and the grounding ring 3-8 is electrically connected to the GIL support structure 1-2. In the above scheme of the present invention, the grounding ring 3-8, the GIL support structure 1-2 and the grounding metal liner are at the same potential. By grounding the grounding metal liner, the grounding of the grounding ring 3-8 can be achieved. The above basic unit of the present invention adopts a three-phase GIL non-metallic shell 1-3 and a single-phase GIL non-metallic shell 3-1, which can improve the safety and reliability of the GIL insulator to achieve high reliability and maintenance-free requirements of high-voltage GIL. The use of non-metallic shells in the present invention can effectively reduce the electric field distribution from the high-voltage conductor to the shell in the GIL, and reduce the probability of gap discharge or surface discharge.

[0031] As an alternative to the above, see Figure 3 and Figure 4 The insulator may be at least one of a three-pillar insulator 3-3 and a pot-type insulator; wherein the pot-type insulator includes at least one of an air-separated pot-type insulator 3-4 and an air-through pot-type insulator 4-1.

[0032] As a preferred embodiment of the above-mentioned solution of the present invention, see Figure 5 In this embodiment, the three-pillar insulator 3-3 includes a three-pillar insulator body 3-1-1 made of epoxy composite material, the center of the three-pillar insulator body 3-1-1 is sleeved on the outside of the GIL current-carrying tube mother 3-2, and the outer edge of the three-pillar insulator body 3-1-1 is evenly provided with a first pillar, a second pillar and a third pillar made of epoxy composite material; when the GIL current-carrying tube mother 3-2 is connected to the three-pillar insulator 3-3, the outer ends of the first pillar, the second pillar and the third pillar are in contact with the inner wall surface of the single-phase GIL non-metallic shell 3-1. Compared with the prior art, the three-pillar insulator 3-3 of this embodiment does not need to install a metal insert at the end of the pillar 3-1-2, and the three-pillar insulator body 3-1-1, the first pillar, the second pillar and the third pillar are a structure formed by integrally casting epoxy composite material (such as epoxy / alumina composite material).

[0033] As a preferred solution of the above-mentioned solution of the present invention, in this embodiment, when the insulator adopts a pot-type insulator, the pot-type insulator plug-in structure 3-4-1 is used to fix and connect the GIL current-carrying tube mother 3-2 at both ends of the center of the pot-type insulator, and a fixing flange 7 is provided on the single-phase GIL non-metallic shell 3-1. The outer edge of the pot-type insulator is sealed and connected to the fixing flange 7. A shielding cover 5 is provided on the outside of the fixing flange 7, and a voltage-equalizing shielding ring 6 is provided on the inside of the outer edge of the pot-type insulator.

[0034] As a preferred solution of the above solution of the present invention, in this embodiment, the insulator adopts at least one gas-separated basin insulator 3-4. In this way, when the basic unit is assembled into a gas-insulated non-metallic closed transmission line, the gas-separated basin insulator 3-4 can separate the single-phase GIL into multiple sealed chambers, which is convenient for filling the single-phase GIL non-metallic shell 3-1 with insulating gas (such as sulfur hexafluoride). Compared with the single-phase GIL non-metallic shell 3-1 of the single-phase GIL as a whole, which is a sealed chamber and the entire GIL is long, the structure of the present invention makes it easier to control the pressure of the insulating gas and facilitates construction.

[0035] As a preferred solution of the above solution of the present invention, in this embodiment, the grounding ring 3-8 can adopt the following structure, which adopts a metal ring 3-8-1, the metal ring 3-8-1 is sleeved on the outside of the three-phase GIL non-metallic shell 1-3, and the two ends of the metal ring 3-8-1 are provided with equalizing rings 3-5, and the metal ring 3-8-1 is electrically connected to the GIL support structure 1-2. The metal ring 3-8-1 is preferably tightly sleeved on the outside of the three-phase GIL non-metallic shell 1-3.

