A fan switching method

Abstract

The application provides a fan switching method, which comprises the following steps: reducing the frequency of a second fan to the lowest frequency at which the second fan can run, opening a main pressure relief valve, and controlling the pressure of a main pipeline within a first set range; starting a first fan, and simultaneously opening a first pressure relief valve and closing a first outlet valve; opening the main pressure relief valve, running the first fan for a certain time, closing the first pressure relief valve, opening the first outlet valve, and controlling the pressure of the main pipeline within a second set range; closing the second fan, gradually closing the main pressure relief valve, closing a second outlet valve, and opening a second pressure relief valve; after the second fan stops running, closing a second valve; and increasing the frequency of the first fan until the pressure of the main pipeline is within a third set range. The application can effectively control the pressure fluctuation in the process of switching the fan within a small range, and solves the problem of large pressure fluctuation in the prior art when switching the fan, and the environmental protection accident caused thereby.

Description

Technical Field

[0001] This invention relates to the field of wind turbine switching technology, and in particular to a wind turbine switching method. Background Technology

[0002] Aeration refers to the process of forcibly transferring oxygen from the air into a liquid to obtain sufficient dissolved oxygen. In addition, aeration also prevents suspended matter from settling and enhances the contact between organic matter, microorganisms, and dissolved oxygen. This ensures that microorganisms in the wastewater can effectively oxidize and decompose organic matter under conditions of sufficient dissolved oxygen.

[0003] Currently, air-suspended fans are used to transport air in aeration systems. During production, when these fans require maintenance or malfunction, they need to be switched. In existing technology, this switching typically involves first shutting down the operating fan and then starting the standby fan. During this process, when two fans are operating and one is on standby, the switching may result in low pipeline pressure due to only one fan running. Conversely, when one fan is operating and one is on standby, there may be no fan running, resulting in no pipeline pressure. Both low pipeline pressure and no pipeline pressure negatively impact the aeration system. For example, it may lead to insufficient air supply, resulting in low dissolved oxygen levels and ultimately, abnormal water quality and exceeding safety standards. Therefore, the existing fan switching method suffers from excessive pressure fluctuations, which can easily lead to environmental accidents. Summary of the Invention

[0004] The purpose of this invention is to provide a fan switching method to solve the technical problem that existing fan switching methods have excessive pressure fluctuations, which can easily lead to environmental accidents.

[0005] To solve the above-mentioned technical problems, the present invention provides a wind turbine switching method, wherein the main and standby wind turbine device includes:

[0006] The main pipeline is equipped with a main pressure relief valve for depressurizing the main pipeline;

[0007] A backup fan system is connected to the main pipeline via a first branch. The first branch is equipped with a first valve, which is used to control the connection and disconnection between the first branch and the main pipeline. The backup fan system includes a first fan, a first air inlet and a first outlet valve, and a first pressure relief valve.

[0008] The operating fan system includes a second fan, a second air inlet and a second outlet valve, a second pressure relief valve, and the second fan is connected to the main pipeline via a second branch. The second branch is equipped with a second valve, which is used to control the connection and disconnection between the second branch and the main pipeline.

[0009] Switching from a first state where the first fan is in a stopped state and the second fan is in a running state to a second state where the first fan is in a running state and the second fan is in a stopped state includes the following steps:

[0010] S1: Open the first valve to power on the first fan;

[0011] S2: When the frequency of the second fan is reduced to the lowest frequency that the second fan is allowed to operate, the main pressure relief valve is opened to maintain the pressure of the main pipeline within the first set range;

[0012] S3: Start the first fan and simultaneously open the first pressure relief valve and close the first outlet valve;

[0013] S4: Open the main pressure relief valve. After the first fan has been running for a set time, close the first pressure relief valve and open the first outlet valve to maintain the pressure of the main pipeline within the second set range.

[0014] S5: Turn off the second fan, close the main pressure relief valve, and simultaneously close the second outlet valve and open the second pressure relief valve;

[0015] S6: After the second fan stops running, close the second valve;

[0016] S7: Increase the frequency of the first fan until the pressure of the main pipeline is within the third set range.

