Composite heat dissipation system and method for oil-immersed transformer

Abstract

The application provides a composite heat dissipation system and method of oil-immersed transformer, and relates to the technical field of power transformer.The composite heat dissipation system comprises a heat dissipation pipeline, a thermoelectric refrigeration module, a heat dissipation module, a fan module and a control system.The refrigeration surface of the thermoelectric refrigeration module is attached to the outer wall of the heat dissipation pipeline, the heat dissipation surface is connected to the heat dissipation fins through the heat dissipation module, and the fan module comprises a first heat dissipation fan and a second heat dissipation fan which are respectively used for blowing the heat dissipation pipeline and the heat dissipation fins.The control system controls the opening and closing of the first heat dissipation fan, the second heat dissipation fan and the thermoelectric refrigeration module according to the transformer oil temperature, so that the system is switched between the pure air cooling mode and the composite refrigeration mode.The application cooperates the active heat absorption of the thermoelectric refrigeration and the high-efficiency heat conduction of the heat pipe, significantly improves the heat dissipation capacity of the transformer under the premise of not increasing the fan greatly, effectively reduces the oil temperature under the heavy load and overload conditions, prolongs the insulation life of the transformer, and improves the safety and reliability of the power grid operation.

Description

Technical Field

[0001] This invention belongs to the field of power transformers, and more specifically, relates to a composite heat dissipation system for an oil-immersed transformer. This invention also relates to a composite heat dissipation method. Background Technology

[0002] Oil-immersed transformers are indispensable core equipment in power systems, and their operational reliability directly affects the safety and stability of the power grid. According to relevant regulations, the benchmark hot spot temperature for oil-immersed transformers is 98℃; for every 6K increase in temperature, the insulation aging rate doubles. The top oil temperature of an oil-immersed transformer should generally not exceed 85℃, and should not exceed 95℃ at most. If heat cannot be dissipated in a timely and effective manner, it will accelerate the aging of insulation materials, shorten the service life of the equipment, and in severe cases, may lead to major accidents such as short circuits and burnout.

[0003] Currently, the heat dissipation of oil-immersed transformers mainly adopts the following methods: One method is oil-immersed self-cooling, which relies on the natural convection of transformer oil to carry heat to the tank walls and cooling pipes, and then dissipates the heat through natural air convection. This method is simple in structure and requires no additional energy consumption, but its heat dissipation efficiency is extremely low, making it only suitable for small-capacity transformers or low-load conditions. The second method, based on oil-immersed self-cooling, adds fans to the tank walls or cooling pipes, using forced air convection to aid cooling. Adding fans can increase the transformer capacity by 30% to 35%. Currently, forced air cooling is commonly used for medium and large-capacity transformers; in engineering practice, horizontal airflow is mostly used for transformers of 35MVA and below, while vertical airflow is mostly used for transformers above 35MVA.

[0004] During application, the heat dissipation capacity of the two types of transformers mentioned above depends on the temperature difference between the transformer oil and the ambient air; the greater the temperature difference, the higher the heat dissipation efficiency. However, in high-temperature environments during summer or when the transformer is under heavy load, the ambient temperature is already high, the temperature difference narrows, and the cooling efficiency of the fans decreases significantly. Simply increasing the fan power to improve heat dissipation capacity exhibits diminishing marginal returns. At the same time, the space around the transformer is limited, and the arrangement of plate-type radiators is constrained by the size of the oil tank. Each radiator can typically only install two fans. Increasing the number of fans is limited by both physical space and cost, making it impossible to meet the heat dissipation requirements under high-temperature, heavy-load conditions by adding an unlimited number of fans. Summary of the Invention

[0005] The purpose of this invention is to provide a composite heat dissipation system for oil-immersed transformers, so as to solve the technical problem that existing oil-immersed transformers are prone to failure due to insufficient heat dissipation when facing emergency overload conditions.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a composite heat dissipation system for an oil-immersed transformer, comprising: The heat dissipation piping is located outside the transformer and connected to the transformer oil tank. A thermoelectric cooling module includes at least one thermoelectric cooling component that operates based on the thermoelectric effect. The thermoelectric cooling component has a cooling surface and a heat dissipation surface that are disposed opposite to each other. The cooling surface is attached to the outer wall surface of the heat dissipation pipe. A heat dissipation module includes a heat pipe and heat dissipation fins, wherein the evaporation end of the heat pipe is in contact with the heat dissipation surface, and the condensation end of the heat pipe is disposed inside the heat dissipation fins. A fan module includes at least two independently controlled cooling fans, one of which is capable of blowing air onto the heat dissipation piping arrangement and the other of which is capable of blowing air onto the heat dissipation fins.

[0007] One possible implementation also includes: Temperature sensor, installed in transformer oil circuit; The control mechanism is electrically connected to the temperature sensor, the thermoelectric cooling module, and the fan module, respectively. The control mechanism is configured as follows: The operating status of the fan module and the thermoelectric cooling module is controlled based on the transformer oil temperature detected by the temperature sensor, so that the composite heat dissipation system can switch between the off heat dissipation mode, the first-level heat dissipation mode, the second-level heat dissipation mode and the enhanced heat dissipation mode.

[0008] In one possible implementation, the fan module includes: The first cooling fan can at least blow air onto the cooling pipes; The second cooling fan can at least blow air onto the heat sink fins; The control mechanism is configured as follows: When the transformer oil temperature is lower than the first preset temperature, the first cooling fan, the second cooling fan, and the thermoelectric cooling module are controlled to stop operating. When the transformer oil temperature is greater than or equal to the first preset temperature and lower than the second preset temperature, the first cooling fan is controlled to run, and the second cooling fan and the thermoelectric cooling module are controlled to stop running. When the transformer oil temperature is greater than or equal to the second preset temperature and lower than the third preset temperature, the second cooling fan or the first cooling fan is controlled to run, and the thermoelectric cooling module is controlled to run. When the transformer oil temperature is greater than or equal to the third preset temperature, the first cooling fan, the second cooling fan, and the thermoelectric cooling module are controlled to operate simultaneously.