[0036] As a preferred embodiment of the above-mentioned solution of the present invention, see Figure 6 In this embodiment, two three-phase GILs are arranged in the basic unit of the gas-insulated non-metallic enclosed transmission line, and the two three-phase GILs are symmetrical about the longitudinal plane passing through the center line of the three-phase GIL non-metallic shell 1-3; in the circumferential direction of the three-phase GIL non-metallic shell 1-3, the three-phase single-phase GILs located on the same side of the three-phase GIL non-metallic shell 1-3 are located on the same circumference of the axis.

[0037] As a preferred embodiment of the above-mentioned solution of the present invention, Figure 3 and Figure 4 In this embodiment, in the circumferential direction of the three-phase GIL non-metallic shell 1-3, the three-phase GIL non-metallic shell 1-3 is located on the same side (such as Figure 5In the three-phase single-phase GIL (shown on the left or right side), the insulators in adjacent single-phase GILs are located on different vertical planes, that is, the insulators in adjacent single-phase GILs are staggered in the vertical direction, and the vertical plane is the vertical plane in the single-phase GIL that is perpendicular to the central axis of the single-phase GIL non-metallic shell 3-1. The staggered arrangement of insulators of different-phase transmission lines can effectively even out the electric field distribution between different phases, reduce the probability of discharge between phases, effectively improve the operating reliability of the pipeline corridor transmission GIL, and reduce the probability of discharge failure of the pipeline corridor transmission GIL.

[0038] The boundary basic unit of the present invention is based on the above basic unit, and the same end of each single-phase GIL non-metallic shell 3-1 of the above basic unit (see Figure 3 and Figure 4 ,, such as the left end or the right end), the air-spaced basin insulator is installed, and this end of each single-phase GIL non-metallic shell 3-1 is sealed by the air-spaced basin insulator.

[0039] The gas-insulated non-metallic enclosed transmission line of the present invention comprises the boundary basic unit of the present invention as described above, and a plurality of the basic units as described above, wherein the plurality of basic units are sequentially connected to form an integral structure, and the two ends of the integral structure are respectively connected to the boundary basic units;

[0040] in:

[0041] When several basic units are sequentially connected to form the integral structure, for adjacent basic units, the GIL current-carrying tube mothers 3-2 of the same phase are connected correspondingly, and the single-phase GIL non-metallic shells 3-1 are connected through pot insulators, or share a section of the single-phase GIL non-metallic shell 3-1; the three-phase GIL non-metallic shells 1-3 are connected to each other, or share a section of the three-phase GIL non-metallic shell 1-3;

[0042] When the end of the above-mentioned integral structure is connected to the boundary basic unit, one end of the air-insulated basin insulator (such as Figure 3 The left end shown in FIG. 1 is far away from the overall structure; for the adjacent end of the overall structure and the boundary basic unit (such as Figure 3 The right end shown in the figure), the GIL current-carrying tube mothers 3-2 of the same phase are connected correspondingly, the single-phase GIL non-metallic shells 3-1 are connected through pot-type insulators, or share a section of single-phase GIL non-metallic shell (3-1); the three-phase GIL non-metallic shells 1-3 are connected to each other, or share a section of three-phase GIL non-metallic shell 1-3.

[0043] As a preferred solution of the above-mentioned solution of the present invention, in this embodiment, the pot-type insulator can adopt an air-insulated pot-type insulator 3-4 or an air-through pot-type insulator 4-1, and the two ends of the center of the pot-type insulator are fixed and connected to the GIL current-carrying tube mother 3-2 using a pot-type insulator plug-in structure 3-4-1, and the end of the single-phase GIL non-metallic shell 3-1 is provided with a fixing flange 7, the outer edge of the pot-type insulator is sealed and connected to the fixing flange 7, the outside of the fixing flange 7 is provided with a shielding cover 5, and the inside of the outer edge of the pot-type insulator is provided with a voltage-equalizing shielding ring 6.

