Transformer cooling system, transformer and using method

Abstract

The invention belongs to the technical field of oil-immersed power transformer manufacturing, and discloses a transformer cooling system, a transformer and a using method, the system comprises a cooler support, and a radiator connected with the interior of the cooler support is arranged on the cooler support; the transformer oil tank is connected with the interior of the cooler support through a transformer oil tank oil outlet pipe. An air cooling device is arranged beside the radiator; the bottom of the cooler support is connected with a plurality of backflow connecting pipes, each backflow connecting pipe is provided with a plurality of first isolation valves, the bottom of each backflow connecting pipe is connected with an oil pump, the other end of each oil pump is connected with a backflow pipe, the other end of each backflow pipe is connected with a collecting pipe, and the collecting pipe is connected with the bottom of the transformer oil tank. And a second isolating valve and a check valve are arranged on the return pipe. The system can adapt to various working modes, and when the oil pump of the set working return pipe breaks down, the faulted oil pump can quit operation, and the standby oil pump is put into use to maintain normal operation.

Description

Technical Field

[0001] This invention belongs to the field of oil-immersed power transformer manufacturing technology, specifically relating to a transformer cooling system, a transformer, and a method of using it. Background Technology

[0002] Transformers using cooling systems combining plate radiators, cooling fans, and oil pumps are becoming increasingly common, and users are increasingly recognizing the advantages of combined cooling methods such as ONAN (Oil-Natural-Air-Natural), ONAF (Oil-Natural-Air-Forced), and ODAF (Oil-Directed-Air-Forced). When the transformer's operating capacity is low, the cooling fan and oil pump are not in operation, i.e., natural oil circulation self-cooling. When the transformer's operating capacity exceeds its self-cooling capacity or the oil surface temperature exceeds a set value, the cooling fan is engaged, i.e., natural oil circulation air-cooling. When the transformer's operating capacity exceeds its air-cooling capacity or it is under overload, the oil pump is engaged, i.e., forced oil circulation air-cooling.

[0003] The type of oil pump can be an axial flow pump or an impeller-lift type oil pump. Even when the oil pump is not running, the resistance it exerts on the entire pipeline is very small. However, as rotating devices, both the cooling fan and the oil pump require inspection and maintenance within a certain operating cycle, and replacement is necessary if a malfunction occurs. Replacing the cooling fan does not involve the oil circuit and is relatively easy to implement. However, if the oil pump is not working properly, the entire transformer's operating capacity will be limited to the natural oil circulation air-cooling stage, directly or indirectly causing economic losses.

[0004] Chinese patent publication number CN119028707A, entitled "A Transformer Cooling Device, a Transformer, and a Transformer Cooling Method," describes a device comprising a plate-type radiator, a fan, an oil pump, a first manifold, and a second manifold. The first and second manifolds are connected to the transformer tank. The plate-type radiator is connected between the first and second manifolds to form a circulating oil path that flows sequentially from the tank through the first manifold, the plate-type radiator, and the second manifold before returning to the tank. The fan is connected to the plate-type radiator, and the oil pump, an axial flow pump, is located on the connecting pipe between the tank and the second manifold. While this patent application can achieve circulating cooling, the device cannot guarantee the normal operation of the oil pump during malfunctions or maintenance in various operating modes (ONAN / ONAF / ODAF). Summary of the Invention

[0005] To overcome the problems existing in the prior art, the present invention aims to provide a transformer cooling system, a transformer, and a method of use. By setting multiple return pipes in the entire oil circulation system, and installing a second isolation valve and a check valve on the return pipes, the check valve is closed by controlling the oil pump to shut off or when the oil pump in the return pipe fails, thereby taking the faulty oil pump out of operation and connecting it to a backup return pipe. After the oil pump resumes operation, the check valve can be opened under the action of the downstream oil, which can greatly increase the reliability of transformer operation and adapt to multiple working modes such as ONAN / ONAF / ODAF.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a transformer cooling system, comprising a cooler bracket, a cooler device mounted on the cooler bracket, the cooler device including a radiator connected to the interior of the cooler bracket; a transformer oil tank connected to the interior of the cooler bracket via a transformer oil tank outlet pipe; an air-cooling device mounted next to the radiator; a plurality of return flow connection pipes connected to the bottom of the cooler bracket, each return flow connection pipe being provided with a plurality of first isolation valves, an oil pump connected to the bottom of each return flow connection pipe, a return flow pipe connected to the other end of each oil pump, and a manifold connected to the other end of each return flow pipe, the manifold being connected to the bottom of the transformer oil tank; and a second isolation valve and a check valve mounted on the return flow pipe.

