Oil-immersed electric pump transformer with star-delta conversion function

Abstract

The star-delta conversion oil-immersed electric pump transformer comprises an organ cover assembly, a transformer body, a base and an oil gas recovery assembly, the organ cover assembly comprises an upper cover plate and an organ cover, and the top of the organ cover is fixedly connected with the edge of the upper cover plate; the oil gas recovery assembly comprises a gas inlet pipe, an oil discharge pipe, an exhaust pipe and an explosion-proof oil tank, the top end of the oil discharge pipe is connected with the side face of the transformer body, a partition plate capable of moving in the axial direction of the oil tank is arranged in the explosion-proof oil tank, and one end of the gas inlet pipe is connected into a hollow screw. The end, connected with the exhaust pipe, of the air inlet pipe is further connected to a nitrogen release pipe of the fire-fighting cabinet. The nitrogen injection and oil discharge system provided by the invention can monitor fire behavior inside and outside a transformer box body, and can act on dangerous cases inside and outside respectively; the insulating oil can be rapidly recycled after being discharged, the oil discharging and exhausting process is isolated from air, the oil can be rapidly cooled, and the oil-lacking operation time of the transformer is shortened.

Description

Technical Field

[0001] The invention relates to the technical field related to transformers, in particular to a star-angle conversion oil-immersed electric pump transformer. Background Art

[0002] The insulating oil of oil-immersed transformers has the dual functions of insulation and heat dissipation. The normal working oil temperature of the transformer is generally 50-70℃, and the maximum oil temperature does not exceed 95℃. In the event of a fault, when the oil temperature reaches 400℃, it will slightly decompose gaseous combustibles such as methane, ethane and propane, which are saturated hydrocarbons. Therefore, it is very important for the transformer to be equipped with a fixed automatic fire extinguishing system. The existing nitrogen injection and oil discharge system generally includes a fire control cabinet, a fire cabinet, pipelines, and various sensors for fire and temperature monitoring. Among them, the fire cabinet includes functional components such as storage, nitrogen decompression, nitrogen release, flow control, and oil discharge. When the transformer has abnormal oil overflow or fire discharge, the high-temperature oil on the surface of the oil tank is discharged into the underground oil pool. After a few seconds of oil discharge, the nitrogen filling valve is opened to allow nitrogen to be injected from the bottom of the oil tank for stirring, forcing the hot and cold oils to mix, and heat exchange is performed to reduce the oil temperature to below the flash point.

[0003] At present, the nitrogen injection and oil drainage systems of transformers have basically been modified, but the following problems still exist: a. After the nitrogen injection and oil drainage system is started, the insulating oil is discharged into the oil pool and is difficult to be recovered, so it is necessary to refill the oil into the box, which causes waste on the one hand and takes a certain amount of time for manual oil replenishment on the other hand. In order to avoid serious damage to the main transformer caused by short circuits due to lack of oil, the transformer needs to be disconnected, which increases the loss to industrial production; b. A small amount of flammable gas generated in the box is discharged with the oil liquid and discharged after oil and gas separation. At this time, the temperature of the flammable gas is still very high and may still be at the flash point temperature. If it is directly discharged and contacts with the air, there will be a risk of explosion; c. At present, the nitrogen injection and oil drainage system simultaneously monitors the oil temperature in the box and the arc outside the box, such as the upper and lower porcelain sleeves, bushings, etc., but its nitrogen injection and oil drainage can solve the sharp increase in pressure and oil temperature in the box, but it cannot directly act to extinguish the external arcs and sparks, especially for some special transformers such as oil and gas well pump transformers. The gas environment is complex and inevitably contains a certain amount of flammable gas. There are also great safety hazards after contacting the arc. Summary of the invention