[0017] Preferably, the main and backup blower unit further includes at least one branch pipe system, the branch pipe system being provided with a fourth valve, the fourth valve being used to control the connection and disconnection between the branch pipe system and the main pipe, wherein the main and backup blower unit is used to supply air to the aeration system;

[0018] After switching from the first state to the second state, the fan switching method further includes:

[0019] Based on the air demand of the aeration system, the fourth valve and the frequency of the first blower are adjusted to maintain the pressure of the main pipeline within the third set range.

[0020] Preferably, after switching from the first state to the second state, the fan switching method further includes:

[0021] Adjust the frequency of the first fan and the fourth valve to maintain the operating pressure of the first fan within the fourth set range.

[0022] Preferably, the backup fan system further includes a first control panel, through which the first fan is set to operate at a fixed frequency, wherein the frequency setting of the first fan from 0 to 100% corresponds to 380Hz to 415Hz, and in step S7, the frequency of the first fan is adjusted by no more than 10% each time through the first control panel;

[0023] The operating fan system also includes a second control panel, through which the second fan is set to operate at a fixed frequency. The frequency setting of the second fan from 0 to 100% corresponds to 380Hz to 415Hz. In step S2, the frequency of the second fan is adjusted by no more than 5% each time through the second control panel.

[0024] Preferably, both the first outlet valve and the first pressure relief valve are DCS electric valves, and both the first outlet valve and the first pressure relief valve are electrically connected to the first control panel. In step S3, when the first fan is started, the first pressure relief valve automatically opens and the first outlet valve automatically closes.

[0025] Both the second outlet valve and the second pressure relief valve are DCS electric valves. Both the second outlet valve and the second pressure relief valve are electrically connected to the second control panel. In step S5, when the second fan is turned off, the second pressure relief valve automatically opens and the second outlet valve automatically closes.

[0026] Preferably, the main pipeline is equipped with a pressure sensor for detecting the pressure of the main pipeline.

[0027] Preferably, the third setting range is 78 kPa to 89 kPa.

[0028] Preferably, before step S1, the fan switching method further includes:

[0029] Check whether the level of the refrigerant in the first fan is within the specified range, and check whether the surface of the filter cotton installed at the first air inlet is clean.

[0030] Preferably, the operating fan system further includes:

[0031] The third fan is provided with a third air inlet valve, a third outlet valve, and a third pressure relief valve.

[0032] A third branch is provided between the third fan and the main pipeline, and the third branch is provided with a third valve for controlling the connection and disconnection between the third branch and the main pipeline;

[0033] Step S2 also includes reducing the frequency of the third fan to the minimum frequency at which the third fan is allowed to operate, and maintaining the pressure in the main pipeline within a first set range;

[0034] Step S7 also includes adjusting the frequencies of the first and third fans until the pressure of the main pipeline is within a third set range.

[0035] Preferably, both the first setting range and the third setting range are 78 kPa to 89 kPa.

[0036] Compared with the prior art, the wind turbine switching method of the present invention has the following advantages:

[0037] This invention first opens the first valve to energize the first fan; then, when the frequency of the second fan is reduced to its minimum permissible operating frequency, the main pressure relief valve is opened to maintain the main pipeline pressure within a first set range; the first fan is started, and simultaneously the first pressure relief valve is opened while the first outlet valve is closed; after the first fan has run for a set time, the main pressure relief valve is opened, and the first outlet valve is opened to maintain the main pipeline pressure within a second set range; the second fan is shut down, the main pressure relief valve is gradually closed, and simultaneously the second outlet valve is closed while the second pressure relief valve is opened; after the second fan stops operating, the second valve is closed; the frequency of the first fan is adjusted until the main pipeline pressure is within a third set range; thus completing the switching process, the pressure in the main pipeline is maintained at a stable state throughout the entire fan switching process, effectively controlling the pressure fluctuations generated during fan switching within a small range. This solves the environmental accident problem caused by large pressure fluctuations during fan switching in existing technologies. Attached Figure Description

[0038] Figure 1 This is a flowchart of a wind turbine switching method provided by the present invention;

[0039] Figure 2 This is a schematic diagram of the main and standby fan device in one embodiment of the present invention;

[0040] Figure 3 This is a diagram of the operating area of ​​a wind turbine according to one embodiment of the present invention;

[0041] In the picture,

[0042] 100 - Main pipeline; 110 - Main pressure relief valve;

[0043] 120 - First branch; 121 - First valve;

[0044] 130 - Second branch; 131 - Second valve;