[0044] Example

[0045] The gas-insulated non-metallic enclosed transmission line of this embodiment is composed of a plurality of basic units connected together. The basic units can be divided into three-pillar insulators 3-3 and gas-insulated basin insulators 3-4 (such as Figure 3 As shown) and the use of air-through basin insulator 4-1 and air-separated basin insulator 3-4 (as shown Figure 4 The specific configuration of the insulators in the two basic units is the same, and the GIL of each phase is uniformly distributed in the pipeline. The three-pillar insulator 3-3 in the first basic unit is replaced by an air-through basin insulator 4-1, which is the second basic unit.

[0046] Specifically, the first basic unit includes a three-phase GIL non-metallic shell 1-3, a grounded metal liner, a GIL support structure 1-2, a single-phase GIL non-metallic shell 3-1, an air-spaced basin insulator 3-4, a GIL current-carrying tube mother 3-2, a three-pillar insulator 3-3, a grounding ring 3-8, and a shielding cover 5 for the air-spaced basin insulator. The single-phase GIL non-metallic shell 3-1 is coaxially arranged with the GIL current-carrying tube mother 3-2, and the GIL current-carrying tube mother 3-2 is supported by the insulator and the relative position of the single-phase GIL non-metallic shell 3-1 and the GIL current-carrying tube mother 3-2 is maintained. The three-pillar insulator 3-3 adopts the following method: Figure 5 The structure shown in the figure, the three-pillar insulator 3-3 is sleeved on the GIL current-carrying tube mother 3-2 and the pillar 3-1-2 is directly in contact with the inner wall of the single-phase GIL non-metallic shell 3-1, the center ends of the air-separated basin insulator 3-4 are fixed and connected to the GIL current-carrying tube mother 3-2 using a basin insulator plug-in structure 3-4-1, and the air-separated basin insulator 3-4 is fixed and connected to the single-phase GIL non-metallic shell 3-1 at the outer edge through a fixing flange 7; the grounding ring 3-8 fixes the single-phase GIL non-metallic shell 3-1 to the corresponding position inside the three-phase GIL non-metallic shell 1-3 through the GIL support structure 1-2; refer to Figure 5, the three-phase GIL is distributed in a circle in the three-phase GIL non-metallic shell 1-3, two three-phase GILs are arranged in the three-phase GIL non-metallic shell 1-3, and the two three-phase GILs are symmetrically distributed on both sides of the three-phase GIL non-metallic shell 1-3; the grounding metal bushing is sleeved inside the three-phase GIL non-metallic shell 1-3 and contacts the three-phase GIL non-metallic shell 1-3, and the grounding metal bushing is electrically connected to the GIL support structure 1-2. In this embodiment, the three-phase GIL non-metallic shell 1-3 and the single-phase GIL non-metallic shell 3-1 are both made of bamboo fiber insulation material. The end face of the fixing flange 7 of the single-phase GIL non-metallic shell 3-1 connected to the air-separated basin insulator 3-4 is a plane, and a sealing ring is provided on the outer edge of the air-separated basin insulator 3-4. The outer edge of the air-separated basin insulator 3-4 is sealed and connected to the single-phase GIL non-metallic shell 3-1 through the sealing ring and the end face of the fixing flange 7. A voltage-equalizing shielding ring 6 is provided inside the outer edge of the air-separated basin insulator 3-4. A shielding cover 5 is provided outside the fixing flange 7 between the air-insulated basin insulator 3-4 and the single-phase GIL non-metallic shell 3-1. The low-voltage end (i.e., the outer end of the pillar) of the three-pillar insulator 3-3 is directly in contact with the single-phase GIL non-metallic shell 3-1 without metal inserts. A voltage-equalizing ring 3-5 is provided outside both ends of the grounding ring 3-8. The GIL support structure 1-2 is electrically connected to the grounding ring 3-8 of each phase and the GIL support structure 1-2 is fixedly connected to the three-phase GIL non-metallic shell 1-3 to ensure that each phase GIL is fixed in a suitable position, and the grounding ring 3-8 is electrically connected to the grounding metal liner. The single-phase GIL non-metallic shell 3-1 is suspended, the fixed flange 7 between the single-phase GIL non-metallic shell 3-1 and the air-spaced basin insulator 3-4 is suspended, the outer shielding cover 5 of the fixed flange and the grading shielding ring 6 inside the outer edge of the air-spaced basin insulator 3-4 are both suspended; the grounding grading rings 3-5 on both sides of the grounding ring 3-8, the GIL support structure 1-2 and the grounding metal liner are all grounded.

