Functional section type noise reduction and ventilation system for electric power facilities and control method

Abstract

The invention discloses a functional section type noise reduction and ventilation system for electric power facilities and a control method, and belongs to the technical field of noise reduction and ventilation of the electric power facilities. The system comprises a forced exhaust ventilation section, a sound absorption and noise reduction section and an orientation adjusting section; wherein the forced exhaust ventilation section is connected with a ventilation opening of the main transformer chamber; the forced exhaust ventilation section comprises a turbine fan, an execution motor and a forced exhaust ventilation baffle, the turbine fan is arranged at a ventilation opening of the main transformer chamber, the execution motor is arranged on the inner side of the forced exhaust ventilation baffle, and the execution motor can control the forced exhaust ventilation baffle to be bounced off; a local square-hole-shaped silicon rubber micro-perforated sound absorption plate is fixed in the sound absorption and noise reduction section; the orientation adjusting section comprises an extension section, an orientation adjusting structure and an air outlet and is used for adapting to the height of the main transformer chamber and adjusting the orientation of the air outlet of the noise reduction ventilation system. According to the invention, different functional sections are arranged, so that the problems of noise control of the turbine fan and the main transformer and rapid ventilation and smoke discharge during the high-temperature and large-load period of the transformer substation in summer are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of noise reduction and ventilation for electric power facilities, and in particular, relates to a functional section type noise reduction and ventilation system and a control method for electric power facilities. Background Art

[0002] At present, power facilities generally have problems such as loud noise and weak ventilation. Take indoor substations as an example. Indoor substations are widely used in today's urban power systems. However, due to the small internal space and closed environment, the ventilation and heat dissipation effect is poor, resulting in the inability to effectively dissipate the Joule heat generated by the main transformer running inside. Especially in the high temperature of summer, the residents' electricity load is high, and the transformer heats up more seriously, resulting in problems such as increased transformer oil temperature, accelerated aging of insulation materials and shortened transformer life, and even threatening the safe operation of the power grid. At present, the above problems are generally solved by setting ventilation windows with turbine fans, but because of the high speed of the fan and the noise pollution generated by the transformer during operation, the noise at the boundary of the power facility exceeds the standard, affecting the daily life of nearby residents, and when the power equipment inside the main transformer room encounters a fire, the existing air duct cannot respond to the corresponding situation in time.

[0003] Prior art document 1 (CN205846547U) discloses a 110kV fully indoor substation main transformer room noise reduction and intelligent ventilation system, wherein the fan room is arranged on the top of the main transformer room, and is provided with a fan, a linkage air valve and a ventilation duct; an underground ventilation shaft is arranged at the entrance of the main door to form a ventilation system; a temperature detector and a temperature control box constitute a main transformer room temperature control system; an impedance muffler, a static pressure box, a double-layer sound-absorbing wall panel, a pressure relief wall, and a sound-absorbing and anti-drifting rain shutter constitute a noise reduction system, but the prior art (1) only realizes the temperature control. (1) The detection of indoor smoke and oxygen content cannot be effectively detected when fire hazards or open flames occur in the indoor equipment of the main transformer, and it is impossible to achieve linkage fire extinguishing with the fire extinguishing device; (2) The ventilation path involved in the technology of this patent is fixed in length, and it is impossible to shorten the ventilation path to improve ventilation efficiency under special conditions such as abnormally high temperature or smoke; (3) The noise reduction system composed of impedance silencers, static pressure boxes and other devices in this patent technology does not combine the sound pattern characteristics of the main transformer body, main transformer fan, and turbine fan to carry out targeted noise reduction effect improvement design.

[0004] Prior art document 2 (CN207728052U) discloses a ventilation and silencing channel for an indoor substation, which is provided with indoor vents and outdoor vents, and a noise reduction system is provided in the channel. However, the essence of this prior art is the application of active noise control technology (Active Noise Control, ANC) in the air duct. According to the principle of ANC technology, this technology can only achieve noise control at the error sensor position, and because the secondary sound source itself provides additional sound wave energy injection, the noise level may increase outside the vent outside the duct due to the superposition of sound waves, and then the noise control in a wider area outside the vent outside the duct cannot be achieved.