[0045] 140 - Third branch; 141 - Third valve;

[0046] 150 - Fifth valve; 160 - Branch pipe system;

[0047] 161 - Fourth valve; 200 - Standby fan system;

[0048] 210 - First fan; 220 - First pressure relief valve;

[0049] 230 - First air inlet; 240 - First outlet valve;

[0050] 300 - Operating fan system; 310 - Second fan;

[0051] 320 - Second pressure relief valve; 330 - Second air inlet;

[0052] 340 - Second outlet valve; 350 - Third fan;

[0053] 360 - Third pressure relief valve; 370 - Third air inlet

[0054] 380 - Third outlet valve; 10 - Main and standby fan device. Detailed implementation mode

[0055] The following further elaborates on the fan switching method proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise scales, only for conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention.

[0056] Refer Figures 1 to 2This invention discloses a specific implementation of a fan switching method. The main / standby fan unit 10 includes: a main pipeline 100, equipped with a main pressure relief valve 110 for depressurizing the main pipeline 100; a standby fan system 200, connected to the main pipeline 100 via a first branch 120, the first branch 120 being equipped with a first valve 121 for controlling the connection and disconnection between the first branch 120 and the main pipeline 100; the standby fan system 200 includes a first fan 210, a first air inlet 230 and a first outlet valve 240 located at the first fan 210, a first pressure relief valve 220, and a first control panel electrically connected to the first fan 210; and a running fan system 300, including a second fan 3... 10. A second air inlet 330 and a second outlet valve 340, a second pressure relief valve 320, and a second control panel electrically connected to the second fan 310 are provided at the second fan 310. The second fan 310 is connected to the main pipeline 100 through a second branch 130. The second branch 130 is provided with a second valve 131, which is used to control the opening and closing of the second branch 130 and the main pipeline 100. The switching from a first state where the first fan 210 is in a stopped state and the second fan 310 is in a running state to a second state where the first fan 210 is in a running state and the second fan 310 is in a stopped state includes the following steps:

[0057] S1: Open the first valve 121 and put the first fan 210 into the energized state;

[0058] Specifically, refer to Figure 1 and Figure 2 As shown, the first valve 121 can be a butterfly valve. By manually positioning the closing element of the first valve 121 to the 90° position, the first valve 121 is opened, connecting the first branch 120 to the main pipeline 100. The first fan 210 is then energized via the first control panel. Butterfly valves are existing technology, and their specific structure is familiar to those skilled in the art; therefore, it will not be described in detail here.

[0059] For example, before step S1, the fan switching method further includes: checking whether the liquid level of the refrigerant in the first fan 210 is within a specified range, and checking whether the surface of the filter cotton installed at the first air inlet 230 is clean.

[0060] Specifically, refer to Figure 1 and Figure 2 As shown, check whether the coolant level is within the specified range to prevent insufficient coolant from affecting the normal operation of the first fan 210. The first air inlet 230 is equipped with filter cotton to filter impurities from the incoming air, preventing impurities from entering the first fan 210 and causing damage.

[0061] It should be noted that the second air inlet 330 is also equipped with filter cotton to filter the incoming air and prevent impurities from damaging the second fan 310.

[0062] S2: When the frequency of the second fan 310 is reduced to the lowest frequency that the second fan 310 is allowed to operate, the main pressure relief valve 110 is opened to control the pressure of the main pipeline 100 within the first set range.

[0063] Specifically, continue to participate Figure 1 and Figure 2 As shown, the second fan 310 is set to operate at a fixed frequency via the second control panel. The frequency setting of the second fan 310 from 0 to 100% corresponds to 380Hz to 415Hz. A pressure sensor is installed in the main pipeline 100 to detect the pressure in the main pipeline 100. The pressure setting range of the main pipeline 100 is 78KPa to 89KPa. When the frequency of the second fan 310 is reduced to the lowest permissible operating frequency of the second fan 310 in increments not exceeding 5% via the second control panel, the main pressure relief valve 110 is opened to control the pressure in the main pipeline 100 within the range of 78KPa to 89KPa, and close to 78KPa.

