Oil-immersed electric pump transformer with star-delta conversion

Abstract

The application discloses a star-angle conversion oil-immersed electric pump transformer, which comprises an organ case assembly, a transformer body, a base and an oil gas recovery assembly. The organ case assembly comprises an upper cover plate and an organ case, and the top of the organ case is fixedly connected with the edge of the upper cover plate. The oil gas recovery assembly comprises an air inlet pipe, an oil discharge pipe, an air outlet pipe and an explosion-proof oil tank. The top end of the oil discharge pipe is connected with the side surface of the transformer body. A partition plate which can move along the axial direction of the oil tank is arranged in the explosion-proof oil tank. One end of the air inlet pipe is connected with the inside of a hollow screw rod. The air inlet pipe is also connected with a nitrogen release pipe of a fire-fighting cabinet at the connection end with the air outlet pipe. The nitrogen injection and oil discharge system of the application comprises fire monitoring inside and outside the transformer tank, and can take actions on the inside and outside dangers respectively. After the discharge of the insulating oil, the insulating oil can be quickly recycled. The oil discharge and air exhaust process is isolated from air, and the oil can be cooled faster, so that the oil shortage operation time of the transformer is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transformer, and particularly relates to an oil-immersed electric pump transformer for star-delta conversion. BACKGROUND

[0002] The insulating oil of the oil-immersed transformer has double functions of insulation and heat dissipation, the oil temperature of the transformer in normal operation is generally 50-70 DEG C, and the maximum oil temperature is not more than 95 DEG C. When a fault occurs, when the oil temperature reaches 400 DEG C, gaseous combustible materials such as methane, ethane and propane and other saturated hydrocarbons are slightly decomposed. 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 comprises a fire control cabinet, a fire cabinet, pipelines and various sensors for fire and temperature monitoring. The fire cabinet comprises function components such as storage, nitrogen pressure reduction, nitrogen release, flow control and oil discharge. When the transformer has abnormal oil overflow or oil discharge due to fire, the high-temperature oil on the upper surface of the oil tank is discharged into the underground oil tank, and after the oil is discharged for a few seconds, the nitrogen charging valve is opened to inject nitrogen from the bottom of the oil tank to stir and forcibly mix the hot and cold oil, so that heat exchange is performed to reduce the oil temperature below the flash point.

[0003] At present, the nitrogen injection and oil discharge system of the transformer has been basically transformed, but the following problems still exist: a. After the nitrogen injection and oil discharge system is started, the insulating oil discharged into the oil tank is difficult to be recovered, so it is necessary to re-supply oil into the tank, which not only causes waste, but also requires a certain time for manual oil supply. In order to avoid the problem of short circuit caused by lack of oil and cause serious damage to the main transformer, the transformer needs to be cut off, which causes great loss to the industrial production; b. A small amount of flammable gas generated in the tank is discharged with the oil, and after oil-gas separation, the flammable gas is discharged. At this time, the temperature of the flammable gas is still very high, and it may still be at the flash point temperature. After being directly discharged and contacted with air, there is a risk of combustion and explosion; c. The current nitrogen injection and oil discharge system simultaneously monitors the oil temperature in the tank and the electric arc outside the tank body, such as the upper and lower porcelain sleeves and the sleeve. However, the nitrogen injection and oil discharge can solve the problems of rapid increase of pressure in the tank and high oil temperature, but it cannot directly act on the external electric arc and electric spark for fire extinguishing operation. Especially for some special transformers such as oil and gas well pump transformers, the gas environment is complex and contains a certain amount of flammable gas. After contacting the electric arc, there is a great safety hazard. SUMMARY

[0004] The present application aims to provide an oil-immersed electric pump transformer for star-delta conversion, so as to solve the problems of the existing nitrogen injection and oil discharge system of the oil-immersed electric pump transformer that cannot quickly recover the insulating oil and cannot take into account the fire outside the tank body.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[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, and 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, and the accordion cover is composed of a plurality of mutually slidably connected channel steel plates, a group of accordion covers is provided 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 mounted in the middle of the bottom side of the upper cover plate, and the ends of the direct-acting actuator are rotatably connected to four groups of telescopic support rods arranged in an array, the middle of the telescopic support rods is rotatably connected to the upper cover plate, and the other end of the telescopic support rods is located below the bottom end of the accordion cover after contraction;

[0007] The oil and gas recovery assembly 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 with 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 wires are provided on the upper cover plate.