[0009] In one possible implementation, there are multiple first cooling fans and multiple second cooling fans.

[0010] In one possible implementation, the heat dissipation module further includes: A heat-conducting layer is disposed between the cooling surface of the thermoelectric refrigeration component and the heat dissipation pipe, and between the heat dissipation surface of the thermoelectric refrigeration component and the evaporation end of the heat pipe. The thermally conductive layer includes at least one of thermally conductive grease, thermally conductive gel, and thermally conductive pad.

[0011] One possible implementation includes: The oil circulation mechanism includes an oil pump located between the transformer oil tank and the heat dissipation pipes.

[0012] In one possible implementation, the oil circulation mechanism further includes: The oil inlet pipe is connected at one end to the transformer oil tank and at the other end to the heat dissipation pipe. The return oil pipeline is connected at one end to the heat dissipation pipeline and at the other end to the transformer oil tank; The oil pump is located in the oil inlet pipeline and / or the oil return pipeline.

[0013] In one possible implementation, the heat dissipation conduit includes a plurality of flat tubes, each of which is in close contact with the cooling surface of the thermoelectric cooling assembly.

[0014] Compared with the prior art, the beneficial effects of the composite heat dissipation system for oil-immersed transformers provided by this invention are as follows: Firstly, this application establishes a complete heat dissipation channel by directly attaching the cooling surface of the thermoelectric cooling component to the heat dissipation pipes, connecting the heat dissipation surface to the heat dissipation fins via heat pipes, and configuring two independent fans to blow heat from the heat dissipation pipes and heat dissipation fins respectively. This creates a channel where the thermoelectric cooling actively absorbs heat from the heat pipes, the heat pipes efficiently transport heat from the hot end, and the dual fans provide zoned forced convection. The heat dissipation pipes serve as the basic heat dissipation surface; the thermoelectric cooling overcomes the limits of passive heat dissipation; the heat pipes solve the problem of heat accumulation at the hot end of the thermoelectric cooling; and the dual fans each serve different heat dissipation paths without interference. All modules work collaboratively, achieving a complementary advantage between passive air cooling and active thermoelectric cooling. This solves the problems of poor adaptability and high energy consumption of traditional single heat dissipation methods under varying load conditions.

[0015] In addition to the aforementioned beneficial effects, in this application, the temperature sensor serves as a sensing element to monitor changes in transformer oil temperature in real time, providing an accurate data basis for intelligent system regulation; the control mechanism, as the decision-making core, receives temperature signals and issues control commands to the fan module and thermoelectric cooling module accordingly; after combining the two with the heat dissipation system architecture described above, the control mechanism controls the activation and deactivation of the heat dissipation module in stages based on oil temperature, the most direct parameter reflecting the transformer's thermal load.

[0016] Overall, the control mechanism mainly enables dynamic matching of heat dissipation power with real-time heat generation, solving the problems of energy waste in fixed heat dissipation capacity systems under light load, insufficient heat dissipation under heavy load, and shortened lifespan of heat dissipation modules due to prolonged full-load operation. Through the design of switching between four heat dissipation modes, the system can completely shut down to save energy when the transformer is under light load and the ambient temperature is low, engage partial air cooling to meet basic heat dissipation under medium load, and engage thermoelectric cooling to enhance heat dissipation capacity under high load or high temperature. This enables on-demand cooling across the entire operating range, solving the problem of insufficient precision in the control of heat dissipation capacity in traditional heat dissipation systems and the inability of heat dissipation capacity to meet heat dissipation needs under high load.

[0017] Based on the control logic of the control structure described above, this application can meet the transformer's heat dissipation requirements at the lowest power consumption by shutting down all fans and thermoelectric cooling modules and utilizing only the natural heat dissipation of the heat dissipation pipes. This application can also use a first cooling fan primarily to blow air onto the heat dissipation pipes, undertaking basic air-cooling tasks. Its operation is independent of the thermoelectric cooling system, and it can meet the heat dissipation requirements with low additional power consumption when the transformer oil temperature is in a moderate range, solving the problem of ensuring normal heat dissipation without activating thermoelectric cooling under low heat load conditions.

[0018] Furthermore, the second cooling fan in this application mainly blows on the heat dissipation fins and undertakes the task of forced convection heat dissipation at the hot end of the thermoelectric cooling component. It works in conjunction with the thermoelectric cooling module to ensure that the heat on the heat dissipation surface is dissipated in a timely manner, thus solving the problem of poor heat dissipation at the hot end leading to a sharp drop in cooling efficiency when the thermoelectric cooling is operated alone.

[0019] In this application, the control mechanism implements a four-level progressive control strategy based on different oil temperature ranges. When the oil temperature is below the first preset temperature, all components shut down, achieving zero-energy standby. When the oil temperature rises between the first and second preset temperatures, only the first cooling fan is activated for pure air cooling. At this time, neither the thermoelectric cooling nor the second fan consumes power, achieving minimum energy consumption for heat dissipation. When the oil temperature continues to rise between the second and third preset temperatures, the second cooling fan and the thermoelectric cooling module are activated. At this time, the second fan is dedicated to heat dissipating the hot end of the thermoelectric cooling system, ensuring that the thermoelectric cooling system operates in the high-efficiency range. This solves the problem that the hot end must have sufficient heat dissipation capacity when the thermoelectric cooling system starts up, otherwise the temperature difference between the hot and cold ends will be too large, and the cooling capacity will be offset by its own power consumption or even result in negative benefits.

