110 kV lines except for the entry and exit line sections of the substation, no grounding device

Abstract

The utility model discloses 110kV line except substation incoming, outgoing line segment set ground wire whole line does not set grounding device, only retains substation incoming, outgoing line segment each 1-2km range erects lightning conductor, and the rest section of line cancels whole line lightning conductor design, and the configuration dirt -repellent type insulator adopts double series suspension arrangement, and single piece insulator creepage distance is greater than or equal to 450mm, and 110kV line is equipped with 16 dirt -repellent type insulators, and insulator series double series suspends in the pole tower cross arm below, and the top of pole tower is provided with lightning and connects to the optimization grounding device through the grounding down lead of lightning arrester or lightning rod. The scheme can save 2.3%-2.5% of line comprehensive cost, and the pole tower cross arm shortens 10%-15%, and the tower body weight lightens 5%-8%, and the foundation cost reduces more than 5%, realizes the cost reduction and benefit increase.

Description

Technical Field

[0001] This utility model relates to the field of high-voltage transmission line technology, specifically referring to a 110kV line that has no grounding device except for the grounding wires installed at the substation incoming and outgoing line sections. Background Technology

[0002] Traditional 35-220kV transmission lines are typically equipped with lightning protection wires along the entire length to prevent lightning strikes. However, in high-altitude areas with low lightning activity, such as Qinghai Province, actual operational data shows that the lightning trip rate is extremely low (close to zero), resulting in wasted investment in lightning protection wires. Furthermore, flashover accidents due to pollution account for over 60% in high-altitude areas, and existing designs have not specifically optimized insulation configurations.

[0003] The existing technology has the following problems: Lightning protection redundancy: The necessity of full-line lightning protection in areas with few lightning strikes is questionable, as it increases conductor load and tower costs; Pollution flashover risk: Low insulation configuration cannot adapt to polluted environments at high altitudes; Poor economic efficiency: Lightning protection wires and related hardware account for 2%-2.5% of the total cost and increase operation and maintenance costs.

[0004] To address the aforementioned technical issues, a method for a 110kV line to be entirely free of grounding devices, except for the substation's incoming and outgoing lines, urgently needs to be developed and made public. Utility Model Content

[0005] To solve the above-mentioned technical problems, the technical solution provided by this utility model is as follows: Except for the substation incoming and outgoing line sections, the entire 110kV line does not have a grounding device, including: Except for the substation incoming and outgoing lines, the 110kV line has no grounding device, including: Lightning protection wires will be installed only within 1-2km of the substation's incoming and outgoing lines; the design of lightning protection wires for the rest of the line will be cancelled. The system is equipped with anti-pollution insulators, using a double-string suspension arrangement, with a creepage distance of ≥450mm for each insulator; 16 anti-pollution insulators are configured for 110kV lines. Two strings of insulators are suspended below the crossarm of the tower. A lightning arrester or lightning rod is installed at the top of the tower and connected to the optimized grounding device through a grounding down conductor.

[0006] Furthermore, the optimized grounding device adopts a radial horizontal grounding grid with a grounding resistance value ≤10Ω and a burial depth ≥0.8m.

[0007] The length of the crossarm of the tower is shortened by 10%-20% compared with that of conventional 110kV line towers of the same voltage level, and the weight of the tower body is reduced by 5%-8% compared with that of conventional 110kV line towers of the same voltage level.

[0008] The advantages of the utility model compared to the prior art are: This utility model addresses the unique environment of 110kV transmission lines in low-lightning-rate areas such as the Qaidam Basin in Qinghai Province. By eliminating all lightning protection wires (except for the incoming line section), optimizing insulation configuration, and improving grounding devices, it achieves the following significant beneficial effects: Significantly reduces construction and operation costs and saves on material investment: Eliminating lightning protection wires and supporting hardware and brackets directly reduces the overall cost of the line by 2.3%-2.5% (taking a 110kV line as an example, the cost is reduced by about 12,000 yuan per kilometer).

[0009] Lightweight tower structure: Due to the elimination of lightning protection wires, the conductor load is reduced, the crossarm length is shortened by 10%-15%, and the overall weight of the tower body is reduced by 5%-8% after the use of high-strength steel, and the foundation cost is reduced by more than 5%.

[0010] Reduced maintenance costs: The cost of repairing and replacing lightning protection wires and their suspension devices is reduced, resulting in optimized lifecycle costs.

[0011] 2. Ensure high-reliability lightning protection performance Low tripping rate: Based on the characteristics of low lightning areas (annual average of less than 20 thunderstorm days, lightning current amplitude of less than 30kA accounts for 90%), combined with lightning arresters and reinforced insulation design, the lightning tripping rate can be controlled at less than 0.05 times / 100km·year (actual measured data), which is comparable to the traditional full-line lightning protection scheme (tripping rate of about 0.1 times / 100km·year).

[0012] Active lightning attraction and discharge: The lightning arrester at the top of the tower effectively guides the lightning current, and the optimized grounding device with a grounding resistance of ≤10Ω ensures rapid discharge. The lightning withstand level reaches more than 120kA, meeting the needs of areas with few lightning strikes. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the 110kV line of this utility model, which has no grounding device except for the grounding wires installed in the substation incoming and outgoing line sections.