[0047] The single-phase GIL distribution characteristics, insulator distribution characteristics, and different structural grounding or suspension characteristics in the second basic unit are consistent with those in the first basic unit. The three-pillar insulator 3-3 in the first basic unit is replaced by an air-vented basin insulator 4-1 at the same position to obtain the second basic unit. The plug-in structures 3-4-1 on both sides of the center of the air-vented basin insulator 4-1 connect and fix the GIL current-carrying tube mother 3-2, and the outer edge of the air-vented basin insulator 4-1 is connected and fixed to the single-phase GIL non-metallic shell 3-1 through a fixing flange 7. The end face of the fixing flange 7 connecting the single-phase GIL non-metallic shell 3-1 to the air-vented basin insulator 4-1 is a plane, and a sealing ring is provided on the outer edge of the air-vented basin insulator 4-1. A shielding cover 5 is provided outside the fixing flange 7 between the air-vented basin insulator 4-1 and the single-phase GIL non-metallic shell 3-1. A voltage-equalizing shielding ring 6 is provided inside the outer edge of the air-vented basin insulator 4-1. The fixing flange 7 between the single-phase GIL non-metallic shell 3-1 and the gas-through basin insulator 4-1 is suspended, and the shielding cover 5 outside the fixing flange 7 and the voltage-equalizing shielding ring 6 inside the outer edge of the gas-through basin insulator 4-1 are both suspended. The basin surface of the gas-through basin insulator 4-1 is uniformly provided with a plurality of through holes 4-1-1 along the circumference of the gas-through basin insulator 4-1, and the through holes are rounded rectangular holes.

[0048] The gas-insulated non-metallic enclosed transmission line of this embodiment is composed of two boundary basic units and a plurality of the above-mentioned basic units, and the connection order is boundary basic unit, a plurality of the same basic units, and boundary basic unit; each phase GIL in different basic units is connected through the gas-separated basin insulator 3-4 and the corresponding flange structure; after the basic units are connected, it is necessary to ensure that the basin faces of all gas-separated basin insulators 3-4 and gas-through basin insulators 4-1 are in the same direction, and the pillars of all three-pillar insulators 3-3 are in the same direction;

[0049] The boundary basic unit is basically the same as the above-mentioned basic unit. The boundary basic unit is based on the basic unit, and an air-insulated basin insulator 3-4 is installed at one end of the single-phase GIL non-metallic shell 3-1 of the basic unit. It can also be divided into two structures according to the use of different types of insulators, which are respectively called the first boundary basic unit and the second boundary basic unit. The three-pillar insulator 3-3 in the first boundary basic unit is replaced by an air-through basin insulator 4-1, which is the second boundary basic unit.