[0020] In addition, the temperature range in this application offers two optional configurations: the second fan with thermoelectric cooling focuses on enhancing heat dissipation on the heat sink fin side, allowing the heat pipes and fins to be fully cooled, thereby reducing the hot end temperature of the thermoelectric cooling system and narrowing the temperature difference between the hot and cold ends to improve cooling efficiency; while the first fan with thermoelectric cooling focuses on enhancing heat dissipation on the heat dissipation pipe side, and at the same time, thermoelectric cooling also directly acts on the heat dissipation pipe, with both paths simultaneously cooling the pipe wall to form a superimposed effect: designers can flexibly choose according to the actual installation layout and heat dissipation focus; when the oil temperature is higher than the third preset temperature, all three components operate at full power simultaneously. At this time, the first fan cools the heat dissipation pipe, the second fan cools the heat sink fins, thermoelectric cooling actively cools the pipe, and the heat pipe passively conducts heat to the hot end. The four heat dissipation paths work together to achieve maximum heat dissipation power output, solving the problem that under extreme working conditions, a single or two combined heat dissipation methods are still insufficient to suppress the temperature rise.

[0021] Another object of the present invention is to provide a composite heat dissipation method, comprising the following steps: Collect transformer oil temperature; Based on the real-time value of the transformer oil temperature, the start and stop of the oil circulation mechanism, the start and stop and power of the thermoelectric cooling module, and the start and stop and speed of each cooling fan in the fan module are dynamically adjusted to reduce energy consumption under low load conditions and to achieve coordinated heat dissipation through active cooling and forced air cooling of the thermoelectric cooling module under high load or high temperature conditions.

[0022] In another aspect, the composite heat dissipation method of the present invention further includes the following steps: Obtain the transformer oil temperature; When the transformer oil temperature is lower than the first preset temperature, the fan module and the thermoelectric cooling module are controlled to stop operating. When the transformer oil temperature is greater than or equal to the first preset temperature and lower than the second preset temperature, the cooling fan corresponding to the heat dissipation pipe is controlled to run, and the cooling fan corresponding to the heat dissipation fin and the thermoelectric cooling module are controlled to stop running. When the transformer oil temperature is greater than or equal to the second preset temperature and lower than the third preset temperature, the cooling fan and the thermoelectric cooling module corresponding to the heat dissipation fins are controlled to operate, or the cooling fan and the thermoelectric cooling module corresponding to the heat dissipation pipes are controlled to operate. When the transformer oil temperature is greater than or equal to the third preset temperature, control all the cooling fans of the fan module and the thermoelectric cooling module to run simultaneously.

[0023] Compared to existing technologies, the composite heat dissipation method of this invention possesses all the advantages of the aforementioned composite heat dissipation system for oil-immersed transformers, which will not be elaborated upon here. Furthermore, the step of driving the oil circulation mechanism to allow transformer oil to flow from the tank into the heat dissipation pipes actively extracts hot oil from the tank and directs it to the external heat dissipation area, preventing the problem of hot oil accumulating upwards solely through conduction and natural convection, and the inability to quickly dissipate heat to the external heat dissipation surface. Moreover, this application, by setting the operating logic of the thermoelectric cooling module and fan, enables the thermoelectric cooling component to actively absorb heat from the oil in the heat dissipation pipes and discharge it to the heat dissipation surface, solving the problem of weakened passive heat dissipation driving force when the temperature difference between the oil and the environment is insufficient, thereby improving heat dissipation efficiency with a higher temperature difference.

[0024] The thermoelectric refrigeration unit acts as an intermediate hub. Its cooling surface absorbs heat from the oil through the pipe walls, while its heat dissipation surface transfers the heat to the evaporator end of the heat pipe. The heat pipe then conducts the heat to the condenser end, releasing it to the fins. This forms a directional heat flow channel from the oil, cooling surface, heat dissipation surface, heat pipe, and finally to the fins, preventing heat accumulation on the heat dissipation surface of the thermoelectric refrigeration unit from reducing the heat absorption capacity of the cold end and causing the cooling effect to cancel out. By controlling the fans of the corresponding heat dissipation pipes for air cooling, forced convection can replace natural convection, significantly improving the heat transfer coefficient between the outer wall of the heat dissipation pipes and the air.

[0025] Correspondingly, the fans of the corresponding heat dissipation fins are controlled for air cooling, promptly expelling the heat released from the condenser end of the heat pipe to the ambient air. This ensures that the fin surface remains at a low temperature, allowing the working fluid inside the heat pipe to continuously and fully condense at the condenser end and maintain the pressure difference between the evaporator and condenser ends. This reduces the surface heat accumulation on the fins and prevents excessively high oil temperatures after heat exchange, which could lead to poor cooling of the oil tank.