[0004] The purpose of the present invention is to provide a star-delta conversion oil-immersed electric pump transformer to solve the problems mentioned in the above background technology that the nitrogen injection and oil discharge system of the existing oil-immersed electric pump transformer cannot quickly recover the insulating oil and cannot take into account the fire situation outside the box.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A star-angle conversion oil-immersed electric pump transformer, comprising an accordion cover assembly, a transformer body, a base and an oil and gas recovery assembly, wherein the transformer body is fixedly mounted on the base, the accordion cover assembly comprises an upper cover plate and an accordion cover, wherein the upper cover plate is located directly above the transformer body, the accordion cover is composed of a plurality of mutually slidably connected grooved steel plates, a group of accordion covers are arranged on each of the four sides of the upper cover plate, and the top of the accordion cover is fixedly connected to the edge of the upper cover plate; the sensors are all connected to a fire control cabinet of a nitrogen injection and oil discharge system, a direct-acting actuator is installed in the middle of the bottom side of the upper cover plate, and the end of the direct-acting actuator is rotatably connected to four groups of telescopic support rods arranged in an array, the middle of the telescopic support rod is rotatably connected to the upper cover plate, and the other end of the telescopic support rod is located below the bottom end of the accordion cover after contraction;

[0007] The oil and gas recovery component includes: an air intake pipe, an oil drain pipe, an exhaust pipe, and a flameproof oil tank. The top end of the oil drain pipe is connected to the side of the transformer body, the bottom end of the oil drain pipe is connected to one end of the flameproof oil tank, and an oil drain valve is arranged between the two. A partition that can move along the axial direction of the oil tank is arranged in the flameproof oil tank, and the partition is sealed and connected to the inner wall of the flameproof oil tank. One end of the air intake pipe is connected to the inside of the hollow screw, and a dynamic sealing ring is arranged between the partition and the air intake pipe. The other end of the air intake pipe is connected to the exhaust pipe, and the top end of the exhaust pipe is connected to the top of the transformer body. The air intake pipe is also connected to the nitrogen release pipe of the fire cabinet at the connection end with the exhaust pipe.

[0008] As a further solution of the present invention: a plurality of through holes for threading are arranged on the upper cover plate.

[0009] As a further solution of the present invention: angle steel pieces are arranged at the four vertices of the upper cover plate, and the angle steel pieces are welded and fixed on the base.

[0010] As a further solution of the present invention: a sensor for fire monitoring is installed on the bottom side of the upper cover plate.

[0011] As a further solution of the present invention: the direct-acting actuator is a mechanism or device that performs linear motion when powered.

[0012] As a further solution of the present invention: a hollow screw is connected to one side of the partition, a nut sleeve threadably connected to the hollow screw is provided on the hollow screw, and an operating rod is fixedly connected to the nut sleeve.

[0013] As a further solution of the present invention: a plurality of release ports are arranged on the inner side of the base, and the release ports are connected to the nitrogen release pipes of the fire cabinet, and electromagnetic valves are arranged on the release ports, the air inlet pipe and the exhaust pipe.

[0014] As a further solution of the present invention: a plurality of exhaust slots are arranged on the top of the accordion cover.

[0015] As a further solution of the present invention: an extension tube connected to the exhaust pipe orifice is arranged in the transformer body, exhaust holes are arranged at the bottom and top of the extension tube, and the size of the exhaust hole at the top is smaller than that at the bottom.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The nitrogen injection and oil drainage system of the present invention includes fire monitoring inside and outside the transformer box, and can take actions for internal and external dangerous situations respectively, or can take actions at the same time to extinguish the fire;

[0017] 2. The insulating oil can be quickly recycled after draining. The oil draining and exhausting process is isolated from the air, and the oil can be cooled faster, reducing the transformer's oil-deficient operation time;

[0018] 3. The transformer in a critical state is enclosed by an automatically deployed accordion cover to prevent the generated arcs and sparks from contacting the outside and prevent the fire from spreading. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention.

[0020] Figure 2 It is a schematic diagram of the cross-sectional structure of the present invention.

[0021] Figure 3 It is a schematic diagram of the bottom end surface structure of the accordion cover assembly of the present invention.

[0022] Figure 4 It is a schematic diagram of the structure of the oil and gas recovery component in the present invention.

[0023] Figure 5 for Figure 2 Schematic diagram of the enlarged structure at point A in the middle.

