Deep underground GIL electric power pipe gallery SF6 leakage gas gravity trap collection device and method

Abstract

According to the gravity trap collecting device and method for the SF6 leaked gas of the deep underground GIL electric power pipe gallery, through the synergistic effect of the heavy gas particle trap and the micro-pressure air system, a zero-pressure or micro-negative-pressure collecting space is formed in the heavy gas particle trap by utilizing the characteristic that the density of SF6 gas is large, and the capturing efficiency of SF6 heavy gas particles is remarkably improved; by combining linkage control of the SF6 gas leakage monitoring mechanism and the micro-pressure air system, closed-loop management of leakage real-time detection, automatic starting and rapid collection is achieved, the manual intervention requirement is reduced, leakage recovery automation of SF6 gas is greatly improved, greenhouse gas emission is reduced, and meanwhile potential safety hazards caused by SF6 gas accumulation in the pipe gallery are avoided. According to the invention, the gravity settling principle and fluid dynamics are combined, passive capture and active recovery of SF6 heavy gas are realized through structure optimization and system collaboration, and the device is extremely suitable for emergency treatment of dangerous heavy gas leakage in limited spaces such as deep underground pipe galleries and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechatronic engineering and relates to a leakage gas gravity trap collection device and method. Background Art

[0002] High-voltage SF 6 Gas-insulated metal-enclosed transmission line, abbreviated as GIL in English, is a power transmission equipment. Its metal shell is welded in a fully connected manner, and the internal conductor is supported on the shell by supports or pot-type insulators with gas separation functions. The inside is filled with 0.2 - 0.8 Mpa of SF6 insulating gas.

[0003] SF 6 Its Chinese name is sulfur hexafluoride. It is colorless, odorless, and non-toxic by itself. However, under certain specific conditions such as in arcs, high temperatures, etc., sulfur hexafluoride may decompose to produce some toxic low fluorides, such as hydrogen fluoride. If personnel inhale these decomposition products, it will cause irritation and harm to the respiratory tract, eyes, etc., and even endanger life in severe cases. Therefore, although GIL is a sealed structure, during long-term operation, due to equipment aging, seal damage, etc., sulfur hexafluoride gas leakage may occur. If the leaked gas accumulates in a closed space, it will cause asphyxiation of personnel when the concentration is too high. Moreover, the density of sulfur hexafluoride gas is about 6 times that of air. After leakage, it is easy to accumulate in low-lying areas, and high concentrations of sulfur hexafluoride are more likely to appear in places such as deep underground power cable galleries, increasing the safety risk when personnel enter these areas. Therefore, in engineering, GIL must monitor the concentration of sulfur hexafluoride gas to detect leakage in a timely manner and take corresponding measures, such as ventilation and air change, to reduce the concentration of the leaked gas and ensure the safety of personnel. In addition, sulfur hexafluoride is also a greenhouse gas, and its global warming potential is 23,500 times that of carbon dioxide. Although the leakage of sulfur hexafluoride gas in GIL is usually small, in the long run, it will also have a certain impact on the environment.

[0004] For underground power cable galleries, monitoring and ventilation can reduce the leakage of sulfur hexafluoride gas and reduce the impact of the greenhouse effect on the environment. At the same time, during equipment maintenance, repair, etc., properly treating the discharged sulfur hexafluoride gas to avoid direct emission into the atmosphere is also an important measure and requirement in line with environmental protection requirements. However, for long-distance, multi-circuit GIL power cable galleries in deep underground spaces, due to multi-circuits and long distances, the number of GIL gas chamber units is huge, and it is difficult to comprehensively and accurately actively monitor the tiny leakage and initial leakage of SF 6 gas in GIL. Even if leakage is detected, due to the deep underground, long-distance, and large space, it cannot be discharged in a timely and effective manner. Summary of the Invention

[0005] To solve the problem of SF in the deep underground GIL power cable gallery described in the background art6 Regarding the problem that the leaked gas cannot be discharged in a timely and effective manner, the present invention provides a gravity trap collection device and method for leaked gas in a deep underground GIL power pipe gallery SF 6

[0006] The device of the present invention is arranged outside the SF 6 pipe bus. The periphery of the SF 6 pipe bus is provided with a GIL power pipe gallery with a smooth wall surface and no gravity depression settlement area; a micro-pressure air system for providing longitudinal wind along the GIL power pipe gallery is arranged in the GIL power pipe gallery, and SF 6 gas leakage monitoring mechanism is arranged in the GIL power pipe gallery; a plurality of heavy gas particle traps are arranged at the bottom of the GIL power pipe gallery, and a 0-pressure or micro-negative pressure SF 6 heavy particle collection space is formed inside the heavy gas particle trap through the longitudinal wind of the micro-pressure air system; the bottom of the heavy gas particle trap is connected to a gas recovery mechanism.