[0009] As a further solution of the present invention: angle steel pieces are provided at the four vertices of the upper cover plate, and the angle steel pieces are welded and fixed to 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 threadedly connected to the hollow screw is provided on the hollow screw, and the nut sleeve is fixedly connected to the operating rod.

[0013] As a further solution of the present invention: a plurality of release ports are provided on the inner side of the base, the release ports are connected to the nitrogen release pipe of the fire cabinet, and electromagnetic valves are provided 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 provided on the top of the accordion cover.

[0015] As a further scheme of the present application, the transformer body is provided with an extension pipe connected with the pipe orifice of the exhaust pipe, the bottom end and the top end of the extension pipe are provided with exhaust holes, and the size of the exhaust hole at the top end is smaller than that of the exhaust hole at the bottom end.

[0016] Compared with the prior art, the beneficial effects of the present application are: 1. The nitrogen injection and oil discharge system of the present application includes monitoring of the fire condition inside and outside the transformer tank, and can act on the inside and outside danger respectively, or simultaneously act to extinguish the fire;

[0017] 2. The insulation oil can be quickly recycled after being discharged, the oil discharge and exhaust process is isolated from air, and the oil can be cooled faster, reducing the time of transformer operation with insufficient oil;

[0018] 3. The transformer in critical state is enclosed by the automatically deployed concertina cover outside, avoiding contact of the generated arc and spark with the outside, and preventing the spread of fire. BRIEF DESCRIPTION OF DRAWINGS

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

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

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

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

[0023] Figure 5 It is Figure 2 It is an enlarged structure schematic diagram of position A.

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

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0026] Please refer to Figure 1 , 2 In the embodiments of the present application, an oil-immersed electric pump transformer for star-delta conversion comprises an organ case assembly 1, a transformer body 2, a base 3 and an oil gas recovery assembly 4. The transformer body 2 is fixedly installed on the base 3. The organ case assembly 1 comprises an upper cover plate 12 and organ cases 13. The upper cover plate 12 is located directly above the transformer body 2. A plurality of through holes 121 for threading are arranged on the upper cover plate 12. After threading, sealing glue can be poured into the holes to seal the gap between the cable and the through hole. An angle steel piece 11 is arranged at each of the four vertex positions of the upper cover plate 12. The angle steel piece 11 is welded and fixed on the base 3. The organ case 13 is composed of a plurality of groove steel plates that are connected to each other in sliding mode, forming a retractable and expandable protective cover structure. One set of organ cases 13 is arranged at each of the four edges of the upper cover plate 12. The top of the organ case 13 is fixedly connected with the edge of the upper cover plate 12. In the normal state, the organ case 13 is retracted and folded, and the bottom end thereof is located above the edge of the transformer. The upper cover plate 12 and the organ case 13 play a protective role of sun protection, rain protection and the like for the transformer. After the organ case 13 is expanded, the bottom end thereof is in contact with the base 3. When all the four organ cases 13 are expanded, the transformer body 2 is covered in the organ cases 13, forming a relatively closed space.

