Cold starting device of oil-immersed transformer

Abstract

The utility model relates to a cold starting device for an oil-immersed transformer, which is used for realizing rapid heating of the oil-immersed transformer, is arranged between a hot oil end and a cold oil end of the oil-immersed transformer, and comprises a main body of the cold starting device for the oil-immersed transformer, a main body of the oil-immersed transformer cold starting device comprises a valve and an oil pump which are connected with each other through a second oil pipe, the other end of the valve is connected to the hot oil end of the oil-immersed transformer through a first oil pipe, and the other end of the oil pump is connected to the cold oil end of the oil-immersed transformer through a third oil pipe, so that a circulating bypass oil way is formed. On the premise that the heat dissipation performance is not affected, the engine heating time of low-temperature cold start of the oil-immersed transformer can be shortened, the oil-immersed transformer is protected against local overheating damage caused by poor heat circulation at low temperature, and the application range of the oil-immersed transformer is expanded. Meanwhile, the oil pump is protected from being influenced during normal heat dissipation work of the oil-immersed transformer through the valve, and the service life of the oil pump is prolonged.

Description

Technical Field

[0001] The utility model relates to a transformer cold starting device, in particular to an oil-immersed transformer cold starting device, which is used to shorten the cold starting time of the oil-immersed transformer when it is used in extremely cold areas and broaden the application environment range thereof. Background Art

[0002] When the transformer is cold-started in an extremely cold region, the viscosity of the cooling oil inside it will increase due to the decrease in oil temperature, thus affecting the circulation of the cooling oil inside the transformer. If the transformer is operated under load at this time, the cooling oil will not flow sufficiently inside the transformer, which may easily lead to local overheating of the transformer winding, thus damaging the transformer.

[0003] Chinese patent application CN202311545812.X, title: transformer cold start method and transformer cold start device, including a controller, an oil storage cabinet filled with transformer oil, and a transformer composed of winding coils. The oil storage cabinet is connected to the oil pump through an external oil pipe for transmitting transformer oil. The flow rate of the external oil pipe is detected by a flow detection device and compared with the preset flow rate parameter. According to the obtained flow rate comparison result, it is judged whether the transformer oil filled in the transformer oil storage cabinet is solidified, so as to instruct the winding coil to cold start the transformer. In other words, although this scheme can determine whether the transformer can be started, it cannot guarantee that the transformer can be quickly started and enter normal use even in extremely cold weather, nor can it accelerate the cold start process of the transformer under low temperature conditions. Utility Model Content

[0004] The purpose of the utility model is to solve the cold start problem of the above-mentioned existing oil-immersed transformer in extremely cold areas, expand its application environment range, and propose a rapid heat-up device for a cold start device of an oil-immersed transformer. By reasonably setting a bypass oil circuit, the cold start time of the oil-immersed transformer in a low temperature environment is effectively shortened, and the risk of damage to the transformer during cold start is eliminated to realize its application of cold start in a low temperature environment.

[0005] The implementation method of the utility model is: an oil-immersed transformer cold starting device, which is arranged between the hot oil end and the cold oil end of the oil-immersed transformer, and includes a main body of the oil-immersed transformer cold starting device, and the main body of the oil-immersed transformer cold starting device includes a valve and an oil pump connected to each other through a second oil pipe, the other end of the valve is connected to the hot oil end of the oil-immersed transformer through a first oil pipe, and the other end of the oil pump is connected to the cold oil end of the oil-immersed transformer through a third oil pipe, forming a circulating bypass oil circuit.

[0006] The oil-immersed transformer comprises a transformer body arranged in a shell, the cavity between the transformer body and the shell is a transformer oil chamber, the transformer oil chamber is filled with heat dissipation oil, the top of the transformer oil chamber is connected to the oil pillow, and the radiator is arranged between the cold oil end and the hot oil end of the oil-immersed transformer in a pipeline connection manner to form a radiator oil circuit.

[0007] The main body of the oil-immersed transformer cold starting device is arranged in parallel with the radiator of the oil-immersed transformer.

[0008] According to the capacity of the oil-immersed transformer, a corresponding number of sets of parallel-arranged oil-immersed transformer cold starting devices are used.

[0009] The oil-immersed transformer adopts an oil-immersed multi-winding phase-shifting transformer.

[0010] The oil pump is a low-temperature heat dissipation oil pump with an operating range of -60°C to 40°C.

