Heat dissipation mechanism of oil immersed transformer

Abstract

The utility model discloses a heat dissipation mechanism of an oil immersed transformer, which relates to the technical field of oil immersed transformers, and comprises a transformer shell and a heat dissipation assembly, the heat dissipation assembly comprises a cooling water tank, a circulating water pump and a plurality of micro-channel cold plates; the micro-channel cold plates are fixed to the outer wall of the transformer shell at intervals, inlets of the micro-channel cold plates are connected with the circulating water pump through liquid inlet headers, outlets of the micro-channel cold plates are connected with the cooling water tank through liquid return headers, and the circulating water pump and the cooling water tank are connected to form a closed liquid circulation loop. According to the mechanism, heat exchange is enhanced through the micro-channel cold plate, closed liquid circulation continuous heat dissipation is matched, the heat dissipation efficiency is greatly improved, and the heat dissipation requirement of a high-power transformer can be met; an independent large radiator is not needed, the structure is compact, the equipment size is reduced, the narrow space adaptability is improved, and the problems that an existing heat dissipation mode is low in efficiency and large in size are effectively solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to oil -immersed transformer technical field, concretely relates to a heat abstractor of oil -immersed transformer. BACKGROUND

[0002] As the core equipment for realizing power transmission and voltage conversion in the power system, oil-immersed transformers are widely used in power stations, substations, industrial plants and civil power distribution networks. During operation, the hysteresis loss of the transformer core, the eddy current loss and the copper loss of the winding will continuously generate heat. If this heat cannot be dissipated in time and efficiently, it will cause the temperature of the internal insulating oil of the transformer to rise, which not only reduces the insulation performance and service life of the insulating oil, but also may cause accelerated aging of the winding insulation, local overheating and even burning, directly threatening the safe and stable operation of the power system. Therefore, the performance of the heat dissipation mechanism is one of the key factors determining the operation reliability and service life of the oil-immersed transformer.

[0003] At present, the main heat dissipation methods of existing oil-immersed transformers include natural cooling, forced oil circulation cooling and forced oil circulation guided cooling. Among them, the natural cooling (such as ONAN method) relies on the natural convection heat exchange between the heat dissipation fins on the surface of the transformer shell and the air. Its structure is simple and the cost is low, but the heat dissipation efficiency is greatly affected by external factors such as environmental temperature and air flow rate. In high-power transformers or high-temperature environments, it is often difficult to meet the heat dissipation requirements, and the problem of excessive oil temperature is prone to occur.

[0004] The forced oil circulation cooling (such as ONAF and ODAF methods) uses an oil pump to force the circulation of insulating oil, so that the hot oil flows through the heat sink and exchanges heat with the air (or forced air cooling). Compared with natural cooling, its heat dissipation efficiency is improved to some extent. However, this type of heat dissipation method still has obvious defects: on the one hand, the heat sink usually adopts the traditional finned tube structure, with large fin spacing, high air flow resistance and low utilization rate of heat exchange area, resulting in limited improvement of heat dissipation capacity; on the other hand, the entire heat dissipation system relies on moving parts such as oil pumps and fans, which not only increases the energy consumption and noise of the equipment, but also has the risk of failure of the moving parts leading to failure of the heat dissipation system, and the equipment has a large volume and high requirements for installation space.

[0005] With the development of the power system towards high voltage and large capacity, the power loss of oil-immersed transformers is increasing, which puts higher requirements on the heat dissipation efficiency, reliability and compactness of the heat dissipation mechanism. The limitations of existing heat dissipation methods in terms of heat dissipation efficiency, equipment size and operation reliability are increasingly prominent, and it is difficult to meet the heat dissipation requirements of high-power oil-immersed transformers. Therefore, it has become a technical problem to be solved by those skilled in the art to develop an oil-immersed transformer heat dissipation mechanism with high heat dissipation efficiency, compact structure, reliable operation and low energy consumption. SUMMARY

[0006] In view of the deficiencies in the background art, the utility model provides a heat dissipation mechanism of oil immersed transformer.

[0007] The utility model employs the technical scheme, a heat dissipation mechanism of oil immersed transformer, including transformer shell and heat dissipation subassembly, the heat dissipation subassembly includes cooling water tank, circulating water pump and a plurality of microchannel cold plate,

[0008] The microchannel cold plate is fixed on the outer wall surface of the transformer shell, the inlet of the microchannel cold plate is connected with the circulating water pump through the liquid inlet header, and the outlet is connected with the cooling water tank through the liquid return header.