[0026] In this way, this application can solve the problem that existing fan cooling cannot meet the cooling requirements of high-load transformers by constructing a relatively complete heat transfer channel in each step, including oil tank heat extraction, pipeline transportation, thermoelectric cooling active cooling, efficient heat pipe conduction, dual-fan forced heat dissipation, and low-temperature oil recirculation. Furthermore, this application increases the temperature difference between the heat dissipation end and the oil body, improving the cooling capacity of the oil body and enabling the transformer to operate at a lower temperature. Therefore, although this application adds a thermoelectric cooling module, its cooling energy consumption is actually lower than that of existing pure fan cooling systems. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 A schematic diagram of the overall structure of the composite heat dissipation system for an oil-immersed transformer provided by the present invention; Figure 2 A three-dimensional structural diagram of the composite heat dissipation system for the oil-immersed transformer provided by the present invention, viewed from a top perspective. Figure 3 This is a schematic diagram of the overall structure of the composite heat dissipation system of the oil-immersed transformer of the present invention from another top view. Figure 4 This is a schematic diagram of the overall structure of the composite heat dissipation system of the oil-immersed transformer of the present invention from a bottom-view perspective. Figure 5 This is a schematic diagram showing the connection relationship between the thermoelectric cooling module, the heat dissipation module, and the fan module in the composite heat dissipation system of the oil-immersed transformer of the present invention.

[0028] In the picture: 1. Heat dissipation piping; 2. Thermoelectric refrigeration module; 21. Cooling surface; 22. Heat dissipation surface; 3. Heat dissipation module; 31. Heat pipe; 32. Heat dissipation fins; 33. Thermal conductive layer; 4. Fan module; 41. First cooling fan; 42. Second cooling fan; 5. Oil circulation mechanism; 51. Oil pump; 52. Oil inlet pipeline; 53. Oil return pipeline; 6. Transformer oil tank. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0030] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "back" appear, indicating orientation or positional relationship, they are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this 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 this invention.

[0031] Furthermore, in the description of this invention, unless otherwise explicitly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention in light of the specific circumstances.

[0032] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0033] Please refer to the following: Figure 1 and Figure 5 The composite heat dissipation system for an oil-immersed transformer provided by the present invention will now be described. This composite heat dissipation system for an oil-immersed transformer includes a heat dissipation pipe 1, a thermoelectric cooling module, a heat dissipation module 3, and a fan module 4. The heat dissipation pipe 1 is located outside the transformer and communicates with the transformer oil tank 6. The thermoelectric cooling module 2 includes at least one thermoelectric cooling component operating based on the thermoelectric effect. The thermoelectric cooling component has a cooling surface 21 and a heat dissipation surface 22 arranged opposite to each other, with the cooling surface 21 attached to the outer wall surface of the heat dissipation pipe 1. The heat dissipation module 3 includes a heat pipe 31 and heat dissipation fins 32. The evaporation end of the heat pipe 31 is attached to the heat dissipation surface 22, and the condensation end of the heat pipe 31 is located within the heat dissipation fins 32. The fan module 4 includes at least two independently controlled cooling fans, one of which can blow air onto the heat dissipation pipe 1, and the other of which blow air onto the heat dissipation fins 32.

[0034] In the specific implementation of the above embodiments, the airflow blown by the cooling fan is in a flowing state. A cooling fan that blows air only onto the cooling pipe 1 can also allow airflow to pass through the heat dissipation fins 32, and the same applies to a fan that blows air onto the heat dissipation fins 32. Of course, the fans in this embodiment also include cooling fans that blow air only onto the cooling pipe 1, and cooling fans that blow air only onto the heat dissipation fins 32, in order to broaden the applicability of the fan module 4 to different heat dissipation conditions as much as possible.

[0035] In addition, the thermoelectric cooling module 2 operates based on the thermoelectric effect (Peltier effect), which has a fast start-up and strong cooling capacity. From the perspective of selection of cooling power, the cooling power of the thermoelectric cooling module 2 is generally between 100 watts and 1500 watts, which can be flexibly adjusted according to needs.

[0036] The heat dissipation pipe 1 is placed externally in the transformer oil tank 6 as a basic heat dissipation element. Its pipe wall is in direct contact with the transformer oil, which can transfer the heat in the oil to the surface of the pipe wall by heat conduction, realize the primary heat exchange between oil, pipe wall and air, and solve the problem of the channel for the conduction of heat from the transformer oil to the outside.

[0037] The thermoelectric cooling component actively generates cooling energy below the oil temperature on the cooling surface 21. Its cooling surface 21 is directly attached to the outer wall of the heat dissipation pipe 1, which can overcome the limitation of passive heat dissipation by ambient temperature in an active cooling manner, and greatly increase the heat flux density per unit area. Its heat dissipation surface 22 serves as the outlet for heat dissipation, solving the problem of insufficient heat dissipation capacity of passive heat dissipation in high temperature environments or heavy load conditions.

[0038] In addition, the heat pipe 31 utilizes the evaporation-condensation phase change cycle of the internal working fluid, and its equivalent thermal conductivity can reach tens of times that of pure copper. After the evaporation end is attached to the heat dissipation surface 22 of the thermoelectric cooling component, it can quickly conduct the high-density heat flow accumulated on the heat dissipation surface 22 to the far-end condensation end and release it to the large-area heat dissipation fins 32, thus solving the problem of heat accumulation on the heat dissipation surface 22 of the thermoelectric cooling component leading to an increase in the temperature difference between the hot and cold ends and a sharp drop in cooling efficiency. As the final air-side heat dissipation terminal, the large surface area structure of the heat dissipation fins 32 can efficiently diffuse the heat transferred from the condensation end of the heat pipe 31 into the air.

[0039] In fan module 4, at least two independently controlled cooling fans provide forced convection cooling for the heat pipe 1 and the heat sink fins 32, respectively. The ingenuity of this design lies in the fact that the two fans each undertake different heat exchange tasks. One fan serves the heat dissipation chain of base oil-pipe wall-air, while the other serves the heat dissipation chain of Peltier hot end-heat pipe 31-fins. The two are independent of each other and do not interfere with each other, avoiding the drawbacks of uneven airflow distribution, airflow short circuit or mutual obstruction when a single fan takes care of multiple heat dissipation surfaces 22. Thus, at the structural level, it is ensured that both heat paths can obtain sufficient and stable convection heat transfer conditions.