[0007] Further, the heavy gas particle trap includes a groove arranged longitudinally along the GIL power pipe gallery.

[0008] Further, the transverse cross-section of the groove is semi-circular. The design of the semi-circular cross-section groove can reduce air flow disturbance and avoid secondary escape of SF 6 gas.

[0009] Further, the groove is arranged in a wavy line along the longitudinal direction. The wavy longitudinal layout of the groove can extend the residence path of SF 6 gas and improve the collection efficiency.

[0010] Further, the gas recovery mechanism is arranged at intervals along the longitudinal groove of the heavy gas particle trap. The spaced gas recovery mechanism can balance the negative pressure distribution in the heavy gas particle trap and ensure continuous recovery.

[0011] Based on the above device, the present invention proposes a gravity trap collection method for leaked gas in a deep underground GIL power pipe gallery SF 6 When the SF 6 gas leakage monitoring mechanism detects SF 6 gas leakage in the GIL power pipe gallery, start the micro-pressure air system; Accelerate the air gas particles and SF 6 gas particles in the GIL power pipe gallery through the longitudinal wind generated by the micro-pressure air system; Accelerate the flow velocity of the air gas particles to be greater than the escape velocity v r of the heavy gas particle trap, so that the SF 6 gas particles enter the 0-pressure or micro-negative pressure SF 6 ​​Heavy particle collection space; SF 6 After gas particles enter the inside of the heavy gas particle trap and their flow velocity decreases until they lose their flow, the SF is recovered through the gas recovery mechanism. 6 Gas.

[0012] The escape velocity v of the heavy gas particle trap r is a set value, which needs to be between the velocities of air and heavy gas particles accelerated by longitudinal wind flow.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) High efficiency in SF gas collection: Through the synergistic effect of the heavy gas particle trap and the micro-pressure wind system, and by utilizing the characteristic of the large density of SF gas, a 0-pressure or micro-negative pressure collection space is formed inside the heavy gas particle trap, significantly improving the capture efficiency of SF heavy gas particles and solving the problem that it is difficult to effectively collect SF gas in traditional pipe corridors. 6 Gas collection is efficient: Through the synergistic effect of the heavy gas particle trap and the micro-pressure wind system, taking advantage of the large density of SF gas, a 0-pressure or micro-negative pressure collection space is formed inside the heavy gas particle trap, significantly enhancing the capture efficiency of SF heavy gas particles and solving the problem that it is difficult to effectively collect SF gas in traditional pipe corridors. 6 Gas density is large, forming a 0-pressure or micro-negative pressure collection space inside the heavy gas particle trap, significantly improving the capture efficiency of SF heavy gas particles and solving the problem that it is difficult to effectively collect SF gas in traditional pipe corridors. 6 Heavy gas particles, solving the problem that it is difficult to effectively collect SF gas in traditional pipe corridors. 6 Gas problem; (2) Strong directivity in gas separation and recovery: The longitudinal wind generated by the micro-pressure wind system accelerates the flow of air particles, making their speed exceed the trap escape velocity, while SF gas particles are separated due to gravitational settlement and remain in the heavy gas particle trap, realizing the dynamic separation and directional enrichment recovery of SF gas; 6 Gas particles are separated and retained in the heavy gas particle trap due to gravity settlement, achieving the dynamic separation and directional enrichment recovery of SF gas; 6 Gas dynamic separation and directional enrichment recovery; (3) High degree of automation: Combining the linkage control of the SF gas leakage monitoring mechanism and the micro-pressure wind system, realizing the closed-loop management of real-time leakage detection - automatic start - rapid collection, reducing the need for manual intervention, and greatly improving the automation of SF gas leakage recovery; 6 Gas leakage monitoring mechanism and the micro-pressure wind system for linkage control, realizing real-time leakage detection - automatic start - rapid collection of closed-loop management, reducing the need for manual intervention, and greatly improving the automation of SF gas leakage recovery. 6 Gas leakage recovery automation; (4) Environmental protection and safety: By actively recovering SF gas with a high global warming potential, reducing greenhouse gas emissions, and at the same time avoiding potential safety hazards caused by the accumulation of SF gas in the pipe corridor. 6 Gas, reducing greenhouse gas emissions, and at the same time avoiding potential safety hazards caused by the accumulation of SF gas in the pipe corridor. 6 Gas accumulation-induced safety hazards.