[0011] The beneficial effects of the utility model are:

[0012] 1. The utility model adds a bypass oil circuit to the oil-immersed transformer, which can force the cooling oil to circulate through the oil pump when the cold machine is started, thereby overcoming the problem of insufficient circulation and local overheating that damages the transformer due to the increase in viscosity of the low-temperature cooling oil, so that the oil-immersed transformer can be cold-started in situations where it could not be used without the utility model.

[0013] 2. The bypass oil circuit of the utility model can bypass the radiator when the cold engine is started, reducing the heat dissipation oil flow through the radiator in the natural circulation, thereby reducing the heat exchange amount of the radiator and increasing the oil temperature rise speed.

[0014] 3. The bypass oil circuit described in the utility model is equipped with a valve. When the valve is closed under normal operating conditions, the bypass oil circuit does not work and does not affect the heat dissipation performance of the transformer. The heat conduction and flow of the hot oil will not affect the oil pump in the bypass oil circuit, and will not affect the life of the oil pump during normal operation.

[0015] 4. The bypass oil circuit of the utility model is equipped with a valve, which can completely block the bypass oil circuit. When the oil pump fails or the oil pipe is blocked or leaks, it will not affect the normal use of the transformer.

[0016] 5. The bypass oil circuit described in the utility model is composed of conventional mechanical components such as oil pumps, valves, and oil pipes. The technology is mature and low-cost, and the interchangeability and reliability are high. The volume is small, and the impact on the design and cost considerations of the original oil-immersed transformer is small.

[0017] To sum up, the utility model of the cold start device for oil-immersed transformer has a flexible design, does not affect the normal performance of the original transformer, has low cost and has the effect of preventing local overheating of the oil-immersed transformer in a low temperature environment, thereby expanding its use environment and shortening its cold start time, and provides a suitable solution for the application of oil-immersed transformers in extremely cold areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram showing the main connection relationship between the utility model and the oil-immersed transformer.

[0019] Figure 2 The utility model is a schematic structural diagram of an application example in which multiple sets of the utility model are arranged in parallel on a large oil-immersed transformer.

[0020] Figure 3 The utility model is used to implement the cold start process of the oil-immersed transformer.

[0021] In the figure: 1. first oil pipe; 2. second oil pipe; 3. third oil pipe; 4. valve; 5. oil pump; 6. transformer body; 7. housing; 8. oil pillow; 9. radiator; 10. radiator oil circuit; 11. transformer oil cavity; 12. main body of the oil-immersed transformer cold starting device. DETAILED DESCRIPTION

[0022] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments.

[0023] According to the attached Figures 1 to 3 The utility model is a cold start device for an oil-immersed transformer, which is used to realize a rapid heat-up of the oil-immersed transformer. The oil-immersed transformer includes a transformer body 6 arranged in a shell 7, a cavity between the transformer body 6 and the shell 7 is a transformer oil chamber 11, the transformer oil chamber 11 is filled with heat dissipation oil, and its top is connected to an oil pillow 8, a radiator 9 is arranged between the cold oil end and the hot oil end of the transformer oil chamber 11 by a pipeline connection method, and a radiator oil circuit 10 is formed. The oil-immersed transformer cold start device includes a main body 12 of the oil-immersed transformer cold start device arranged in parallel with the radiator 9, and is also arranged between the hot oil end and the cold oil end of the transformer oil chamber 11, forming a circulating bypass oil circuit, and the main body 12 of the oil-immersed transformer cold start device includes a valve 4 and an oil pump 5 connected to each other through a second oil pipe 2, the other end of the valve 4 is connected to the hot oil end of the transformer oil chamber 11 through a first oil pipe 1, and the other end of the oil pump 5 is connected to the cold oil end of the transformer oil chamber 11 through a third oil pipe 3.

[0024] Under normal operating conditions where the oil-immersed transformer does not require cold start, the valve 4 is closed, the oil pump 5 does not work, and the hot oil in the transformer oil chamber 11 is cooled by the radiator oil circuit 10 where the radiator 9 is located and then returns to the transformer oil chamber 11, and circulates around the transformer body 6 in this way. Figure 1 The direction of the middle dotted arrow is the flow direction of the cooling oil in the radiator oil circuit 10. At this time, the closed valve 4 can block the flow of the cooling oil in the pipeline of the oil-immersed transformer cold starting device without affecting the normal operation of the radiator 9, and can also protect the oil pump 5.

