A large-capacity three-winding wind power box transformer

Abstract

The present invention relates to a large-capacity three-winding wind power box transformer, which includes a cuboid box transformer housing. A metal partition is provided inside the box transformer housing, and the metal partition divides the box transformer into a high-voltage chamber on the left, a transformer chamber in the middle, a medium-voltage chamber in the right rear part, and a low-voltage chamber in the right front part; 35 kV high-voltage bushings are installed on the partition between the high-voltage chamber and the transformer chamber, 10 kV medium-voltage bushings are provided on the partition between the transformer chamber and the medium-voltage chamber, 1.14 kV low-voltage bushings are provided on the partition between the transformer chamber and the low-voltage chamber, and the medium-voltage chamber and the low-voltage chamber are separated by a steel plate; the box body adopts an independent standard high box that can be stacked for transportation, which is convenient for transportation; it adopts oil-immersed air-cooling, can start the fan under the condition of a large continuous load, control the temperature rise of the transformer, and rely on self-cooling operation for heat dissipation when not operating at full load, saving energy and reducing consumption.

Description

Technical Field

[0001] The present invention relates to the field of box-type substations, and particularly to a large-capacity three-winding wind power box-type substation. Background Art

[0002] As a clean energy source, wind power generation is clean, has a low cost, and has the advantages of being inexhaustible. Since the use of large-capacity wind turbine generators helps to reduce the cost per watt, the single-unit installed capacity of wind turbine generators has been rapidly increasing in recent years.

[0003] Large-capacity wind turbine generators mostly adopt doubly-fed asynchronous generators, which are currently the most widely used wind generators. It consists of a wound-rotor asynchronous generator with a stator winding directly connected to a fixed-frequency three-phase power grid and a bidirectional back-to-back IGBT voltage source converter installed on the rotor winding. When this type of generator set operates, it requires an excitation power supply, usually consistent with the generator set voltage. For example, the excitation voltage of a 0.69 kV generator set is 0.69 kV, and the excitation power supply voltage of a 1.14 kV generator set is 1.14 kV. Up to now, 1.14 kV is the highest power generation voltage level for onshore power generation in the current market.

[0004] In order to pursue the ultimate cost performance, appropriately increasing the power generation voltage can reduce the system cost. Taking a 9 MW wind turbine as an example, the cable usage of a single unit installed capacity can be reduced by 200,000 - 300,000 yuan. Since the excitation voltage is affected by the insulation strength, it is generally not suitable to exceed 1.14 kV. When using 9 MW and larger-capacity wind turbine generators, the 10 kV voltage level output by the generator set has greater economic advantages.

[0005] Using the traditional supporting system, it is necessary to arrange 1 box-type substation of 9.2 MW (35 kV / 10 kV) and 1 box-type substation of 1.3 MW (35 kV / 1.14 kV), with some redundant functions and a large floor area. How to promote the rapid popularization of large-capacity wind turbine generators, and at the same time provide an excitation voltage of 1.14 kV and a power generation voltage of 10 kV, its operation reliability and economy are particularly important. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a large-capacity three-winding wind power box-type substation, and its technical solution is as follows:

[0007] It includes a cuboid box-type substation shell, and a metal partition is provided inside the box-type substation shell. The metal partition divides the box-type substation into a high-voltage chamber on the left, a transformer chamber in the middle, a medium-voltage chamber in the right rear part, and a low-voltage chamber in the right front part; 35 kV high-voltage bushings are installed on the partition between the high-voltage chamber and the transformer chamber, 10 kV medium-voltage bushings are provided on the partition between the transformer chamber and the medium-voltage chamber, 1.14 kV low-voltage bushings are provided on the partition between the transformer chamber and the low-voltage chamber, and the medium-voltage chamber and the low-voltage chamber are separated by a steel plate;

[0008] The external power grid for the high-voltage outdoor connected wind power system. A 35kV high-voltage switchgear is installed indoors. The switch of the high-voltage switchgear is a 40.5kV gas-insulated high-voltage unit and a horizontal SF6 vacuum circuit breaker structure. The switch connecting the high-voltage room to the transmission power grid is a 40.5kV gas-insulated high-voltage unit;

[0009] A three-winding transformer and air-cooled fans are installed in the transformer room. The air-cooled fans are arranged on the front and back sides of the three-winding transformer. An oil conservator is horizontally installed on the top of the three-winding transformer, and the bottom of the oil conservator is connected to the three-winding transformer through a gas relay;

[0010] A cable lifting cabinet and a circuit breaker cabinet are installed in the medium-voltage room. The cable lifting cabinet is installed on the right side of the circuit breaker cabinet;

[0011] Low-voltage cabinets, auxiliary transformers, UPS, and manholes are provided in the low-voltage room. The low-voltage cabinets are arranged on the left side of the manholes. Among them, the low-voltage cabinets and auxiliary transformers are respectively connected to the low-voltage busbars, and the UPS is connected to the power supply end of the auxiliary transformer.