[0064] S3: Start the first fan 210, and at the same time open the first pressure relief valve 220 and close the first outlet valve 240;

[0065] Specifically, continue to participate Figure 1 and Figure 2 As shown, the first fan 210 is started via the first control panel, and the first pressure relief valve 220 is opened while the first outlet valve 240 is closed. The first pressure relief valve 220 and the first outlet valve 240 can be DCS electric valves. The first pressure relief valve 220 and the first outlet valve 240 are electrically connected to the first control panel. When the first fan 210 is started via the first control panel, the pressure in the main pipeline 100 will be too high due to the simultaneous start of the first fan 210 and the second fan 310. The first pressure relief valve 220 will automatically open and the first outlet valve 240 will automatically close.

[0066] S4: Open the main pressure relief valve 110. After the first fan 210 has been running for a set time, close the first pressure relief valve 220 and open the first outlet valve 240 to control the pressure of the main pipeline 100 within the second set range.

[0067] Specifically, continue to participate Figure 1 and Figure 2As shown, the main pressure relief valve 110 can be a butterfly valve. By manually positioning the closing element of the main pressure relief valve 110 to the 90° position, the main pressure relief valve 110 is opened to relieve pressure in the main pipeline 100, reducing the pressure within the main pipeline 100. After the first fan 210 runs for 10 seconds and reaches a stable state, the first control panel controls the first outlet valve 240 to open and the first pressure relief valve 220 to close, thereby enabling the first branch 120 to connect with the main pipeline 100. At this time, the pressure in the main pipeline 100 increases, and the pressure in the main pipeline 100 is controlled within 78 kPa to 89 kPa by the opened main pressure relief valve 110.

[0068] S5: Turn off the second fan 310, gradually close the main pressure relief valve 110, and at the same time close the second outlet valve 340 and open the second pressure relief valve 320;

[0069] Specifically, continue to participate Figure 1 and Figure 2 As shown, when the second fan 310 is shut down via the second control panel, the pressure in the main pipeline 100 decreases. At this time, the closing element of the main pressure relief valve 110 is manually moved to the 0° position, closing the main pressure relief valve 110 to maintain the pressure in the main pipeline 100 within the range of 78 kPa to 89 kPa. The second outlet valve 340 and the second pressure relief valve 320 can be DCS electric valves, both of which are electrically connected to the second control panel. When the second fan 310 is shut down and the main pressure relief valve 110 is closed, the second outlet valve 340 automatically closes, and the second pressure relief valve 320 automatically opens to relieve pressure on the second fan 310.

[0070] S6: After the second fan 310 stops running, close the second valve 131;

[0071] Specifically, continue to participate Figure 1 and Figure 2 As shown, the second valve 131 can be a butterfly valve. After the second fan 310 stops running, the closing element of the second valve 131 is manually placed at the 0° position to close the second valve 131, thereby disconnecting the second branch 130 from the main pipeline 100 and reducing the pressure in the main pipeline 100.

[0072] S7: Increase the frequency of the first fan 210 until the pressure of the main pipeline 100 is within the third set range;

[0073] Specifically, continue to participate Figure 1 and Figure 2As shown, the first fan 210 is set to operate at a fixed frequency via the first control panel. The frequency setting of the first fan 210 from 0 to 100% corresponds to 380Hz to 415Hz. When the second fan 310 is turned off, the pressure in the main pipeline 100 decreases. The frequency of the first fan 210 is increased by no more than 10% each time via the first control panel to increase the amount of power delivered by the first fan 210. Each time the frequency of the first fan 210 is adjusted, it is allowed to stabilize before the next adjustment is performed. By increasing the frequency of the first fan 210, the pressure in the main pipeline 100 is controlled within the range of 78KPa to 89KPa.

[0074] It should be noted that the first, second, and third setting ranges mentioned above are all 78 kPa to 89 kPa. By maintaining the pressure of the main pipeline 100 within 78 kPa to 89 kPa, the pressure fluctuations generated during the fan switching process can be effectively controlled within a small range, solving the environmental accident problem caused by large pressure fluctuations during fan switching in the existing technology.

[0075] S8: Switching complete.

[0076] Specifically, continue to participate Figure 1 and Figure 2 As shown, the fan switching is completed by switching from a first state where the first fan 210 is in a stopped state and the second fan 310 is in a running state to a second state where the first fan 210 is in a running state and the second fan 310 is in a stopped state. Throughout the entire fan switching process, the pressure in the main pipeline 100 is maintained within 78 kPa to 89 kPa, effectively controlling the pressure fluctuations generated during the fan switching process within a small range, thereby reducing the pressure fluctuation range during fan switching and avoiding environmental accidents caused by fan switching.