[0024] In the figure, 1. bellows cover assembly; 11. angle steel piece; 12. upper cover plate; 121. through hole; 13. bellows cover; 131. exhaust groove; 14. direct-acting actuator; 15. telescopic support rod; 16. sensor; 2. transformer body; 21. extension pipe; 211. exhaust hole; 3. base; 4. oil and gas recovery assembly; 41. air inlet pipe; 42. oil drain pipe; 421. oil drain valve; 43. exhaust pipe; 44. flameproof oil tank; 441. pressure reducing valve; 442. partition; 443. hollow screw; 444. nut sleeve; 445. operating lever. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] See also Figure 1 , 2 In an embodiment of the present invention, a star-angle conversion oil-immersed electric pump transformer includes an accordion cover assembly 1, a transformer body 2, a base 3 and an oil and gas recovery assembly 4. The transformer body 2 is fixedly mounted on the base 3. The accordion cover assembly 1 includes an upper cover plate 12 and an accordion cover 13. The upper cover plate 12 is located directly above the transformer body 2. A plurality of through holes 121 for threading are provided on the upper cover plate 12. After threading, sealant can be poured into the hole to seal the gap between the cable and the through hole; angle steel pieces 11 are provided at the four vertices of the upper cover plate 12, and the angle steel pieces 11 are welded and fixed to the base 3. The accordion cover 13 is composed of a plurality of mutually slidably connected groove steel plates to form a retractable and expandable protective cover structure. A group of accordion covers 13 are arranged on each of the four sides of the upper cover plate 12. The top of the accordion cover 13 is fixedly connected to the edge of the upper cover plate 12. Under normal conditions, the bottom end of the accordion cover 13 is located above the edge of the transformer after it is shrunk and folded. The upper cover plate 12 and the accordion cover 13 play a role in protecting the transformer from the sun and rain. When the accordion cover 13 is unfolded, its bottom end contacts the base 3. When the accordion covers 13 on the four sides are fully unfolded, the transformer body 2 is covered therein to form a relatively closed space.

[0027] like Figure 3 The upper cover plate 12 is provided with a sensor 16 for fire monitoring at the bottom, including but not limited to a point-type smoke detector, a point-type temperature detector, an arc sensor, a glass ball-type fire detection device, etc. The sensors 16 are all connected to the fire control cabinet of the nitrogen injection and oil discharge system. A direct-acting actuator 14 is installed at the middle of the bottom of the upper cover plate 12. The direct-acting actuator 14 can be a mechanism or device for linear motion when powered on, such as a direct-acting electromagnetic mechanism or a direct electric push rod, etc. The end of the direct-acting actuator 14 is rotatably connected to four sets of telescopic supports arranged in an array. Rod 15, the middle part of the telescopic support rod 15 is rotatably connected to the upper cover plate 12, and the other end of the telescopic support rod 15 is located below the bottom end of the accordion cover 13 after contraction, and is used to support the accordion cover 13. The control circuit of the direct-acting actuator 14 is introduced into the fire control cabinet. When the sensor 16 detects external arcs, electric sparks, etc., the direct-acting actuator 14 is controlled to operate, so that the telescopic support rod 15 rotates its end to separate from the bottom end of the accordion cover 13, and the accordion cover 13 automatically unfolds, enclosing the transformer in the cover, and isolating the arc from external air and cables.

[0028] like Figure 4 The oil and gas recovery component 4 includes: an air inlet pipe 41, an oil drain pipe 42, an exhaust pipe 43, and a flameproof oil tank 44. The top of the oil drain pipe 42 is connected to the side of the transformer body 2, and the top height is a certain distance from the top surface of the transformer body 2. The distance is the upper surface high-temperature oil (the specific gravity of the high-temperature oil is less than that of the low-temperature oil, and the oil gathers at the top after being heated), that is, the oil that needs to be discharged after the oil drain and nitrogen injection system is started. The bottom end of the oil drain pipe 42 is connected to one end of the flameproof oil tank 44, and an oil drain valve 421 is arranged between the two. A partition 442 that can move along the axial direction of the oil tank is arranged in the flameproof oil tank 44. The partition 442 is sealed and connected to the inner wall of the flameproof oil tank 44. The partition 442 divides the flameproof oil tank 44 into two independent cavities. One side of the partition 442 A hollow screw 443 is connected, and a nut sleeve 444 threadedly connected thereto is provided on the hollow screw 443, and an operating rod 445 is fixedly connected to the nut sleeve 444; one end of the air inlet pipe 41 is connected to the inside of the hollow screw 443, and a dynamic sealing ring is provided between the partition 442 and the air inlet pipe 41, and the other end of the air inlet pipe 41 is connected to the exhaust pipe 43, and the top end of the exhaust pipe 43 is connected to the top end of the transformer body 2, and the air inlet pipe 41 is also connected to the nitrogen release pipe of the fire cabinet at this end. Compared with the nitrogen injection and oil discharge system in the prior art, the nitrogen release pipe is connected to the air inlet pipe 41 and several release ports (not shown in the figure) located on the inner side of the base 3 in addition to the pipeline introduced into the bottom of the transformer oil tank, and solenoid valves are provided on each pipeline to achieve independent control.