[0009] Further, the microchannel cold plate and the outer wall surface of the transformer shell are fixed by a heat-conducting adhesive layer, and the heat conductivity coefficient of the heat-conducting adhesive layer is not less than 1.5 W / m·K.

[0010] Further, the microchannel cold plate and the outer wall surface of the transformer shell are fixed by brazing to form a metallurgical bond.

[0011] Further, the lower end of the microchannel cold plate is provided with the inlet and the inlet converging cavity communicated with the inlet, and the upper end is provided with the outlet and the outlet converging cavity communicated with the outlet, and the inlet converging cavity and the outlet converging cavity are communicated through a plurality of parallel and straight-line arranged microchannels.

[0012] Further, the hydraulic diameter of the microchannel ranges from 0.5 to 1.2 mm.

[0013] Further, the liquid inlet header includes a water inlet pipe connected with the circulating water pump, a water inlet series pipe connected with the water inlet pipe, and water inlet micro-pipes respectively connected with the inlets of the microchannel cold plates; and the liquid return header includes a liquid return pipe connected with the cooling water tank, a liquid return series pipe connected with the liquid return pipe, and liquid return micro-pipes respectively connected with the outlets of the microchannel cold plates.

[0014] Further, the outer surface of the microchannel cold plate is distributed with heat dissipation fins at intervals, and the height of the heat dissipation fins is 5-15 mm.

[0015] The utility model has the advantages of:

[0016] I. Significantly improve the heat dissipation efficiency: the micro-channel cold plate is used as the core heat exchange component, compared with the traditional finned tube radiator in the existing heat dissipation mode, the micro-channel cold plate has dense micro-flow channels inside, which greatly increases the contact area of the cooling medium and the transformer shell, and the micro-flow channels can strengthen the turbulent effect of the cooling medium, reduce the thermal resistance, and greatly improve the heat exchange efficiency. At the same time, through the design of the inlet header and the return liquid header, multiple micro-channel cold plates can be synchronized and uniformly cooled to the transformer shell to avoid the problem of "hot spots" caused by uneven local cooling; combined with the closed liquid circulation loop driven by the circulating water pump, the cooling medium can continuously take away the heat transferred by the transformer shell, ensuring that the heat is quickly and stably dissipated, even in the high-power oil-immersed transformer high-loss heating scene or high-temperature environment, the internal insulation oil temperature of the transformer can be effectively controlled to meet the high heat dissipation demand.

[0017] II. Compact structure: the micro-channel cold plates are directly fixed at intervals on the outer wall surface of the transformer shell, without the need to set up a large independent radiator, and the layout of the inlet header, the return liquid header and the circulating water pump can be closely matched with the transformer shell, greatly simplifying the overall structure of the heat dissipation system, reducing the equipment footprint and overall volume, and improving the adaptability to narrow installation space, especially suitable for scenes with limited space resources such as transformer substations and industrial plants.

[0018] In addition to the purposes, features and advantages described above, the utility model has other purposes, features and advantages.

[0019] The utility model will be further described in detail below with reference to the drawings. DRAWINGS

[0020] Fig. 1 It is a structural schematic view of the utility model.

[0021] Fig. 2 It is a structural schematic view of the utility model from another perspective.

[0022] Fig. 3 It is a schematic view of the micro-channel cold plate.

[0023] Figs. 1-3 I, transformer shell; 2, cooling water tank; 3, circulating water pump; 4, micro-channel cold plate; 5, inlet; 6, inlet convergence cavity; 7, outlet; 8, outlet convergence cavity; 9, micro-channel communication; 10, water inlet pipe; 11, water inlet series pipe; 12, water inlet micro-pipe; 13, return liquid pipe; 14, return liquid series pipe; 15, return liquid micro-pipe; 16, heat dissipation fin. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the utility model.

[0025] It should be noted that if the embodiments of the utility model involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications will also change accordingly.

[0026] The utility model provides a heat dissipation mechanism of oil immersed transformer.

[0027] In the embodiment, with reference to Figs. 1-3 The heat dissipation mechanism of the oil immersed transformer comprises a transformer shell 1 and a heat dissipation assembly, the heat dissipation assembly comprises a cooling water tank 2, a circulating water pump 3 and a plurality of micro-channel cold plates 4;

[0028] The micro-channel cold plates are fixedly arranged on the outer wall surface of the transformer shell, the inlets of the micro-channel cold plates are connected with the circulating water pump through the liquid inlet header, the outlets are connected with the cooling water tank through the liquid return header, and the circulating water pump is connected with the cooling water tank to form a closed liquid circulation loop.