[0040] Finally, in the above scheme, the complete thermal path formed by the combination of various components is as follows: transformer oil, heat dissipation pipe 1 wall, (thermoelectric cooling component cooling surface 21 actively absorbs heat, thermoelectric cooling component heat dissipation surface 22 discharges heat), heat pipe 31 evaporation end, heat pipe 31 condensation end, heat dissipation fins 32, fan forced convection air, and a parallel dual-channel heat dissipation architecture of transformer oil, heat dissipation pipe 1 wall, and fan forced convection air. The two channels work together to achieve the complementary advantages and decoupled operation of passive air cooling and active thermoelectric cooling, and solve the problem of poor adaptability of traditional single heat dissipation methods under wide temperature range and variable load conditions.

[0041] Based on the above embodiments, in one feasible implementation, the composite heat dissipation system of the oil-immersed transformer in this invention further includes a temperature sensor and a control mechanism (not shown in the figure), wherein the temperature sensor is disposed in the transformer oil circuit; the control mechanism is electrically connected to the temperature sensor, the thermoelectric cooling module 2 and the fan module 4 respectively; and the control mechanism is configured to control the working state of the fan module 4 and the thermoelectric cooling module 2 according to the transformer oil temperature detected by the temperature sensor, so that the composite heat dissipation system switches between a closed heat dissipation mode, a primary heat dissipation mode, a secondary heat dissipation mode and an enhanced heat dissipation mode.

[0042] With this setup, the temperature sensor acts as a sensing element to monitor changes in transformer oil temperature in real time, providing an accurate data basis for intelligent system regulation; the control mechanism, as the decision-making core, receives the temperature signal and issues control commands to the fan module 4 and the thermoelectric cooling module 2 accordingly; after combining the two with the heat dissipation system architecture mentioned above, the control mechanism controls the activation and deactivation of the heat dissipation module 3 in stages based on the oil temperature, the most direct parameter reflecting the transformer's heat load.

[0043] Overall, the control mechanism mainly enables dynamic matching of heat dissipation power with real-time heat generation, solving the problems of energy waste in fixed heat dissipation capacity systems under light load, insufficient heat dissipation under heavy load, and shortened lifespan caused by prolonged full-load operation of heat dissipation module 3. Through the design of switching between four heat dissipation modes, the system can completely shut down to save energy when the transformer is under light load and the ambient temperature is low, engage partial air cooling to meet basic heat dissipation under medium load, and engage thermoelectric cooling to enhance heat dissipation capacity under high load or high temperature. Thus, it can achieve on-demand cooling across the entire operating range, solving the problem that traditional heat dissipation systems do not have precise control over heat dissipation capacity and cannot meet heat dissipation needs under high load.

[0044] Based on the above embodiments, in one feasible implementation method (such as...) Figure 2 , Figure 3 and Figure 4 As shown, the fan module 4 includes a first cooling fan 41 and a second cooling fan 42. The first cooling fan 41 can at least blow air onto the cooling pipe 1; the second cooling fan 42 can at least blow air onto the cooling fins 32. The control mechanism is configured to: when the transformer oil temperature is lower than a first preset temperature, control the first cooling fan 41, the second cooling fan 42, and the thermoelectric cooling module 2 to stop operating; when the transformer oil temperature is greater than or equal to the first preset temperature and lower than the second preset temperature, control the first cooling fan 41 to operate and control the second cooling fan 42 and the thermoelectric cooling module 2 to stop operating; when the transformer oil temperature is greater than or equal to the second preset temperature and lower than the third preset temperature, control the second cooling fan 42 or the first cooling fan 41 to operate and control the thermoelectric cooling module 2 to operate; when the transformer oil temperature is greater than or equal to the third preset temperature, control the first cooling fan 41, the second cooling fan 42, and the thermoelectric cooling module 2 to operate simultaneously.

[0045] Based on the above embodiments, in the specific implementation process, a comparative study was conducted on the cooling effect of the transformer and the cooling effect of the existing air-cooled oil-immersed transformer, and the data and research results are as follows: The data collected from a traditional air-cooled oil-immersed transformer under different load rates are shown in the figure below (for ease of comparison, integer nodes are used; only a cooling fan is configured to force air cooling of the flat heat dissipation pipe 1, without the thermoelectric cooling module 2. The fan power is adjusted in stages according to the heat dissipation requirements). In the existing design, the temperature rise increases almost linearly with the amount of heat generated. Under rated load (100%), the oil temperature rise reaches 72°C, exceeding the conventional temperature rise limit of 55°C to 65°C for typical oil-immersed transformers; under 110% overload, the temperature rise reaches 79°C, which is close to the upper limit for safe operation. For safety and property security reasons, subsequent overload tests will not be conducted here.

[0046] In the composite heat dissipation scheme of this application, the data collected from the transformer under different load rates are shown in the following table: In the table above: Mode 0 (Off): All devices are shut down; Mode 1 (Level 1 / Air Cooling): Only the first fan operates; Mode 2 (Secondary / Thermoelectric Cooling): Second fan and thermoelectric cooling module 2 are running; Mode 3 (Level 3 / Enhanced): Second fan and thermoelectric cooling module 2 are running; Mode 4 (Level 4 / Full Operation): First fan, second fan, and thermoelectric cooling module 2 are running.