[0077] Furthermore, the main and backup blower unit 10 also includes at least one branch pipe system 160, which is equipped with a fourth valve 161. The fourth valve 161 is used to control the connection and disconnection between the branch pipe system 160 and the main pipe 100. The main and backup blower unit 10 is used to supply air to the aeration system. After switching from the first state to the second state, the blower switching method further includes: adjusting the fourth valve 161 and the frequency of the first blower 210 based on the air volume requirement of the aeration system, so as to control the pressure of the main pipe 100 within a third set range.

[0078] Specifically, refer to Figure 2As shown, when the aeration system's air demand increases, the air delivery volume can be increased by increasing the frequency of the first blower 210. At this time, the pressure in the main pipeline 100 increases, and the air delivery volume of the branch system 160 can be adjusted by regulating the fourth valve 161, thereby controlling the pressure in the main pipeline 100 within the range of 78 kPa to 89 kPa. Conversely, when the aeration system's air demand decreases, the air delivery volume can be reduced by decreasing the frequency of the first blower 210. At this time, the pressure in the main pipeline 100 decreases, and the air delivery volume of the branch system 160 can be adjusted by regulating the fourth valve 161, thereby controlling the pressure in the main pipeline 100 within the range of 78 kPa to 89 kPa, thus maintaining stable production.

[0079] Furthermore, after switching from the first state to the second state, the fan switching method also includes: adjusting the frequency of the first fan 210 and the fourth valve 161 to maintain the operating pressure of the first fan 210 within the fourth set range.

[0080] Specifically, refer to Figure 2 and Figure 3 As shown, the main pipeline 100 is also equipped with a fifth valve 150, which is used to control the air flow rate within the main pipeline 100, thereby controlling the pressure of the main pipeline 100. A fourth valve 161 is used to control the connection and disconnection between the branch system 160 and the main pipeline 100, thereby controlling the pressure of the main pipeline 100 to be within the range of 78 kPa to 89 kPa. By adjusting the frequency of the first fan 210, the fourth valve 161, and the fifth valve 150, the operating pressure of the first fan 210 is controlled to be within the fourth set range. (See reference...) Figure 3 As shown, the outlet pressure range of the first fan 210 is 30 kPa to 100 kPa. Therefore, the operating pressure of the first fan 210 can be maintained between 30 kPa and 100 kPa, that is, the fourth setting range is 30 kPa to 100 kPa. However, in order to ensure the air volume requirements of the production site, the flow rate of the first fan 210 must also be maintained within the set range during operation. Figure 3 As shown, the horizontal axis represents the inlet flow rate of the first fan 210, and the vertical axis represents the outlet pressure of the first fan 210. By adjusting the frequency of the first fan 210, the fourth valve 161, and the fifth valve 150, the intersection of the inlet flow rate and outlet pressure of the first fan 210 falls into the range shown. Figure 3 When the circuit is within the closed graphical structure shown, it can be assumed that the operating pressure and flow rate of the first fan 210 are both within the set range. For example, when the intersection of the inlet flow rate and outlet pressure of the first fan 210 is within a certain range... Figure 3At the center point shown, the outlet pressure of the first fan 210 is 88.7 kPa and the inlet flow rate is 95.8 cmM. The operating pressure of the first fan 210 can be maintained at 88.7 kPa and the flow rate of the first fan 210 can be maintained at 95.8 cmM. At this time, it can be considered that the operating pressure and operating flow rate of the first fan 210 are both within the set range.

[0081] For example, the operating fan system 300 further includes: a third fan 350, a third air inlet 370 and a third outlet valve 380 disposed on the third fan 350, a third pressure relief valve 360, and a third control panel electrically connected to the third fan 350; a third branch 140 is disposed between the third fan 350 and the main pipeline 100, and the third branch 140 is provided with a third valve 141 for controlling the connection and disconnection between the third branch 140 and the main pipeline 100. Step S2 further includes reducing the frequency of the third fan 350 to the lowest frequency at which the third fan 350 is allowed to operate, and maintaining the pressure of the main pipeline 100 within a first set range; step S7 further includes gradually increasing the frequency of the third fan 350 until the pressure of the main pipeline 100 is within the third set range. The first set range and the second set range are both 78 kPa to 89 kPa.