[0029] In the above technical solution, the heat generated by the operation of the transformer is first transmitted to the shell, and the micro-channel cold plates fixed on the outer wall of the shell absorb the heat of the shell through heat conduction; the circulating water pump drives the cooling medium (such as special cooling liquid) in the cooling water tank to flow, the cooling medium is uniformly distributed to each micro-channel cold plate through the liquid inlet header, and the cooling medium exchanges heat with the cold plate in the internal flow channel of the cold plate, and becomes hot after absorbing heat; then the cooling medium is collected through the liquid return header and flows back to the cooling water tank to complete cooling, forming a closed liquid circulation loop of "heat absorption-heat exchange-cooling-circulation", and realizing continuous heat dissipation.

[0030] The traditional heat dissipation mode is broken, the high-efficiency heat conduction of the micro-channel cold plate and the continuous heat exchange of the closed liquid circulation are adopted, the heat dissipation efficiency is greatly improved, the high heat dissipation demand of the high-power transformer can be met, and problems such as aging of insulating oil and equipment failure caused by heat accumulation can be avoided.

[0031] Specifically, the micro-channel cold plate and the outer wall surface of the transformer shell are fixed by using a heat-conducting adhesive layer, and the thermal conductivity coefficient of the heat-conducting adhesive layer is not less than 1.5 W / m·K.

[0032] In the embodiment, the micro-channel cold plate is fixedly connected with the transformer shell, and the technical principle is "high-thermal-conductivity adhesive reinforced heat transfer". A high-thermal-conductivity adhesive layer with a thermal conductivity not less than 1.5 W / m·K is used to tightly adhere the micro-channel cold plate to the outer wall of the shell through the adhesive effect of the adhesive, so as to eliminate the air gap between the cold plate and the shell (air has very low thermal conductivity, only about 0.023 W / m·K, and will form thermal resistance), and the high-thermal-conductivity adhesive layer itself has excellent heat conduction performance, can quickly transfer the heat of the shell to the micro-channel cold plate, reduce the interface thermal resistance, and strengthen the heat transfer efficiency.

[0033] Specifically, the micro-channel cold plate and the outer wall surface of the transformer shell are fixedly connected through brazing.

[0034] In the embodiment, another fixing method is used, and the technical principle is "brazing metallurgical bonding to realize gapless heat conduction". Through the brazing process (using a filler metal with a lower melting point than the base metal, and when the heating temperature is lower than the melting point of the base metal and higher than the melting point of the filler metal, the filler metal is melted to fill the gap between the micro-channel cold plate and the outer wall of the shell, and after cooling, a firm metallurgical bonding layer is formed), the cold plate and the shell become a tightly connected whole, the physical gap between them is eliminated, direct heat conduction between metals is realized, and the interface thermal resistance is minimized.

[0035] Specifically, the lower end of the micro-channel cold plate is provided with the above-mentioned inlet 5 and an inlet converging cavity 6 communicated with the inlet 5, and the upper end is provided with the above-mentioned outlet 7 and an outlet converging cavity 8 communicated with the outlet, and the inlet converging cavity and the outlet converging cavity are communicated through a plurality of parallel and straight micro-channels 9.

[0036] In the embodiment, the inlet converging cavity at the lower end of the cold plate first concentrates the cooling medium delivered by the inlet header, and then uniformly distributes the cooling medium to a plurality of parallel and straight micro-channels; when the cooling medium flows in the micro-channels, it fully contacts the wall surface of the cold plate, and high-efficiency heat exchange is performed through forced convection; the cooling medium after absorbing heat enters the outlet converging cavity at the upper end, is collected, and then flows into the outlet header through the outlet. The parallel and straight micro-channels can increase the flow path and contact area of the cooling medium, and the inlet and outlet converging cavities can ensure the uniformity of the distribution and collection of the medium, so as to avoid uneven heat exchange caused by local insufficient flow.

[0037] Specifically, the hydraulic diameter of the micro-channel ranges from 0.5 mm to 1.2 mm.

[0038] In the embodiment, the fine-diameter micro-channel with a diameter ranging from 0.5 mm to 1.2 mm is easy to form turbulent flow, greatly reduces the thermal resistance, improves the heat exchange efficiency of the cooling medium and the cold plate, makes the cold plate absorb the heat of the shell faster, and improves the overall heat dissipation performance, and is especially suitable for high-heat-density scenes.