[0014] All in all, the present invention utilizes the cross-sectional structure of the smooth and gravity-free depression settlement area of the deep underground GIL power pipe corridor, taking advantage of the characteristic that the density of SF gas is much greater than that of air. Under the condition of a certain longitudinal ventilation wind speed, the gas in the pipe corridor is actively accelerated and stratified by wind pressure, and the SF gas is introduced into the SF set at the bottom of the pipe corridor after being stratified by longitudinal gentle wind. 6 Gas density is much greater than that of air. Under the condition of a certain longitudinal ventilation wind speed, the gas in the pipe corridor is actively accelerated and stratified by wind pressure, and the SF gas is introduced into the SF set at the bottom of the pipe corridor after being stratified by longitudinal gentle wind. 6 Gas is introduced into the SF set at the bottom of the pipe corridor after being stratified by longitudinal gentle wind. 6Inside the heavy gas particle trap for heavy density gas, the purpose of long-term safe collection of SF6 leakage gas in the long-distance GIL power corridor underground is achieved. The present invention combines the principle of gravity sedimentation with hydrodynamics, and through structural optimization and system coordination, passive capture and active recovery of heavy gas are realized, which is extremely suitable for emergency treatment of dangerous heavy gas leakage in restricted spaces such as deep underground pipe galleries. 6 Passive capture and active recovery of heavy gas are extremely suitable for emergency treatment of dangerous heavy gas leakage in restricted spaces such as deep underground pipe galleries. Description of the Drawings

[0015] Figure 1 It is a cross-sectional schematic diagram of the gravity trap collection device.

[0016] Figure 2 It is a longitudinal sectional schematic diagram of the gravity trap collection device.

[0017] Figure 3 It is a bottom-up view schematic diagram of the gravity trap collection device.

[0018] Description of the reference numerals: 1 - GIL power corridor; 2 - SF 6 Pipeline busbar; 3 - micro-pressure air system; 4 - heavy gas particle trap; 5 - gas recovery mechanism. Detailed Embodiments

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0020] The SF6 pipeline busbar 2 is generally a high-voltage SF 6 Pipeline busbar (GIL), which is a power high-voltage transmission device, adopts a fully welded metal shell, and the internal conductor is supported on the shell by supports or pot-type insulators with gas separation functions, and is filled with 0.2 Mpa - 0.8 Mpa of SF 6 Insulating gas. Among them, the high-voltage SF 6 The pipeline busbar is usually filled with 0.5 Mpa of SF 6 Insulating gas.

[0021] As Figure 1 、 Figure 2 And Figure 3 Shown, the gravity trap collection device for SF 6 Leakage gas in the deep underground GIL power corridor is arranged outside the SF 6 Pipeline busbar 2, SF 6The GIL power corridor 1 with a smooth wall surface and no gravity depression settlement area is provided around the pipeline busbar 2. Specifically, the internal structural walls of the GIL power corridor 1, the GIL pipeline busbar and its support structures and other equipment are all smooth, without sharp corners and without depression settlement areas in the direction of gravity, that is, in the whole corridor, the parts where SF 6 gas leakage may occur. In the windless and static state, the SF 6 gas can sink to the bottom of the corridor or into the heavy gas particle trap 4 described below.

[0022] A micro-pressure wind system 3 that provides longitudinal wind along the GIL power corridor 1 is provided in the GIL power corridor 1; through and by using the natural ventilation and mechanical ventilation of the micro-pressure wind system 3 in the longitudinal direction of the corridor, the acceleration of air and SF 6 gas in the above-mentioned GIL power corridor 1 is realized, and the stratification of gases with different masses is achieved by using the gravity and wind pressure, with different flow velocities, and the SF 6 leakage gas is actively guided into the heavy gas particle trap 4 described below.

[0023] An SF 6 gas leakage monitoring mechanism is provided in the GIL power corridor 1.