[0012] Furthermore, the three-winding transformer combines a power generation transformer and an excitation transformer, with a capacity of 6MVA to 10.5MVA, matching 5MW to 9.3MW single-unit generators. The transformer uses oil-immersed air-cooling.

[0013] Furthermore, the capacity of this box-type transformer adopts an asymmetric structure, that is, the side close to the high-voltage room is at full capacity; the side close to the low-voltage room undertakes 12.3% of the capacity for receiving the excitation voltage of the wind turbine generator; the side of the medium-voltage room undertakes 87.6% of the capacity for receiving the output voltage of the wind turbine generator.

[0014] Furthermore, with respect to the entire box body, cabinet doors are provided in front of the high-voltage room and the low-voltage room, and a cabinet door is provided at the back of the medium-voltage room.

[0015] Furthermore, the outer shell of the box-type transformer is an independent standard 20-foot high container structure that can be stacked for shipping.

[0016] Furthermore, the top of the oil conservator protrudes from the outer shell of the box-type transformer, and the oil conservator is covered within the frame through the frame, and the frame is fixedly connected to the outer shell of the box-type transformer.

[0017] Furthermore, a terminal box is also provided on the right side inside the low-voltage cabinet for collecting the external transmission signals of the entire box-type transformer and having sufficient maintenance space.

[0018] The beneficial effects of the present invention are as follows: The present invention is a large-capacity three-winding wind power box-type transformer,

[0019] ① The three-winding transformer together with the high, medium, and low-voltage switchgears are installed in the box body of the container structure. The box body adopts an independent standard high container that can be stacked for transportation, which is convenient for transportation;

[0020] ② The three-winding transformer combines the functions of a power generation transformer and an excitation transformer. It uses oil-immersed air-cooling. The fan can be started under a large continuous load to control the temperature rise of the transformer. When it is not operating at full load, it relies on natural cooling for heat dissipation, saving energy and reducing consumption.

[0021] ③ The switch connecting the high-voltage chamber to the transmission power grid is a 40.5 kV gas-insulated high-voltage unit with a horizontal SF6 vacuum circuit breaker structure. Compared with traditional air-insulated vacuum circuit breakers, it has a more compact structure, which is more conducive to reducing the overall size of the box-type substation. Secondly, since the gas-insulated switchgear is a fully sealed structure, the internal operating and insulation environment is not affected by the external environment, with stronger breaking capacity and better weather resistance, and can adapt to any harsh operating environment.

[0022] ④ The medium-voltage chamber and the low-voltage chamber respectively undertake 87.6% and 12.3% of the capacity (usually selected according to the capacity of a single generator set), and are used to receive the output voltage of the wind turbine and the excitation voltage respectively. The output voltage of the high voltage level is conducive to reducing the overall cost of the wind power system. The excitation voltage not only retains the characteristic of small capacity of the excitation voltage but also has the economy of small-capacity power transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of the present invention;

[0024] Figure 2 is Figure 1 a top view;

[0025] Figure 3 is Figure 1 a side view;

[0026] As shown in the figure, 1 is the high-voltage chamber, 1.1 is the 35 kV high-voltage switchgear (SF6), 1.2 is the gas-insulated high-voltage unit, 1.3 is the high-voltage switchgear cabinet door, 1.4 is the 35 kV high-voltage bushing, 1.5 is the high-voltage switchgear through-wall bushing, 2 is the transformer chamber, 2.1 is the three-winding transformer, 2.2 is the air-cooling fan, 2.3 is the oil conservator, 2.4 is the gas relay, 3 is the medium-voltage chamber, 3.1 is the circuit breaker cabinet, 3.2 is the cable lifting cabinet, 3.3 is the medium-voltage chamber cabinet door, 3.4 is the 10 kV medium-voltage bushing, 4 is the low-voltage chamber, 4.1 is the low-voltage switchgear, 4.2 is the manhole, 4.3 is the low-voltage chamber cabinet door, 4.4 is the UPS, 4.5 is the auxiliary transformer, 4.6 is the 1.14 kV low-voltage bushing, and 5 is the box-type substation housing. DETAILED DESCRIPTION OF THE INVENTION