[0047] In the above mode, the combined cooling solution only raises the oil temperature by 50°C under rated load, far lower than the 72°C of the pure air-cooling solution; even under 110% overload conditions, the temperature rise is only 54°C, still within the safe operating range. Of course, the trade-off is a significant increase in power consumption—the total power consumption of the combined cooling solution is 1600W under rated load, which is 3.3 times that of the pure air-cooling solution's 480W.

[0048] However, it is evident that the problem hindering the current cooling effect is not power, but rather the inability to increase the cooling capacity of air cooling (mainly due to the limitation of fan speed and number by the overall transformer structure). With a 600-watt fan (reaching the fan's power limit), the transformer oil temperature approaches 80°C under high load; while in this application, at 550 watts, the transformer temperature is only 44°C. Furthermore, under corresponding ultra-high load conditions, i.e., 150% load, the temperature rise is only 74°C, which is not only far lower than the 72°C at 100% load for a pure air-cooled solution, but also still below the recommended safe operating value of 85°C. This means that the transformer using this solution has the ability to withstand 150% overload for short periods, and overload capacity is a key indicator for the power grid to cope with peak electricity demand and sudden operating conditions. This provides reliable protection for the transformer's short-term extreme overload (such as during concentrated air conditioning use in summer, the Spring Festival period on agricultural power grids, and peak production periods in industrial areas or load compensation due to transformer maintenance, etc.).

[0049] It should be noted that, under 50% load, although this application achieves better cooling effect with the same power consumption, the cooling at this time is mainly due to the combined effect of heat pipe 31 and fan, and is not significantly related to the thermoelectric cooling component in this application, so it will not be described in detail here.

[0050] In addition to the above description, it is even more important that, compared with the electricity consumed by the thermoelectric cooling components, this application can also indirectly reduce the heat loss of the transformer by reducing the transformer's heating rate.

[0051] Since the temperature of metallic copper is positively correlated with its resistance, and existing transformer cooling fans have a high temperature rise coefficient, although this application reduces the transformer temperature through higher energy consumption, the energy consumption of the thermoelectric cooling component in this application is lower than the copper loss generated when the transformer operates under overload (150% load with cooling only by the fan). Furthermore, since temperature has a significant impact on the lifespan of transformer windings (every 8°C increase reduces lifespan by half), the reduction of several tens of degrees Celsius in this application represents a substantial benefit in terms of overall performance.

[0052] In addition to the aforementioned beneficial effects, in one feasible implementation, such as Figure 3 As shown, there are multiple first cooling fans 41 and multiple second cooling fans 42. In this way, this embodiment forms a fan array by setting multiple first fans and second fans, which not only achieves airflow superposition and large-area uniform coverage, but also provides redundancy backup. This solves the reliability problem that a single fan failure will lead to system failure, as well as the technical problem that a single fan cannot meet the placement requirements of the location requiring heat dissipation in high-power heat dissipation scenarios.

[0053] Based on the above embodiments, in one feasible implementation, such as Figure 5 As shown, the heat dissipation module 3 also includes a heat-conducting layer 33, which is disposed between the cooling surface 21 of the thermoelectric cooling component and the heat dissipation pipe 1, and between the heat dissipation surface 22 of the thermoelectric cooling component and the evaporation end of the heat pipe 31; and the heat-conducting layer 33 includes at least one of thermal grease, thermal gel and thermal pad.

[0054] This embodiment achieves heat transfer between the two key interfaces with minimal thermal resistance, preventing the actual heat transfer efficiency from being far lower than the theoretical value due to the dominance of contact thermal resistance caused by the existence of microscopic gaps. Furthermore, the thermal grease mentioned above is more suitable for transformers with permanent fixtures and high thermal conductivity requirements; the thermal pad is suitable for the modular assembly scenario of the thermoelectric cooling module 2 in this application. The thermal gel primarily fills the gap between the transformer's heat dissipation pipe 1 and the cooling surface 21, with lower requirements on the shape of the transformer's heat dissipation pipe 1 (irregularly shaped transformer heat dissipation pipe 1 with large tolerances).

[0055] Based on the above embodiments, in one feasible implementation, the composite heat dissipation system of the oil-immersed transformer further includes, for example: Figure 1 and Figure 4 The diagram shows an oil circulation mechanism 5, an oil inlet pipe 52, and an oil return pipe 53. The oil circulation mechanism 5 includes an oil pump 51 located between the transformer oil tank 6 and the cooling pipe 1. The oil pump 51 forces the oil in the pipe to flow, enhancing the heat dissipation effect on the transformer.

[0056] Based on the above embodiments, in one feasible implementation, the oil circulation mechanism 5 further includes an oil inlet pipe 52 and an oil return pipe 53. One end of the oil inlet pipe 52 is connected to the transformer oil tank 6, and the other end is connected to the cooling pipe 1. One end of the oil return pipe 53 is connected to the cooling pipe 1, and the other end is connected to the transformer oil tank 6. The oil pump 51 is disposed in the oil inlet pipe 52 and the oil return pipe 53, or separately in either the oil inlet pipe 52 or the oil return pipe 53. In this way, hot oil is drawn from the upper part of the oil tank through the oil inlet pipe 52, and cold oil is returned from the lower part through the oil return pipe 53, forming a directional circulation path. The oil pump 51 can be flexibly disposed in either the oil inlet pipe or the oil return pipe. This improves the problems of short-circuiting of hot and cold oil mixing in the circulation path and the limited installation space caused by the fixed pump position.

[0057] Based on the above embodiments, in one feasible implementation, the heat dissipation pipe 1 includes a plurality of flat pipes, each of which is tightly fitted to the cooling surface 21 of the thermoelectric refrigeration component. In this application, by using flat pipes or corrugated pipes as the heat dissipation pipe 1, the outer surface area is significantly increased and the heat transfer path from the oil flow center to the pipe wall is shortened. It is also easier to transfer heat in the heat dissipation pipe 1 to the flat pipes using the various thermally conductive materials mentioned above.