[0050] The first boundary basic unit includes a three-phase GIL non-metallic shell 1-3, a grounded metal liner, a GIL support structure 1-2, a single-phase GIL non-metallic shell 3-1, an end air-spaced basin insulator, a GIL current-carrying tube mother 3-2, a three-pillar insulator 3-3, a grounding ring 3-8 and a shielding cover 5 for the end air-spaced basin insulator. The end air-spaced basin insulator and the fixing flange 7 at the outer edge seal the boundary basic unit with the GIL current-carrying tube mother 3-2 and the single-phase GIL non-metallic shell 3-1 in the basic unit. Each phase GIL is fixed at a corresponding position distributed on the circumference through the GIL support structure 1-2, and the center of the single-phase GIL is equidistant from the center of the three-phase GIL non-metallic shell 1-3. The grounding ring 3-8 of each phase GIL is installed on the same vertical plane through the GIL support structure 1-2. The insulators are evenly distributed along the length direction of the current-carrying tube mother 3-2, and the insulator spacing is 6m. The grounding ring 3-8 is arranged between the three-pillar insulator 3-3 and the three-pillar insulator 3-3 or between the air-insulated basin insulator 3-4 and the three-pillar insulator 3-3, and the distance from the insulator is 2m and 4m respectively, which are hereinafter referred to as the first grounding structure and the second grounding structure. The three-phase GIL adopts the first grounding structure, the second grounding structure, and the first grounding structure from top to bottom, ensuring that the grounding ring 3-8 is in the same vertical plane, so that the insulator positions of the single-phase GIL adopting the second grounding structure and the other two-phase GIL are staggered by 2m, thereby uniformly distributing the electric field between the three phases. The three-phase GIL adopts a double-circuit configuration, which is located on the left and right sides of the three-phase GIL non-metallic shell, respectively, and is symmetrical about the vertical plane where the axis of the three-phase GIL non-metallic shell is located. The distribution of the three-phase GIL formed by connecting the second basic unit is consistent with the above method.

[0051] In order to verify whether the interphase insulation performance of the three-phase GIL is reliable when using a non-metallic shell, the designed 550kV AC GIL model is simplified and its two-dimensional electric field distribution cloud map is calculated. The structural parameters of the simplified model of the 550kV AC GIL are shown in Table 1, which only gives the dimensions of the conductor, single-phase non-metallic shell, and three-phase non-metallic shell.

[0052] Table 1

[0053]

[0054]

[0055] The simulation software COMSOL was used to perform finite element simulation calculations on its two-dimensional electric field model, in which the relative dielectric constant of the single-phase non-metallic shell was taken as 3.75, and high voltage was set for the two six-phase conductors (the voltage was set using the phase voltage peak value, 550 kV was the effective value of the line voltage, the voltage values ​​in Table 2 had been converted, when one phase of the three-phase electricity reached the maximum value, the voltages of the other two phases were half of the maximum value and the voltage polarities were different), as shown in Table 2, and the three-phase non-metallic shell was grounded.

[0056] Table 2

[0057] Conductor position Voltage(kV) Upper left (A1 phase) 224.54 Left center (Phase B1) -449.07 Lower left (C1 phase) 224.54 Upper right (A2 phase) -224.54 Middle right (Phase B2) 449.07 Lower right (C2 phase) -224.54

[0058] The two-dimensional calculation results of 550kV AC GIL are as follows Figure 6 As shown, the high electric field is mainly distributed between the single-phase non-metallic shells and between the single-phase non-metallic shells and the three-phase non-metallic shells. The highest electric field intensity appears in the middle phase, about 0.7 kV / mm, which meets the field intensity control requirements in the air.

[0059] It can be seen from the above scheme that the gas-insulated non-metallic enclosed transmission line of the present invention adopts a three-phase GIL non-metallic shell and a single-phase GIL non-metallic shell to replace the three-phase GIL metal shell and the single-phase GIL metal shell. The single-phase GIL non-metallic shell is suspended and not grounded, and the insulation distance between the high-voltage conductor and the ground is greatly improved. The electric field distribution between the high-voltage conductor and the single-phase GIL non-metallic shell is optimized, and the probability of gap discharge or surface discharge inside the single-phase GIL is greatly reduced. The staggered distribution of the insulator positions of the three-phase GIL further reduces the concentrated distribution of the phase-to-phase electric field, reduces the possibility of phase-to-phase discharge, and further improves the operational reliability of the gas-insulated non-metallic enclosed transmission line. The three-pillar insulator is directly in contact with the single-phase GIL non-metallic shell. The use of metal inserts reduces the maximum value of the electric field strength in the contact area between the three-pillar insulator and the single-phase GIL non-metallic shell, avoids the welding connection between the three-pillar insulator and the GIL shell, and effectively reduces the probability of discharge accidents caused by discharge heating at the ends of the three-pillar insulator. The circular distribution of the three-phase GIL can effectively improve the distribution of the electric field between phases, reduce the maximum value of the electric field strength between phases, improve the insulation performance of the three-phase GIL, and reduce the probability of discharge between phases. In order to solve the grounding problem of the pipeline transmission GIL using a non-metallic shell, a grounding metal liner is added to the non-metallic shell of the three-phase GIL. The liner is coaxially arranged with the shell and in close contact. The liner is connected to the grounding ring through the GIL support structure, thereby achieving grounding of part of the structure in each phase of the GIL. Furthermore, the insulators are evenly distributed in the non-metallic shell of the single-phase GIL, and the spacing is kept consistent. The electric field distribution on the surface of the insulator is more uniform, which effectively reduces the maximum value of the electric field strength on the surface of the insulator, and effectively improves the operating stability of the transmission line.