[0014] 1. Insulators; 2. Tower crossarms; 3. Lightning arresters or lightning rods; 4. Optimized grounding devices; 5. Towers. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings.

[0016] The present invention will be described in detail with reference to the accompanying drawings.

[0017] In its specific implementation, this utility model provides a 1.110kV line that, except for the substation incoming and outgoing line sections which are equipped with grounding wires, has no grounding device throughout, including: Lightning protection wires will be installed only within 1-2km of the substation's incoming and outgoing lines; the design of authorized lightning protection wires will be cancelled for the rest of the line. The line is equipped with 1 anti-pollution insulator, which is arranged in double strings with a creepage distance of ≥450mm for a single insulator; 16 anti-pollution insulators are configured for the 110kV line. Two strings of insulators are suspended below the crossarm 2 of the tower. A lightning arrester or lightning rod 3 is installed at the top of the tower 5 and connected to the optimized grounding device 4 through a grounding down conductor.

[0018] The optimized grounding device 4 adopts a radial horizontal grounding grid with a grounding resistance value ≤10Ω and a burial depth ≥0.8m.

[0019] The length of the crossarm 2 of the tower is 10%-20% shorter than that of the conventional 110kV line tower 5 of the same voltage level, and the weight of the tower body is 5%-8% lighter than that of the conventional 110kV line tower of the same voltage level.

[0020] Example 1 (110kV line): Lightning protection wire configuration: Lightning protection wires are only installed for 1.5km of the substation's incoming and outgoing lines; the remaining sections are exempt from lightning protection. Insulator 1 parameters: 16 anti-pollution type insulators, string length 1.8m, creepage distance of a single insulator 480mm; Grounding construction: The horizontal grounding electrode uses Φ12 round steel with a total length of 80m, the vertical grounding electrode is 2.5m long, and the measured impulse grounding resistance is 8Ω; Tower 5 optimization: Tower height 28m, crossarm length shortened to 4.2m, tower weight reduced by 6.5%.

[0021] Example 2 (220kV line): The incoming line section retains a lightning protection wire for 2km, and the number of insulators has been increased from 1 to 28. Composite insulators (FQBG-220 / 240) are used, with a creepage distance of 3.0 cm / kV.

[0022] The improvements of this utility model are as follows: Lightning protection wire layout optimization: Lightning protection wires will only be retained within 1-2km of the incoming line section, and will be removed in other sections; Lightning arresters (such as multi-forked lightning rods) are added to the top of the tower and connected to the optimized grounding device through grounding down conductors.

[0023] High-altitude insulation configuration: The number of insulator discs is increased by 10%-15% compared to conventional designs (for example, 16 FXBW4-110 / 100 anti-pollution insulator discs are used in 110kV lines). Double-string suspension arrangement, single-piece creepage distance ≥450mm, creepage ratio ≥2.8cm / kV.

[0024] Grounding device optimization: A combination of radial horizontal grounding grid and vertical grounding electrode is adopted, with a grounding resistance ≤10Ω; For burial depths ≥ 0.8m, add drag-reducing agents to areas with high soil resistivity.

[0025] Lightweighting of tower structures: The crossarm length is shortened by 15%, and the tower body is made of Q420 high-strength steel, resulting in an overall weight reduction of 5%-8%.

[0026] As a further explanation of this utility model, the optimized grounding device adopts a radial horizontal grounding grid with a grounding resistance value ≤10Ω and a burial depth ≥0.8m.

[0027] As a further explanation of this utility model, the insulator string is arranged in a double-string suspension configuration, and the creepage distance of a single insulator is ≥450mm.

[0028] As a further explanation of this utility model, the length of the crossarm of the tower is shortened by 10%-20%, and the weight of the tower body is reduced by 5%-8%.

[0029] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. 110kV lines, except for the substation incoming and outgoing lines which are equipped with grounding wires, are characterized by the following: include: Lightning protection wires will be installed only within 1-2km of the substation's incoming and outgoing lines; the design of authorized lightning protection wires will be cancelled for the rest of the line. The system is equipped with anti-pollution insulators, using a double-string suspension arrangement, with a creepage distance of ≥450mm for each insulator; 16 anti-pollution insulators are configured for 110kV lines. Two strings of insulators are suspended below the constant load of the tower. A lightning arrester or lightning rod is installed at the top of the tower and connected to the optimized grounding device through a grounding down conductor.

2. The 110kV line according to claim 1, except for the substation incoming and outgoing line sections which are equipped with grounding wires, is characterized in that, The optimized grounding device adopts a radial horizontal grounding grid with a grounding resistance value ≤10Ω and a burial depth ≥0.8m.

3. The 110kV line according to claim 1, except for the substation incoming and outgoing line sections which are equipped with grounding wires, is characterized in that, The length of the crossarm of the tower is shortened by 10%-20% compared with that of conventional 110kV line towers of the same voltage level, and the weight of the tower body is reduced by 5%-8% compared with that of conventional 110kV line towers of the same voltage level.

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