[0027] As Figure 3 shown, a sensor 16 for fire monitoring is installed on the bottom side of the upper cover plate 12, including but not limited to a point-type smoke detector, a point-type temperature detector, an electric arc sensor, a glass ball type fire detection device and the like. The sensor 16 is connected to a fire control cabinet of a nitrogen injection and oil discharge system. A direct acting execution mechanism 14 is installed on the middle of the bottom side of the upper cover plate 12. The direct acting execution mechanism 14 can be a mechanism or device for linear motion after being electrified, such as a direct acting electromagnetic mechanism or a direct use of an electric push rod and the like. An end of the direct acting execution mechanism 14 is rotatably connected with four groups of telescopic support rods 15 arranged in an array. The middle of the telescopic support rod 15 is rotatably connected with the upper cover plate 12. The other end of the telescopic support rod 15 is located below the bottom end of the organ case 13 after the organ case 13 is retracted, and is used for supporting the organ case 13. The control circuit of the direct acting execution mechanism 14 is introduced into the fire control cabinet. When the sensor 16 detects external electric arc, electric spark and the like, the direct acting execution mechanism 14 is controlled to act, so that the telescopic support rod 15 rotates the end thereof to be separated from the bottom end of the organ case 13. The organ case 13 is automatically expanded, the transformer is enclosed in the organ case 13, and the electric arc is isolated from the external air and the cable.

[0028] AsFigure 4 The oil gas recovery assembly 4 comprises an air inlet pipe 41, an oil discharge pipe 42, an exhaust pipe 43, and an explosion-proof oil tank 44. The top end of the oil discharge pipe 42 is connected to the side of the transformer body 2, and the top end is at a distance from the top surface of the tank body of the transformer body 2. The distance is for the upper surface layer high-temperature oil (the high-temperature oil has a smaller specific gravity than the low-temperature oil, and the oil liquid gathers to the top after being heated). That is, the oil liquid needs to be discharged after the oil discharge and nitrogen injection system is started. The bottom end of the oil discharge pipe 42 is connected to one end of the explosion-proof oil tank 44, and an oil discharge valve 421 is arranged between the two. An isolation plate 442 that can move along the axial direction of the oil tank is arranged in the explosion-proof oil tank 44. The isolation plate 442 is in sealing connection with the inner wall of the explosion-proof oil tank 44. The isolation plate 442 divides the explosion-proof oil tank 44 into two independent cavities. A hollow screw rod 443 is connected to one side of the isolation plate 442. A nut sleeve 444 that is in threaded connection with the hollow screw rod 443 is arranged on the hollow screw rod 443. 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 rod 443, and a dynamic sealing ring is arranged between the isolation plate 442 and the air inlet pipe 41. The other end of the air inlet 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. The air inlet pipe 41 is also connected to a nitrogen release pipe of the fire-fighting cabinet at the end. Compared with the nitrogen injection and oil discharge system in the prior art, in addition to being connected to the pipe that leads to the bottom of the transformer oil tank, the nitrogen release pipe is also connected to the air inlet pipe 41 and a plurality of release openings (not shown in the figure) inside the base 3. An electromagnetic valve is arranged on each pipe to achieve independent control.

[0029] When the sensor 16 on the upper cover plate 12 detects an abnormality that needs to be handled, the organ case 13 is unfolded to form a relatively closed space by starting the direct-acting actuator 14. At the same time, the nitrogen tank releases nitrogen and opens the release openings inside the base 3 to release nitrogen into the space outside the transformer. The nitrogen is injected into the closed space from the bottom upwards. On the one hand, the closed space is cooled. On the other hand, the hot air in the closed space is squeezed out of a plurality of exhaust grooves 131 on the organ case 13 until the nitrogen fills the closed space, plays an air isolation role, and avoids the spread of fire caused by electric arc igniting cable insulation.