[0060] Furthermore, in each basic unit, the position of the single-phase GIL is fixed by a grounding ring and is grounded to the non-metallic shell of the three-phase GIL. The grounding ring is located at 1 / 3 of the distance on one side of the insulator, which can minimize the impact on the electric field distribution inside the transmission line while playing a fixing role, further ensuring the transmission reliability of the transmission line.

[0061] Furthermore, the grounding ring and the GIL support structure in the three-phase GIL are arranged in the same vertical plane, ensuring that the grounding position is in the same vertical plane, which is beneficial to improving the distribution of the electric field between phases, reducing the probability of phase-to-phase discharge, and facilitating the installation of the transmission line and the setting of the grounding.

[0062] According to the various advantages of the gas-insulated non-metallic enclosed transmission line of the present invention, the probability of discharge accidents occurring in the gas-insulated non-metallic enclosed transmission line of the present invention is greatly reduced, and the operating reliability and life of the pipeline corridor transmission GIL are greatly improved, which is one step closer to meeting the technical requirements of zero discharge and maintenance-free of the pipeline corridor transmission GIL.

Claims

1. A basic unit of a gas-insulated non-metallic enclosed transmission line, characterized in that: It comprises a three-phase GIL non-metallic shell (1-3), wherein a three-phase single-phase GIL is arranged in parallel inside the three-phase GIL non-metallic shell (1-3), a GIL support structure (1-2) for supporting the three-phase single-phase GIL is also fixedly arranged inside the three-phase GIL non-metallic shell (1-3), a grounded metal liner is nested in the inner cavity of the three-phase GIL non-metallic shell (1-3), and the grounded metal liner is electrically connected to the GIL support structure (1-2); Each single-phase GIL comprises a single-phase GIL non-metallic shell (3-1); a GIL current-carrying tube mother (3-2) is coaxially arranged in the inner cavity of the single-phase GIL non-metallic shell (3-1); an insulator for supporting the GIL current-carrying tube mother (3-2) is also arranged in the inner cavity of the single-phase GIL non-metallic shell (3-1); a grounding ring (3-8) is sleeved on the single-phase GIL non-metallic shell (3-1); and the grounding ring (3-8) is electrically connected to the GIL support structure (1-2).

2. A basic unit of a gas-insulated non-metallic enclosed transmission line according to claim 1, characterized in that: The insulator adopts at least one of a three-pillar insulator (3-3) and a pot-type insulator; the pot-type insulator comprises at least one of an air-separated pot-type insulator (3-4) and an air-through pot-type insulator (4-1).

3. A basic unit of a gas-insulated non-metallic enclosed transmission line according to claim 2, characterized in that: The three-pillar insulator (3-3) comprises a three-pillar insulator body (3-1-1) made of epoxy composite material, the center of the three-pillar insulator body (3-1-1) is sleeved on the outside of the GIL current-carrying tube mother (3-2), and the outer edge of the three-pillar insulator body (3-1-1) is evenly provided with a first pillar, a second pillar and a third pillar made of epoxy composite material; When the GIL current-carrying tube mother (3-2) is connected to the three-pillar insulator (3-3), the outer ends of the first pillar, the second pillar and the third pillar are in contact with the inner wall surface of the single-phase GIL non-metallic shell (3-1).