[0082] Specifically, refer to Figure 2 As shown, the operating fan system 300 also includes a third fan 350, which includes a third air inlet 370, a third outlet valve 380, a third pressure relief valve 360, and a third control panel electrically connected to the third fan 350. A third branch line 140 is provided between the third fan 350 and the main duct 100, and the third branch line 140 is equipped with a third valve 141 for controlling the connection and disconnection between the third branch line 140 and the main duct 100. The third outlet valve 380 and the third pressure relief valve 360 ​​are both DCS electric valves, and both are electrically connected to the third control panel. The third air inlet 370 is equipped with filter cotton for filtering air impurities. The third valve 141 is a butterfly valve, which is opened by placing the closing element of the third valve 141 at 90° and closed by placing the closing element of the third valve 141 at 0°. The third fan 350 is set to operate at a fixed frequency via the third control panel. The frequency setting of the third fan 350 from 0 to 100% corresponds to 380Hz to 415Hz.

[0083] Step S2 also includes gradually reducing the frequency of the third fan 350 to the minimum allowable operating frequency of the third fan 350, while maintaining the pressure in the main pipeline 100 within a first set range. That is, not only is the frequency of the second fan 310 reduced by no more than 5%, but the frequency of the third fan 350 is also reduced by no more than 5% to control the pressure in the main pipeline 100 within 78KPa to 89KPa, thereby reducing the pressure fluctuation range during fan switching and avoiding environmental accidents caused by fan switching. This effectively controls the pressure fluctuations generated during fan switching within a small range.

[0084] Step S7 also includes gradually increasing the frequency of the third fan 350 until the pressure in the main pipeline 100 is within the range of 78 kPa to 89 kPa. When the second fan 310 is shut down, the pressure in the main pipeline 100 decreases. The frequency of the first fan 210 is increased by no more than 10% each time via the first control panel to increase the amount of air delivered by the first fan 210. Each adjustment of the frequency of the first fan 210 is made only after the first fan 210 has stabilized. By increasing the frequency of the first fan 210, the pressure in the main pipeline 100 is controlled within the range of 78 kPa to 89 kPa. Simultaneously, the frequency of the third fan 350 can also be increased by no more than 10% each time via the third control panel to increase the amount of air delivered by the third fan 350, thereby controlling the pressure in the main pipeline 100 within the range of 78 kPa to 89 kPa. This reduces the pressure fluctuation range during fan switching, preventing environmental accidents caused by fan switching, and effectively controlling the pressure fluctuations generated during fan switching within a small range.

[0085] In summary, the present invention first opens the first valve 121 to energize the first fan 210; gradually reduces the frequency of the second fan 310 to the lowest allowable operating frequency; opens the main pressure relief valve 110 to maintain the pressure of the main pipeline 100 within a first set range; starts the first fan 210 and simultaneously opens the first pressure relief valve 220 and closes the first outlet valve 240; after the first fan 210 has been running for a set time with the main pressure relief valve 110 open, the first pressure relief valve 220 is closed and the first outlet valve 240 is opened to maintain the pressure of the main pipeline 100 within a second set range. Shut down the second fan 310, gradually close the main pressure relief valve 110, and simultaneously close the second outlet valve 340 and open the second pressure relief valve 320; after the second fan 310 stops running, close the second valve 131; adjust the frequency of the first fan 210 until the pressure in the main pipeline 100 is within 78KPa to 89KPa; complete the switching. Throughout the entire fan switching process, the pressure in the main pipeline 100 is kept stable, effectively controlling the pressure fluctuations generated during the fan switching process within a small range, thus solving the environmental accident problem caused by large pressure fluctuations during fan switching in the existing technology.