[0007] Optionally, the radiator is a plate-type radiator; the air-cooling device is a cooling fan.

[0008] Optionally, the cooler bracket includes a top main bracket and a bottom main bracket, the bottom of the bottom main bracket being connected to the return connection pipe; the top main bracket being connected to the oil outlet pipe of the transformer tank; the top main bracket being connected to the top of the radiator; and the bottom main bracket being connected to the bottom of the radiator.

[0009] Optionally, the top main bracket is connected to the bottom main bracket via a connecting bracket, the top main bracket is connected to the top of the radiator via a top branch bracket, and the bottom of the radiator is connected to the bottom main bracket via a bottom branch bracket.

[0010] Optionally, there may be multiple radiators, which are arranged on both sides of the cooler bracket.

[0011] Optionally, an oil flow relay is provided on the return pipe, and the oil flow relay is located near the oil pump.

[0012] Optionally, the plurality of return pipes are arranged in parallel, the return pipes are perpendicular to the return connection pipes, and the return pipes are parallel to the transformer tank oil outlet pipes; the manifold is perpendicular to the return pipes, and the manifold is perpendicular to the return connection pipes.

[0013] Optionally, the number of the first isolation valves on each of the return connection pipes is two.

[0014] Secondly, the present invention provides a method of using the aforementioned transformer cooling system, comprising the following steps: In both natural oil circulation self-cooling and natural oil circulation air cooling states, the check valves of all return pipes are in the open state, and all oil flows are merged and enter the transformer oil tank through the manifold. In the forced oil circulation guided air-cooled state, the power to some of the oil pumps is cut off, and the oil flow in the return pipe where the power-off oil pumps are located flows in reverse, causing the check valve to close.

[0015] Thirdly, the present invention provides a transformer, including a transformer tank and a transformer cooling system.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention incorporates several return pipes throughout the oil circulation system, including a designated working return pipe and several standby return pipes, adaptable to various operating modes such as ONAN / ONAF / ODAF. Each oil pump's outlet is equipped with a check valve. In both natural oil circulation self-cooling and natural oil circulation air-cooling states, all circuit check valves are open. In forced oil circulation guided by air cooling, the check valve in the circuit containing the de-energized oil pump closes under the action of reverse oil flow, while the check valve in the circuit containing the working oil pump opens. This invention can disconnect the faulty oil pump and activate the standby oil pump after a fault alarm occurs in the working oil pump. After circuit replacement, the transformer can continue to operate normally. This invention has a simple structure, is easy to implement, and has a wide range of applications, suitable for forced oil-air-cooled finned transformers of different voltage levels and capacities. During implementation, the transformer itself does not need to be de-energized, and manual disconnection of the oil circuit is not required to replace the oil pump. Attached Figure Description

[0017] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely schematic to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. In the drawings: Figure 1 This is a front view of the transformer cooling device in Embodiment 1 of the present invention; Figure 2This is a side view of the transformer cooling device in Embodiment 1 of the present invention; Figure 3 This is a top view of the transformer cooling device in Embodiment 1 of the present invention; The components include: 1. Transformer oil tank; 2. Combustion pipe; 21. Transformer oil tank return pipe; 3. First isolation valve; 30. Second isolation valve; 4. Check valve; 5. Oil flow relay; 6. Oil pump; 7. Cooler bracket; 71. Top main bracket; 72. Connecting bracket; 73. Bottom main bracket; 741. Top branch bracket; 742. Bottom branch bracket; 75. Return connection pipe; 8. Air-cooled equipment; 9. Radiator; 10. Transformer oil tank outlet pipe; 11. Set working return pipe; 12. Spare return pipe. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0019] Therefore, the following detailed description of embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0020] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0021] When an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments. The use of the term "horizontal" does not imply that the component is required to be absolutely horizontal, but rather that it may be slightly tilted. "Horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it may be slightly tilted.