[0039] Specifically, the liquid inlet header includes a water inlet pipe 10 connected with the circulating water pump, a water inlet series pipe 11 connected with the water inlet pipe 10, and water inlet micro-pipes 12 respectively connected with the inlets of the micro-channel cold plates; the liquid return header includes a liquid return pipe 13 connected with the cooling water tank, a liquid return series pipe 14 connected with the liquid return pipe 13, and liquid return micro-pipes 15 respectively connected with the outlets of the micro-channel cold plates.

[0040] In the embodiment, the water inlet pipe in the liquid inlet header receives the cooling medium delivered by the circulating water pump, distributes the medium transversely through the water inlet series pipe, and then connects the medium to the inlets of the micro-channel cold plates through the multiple water inlet micro-pipes to realize the graded delivery of the medium; the liquid return header is the same, the hot oil at the outlets of the cold plates is collected to the liquid return series pipe through the liquid return micro-pipes, and then flows back to the cooling water tank through the liquid return pipe to form the graded collection. The graded structure ensures that the cooling medium can be uniformly distributed to each cold plate, and at the same time, guarantees the efficient collection of the hot oil.

[0041] Specifically, the micro-channel cold plates are externally provided with heat dissipation fins 16 distributed at intervals, and the height of the heat dissipation fins is 5-15 mm.

[0042] In the embodiment, the heat dissipation fins on the external surface of the cold plates greatly expand the contact area of the cold plates with air, and the heat absorbed by the cold plates is partly taken away by the internal cooling medium and partly transferred to the heat dissipation fins through the wall surface of the cold plates; the fins form a temperature difference with the surrounding air, and the air occurs natural convection on the surface of the fins to take away the heat of the fins, forming an auxiliary heat dissipation path of "cold plate conduction-fins expansion-air convection", which forms a synergistic effect with the liquid circulation heat dissipation.

[0043] Skilled persons should know that although the utility model has been described according to the above specific embodiments, the utility model idea is not limited to the utility model, and any modification using the utility model idea will be included in the protection scope of the patent.

Claims

1. A heat dissipation mechanism for an oil-immersed transformer, comprising a transformer casing and heat dissipation components, characterized in that: The heat dissipation components include a cooling water tank, a circulating water pump, and several microchannel cold plates; The microchannel cold plates are fixed at intervals on the outer wall surface of the transformer shell. The inlets of multiple microchannel cold plates are connected to the circulating water pump through the liquid inlet manifold, and the outlets are connected to the cooling water tank through the liquid return manifold. The circulating water pump is connected to the cooling water tank to form a closed liquid circulation loop.

2. The heat dissipation mechanism of the oil-immersed transformer according to claim 1, characterized in that: The microchannel cold plate is fixed to the outer wall surface of the transformer shell by a thermally conductive adhesive layer, the thermal conductivity of which is not less than 1.5 W / m·K.

3. The heat dissipation mechanism of the oil-immersed transformer according to claim 1, characterized in that: The microchannel cold plate is fixed to the outer wall surface of the transformer shell by brazing.

4. The heat dissipation mechanism of the oil-immersed transformer according to claim 1, characterized in that: The microchannel cold plate has an inlet at its lower end and an inlet converging cavity connected to the inlet, and an outlet at its upper end and an outlet converging cavity connected to the outlet. The inlet converging cavity and the outlet converging cavity are connected by multiple parallel microchannels.

5. The heat dissipation mechanism of the oil-immersed transformer according to claim 4, characterized in that: The hydraulic diameter of the microchannel ranges from 0.5 to 1.2 mm.

6. The heat dissipation mechanism of the oil-immersed transformer according to claim 1, characterized in that: The liquid inlet manifold includes a water inlet pipe connected to the circulating water pump, a water inlet series pipe connected to the water inlet pipe, and water inlet micro-tubes respectively connected to the inlet of the microchannel cold plate; the liquid return manifold includes a liquid return pipe connected to the cooling water tank, a liquid return series pipe connected to the liquid return pipe, and liquid return micro-tubes respectively connected to the outlet of the microchannel cold plate.

7. The heat dissipation mechanism of the oil-immersed transformer according to claim 4, characterized in that: The outer surface of the microchannel cold plate is provided with heat dissipation fins spaced apart, and the height of the heat dissipation fins is 5-15mm.

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