[0029] In combination with the above, when the sensor 16 on the upper cover plate 12 detects an abnormality and needs to take action, the direct-acting actuator 14 is started to expand the accordion cover 13 to form a relatively closed space. At the same time, the nitrogen tank releases nitrogen and opens the release port in the base 3 to release nitrogen into the external space of the transformer. The nitrogen is injected into the closed space from the bottom to the top. On the one hand, the closed space is cooled down, and on the other hand, the hot air in the closed space is squeezed out so that the hot air is discharged from the exhaust slots 131 on the accordion cover 13 until the nitrogen fills the closed space, thereby playing an air isolation role and avoiding Avoid the spread of fire caused by arc ignition of cable insulation, etc.; when the oil temperature and pressure monitor in the transformer body 2 issues an instruction, the fire control cabinet controls the start of nitrogen injection and oil drainage operation. At this time, the oil drain valve 421 is opened, and the surface oil in the transformer body 2 flows into the flameproof oil tank 44 through the oil drain pipe 42, and the oil flows faster under the action of internal pressure. At the same time, the nitrogen release pipe located at the bottom of the transformer body 2 is opened, and nitrogen is injected into the transformer body 2 to exchange heat with the oil to cool the oil; when the liquid level drops to the top pipe mouth position of the oil drain pipe 42, the oil drainage stops automatically.

[0030] An extension tube 21 connected to the exhaust pipe 43 is also provided in the transformer body 2. Exhaust holes 211 are provided at the bottom and top of the extension tube 21. The size of the exhaust hole 211 at the top is smaller than that of the exhaust hole 211 at the bottom. Figure 5 The exhaust hole 211 is normally located in the oil. After the oil starts to be discharged, the exhaust hole 211 at the top begins to be exposed to the liquid surface. During the oil discharge process, a small amount of gas is discharged from the exhaust hole 211 at the top. In this way, the internal pressure of the transformer body 2 will not drop suddenly. The gas pressure is used to form an action pressure on the oil to quickly discharge the oil, avoiding the slow flow of the oil due to the viscosity of the oil. When the liquid level drops to the top of the oil discharge pipe 42, the exhaust hole 211 at the bottom is exposed. At this time, the exhaust starts quickly, and a small amount of nitrogen mixed with combustible gas (the insulating oil will precipitate a certain amount of combustible gas after high temperature) is discharged. The combustible gas) is introduced into the flameproof oil tank 44 through the exhaust pipe 43 via the intake pipe 41. After the pressure stabilizes, the solenoid valve on the exhaust pipe 43 is closed, and the connection end of the intake pipe 41 and the nitrogen release pipe is opened. The nitrogen enters the flameproof oil tank 44 through the intake pipe 41, and exchanges heat with the high-temperature oil when passing through the cavity on the oil storage side, so that the high-temperature oil is quickly cooled to below the flash point. A pressure reducing valve 441 is also provided on the flameproof oil tank 44. After the air pressure in the flameproof oil tank 44 increases, it is discharged through the pressure reducing valve 441. In this way, the high-temperature gas is gradually discharged in small quantities after being cooled by the nitrogen, so that the risk of combustion and explosion after the combustible gas comes into contact with the air can be avoided.

[0031] After the temperature and pressure in the flameproof oil tank 44 are reduced to the standard values, the partition 442 is moved by the operating rod 445 and the nut sleeve 444, and the oil in the flameproof oil tank 44 is re-pressed into the transformer body 2 through the oil drain pipe 42. During the process of the oil entering the transformer body 2, the gas in the transformer body 2 is gradually discharged through the exhaust hole 211 at the upper end of the extension pipe 21 until all the oil is re-injected into the transformer; the operating rod 445 can be manually driven or connected to an automatic driving device. The automatically controlled driving device can shorten the oil return time as much as possible, reduce the operating time of the transformer in the oil-deficient state, and avoid transformer damage.