[0027] As shown in the figure, the present invention is a large-capacity three-winding wind power box transformer, which consists of five major parts: a high-voltage chamber 1, a transformer chamber 2, a medium-voltage chamber 3, a low-voltage chamber 4, and a container box transformer shell 5. The size of the container box transformer shell is a standard 20-foot high container, with the selection: length * width * height = 6058mm * 2438mm * 2896mm. Container transportation can assemble goods into container units, facilitating the use of large loading and unloading machinery and large transport vehicles for loading, unloading, handling operations, and completing transportation tasks in the modern circulation field. It can be stacked for transportation, facilitating the overseas export of projects. It is a new, efficient, and high-benefit transportation method for realizing the "door-to-door" transportation of cross-border / transoceanic goods.

[0028] On the high-voltage chamber and the transformer compartment, there is an installed 35kV high-voltage bushing 1.4. Between the transformer chamber and the medium-voltage chamber, there is a 10kV medium-voltage bushing 3.4. On the partition between the transformer chamber and the low-voltage chamber, there is a 1.14kV low-voltage bushing 4.6. The medium-voltage chamber and the low-voltage chamber are separated by a steel plate to prevent the expansion of accidents in case of a failure.

[0029] In front of the high-voltage chamber, there is a high-voltage chamber cabinet door 1.3. The core component in the high-voltage chamber is a 35kV high-voltage cabinet (SF6) 1.1, which is externally connected to the outgoing power grid (35kV) of the wind power system, and the high-voltage side capacity is full capacity. The high-voltage cabinet switch is a 40.5kV gas-insulated high-voltage unit 1.2, with a horizontal SF6 vacuum circuit breaker structure. The horizontal SF6 vacuum circuit breaker is horizontally arranged at the top of the high-voltage chamber. On one side of the horizontal SF6 vacuum circuit breaker, it is connected to the 35kV high-voltage bushing 1.4 through a high-voltage cabinet through-wall bushing 1.5. Compared with the traditional air-insulated vacuum circuit breaker, the structure is more compact, which is more conducive to compressing the overall size of the box transformer. Secondly, since the gas-insulated switchgear is a fully sealed structure, the internal operation and insulation environment are not affected by the external environment, with stronger breaking capacity and better weather resistance, and can adapt to any harsh use environment.

[0030] Inside the transformer chamber, there is a large-capacity three-winding transformer 2.1, an air-cooling fan 2.2, and an oil conservator 2.3. The large-capacity three-winding transformer uses one transformer to combine the functions of a power generation transformer and an excitation transformer, with a capacity of 6MVA to 10.5MVA, matching 5MW to 9.3MW single-unit wind turbines. It adopts a cooling method combining oil-immersed self-cooling and oil-immersed air-cooling, and forced air-cooling fans 2.2 are installed in front of and behind the three-winding transformer respectively. When the transformer operates at full load for a long time, the fans start to dissipate heat. When the transformer starts with a low load for most of the time, natural cooling of the transformer can meet the temperature rise requirements. This design scheme not only saves power consumption but also conforms to the characteristic of high non-load rate of wind turbines, and can effectively limit the size of the transformer within the standard container size.

[0031] There is a medium-voltage chamber cabinet door 3.3 behind the medium-voltage chamber, and inside there are a 10 kV circuit breaker cabinet 3.1 and a 10 kV cable lifting cabinet 3.2. The medium-voltage side undertakes 87.6% of the capacity (usually selected according to the capacity of a single unit, for example, the medium-voltage capacity of a 9 MW wind turbine is generally selected from 9.5 MW to 10 MW), and is used to receive the output voltage of the wind turbine. The output voltage of the high voltage level is beneficial to reducing the overall cost of the wind power system.