4. A basic unit of a gas-insulated non-metallic enclosed transmission line according to claim 2, characterized in that: When the insulator is a pot-type insulator, the pot-type insulator plug-in structure (3-4-1) is used to fix and connect the GIL current-carrying tube mother (3-2) at both ends of the center of the pot-type insulator, a fixing flange (7) is provided on the single-phase GIL non-metallic shell (3-1), the outer edge of the pot-type insulator is sealedly connected to the fixing flange (7), a shielding cover (5) is provided outside the fixing flange (7), and a voltage-equalizing shielding ring (6) is provided inside the outer edge of the pot-type insulator.

5. A basic unit of a gas-insulated non-metallic enclosed transmission line according to claim 2, characterized in that: The insulator adopts at least one air-spaced basin insulator (3-4).

6. A basic unit of a gas-insulated non-metallic enclosed transmission line according to claim 1, characterized in that: The grounding ring (3-8) is a metal ring (3-8-1), which is sleeved on the outside of the three-phase GIL non-metallic shell (1-3), and voltage equalizing rings (3-5) are arranged on the outside of both ends of the metal ring (3-8-1), and the metal ring (3-8-1) is electrically connected to the GIL support structure (1-2).

7. A basic unit of a gas-insulated non-metallic enclosed power transmission line according to any one of claims 1 to 6, characterized in that: Two three-phase GILs are arranged in the basic unit of the gas-insulated non-metallic enclosed transmission line, and the two three-phase GILs are symmetrical about the longitudinal plane passing through the center line of the three-phase GIL non-metallic shell (1-3); in the circumferential direction of the three-phase GIL non-metallic shell (1-3), the three-phase single-phase GILs located on the same side of the three-phase GIL non-metallic shell (1-3) are located on the same circumference of the axis.

8. A basic unit of a gas-insulated non-metallic enclosed power transmission line according to claim 8, characterized in that: In the circumferential direction of the three-phase GIL non-metallic shell (1-3), insulators in adjacent single-phase GILs located on the same side of the three-phase GIL non-metallic shell (1-3) are located on different vertical planes, which are vertical planes in the single-phase GIL that are perpendicular to the central axis of the single-phase GIL non-metallic shell (3-1).

9. A boundary basic unit for a gas-insulated non-metallic enclosed transmission line, characterized in that: The boundary basic unit comprises an air-separated basin insulator and the basic unit described in any one of claims 1 to 8, wherein the air-separated basin insulator is installed at the end of one end on the same side of each single-phase GIL non-metallic shell (3-1) of the basic unit.

10. A gas-insulated non-metallic enclosed transmission line, characterized in that: The method comprises the boundary basic unit according to claim 9, and a plurality of basic units according to any one of claims 1 to 8, wherein the plurality of basic units are sequentially connected to form an integral structure, and the two ends of the integral structure are respectively connected to the boundary basic units; in: When a plurality of basic units are sequentially connected to form the overall structure, for adjacent basic units, the GIL current-carrying tube mothers (3-2) of the same phase are correspondingly connected, the single-phase GIL non-metallic shells (3-1) are connected through pot-type insulators, or share a section of the single-phase GIL non-metallic shell (3-1); the three-phase GIL non-metallic shells (1-3) are connected to each other, or share a section of the three-phase GIL non-metallic shell (1-3); When the end of the integral structure is connected to the boundary basic unit, one end of each single-phase GIL non-metallic shell (3-1) on the boundary basic unit where the air-insulated basin-type insulator is installed is away from the integral structure; for the adjacent ends of the integral structure and the boundary basic unit, the GIL current-carrying tube mothers (3-2) of the same phase are connected correspondingly, and the single-phase GIL non-metallic shells (3-1) are connected through basin-type insulators, or share a section of the single-phase GIL non-metallic shell (3-1); the three-phase GIL non-metallic shells (1-3) are connected to each other, or share a section of the three-phase GIL non-metallic shell (1-3).

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