[0022] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification and appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0024] The present invention will now be described in detail with reference to the accompanying drawings.

[0025] A transformer cooling system of the present invention includes a cooler support 7, on which a cooler device is mounted. The cooler device includes a radiator 9 connected to the interior of the cooler support 7. A transformer oil tank 1 is connected to the interior of the cooler support 7 via a transformer oil tank outlet pipe 10. An air-cooling device 8 is mounted next to the radiator 9. A plurality of return connection pipes 75 are connected to the bottom of the cooler support 7. Each return connection pipe 75 is equipped with a plurality of first isolation valves 3. An oil pump 6 is connected to the bottom of each return connection pipe 75. The other end of each oil pump 6 is connected to a return pipe. The other end of each return pipe is connected to a manifold 2, which is connected to the bottom of the transformer oil tank 1. A second isolation valve 30 and a check valve 4 are mounted on the return pipe.

[0026] This invention provides a transformer to solve the problem of transformer malfunction caused by oil pump 6 failure. The invention incorporates several return pipes in the entire oil circulation system, including a designated working return pipe 11 and several standby return pipes 12, adaptable to various operating modes such as ONAN / ONAF / ODAF. Each oil pump 6's outlet is equipped with a check valve 4. In both natural oil circulation self-cooling and natural oil circulation air-cooling states, all check valves 4 in all circuits are open. In the forced oil circulation guided by air cooling state, the check valve 4 in the circuit containing the de-energized oil pump 6 closes under the action of reverse oil flow, while the check valve 4 in the circuit containing the working oil pump 6 opens.

[0027] In existing cooling circuits, if oil pump 6 fails, the only recourse is to disconnect the faulty pump 6 and either immediately shut down the power for replacement or reduce the load to continue operation. This directly or indirectly impacts economic efficiency and reduces the reliability of transformer operation. This invention, however, can disconnect the faulty oil pump 6 and activate the standby oil pump 6 after a fault alarm occurs. After the circuit replacement is completed, the transformer can continue to operate normally. This invention has a simple structure, is easy to implement, and has a wide range of applications, suitable for various voltage levels and capacities of forced-oil air-cooled finned transformers. During implementation, the transformer itself does not need to be powered off, and manual disconnection of the oil circuit to replace oil pump 6 is unnecessary.

[0028] Example 1 like Figure 1 As shown, a transformer in this embodiment includes a transformer oil tank 1, a cooler bracket 7, and a cooler device.

[0029] The cooler device includes a radiator 9, which is mounted on a cooler bracket 7 and is connected to the interior of the radiator 9.

[0030] Specifically, radiator 9 is a finned radiator. Specifically, cooler bracket 7 is a pipe fitting. The side of cooler bracket 7 is connected to radiator 9 via pipes.

[0031] The transformer oil tank 1 has an oil outlet, and an oil outlet pipe 10 is connected to the oil outlet of the transformer oil tank 1. One end of the oil outlet pipe 10 is connected to the oil outlet of the transformer oil tank 1, and the other end is connected to the interior of the cooler bracket 7. The transformer oil tank 1 is connected to the oil outlet pipe 10, the oil outlet pipe 10 is connected to the cooler bracket 7, and the cooler bracket 7 is connected to the radiator 9.

[0032] Specifically, the oil outlet of transformer oil tank 1 is located at the top of transformer oil tank 1.

[0033] Optionally, a cooling device 8 is provided below the heat sink 9; the airflow direction of the cooling device 8 is from the bottom of the heat sink 9 to the top of the heat sink 9. Specifically, the cooling device 8 is a cooling fan.

[0034] The cooler bracket 7 includes a top main bracket 71 and a bottom main bracket 73. The top main bracket 71 is connected to the bottom main bracket 73 via a connecting bracket 72. The side of the top main bracket 71 is connected to the top of several radiators 9 via several top branch brackets 741. The bottom of the radiators 9 is connected to the side of the bottom main bracket 73 via bottom branch brackets 742.