[0032] There is a low-voltage chamber cabinet door 4.3 in front of the low-voltage chamber, and inside there are a 1.14 kV low-voltage cabinet 4.1, a manhole 4.2, a UPS 4.4 and an auxiliary transformer 4.5. The low-voltage side undertakes 12.3% of the capacity. The low-voltage cabinet is arranged on the left side of the manhole and is used to receive the excitation voltage of the wind turbine. The excitation voltage is different from the generating voltage, which not only retains the characteristic of small capacity of the excitation voltage, but also has the economy of high-voltage power transmission. There is also a terminal box on the right side inside the low-voltage cabinet, which is used to collect the outgoing signals of the whole box-type substation and has sufficient maintenance space to improve the maintenance efficiency. The auxiliary transformer provides power for the auxiliary circuit of the whole box-type substation, and the UPS is used as a voltage stabilizing power supply to ensure that important auxiliary circuits (such as the control of high, medium and low circuit breakers and the continuous monitoring of measurement and control devices) continue to operate after the equipment loses power.

[0033] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A large-capacity three-winding wind power box transformer, comprising a cuboid box transformer housing, characterized in that, Inside the box-type substation enclosure, there is a metal partition, which divides the box-type substation into a high-voltage chamber on the left, a transformer chamber in the middle, a medium-voltage chamber in the rear right, and a low-voltage chamber in the front right; there is a 35 kV high-voltage bushing on the partition between the high-voltage chamber and the transformer chamber, a 10 kV medium-voltage bushing on the partition between the transformer chamber and the medium-voltage chamber, a 1.14 kV low-voltage bushing on the partition between the transformer chamber and the low-voltage chamber, and the medium-voltage chamber and the low-voltage chamber are separated by a steel plate; The high-voltage chamber is externally connected to the outgoing power grid of the wind power system. A 35 kV high-voltage switchgear is installed in the high-voltage chamber. The switch of the high-voltage switchgear is a 40.5 kV gas-insulated high-voltage unit and a horizontal SF6 vacuum circuit breaker structure. The switch connecting the high-voltage chamber to the transmission power grid is a 40.5 kV gas-insulated high-voltage unit; A three-winding transformer and air-cooling fans are installed in the transformer chamber. The air-cooling fans are arranged on the front and rear sides of the three-winding transformer. An oil conservator is installed horizontally on the top of the three-winding transformer, and the bottom of the oil conservator is connected to the three-winding transformer through a gas relay; A cable lifting cabinet and a circuit breaker cabinet are installed in the medium-voltage chamber. The cable lifting cabinet is installed on the right side of the circuit breaker cabinet; A low-voltage switchgear, an auxiliary transformer, a UPS, and a manhole are provided in the low-voltage chamber. The low-voltage switchgear is arranged on the left side of the manhole. Among them, the low-voltage switchgear and the auxiliary transformer are respectively connected to the low-voltage busbar, and the UPS is connected to the power supply end of the auxiliary transformer; The capacity of this box-type substation adopts an asymmetric structure. The three-winding transformer combines a transformer for power generation and a transformer for excitation. The side close to the low-voltage chamber is used to receive the excitation voltage of the wind turbine generator; the side of the medium-voltage chamber is used to receive the output voltage of the wind turbine generator.

2. The large-capacity three-winding wind power box transformer according to claim 1, characterized in that, The capacity of the three-winding transformer is 6 MVA to 10.5 MVA, which matches 5 MW to 9.3 MW single-unit generators. The transformer uses oil-immersed air-cooling.

3. The large-capacity three-winding wind power box transformer according to claim 2, characterized in that, The side close to the high-voltage chamber is at full capacity; the side close to the low-voltage chamber undertakes 12.3% of the capacity; the side of the medium-voltage chamber undertakes 87.6% of the capacity.

4. A large-capacity three-winding wind power box transformer according to claim 1, characterized in that, Relative to the entire box body, there are cabinet doors in front of the high-voltage chamber and the low-voltage chamber, and a cabinet door is provided at the back of the medium-voltage chamber.

5. A large-capacity three-winding wind power box transformer according to any one of claims 1 to 4, characterized in that, The enclosure of the box-type substation is an independent standard 20-foot high container structure that can be stacked and shipped by sea.

6. The large-capacity three-winding wind power box transformer according to claim 5, wherein, The top of the oil conservator protrudes from the enclosure of the box-type substation, and the oil conservator is covered within the frame through the frame. The frame is fixedly connected to the enclosure of the box-type substation.

7. The large-capacity three-winding wind power box transformer according to claim 6, characterized in that, A terminal box is also provided on the right side inside the low-voltage switchgear, which is used to collect the outgoing signals of the entire box-type substation and has sufficient maintenance space.

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