[0058] Based on the same inventive concept, another objective of this invention is to provide a composite heat dissipation method, comprising the following steps: Collect transformer oil temperature; Based on the real-time value of the transformer oil temperature, the start and stop of the oil circulation mechanism, the start and stop and power of the thermoelectric cooling module 2, and the start and stop and speed of each cooling fan in the fan module 2 are dynamically adjusted to reduce energy consumption under low load conditions and to achieve heat dissipation through active cooling and forced air cooling in high load or high temperature conditions.

[0059] Furthermore, in the above heat dissipation method, the oil circulation mechanism 5 can be driven to allow transformer oil to flow from the transformer oil tank 6 into the heat dissipation pipe 1; Control the thermoelectric cooling module 2 to enable the thermoelectric cooling components to exchange heat with the heat dissipation pipe 1 and the heat pipe 31; Control the cooling fan of the corresponding heat dissipation pipe 1 to cool the heat dissipation pipe 1 with air; Control the cooling fan of the corresponding heat sink 32 to cool the heat sink 32 with air; The heat-exchanged transformer oil is returned to the transformer oil tank 6 via the return oil pipeline 53 to reduce the temperature of the circulating oil.

[0060] On the other hand, the dynamic adjustment of the above method also includes the following steps: Obtain the transformer oil temperature; When the transformer oil temperature is lower than the first preset temperature, the control fan module 4 and thermoelectric cooling module 2 stop operating. When the transformer oil temperature is greater than or equal to the first preset temperature and lower than the second preset temperature, the cooling fan of the corresponding heat dissipation pipe 1 is controlled to run, and the cooling fan of the corresponding heat dissipation fin 32 and the thermoelectric cooling module 2 are controlled to stop running. When the transformer oil temperature is greater than or equal to the second preset temperature and lower than the third preset temperature, control the operation of the cooling fan and thermoelectric cooling module 2 of the corresponding heat sink fin 32, or control the operation of the cooling fan and thermoelectric cooling module 2 of the corresponding heat sink pipe 1. When the transformer oil temperature is greater than or equal to the third preset temperature, all cooling fans of the control fan module 4 and thermoelectric cooling module 2 will operate simultaneously.

[0061] Compared to existing technologies, the composite heat dissipation method in this invention has all the advantages of the composite heat dissipation system of the aforementioned oil-immersed transformer, which will not be elaborated here. In addition, obtaining the transformer oil temperature can provide the system with real-time and quantitative heat load data, solving the problem that the control system lacks decision-making basis and cannot determine the current thermal condition. When the oil temperature is lower than the first preset temperature, the fan and thermoelectric cooling are controlled to stop, achieving zero power consumption standby when the transformer heat load is extremely low or the ambient temperature is extremely low, and there is no need for continuous power consumption when heat dissipation is not required.

[0062] When the oil temperature is between the first and second preset temperatures, only the fan of the corresponding heat dissipation pipe 1 is activated, and only the minimum air cooling power is used. Forced convection heat transfer is carried out by utilizing the temperature difference between the heat dissipation pipe 1 and the air. At this time, the thermoelectric cooling is not activated, and the fan of the corresponding fin is not activated either. The heat dissipation needs under medium load are met with minimal power consumption, which solves the inefficiency problem of the input power being greater than the cooling capacity and the overall energy efficiency ratio being negative when the thermoelectric cooling is activated under light load conditions.

[0063] Furthermore, when the oil temperature is between the second and third preset temperatures, the fan corresponding to the heat dissipation fin 32 and the thermoelectric cooling module 2 are activated (or the first fan and the thermoelectric cooling module 2 are activated). The former configuration works by actively cooling the oil in the heat dissipation pipe 1 with thermoelectric cooling, while the fan corresponding to the heat dissipation fin 32 ensures sufficient cooling of the condensing end of the heat pipe 31 and the fins. All the cooling energy generated by thermoelectric cooling is used to cool the oil, while the heat at its own hot end is efficiently dissipated. The latter configuration is that the first fan enhances the air convection cooling of the heat dissipation pipe 1 wall, which is superimposed with the active cooling of the pipe wall by thermoelectric cooling. The outer side of the pipe wall is simultaneously cooled by both fan air cooling and direct cooling by the thermoelectric cooling surface 21. This configuration is suitable for scenarios where the first fan is easier to install in the pipe layout. The two optional configurations solve the problem of poor installation adaptability of the fixed heat dissipation circuit layout on diverse transformer structures.

[0064] When the oil temperature exceeds the third preset temperature, all cooling fans and thermoelectric cooling module 2 are controlled to operate simultaneously. In this step, four heat dissipation paths—air cooling of cooling pipe 1, air cooling of cooling fins 32, active cooling of thermoelectric cooling, and efficient conduction of heat pipe 31—are simultaneously activated to achieve the maximum heat dissipation power output of the system. This prevents the problem of extreme heat dissipation demands where all single or combined heat dissipation methods cannot suppress the oil temperature within the safe threshold under extreme high-temperature environments or when the transformer is operating above its rated load. The entire hierarchical control method triggers different levels of heat dissipation combinations sequentially based on the single criterion of oil temperature. There are clear temperature hysteresis intervals between each step to prevent frequent switching oscillations, effectively avoiding the problem of coarse control where multiple heat dissipation components lack coordination logic and the heat dissipation power cannot be continuously adjusted with the heat load.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A composite heat dissipation system for an oil-immersed transformer, characterized in that, include: The heat dissipation pipe (1) is located outside the transformer and connected to the transformer oil tank (6); The thermoelectric cooling module (2) includes at least one thermoelectric cooling component that operates based on the thermoelectric effect. The thermoelectric cooling component has a cooling surface (21) and a heat dissipation surface (22) that are arranged opposite to each other. The cooling surface (21) is attached to the outer wall surface of the heat dissipation pipe (1). The heat dissipation module (3) includes a heat pipe (31) and heat dissipation fins (32). The evaporation end of the heat pipe (31) is attached to the heat dissipation surface (22), and the condensation end of the heat pipe (31) is disposed inside the heat dissipation fins (32). The fan module (4) includes at least two independently controlled cooling fans, one of which can blow at least the cooling pipe (1) and the other of which blows at least the cooling fins (32).