[0024] A plurality of heavy gas particle traps 4 are provided at the bottom of the GIL power corridor 1. The inside of the heavy gas particle trap 4 forms a 0-pressure or micro-negative pressure SF 6 heavy particle collection space through the longitudinal wind of the micro-pressure wind system 3. Specifically, under a certain gentle wind pressure, the velocity of the small-density gas can be greater than the minimum wind speed entering this space, that is, the flow velocity of the small-density air gas is greater than the trap escape velocity v r and it will not enter the trap; while the SF 6 gas, due to its large gas density, has a much lower flow velocity than air molecules under the longitudinal gentle wind. When the SF 6 gas molecules are less than the minimum escape velocity v r of the trap, they will enter this space. After entering this space, the SF 6 gas molecules will further decrease their velocity to 0 until they lose their flow due to the 0-pressure and micro-negative pressure environment in the trap space, and thus completely fall into the inside of the trap.

[0025] The bottom of the heavy gas particle trap 4 is connected to the gas recovery mechanism 5.

[0026] Specifically, as Figure 1 shown, the heavy gas particle trap 4 includes a groove arranged longitudinally along the GIL power corridor 1. More specifically, the transverse cross-section of the groove is semi-circular. More specifically, as Figure 3 shown, the groove is wavy along the longitudinal direction.

[0027] Specifically, asFigure 2 As shown, the gas recovery mechanism 5 is arranged at intervals along the longitudinal groove of the heavy gas particle trap 4.

[0028] Based on the above device, a method for collecting leaked gas gravity trap of deep underground GIL power cable tunnel SF 6 is proposed, including: When SF 6 the gas leakage monitoring mechanism detects SF in the GIL power cable tunnel 1 6 gas leakage, start the micro-pressure air system 3; The longitudinal wind force generated by the micro-pressure air system 3 accelerates the air gas particles and SF in the GIL power cable tunnel 1 6 gas particles; Accelerate the flow velocity of the air gas particles to be greater than the escape velocity v of the heavy gas particle trap 4 r , so that SF 6 gas particles enter the 0-pressure or micro-negative pressure SF formed inside the heavy gas particle trap 4 6 heavy particle collection space; wherein, the escape velocity v of the heavy gas particle trap r is a set value, and this value needs to be between the velocity values of the air and heavy gas particles accelerated by the longitudinal wind force flow; SF 6 After the gas particles enter the heavy gas particle trap 4 and the flow velocity decreases until the flow stops, the SF is recovered through the gas recovery mechanism 5 6 gas. Embodiment

[0029] Taking the GIL (divided into three single phases) of a certain large underground hydropower station with a rated voltage of 550 kV and a rated current of 6000 A as an example, which is 4 circuits and is used for long-distance transmission in an underground power cable tunnel with an inner diameter of 11 m and a length exceeding 30 km. The single-phase outer shell of the 550 kV GIL is an aluminum pipe with an outer diameter of 500 mm and a thickness of 8 mm, the conductor is a pure aluminum pipe with an outer diameter of 160 mm and a thickness of 15 mm, and the internal SF6 pressure is 0.5 Mpa. The GIL is 10 km - 50 km long and is all located in the deep underground power cable tunnel. The GIL is in a three-single-phase split-phase mode and is evenly distributed in a circular cross-section tunnel.

[0030] First of all, a design of an underground power cable tunnel with a smooth wall and a gravity-free sunken settlement area is adopted, that is, the internal structural wall of the underground GIL power cable tunnel 1, the GIL pipeline busbar and its support structure and other equipment are all smooth, without sharp corners and without sunken settlement areas in the gravity direction, that is, in all parts of the whole corridor where SF 6 gas leakage may occur, in the windless and static state, SF 6All gases can sink to the bottom of the corridor. In this embodiment, there are 4 circuits of 500 kV high-voltage SF6 pipe busbars (GIL), a total of 12 single-phase SF6 pipe busbars, which are power high-voltage transmission equipment. They adopt the fully welded metal shell method. The internal conductor is supported on the shell by supports or pot insulators with gas separation functions, and the inside is filled with 0.2 Mpa - 0.8 Mpa (usually 0.5 Mpa for 550 kV) of SF 6 insulating gas.