[0030] A lengthening pipe 21 is arranged in the transformer body 2 and connected to the pipe opening of the exhaust pipe 43. Exhaust holes 211 are arranged at the bottom end and the top end of the lengthening pipe 21. The size of the exhaust hole 211 at the top end is smaller than that of the exhaust hole 211 at the bottom end.Figure 5 The exhaust hole 211 is located in the oil liquid in normal state, and starts to expose the liquid surface after starting to discharge the oil. The gas is discharged in small amount through the top exhaust hole 211 during the oil discharge process, so that the pressure in the transformer body 2 cannot be suddenly reduced, the gas pressure is used to form an acting pressure on the oil liquid, the oil liquid is quickly discharged, and the slow flow of the oil liquid due to the viscosity of the oil liquid is avoided. When the liquid surface is lowered to the position of the top pipe opening of the oil discharge pipe 42, the bottom exhaust hole 211 is exposed. At this time, the rapid exhaust starts. The nitrogen gas mixed with a small amount of combustible gas (the insulating oil will separate a certain amount of combustible gas after high temperature) is collected into the explosion-proof oil tank 44 through the gas inlet pipe 41 from the exhaust pipe 43. After the pressure is stable, the electromagnetic valve on the exhaust pipe 43 is closed, the connection end of the gas inlet pipe 41 and the nitrogen gas release pipe is opened, the nitrogen gas enters the explosion-proof oil tank 44 through the gas inlet pipe 41, and exchanges heat with the high-temperature oil liquid when passing through the oil storage side cavity, so that the high-temperature oil liquid is quickly cooled below the flash point. The pressure relief valve 441 is also arranged on the explosion-proof oil tank 44. When the gas pressure in the explosion-proof oil tank 44 increases, the gas is discharged through the pressure relief valve 441. In this way, a small amount of high-temperature gas is gradually discharged after being cooled by the nitrogen gas, so that the risk of combustion and explosion of the combustible gas after contacting with the air is avoided.

[0031] When the temperature and pressure in the explosion-proof oil tank 44 are reduced to the standard value, the partition plate 442 is moved by the operating rod 445 and the nut sleeve 444, and the oil liquid in the explosion-proof oil tank 44 is re-pressurized into the transformer body 2 through the oil discharge pipe 42. The gas in the transformer body 2 is gradually discharged through the exhaust hole 211 at the upper end of the extension pipe 21 during the process that the oil liquid enters the transformer body 2, until the oil liquid is completely re-injected into the transformer. The operating rod 445 can be driven by manual or connected with an automatic driving device. The automatic driving device can shorten the oil return time as much as possible, reduce the running time of the transformer in the oil shortage state, and avoid damage to the transformer.

[0032] It is obvious for those skilled in the art that the present application is not limited to the details of the above-mentioned exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0033] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A star-delta 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 accordion cover assembly (1) includes an upper cover plate (12) and an accordion cover (13), wherein the upper cover plate (12) is located directly above the transformer body (2), and the accordion cover (13) is composed of a plurality of mutually slidably connected grooved steel plates, and a group of accordion covers (13) is provided on each of the four sides of the upper cover plate (12), and the top of the accordion cover (13) is fixedly connected to the edge of the upper cover plate (12); the sensors (16) are all connected to the fire control cabinet of the 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 accordion cover (13) after contraction; The oil and gas recovery assembly (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), and an oil discharge valve (421) is provided between the two. A partition (442) movable along the axial direction of the oil tank is provided in the flameproof oil tank (44), and 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), and a dynamic sealing ring is provided 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). The air intake pipe (41) is also connected to the nitrogen release pipe of the fire cabinet at the connection end with the exhaust pipe (43).

2. The oil-immersed electric pump transformer with star-delta conversion according to claim 1, 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-delta conversion according to claim 2, characterized in that: 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 on the base (3).

4. The oil-immersed electric pump transformer with star-delta conversion according to claim 3, 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-delta conversion according to claim 1, characterized in that: The direct-acting actuator (14) is a mechanism or device that performs linear motion when energized.

6. The oil-immersed electric pump transformer with star-delta conversion according to claim 1, 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). The nut sleeve (444) is fixedly connected to an operating rod (445).

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

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

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

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