2. The composite heat dissipation system for an oil-immersed transformer as described in claim 1, characterized in that, Also includes: Temperature sensor, installed in transformer oil circuit; The control mechanism is electrically connected to the temperature sensor, the thermoelectric cooling module (2), and the fan module (4), respectively. The control mechanism is configured as follows: The working state of the fan module (4) and the thermoelectric cooling module (2) is controlled according to the transformer oil temperature detected by the temperature sensor, so that the composite heat dissipation system can switch between the off heat dissipation mode, the first-level heat dissipation mode, the second-level heat dissipation mode and the enhanced heat dissipation mode.

3. The composite heat dissipation system for an oil-immersed transformer as described in claim 2, characterized in that, The fan module (4) includes: The first cooling fan (41) can at least blow on the cooling pipe (1). The second cooling fan (42) can at least blow air onto the cooling fins (32); The control mechanism is configured as follows: When the transformer oil temperature is lower than the first preset temperature, the first cooling fan (41), the second cooling fan (42) and the thermoelectric cooling module (2) are controlled to stop running; When the transformer oil temperature is greater than or equal to the first preset temperature and lower than the second preset temperature, the first cooling fan (41) is controlled to run, and the second cooling fan (42) and the thermoelectric cooling module (2) are controlled to stop running. When the transformer oil temperature is greater than or equal to the second preset temperature and lower than the third preset temperature, the second cooling fan (42) or the first cooling fan (41) is controlled to run, and the thermoelectric cooling module (2) is controlled to run. When the transformer oil temperature is greater than or equal to the third preset temperature, the first cooling fan (41), the second cooling fan (42) and the thermoelectric cooling module (2) are controlled to run simultaneously.

4. The composite heat dissipation system for an oil-immersed transformer as described in claim 3, characterized in that, There are multiple first cooling fans (41) and multiple second cooling fans (42).

5. The composite heat dissipation system for an oil-immersed transformer as described in claim 1, characterized in that, The heat dissipation module (3) also includes: A heat-conducting layer (33) is disposed between the cooling surface (21) of the thermoelectric refrigeration component and the heat dissipation pipe (1), and between the heat dissipation surface (22) of the thermoelectric refrigeration component and the evaporation end of the heat pipe (31); The thermally conductive layer (33) includes at least one of thermally conductive grease, thermally conductive gel, and thermally conductive pad.

6. The composite heat dissipation system for an oil-immersed transformer as described in claim 1, characterized in that, include: The oil circulation mechanism (5) includes an oil pump (51) located between the transformer oil tank (6) and the heat dissipation pipe (1).

7. The composite heat dissipation system for an oil-immersed transformer as described in claim 6, characterized in that, The oil circulation mechanism (5) also includes: The oil inlet pipe (52) is connected at one end to the transformer oil tank (6) and at the other end to the heat dissipation pipe (1); The return oil pipeline (53) is connected at one end to the heat dissipation pipeline (1) and at the other end to the transformer oil tank (6); The oil pump (51) is located in the oil inlet pipeline (52) and / or the oil return pipeline (53).

8. The composite heat dissipation system for an oil-immersed transformer as described in claim 1, characterized in that, The heat dissipation pipe (1) includes multiple flat pipes that are tightly fitted to the cooling surface (21) of the thermoelectric cooling component.

9. A composite heat dissipation method, characterized in that, Includes the following steps: Collect transformer oil temperature; Based on the real-time value of the transformer oil temperature, the start and stop of the oil circulation mechanism, the start and stop and power of the thermoelectric cooling module (2), and the start and stop and speed of each cooling fan in the fan module (2) are dynamically adjusted to reduce energy consumption under low load conditions and to achieve coordinated heat dissipation through active cooling and forced air cooling of the thermoelectric cooling module (2) under high load or high temperature conditions.

10. The composite heat dissipation method as described in claim 9, characterized in that, The dynamic adjustment includes the following steps: Obtain the transformer oil temperature; When the transformer oil temperature is lower than the first preset temperature, the fan module (4) and the thermoelectric cooling module (2) are controlled to stop operating; When the transformer oil temperature is greater than or equal to the first preset temperature and lower than the second preset temperature, the cooling fan corresponding to the heat dissipation pipe (1) is controlled to run, and the cooling fan corresponding to the heat dissipation fin (32) and the thermoelectric cooling module (2) are controlled to stop running. When the transformer oil temperature is greater than or equal to the second preset temperature and lower than the third preset temperature, control the operation of the cooling fan and the thermoelectric cooling module (2) corresponding to the heat dissipation fins (32), or control the operation of the cooling fan and the thermoelectric cooling module (2) corresponding to the heat dissipation pipe (1). When the transformer oil temperature is greater than or equal to the third preset temperature, control all the cooling fans of the fan module (4) and the thermoelectric cooling module (2) to run simultaneously.

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