[0031] There are 3 heavy gas particle traps 4 arranged at the bottom of the GIL power corridor 1. Inside the heavy gas particle trap 4, a 0-pressure or slightly negative-pressure SF 6 heavy particle collection space is formed by the longitudinal wind of the micro-pressure air system 3. The heavy gas particle trap 4 is a groove arranged longitudinally along the GIL power corridor 1. The transverse section of the groove is semi-circular, and the groove is arranged in a wavy line along the longitudinal direction. There is a micro-pressure air system 3 in the GIL power corridor 1 to provide longitudinal wind along the GIL power corridor 1; there is an SF 6 gas leakage monitoring mechanism in the GIL power corridor 1; the bottom of the heavy gas particle trap 4 is connected to the gas recovery mechanism 5.

[0032] When the micro-pressure air system 3 is started, when there are two gases with different densities, upper and lower, in the corridor of the GIL power corridor 1 and there is a certain longitudinal wind speed, these two gases will accelerate separation. That is, the SF 6 gas with a larger density will sink, and the air gas with a smaller density will rise. For the gas with a larger density, due to its own tendency to sink and the longitudinal wind speed making it move horizontally, it will accelerate downward at a certain angle and along the wind direction, thus separating from the gas with a smaller density faster. For the gas with a smaller density, its upward tendency plus the action of the longitudinal wind speed will make it accelerate upward at a certain angle and along the wind direction, and it will also accelerate the separation from the gas with a larger density.

[0033] The gas recovery mechanism 5 is used to collect and recover the SF 6 gas that falls into the heavy gas particle trap 4. It can be a mobile inspection and recovery method or a permanent pipeline segmented connection to the heavy gas particle trap 4 for centralized recovery.

[0034] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included within the protection scope of the present application.

Claims

1. A deep underground GIL power pipeline corridor SF6 leaked gas gravity trap collection device, which is arranged outside the SF6 pipeline busbar (2), and is characterized by: The periphery of the SF6 pipeline busbar (2) is provided with a GIL power corridor (1) having a smooth wall surface and no gravity depression settlement area; the GIL power corridor (1) is provided with a micro-pressure wind system (3) for providing longitudinal wind along the GIL power corridor (1); the GIL power corridor (1) is provided with an SF6 gas leakage monitoring mechanism; a plurality of heavy gas particle traps (4) are provided at the bottom of the GIL power corridor (1); the interior of the heavy gas particle trap (4) forms a SF6 heavy particle collection space with zero pressure or slightly negative pressure through the longitudinal wind of the micro-pressure wind system (3); the bottom of the heavy gas particle trap (4) is connected to a gas recovery mechanism (5).

2. The deep underground GIL power pipeline gallery SF6 leakage gas gravity trap collection device according to claim 1 is characterized by: The heavy gas particle trap (4) comprises a groove arranged longitudinally along the GIL power pipeline gallery (1).

3. The deep underground GIL power pipeline gallery SF6 leakage gas gravity trap collection device according to claim 2 is characterized by: The transverse cross section of the groove is semicircular.

4. The deep underground GIL power pipeline gallery SF6 leakage gas gravity trap collection device according to claim 3 is characterized by: The grooves are arranged in a wavy line along the longitudinal direction.

5. The deep underground GIL power pipeline gallery SF6 leakage gas gravity trap collection device according to claim 2 is characterized by: The gas recovery mechanisms (5) are arranged at intervals along the longitudinal grooves of the heavy gas particle trap (4).

6. A method for collecting SF6 gas leakage from a deep underground GIL power pipeline gallery using a device as described in any one of claims 1 to 5, characterized in that: include: When the SF6 gas leakage monitoring mechanism detects SF6 gas leakage in the GIL power pipeline corridor (1), the micro-pressure air system (3) is started; The longitudinal wind force generated by the micro-pressure wind system (3) accelerates the air gas particles and SF6 gas particles in the GIL power pipeline corridor (1); Accelerate the flow velocity of air gas particles to a speed greater than the escape velocity v of the heavy gas particle trap (4) r , so that the SF6 gas particles enter the SF6 heavy particle collection space with zero pressure or slightly negative pressure formed inside the heavy gas particle trap (4); After the SF6 gas particles enter the heavy gas particle trap (4) and the flow velocity decreases until the flow is lost, the SF6 gas is recovered through the gas recovery mechanism (5).

7. The method for collecting SF6 leaked gas by gravity trap in deep underground GIL power pipeline gallery according to claim 6 is characterized by: The escape velocity v of the heavy gas particle trap r It is a set value, which needs to be between the velocity values ​​of air and heavy gas particles after being accelerated by the longitudinal wind flow.

Images