[0086] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method for switching wind turbines, characterized in that, The main and standby fan units include: The main pipeline is equipped with a main pressure relief valve for depressurizing the main pipeline; A backup fan system is connected to the main pipeline via a first branch. The first branch is equipped with a first valve, which is used to control the connection and disconnection between the first branch and the main pipeline. The backup fan system includes a first fan, a first air inlet and a first outlet valve, and a first pressure relief valve. The operating fan system includes a second fan, a second air inlet and a second outlet valve, a second pressure relief valve, and the second fan is connected to the main pipeline via a second branch. The second branch is equipped with a second valve, which is used to control the connection and disconnection between the second branch and the main pipeline. Switching from a first state where the first fan is in a stopped state and the second fan is in a running state to a second state where the first fan is in a running state and the second fan is in a stopped state includes the following steps: S1: Open the first valve to power on the first fan; S2: When the frequency of the second fan is reduced to the lowest frequency that the second fan is allowed to operate, the main pressure relief valve is opened to maintain the pressure of the main pipeline within the first set range; S3: Start the first fan and simultaneously open the first pressure relief valve and close the first outlet valve; S4: Open the main pressure relief valve. After the first fan has been running for a set time, close the first pressure relief valve and open the first outlet valve to maintain the pressure of the main pipeline within the second set range. S5: Turn off the second fan, close the main pressure relief valve, and simultaneously close the second outlet valve and open the second pressure relief valve; S6: After the second fan stops running, close the second valve; S7: Increase the frequency of the first fan until the pressure of the main pipeline is within the third set range; The first setting range, the second setting range, and the third setting range have the same numerical range.

2. The wind turbine switching method as described in claim 1, characterized in that, The main and backup blower unit also includes at least one branch pipe system, which is equipped with a fourth valve for controlling the connection and disconnection between the branch pipe system and the main pipe. The main and backup blower unit is used to supply air to the aeration system. After switching from the first state to the second state, the fan switching method further includes: Based on the air demand of the aeration system, the fourth valve and the frequency of the first blower are adjusted to maintain the pressure of the main pipeline within the third set range.

3. The fan switching method as described in claim 2, characterized in that, After switching from the first state to the second state, the fan switching method further includes: Adjust the frequency of the first fan and the fourth valve to maintain the operating pressure of the first fan within a fourth set range, which is 30 kPa to 100 kPa.

4. The fan switching method as described in claim 1, characterized in that, The backup fan system also includes a first control panel, through which the first fan is set to operate at a fixed frequency. The frequency setting of the first fan from 0 to 100% corresponds to 380Hz to 415Hz. In step S7, the frequency of the first fan is adjusted by no more than 10% each time through the first control panel. The operating fan system also includes a second control panel, through which the second fan is set to operate at a fixed frequency. The frequency setting of the second fan from 0 to 100% corresponds to 380Hz to 415Hz. In step S2, the frequency of the second fan is adjusted by no more than 5% each time through the second control panel.

5. The fan switching method as described in claim 4, characterized in that, Both the first outlet valve and the first pressure relief valve are DCS electric valves. Both the first outlet valve and the first pressure relief valve are electrically connected to the first control panel. In step S3, when the first fan is started, the first pressure relief valve automatically opens and the first outlet valve automatically closes. Both the second outlet valve and the second pressure relief valve are DCS electric valves. Both the second outlet valve and the second pressure relief valve are electrically connected to the second control panel. In step S5, when the second fan is turned off, the second pressure relief valve automatically opens and the second outlet valve automatically closes.

6. The wind turbine switching method as described in claim 1, characterized in that, The main pipeline is equipped with a pressure sensor to detect the pressure in the main pipeline.

7. The fan switching method as described in claim 2, characterized in that, The third setting range is 78 kPa to 89 kPa.

8. The wind turbine switching method as described in claim 1, characterized in that, Prior to step S1, the fan switching method further includes: Check whether the level of the refrigerant in the first fan is within the specified range, and check whether the surface of the filter cotton installed at the first air inlet is clean.

9. The fan switching method as described in claim 1, characterized in that, The operating fan system also includes: The third fan is provided with a third air inlet valve, a third outlet valve, and a third pressure relief valve. A third branch is provided between the third fan and the main pipeline, and the third branch is provided with a third valve for controlling the connection and disconnection between the third branch and the main pipeline; Step S2 also includes reducing the frequency of the third fan to the minimum frequency at which the third fan is allowed to operate, and maintaining the pressure in the main pipeline within a first set range; Step S7 also includes adjusting the frequencies of the first and third fans until the pressure of the main pipeline is within a third set range.

10. The wind turbine switching method as described in claim 9, characterized in that, Both the first setting range and the third setting range are 78 kPa to 89 kPa.

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