[0032] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0033] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A star-to-angle conversion oil-immersed electric pump transformer, comprising an accordion cover assembly (1), a transformer body (2), a base (3) and an oil and gas recovery assembly (4), wherein the transformer body (2) is fixedly mounted on the base (3), and is characterized in that: The bellows cover assembly (1) comprises an upper cover plate (12) and a bellows cover (13), wherein the upper cover plate (12) is located directly above the transformer body (2), and the bellows cover (13) is composed of a plurality of mutually slidably connected grooved steel plates, and a group of bellows covers (13) is arranged on each of the four sides of the upper cover plate (12), and the top of the bellows cover (13) is fixedly connected to the edge of the upper cover plate (12); the sensors (16) are all connected to a fire control cabinet of a nitrogen injection and oil discharge system, and a direct-acting actuator (14) is installed in the middle of the bottom side of the upper cover plate (12), and the end of the direct-acting actuator (14) is rotatably connected to four groups of telescopic support rods (15) arranged in an array, and the middle of the telescopic support rod (15) is rotatably connected to the upper cover plate (12), and the other end of the telescopic support rod (15) is located below the bottom end of the bellows cover (13) after contraction; The oil and gas recovery component (4) comprises: an air intake pipe (41), an oil discharge pipe (42), an exhaust pipe (43), and a flameproof oil tank (44); the top end of the oil discharge pipe (42) is connected to the side of the transformer body (2); the bottom end of the oil discharge pipe (42) is connected to one end of the flameproof oil tank (44); an oil discharge valve (421) is arranged between the two; a partition (442) movable along the axial direction of the oil tank is arranged in the flameproof oil tank (44); the partition (442) is sealedly connected to the inner wall of the flameproof oil tank (44); one end of the air intake pipe (41) is connected to the inside of the hollow screw (443); a dynamic sealing ring is arranged between the partition (442) and the air intake pipe (41); the other end of the air intake pipe (41) is connected to the exhaust pipe (43); the top end of the exhaust pipe (43) is connected to the top end of the transformer body (2); and the air intake pipe (41) is also connected to the nitrogen release pipe of the fire cabinet at the end connected to the exhaust pipe (43).

2. The oil-immersed electric pump transformer with star-angle conversion according to claim 1 is characterized in that: The upper cover plate (12) is provided with a plurality of through holes (121) for threading wires.

3. The oil-immersed electric pump transformer with star-angle conversion according to claim 2 is characterized in that: Angle steel pieces (11) are arranged at the four vertices of the upper cover plate (12), and the angle steel pieces (11) are welded and fixed on the base (3).

4. The oil-immersed electric pump transformer with star-angle conversion according to claim 3 is characterized in that: A sensor (16) for fire monitoring is installed on the bottom side of the upper cover plate (12).

5. The oil-immersed electric pump transformer with star-angle conversion according to claim 1 is characterized in that: The direct-acting actuator (14) is a mechanism or device that performs linear motion when powered.

6. The oil-immersed electric pump transformer with star-angle conversion according to claim 1 is characterized in that: A hollow screw (443) is connected to one side of the partition (442), a nut sleeve (444) threadedly connected to the hollow screw (443) is provided on the hollow screw (443), and an operating rod (445) is fixedly connected to the nut sleeve (444).

7. The oil-immersed electric pump transformer with star-angle conversion according to claim 1 is characterized in that: A plurality of release ports are arranged on the inner side of the base (3), and the release ports are connected to the nitrogen release pipe of the fire cabinet. Solenoid valves are arranged on the release ports, the air inlet pipe (41) and the air outlet pipe (43).

8. The oil-immersed electric pump transformer with star-angle conversion according to claim 1 or 4, characterized in that: A plurality of exhaust slots (131) are arranged at the top end of the accordion cover (13).

9. The oil-immersed electric pump transformer with star-angle conversion according to claim 1, characterized in that: An extension tube (21) connected to the outlet of the exhaust pipe (43) is arranged in the transformer body (2); exhaust holes (211) are arranged at the bottom and top of the extension tube (21); and the exhaust hole (211) at the top is smaller than the exhaust hole (211) at the bottom.

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