[0035] Specifically, each radiator 9 is connected to the top main bracket 71 via a top branch bracket 741; and each radiator 9 is connected to the bottom main bracket 73 via a bottom branch bracket 742. Optionally, both the top main bracket 71 and the bottom main bracket 73 are horizontally arranged.

[0036] like Figure 2 As shown, the bottom of the bottom main support 73 is connected to multiple return connection pipes 75, which are perpendicular to the bottom main support 73. Each return connection pipe 75 is equipped with several first isolation valves 3, which can control the opening and closing of the return connection pipe 75. Optionally, each return connection pipe 75 has two first isolation valves 3, which can isolate the two ends of the oil pump 6 and cut off the oil circuit.

[0037] The bottom of the return connection pipe 75 is connected to the oil pump 6. One end of the return connection pipe 75 is connected to the bottom main support 73, and the other end is connected to the oil pump 6. The other end of the oil pump 6 is connected to a return pipe, and the other end of the return pipe is connected to the manifold 2. Specifically, the inlet of the oil pump 6 is connected to the return connection pipe 75, and the outlet of the oil pump 6 is connected to the return pipe. Specifically, the return pipe is connected to the bottom side of the oil pump 6.

[0038] A second isolation valve 30 and a check valve 4 are installed on the return pipe; the check valve 4 is installed between the connection point of the return pipe and the oil pump 6 and the second isolation valve 30 on the return pipe. An oil flow relay 5 is installed on the return pipe, and the oil flow relay 5 is located near the oil pump 6.

[0039] like Figure 3 As shown, the reflux pipe includes several set working reflux pipes 11 and several standby reflux pipes 12. Each set working reflux pipe 11 and each standby reflux pipe 12 is connected to a reflux connection pipe 75 via an oil pump 6.

[0040] The manifold 2 is connected to the bottom of the transformer tank 1 through several transformer tank return pipes 21.

[0041] Optionally, the number of transformer tank outlet pipes 10 is the same as the number of transformer tank return pipes 21.

[0042] Optionally, the number of return pipes is the same as the number of transformer tank outlet pipes 10.

[0043] Optionally, the working return pipe 11 and the standby return pipe 12 are set to be parallel to each other.

[0044] Optionally, the number of working reflux tubes 11 is set to one; alternatively, the number of working reflux tubes 11 is set to two; alternatively, the number of working reflux tubes 11 is set to three.

[0045] Optionally, the number of spare return pipes 12 is one. Optionally, the number of spare return pipes 12 is two.

[0046] Example 2 In this embodiment, the transformer oil tank is connected to the transformer oil tank 1 via the transformer oil outlet pipe 10 and the return pipe. The upper transformer oil outlet pipe 10 transports the high-temperature insulating oil to the radiator 9, achieving heat exchange with the air. The cooled insulating oil returns to the transformer oil tank 1 via the lower return pipe.

[0047] In this embodiment, each spare return pipe 12 is equipped with an oil pump 6 and a check valve 4.

[0048] The working principle of natural oil circulation self-cooling (Oil-Natural-Air-Natural) is that the transformer generates heat during operation, causing the hot oil in the tank to rise to the heat sink. The heat is then dissipated into the air through the surface of the heat sink, and the cooled oil sinks, forming a natural circulation. This mode relies entirely on natural air convection and radiation, resulting in slow heat dissipation and limited cooling capacity.

[0049] Natural oil-air-forced cooling uses the same oil circulation method as natural oil-air self-cooling, but it accelerates airflow by forcing air through a cooling device, thus enhancing heat dissipation efficiency.

[0050] Forced oil circulation directed air cooling forces the oil flow precisely to the hottest part. For very large and compact windings, naturally circulating oil may not be able to remove the heat generated in the deepest part of the winding in time, resulting in excessively high local temperature. In the forced oil circulation directed air cooling state, some oil pumps 6 are turned off, while oil pumps 6 in the target area are kept running.

[0051] In practical applications, in order to balance economic operation and overload capacity, medium and large capacity transformers adopt a composite cooling method. When the load is low, the fan does not start and the transformer operates in a natural oil circulation self-cooling mode. At this time, there is no fan loss, the noise is low, and the operation is economical. When the load increases and the oil temperature or winding temperature reaches the set value, the temperature controller automatically starts the fan and the transformer switches to natural oil circulation air-cooling mode, so that the transformer can carry full load or even allow a certain overload.