[0025] When the oil-immersed transformer needs to work in the bypass oil circuit during cold start, and bypass the heat dissipation oil flowing through the radiator oil circuit 10, the valve 4 is opened and the oil pump 5 is operated. Due to the action of the oil pump 5, the heat dissipation oil in the housing 7 cavity is forced to circulate in the bypass oil circuit, and the hot oil that has not been radiated directly returns to the housing 7 cavity, thereby increasing the oil temperature of the heat dissipation oil in the housing 7 cavity. Figure 1 The direction of the solid arrow is the flow direction of the heat dissipation oil in the circulating bypass oil circuit. The hot oil in the housing 7 cavity is bypassed by the circulating bypass oil circuit instead of being dissipated through the radiator oil circuit 10 where the radiator 9 is located. Therefore, the heat dissipation oil in the housing 7 cavity heats up rapidly, solving the problem of insufficient circulation caused by increased viscosity of the heat dissipation oil due to low temperature, which leads to local overheating of the transformer body 6 and causes damage.

[0026] According to the attached Figure 2 The utility model can flexibly adapt to oil-immersed transformers of various capacities by arranging multiple sets in parallel. When the capacity of the transformer is particularly large, the transformer body and the oil cavity will also increase accordingly. A single set of oil-immersed transformer cold start device may not meet the use requirements. For the cold start of such transformers, multiple sets of the utility model can be arranged in parallel to ensure that the bypass effect of the circulating bypass oil circuit is good and the circulation of the heat dissipation oil is uniform and sufficient.

[0027] Attached Figure 3For the cold start process example of the oil-immersed transformer of the utility model, when the 35kV / 80MVA oil-immersed transformer is cold started at an ambient temperature of -50 degrees Celsius, it is necessary to wait for the cooling oil temperature to rise to ≥-20 degrees Celsius when the oil-immersed transformer is running at no-load, and then the oil-immersed transformer cold start device described in the utility model starts to be put into operation, open the valve 4, start the oil pump 5, the cooling oil is bypassed and flows in the circulating bypass oil circuit, and the oil-immersed transformer continues to run at no-load. After the cooling oil temperature rises to ≥-10 degrees Celsius, it is sequentially operated at 10% load for 8 hours, 20% load for 8 hours, 35% load for 8 hours, and 50% load for 8 hours, after which the oil-immersed transformer can run freely and normally within the rated current range. During the operation of this example, when the cooling oil temperature rises to ≥0 degrees Celsius, the valve 4 is closed, the oil pump 5 is stopped, and the oil-immersed transformer cold start device described in the utility model completes the work and exits operation.

Claims

1. A cold starting device for an oil-immersed transformer, characterized in that: The oil-immersed transformer cold starting device is arranged between the hot oil end and the cold oil end of the oil-immersed transformer, and includes a main body of the oil-immersed transformer cold starting device. The main body of the oil-immersed transformer cold starting device includes a valve and an oil pump connected to each other through a second oil pipe, the other end of the valve is connected to the hot oil end of the oil-immersed transformer through a first oil pipe, and the other end of the oil pump is connected to the cold oil end of the oil-immersed transformer through a third oil pipe, forming a circulating bypass oil circuit.

2. The cold starting device for an oil-immersed transformer according to claim 1, characterized in that: The oil-immersed transformer comprises a transformer body arranged in a shell, the cavity between the transformer body and the shell is a transformer oil chamber, the transformer oil chamber is filled with heat dissipation oil, the top of the transformer oil chamber is connected to the oil pillow, and the radiator is arranged between the cold oil end and the hot oil end of the oil-immersed transformer in a pipeline connection manner to form a radiator oil circuit.

3. The cold starting device for an oil-immersed transformer according to claim 1, characterized in that: The main body of the oil-immersed transformer cold starting device is arranged in parallel with the radiator of the oil-immersed transformer.

4. The cold starting device for an oil-immersed transformer according to claim 1, characterized in that: According to the capacity of the oil-immersed transformer, a corresponding number of sets of parallel-arranged oil-immersed transformer cold starting devices are used.

5. The cold starting device for an oil-immersed transformer according to any one of claims 1 to 4, characterized in that: The oil-immersed transformer adopts an oil-immersed multi-winding phase-shifting transformer.

6. The cold starting device for an oil-immersed transformer according to claim 1, characterized in that: The oil pump is a low-temperature heat dissipation oil pump with an operating range of -60°C to 40°C.

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