[0052] The transformer of this embodiment, when used, includes the following steps: In both natural oil circulation self-cooling and natural oil circulation air cooling states, the check valves 4 of all return pipes are in the open state, and all oil flows converge through the manifold 2. After the oil flows converge, they enter the transformer oil tank 1 from the oil inlet at the bottom of the transformer.

[0053] Under forced oil circulation and air cooling conditions, some oil pumps 6 are de-energized. Due to the pressure of the transformer oil tank 1, the oil flow in the return pipe where the oil pumps 6 are located after the power is de-energized flows in reverse. The check valve 4 in the return pipe is closed under the action of the reverse oil flow.

[0054] After normal operation, the closed check valve 4 opens under the action of the forward oil flow.

[0055] Unless otherwise specified, the equipment components involved in the above embodiments are all conventional equipment components, and the structural settings, working methods or control methods involved are all conventional settings, working methods or control methods in the art unless otherwise specified.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A transformer cooling system, characterized in that, The system includes a cooler bracket (7), on which a cooler device is provided. The cooler device includes a radiator (9) connected to the interior of the cooler bracket (7). The transformer oil tank (1) is connected to the interior of the cooler bracket (7) through a transformer oil tank outlet pipe (10). An air-cooling device (8) is provided next to the radiator (9). The bottom of the cooler bracket (7) is connected to multiple return connection pipes (75). Each return connection pipe (75) is provided with several first isolation valves (3). The bottom of each return connection pipe (75) is connected to an oil pump (6). The other end of each oil pump (6) is connected to a return pipe. The other end of each return pipe is connected to a manifold (2). The manifold (2) is connected to the bottom of the transformer oil tank (1). The return pipe is provided with a second isolation valve (30) and a check valve (4).

2. The transformer cooling system according to claim 1, characterized in that, The radiator (9) is a plate radiator; the air-cooling device (8) is a cooling fan.

3. A transformer cooling system according to claim 1, characterized in that, The cooler bracket (7) includes a top main bracket (71) and a bottom main bracket (73). The bottom of the bottom main bracket (73) is connected to the return connection pipe (75). The top main bracket (71) is connected to the oil outlet pipe (10) of the transformer tank. The top main bracket (71) is connected to the top of the radiator (9). The bottom main bracket (73) is connected to the bottom of the radiator (9).

4. A transformer cooling system according to claim 3, characterized in that, The top main bracket (71) is connected to the bottom main bracket (73) via a connecting bracket (72). The top main bracket (71) is connected to the top of the radiator (9) via a top branch bracket (741). The bottom of the radiator (9) is connected to the bottom main bracket (73) via a bottom branch bracket (742).

5. A transformer cooling system according to claim 1, characterized in that, The number of radiators (9) is multiple, and multiple radiators (9) are arranged on both sides of the cooler bracket (7).

6. A transformer cooling system according to claim 1, characterized in that, An oil flow relay (5) is installed on the return pipe, and the oil flow relay (5) is located near the oil pump (6).

7. A transformer cooling system according to claim 1, characterized in that, The multiple return pipes are arranged in parallel, the return pipe is perpendicular to the return connection pipe (75), and the return pipe is parallel to the transformer oil tank outlet pipe (10); the manifold (2) is perpendicular to the return pipe, and the manifold (2) is perpendicular to the return connection pipe (75).

8. A transformer cooling system according to claim 1, characterized in that, The number of the first isolation valves (3) on each of the said return connection pipes (75) is two.

9. A method of using a transformer cooling system according to any one of claims 1 to 8, characterized in that, Includes the following steps: In both natural oil circulation self-cooling and natural oil circulation air cooling states, all the check valves (4) of the return pipes are in the open state, and all oil flows are merged and enter the transformer oil tank (1) through the manifold (2). In the forced oil circulation guided air-cooled state, the power is cut off to part of the oil pump (6), and the oil flow in the return pipe where the power-off oil pump (6) is located flows in reverse, causing the check valve (4) to close.

10. A transformer, characterized in that, It includes a transformer oil tank (1) and a transformer cooling system as described in any one of claims 1 to 8.

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