[0005] Therefore, there is an urgent need for a device that can simultaneously solve the problems of cooling, ventilation and noise reduction, and achieve efficient forced exhaust ventilation and fire extinguishing under fire hazards or fire conditions. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the present invention provides a functional section type noise reduction ventilation system and a control method for power facilities that can simultaneously solve the problems of cooling, ventilation and noise reduction.

[0007] The present invention adopts the following technical solution.

[0008] A first aspect of the present invention provides a functional section type noise reduction ventilation system for electric power facilities, comprising: a strong exhaust ventilation section, a sound absorption and noise reduction section and a direction adjustment section; the strong exhaust ventilation section, the sound absorption and noise reduction section and the direction adjustment section are connected in sequence from bottom to top through sound insulation sealing rubber, wherein the strong exhaust ventilation section is connected to the vent of the main transformer room, and each section is fixed to the outer wall of the main transformer room through a fastening support structure;

[0009] The forced exhaust ventilation section includes: a turbine fan, an executive motor and a forced exhaust ventilation damper. The turbine fan is arranged at the vent of the main transformer room, and the executive motor is arranged on the inner side of the forced exhaust ventilation damper. The executive motor can control the forced exhaust ventilation damper to pop open for forced ventilation and smoke exhaust.

[0010] A partially square-hole-shaped silicone rubber micro-perforated sound-absorbing plate is fixed inside the sound-absorbing and noise-reducing section to absorb noise;

[0011] The direction adjustment section includes an extension section, a direction adjustment structure and an air outlet, which are used to adapt to the height of the main transformer room and adjust the direction of the air outlet of the noise reduction ventilation system.

[0012] Preferably, the forced exhaust ventilation section also includes: an oxygen content sensor, a temperature sensor, a smoke sensor and a foam fire extinguishing device. The oxygen content sensor, the temperature sensor, the smoke sensor and the foam fire extinguishing device are linked to detect and extinguish the fire in the main transformer room.

[0013] Preferably, the forced exhaust ventilation section also includes a pull ring, which is arranged on the outside of the forced exhaust ventilation baffle, and is used for the operation and maintenance personnel to manually open the baffle with the help of an insulating operating rod to ensure ventilation and smoke exhaust when the execution motor or its control system is damaged.

[0014] Preferably, the partially square-hole silicone rubber micro-perforated sound-absorbing plate includes two types, A and B. Type A is a partially square-hole silicone rubber micro-perforated sound-absorbing plate with square holes arranged at right angles to the sound-absorbing plate, and type B is a partially square-hole silicone rubber micro-perforated sound-absorbing plate with square holes arranged in the middle of one side of the sound-absorbing plate.

[0015] Preferably, the two types A and B of partially square-hole silicone rubber micro-perforated sound-absorbing panels have unequal distances between the panels, and are installed in a staggered and rotating manner in the sound absorption and noise reduction section to form a spiral square-hole channel for ventilation.

[0016] Preferably, the length of the extension section can be adjusted accordingly according to the height of the main transformer room to adapt to the height of the main transformer room.

[0017] Preferably, the direction adjustment structure is a retractable structure made of sound-insulating sealing rubber material, which is used to adjust the direction of the air outlet of the noise reduction air duct system.

[0018] Preferably, the air outlet is designed with an oblique incision to prevent rainwater from entering the noise reduction air duct.

[0019] Preferably, the outer wall of each section of the noise reduction ventilation system is made of corrosion-resistant sound-insulating material, and each section is fixed to the outer wall of the main structure of the power facility via expansion bolts.

[0020] A second aspect of the present invention provides a control method for a functional section type noise reduction ventilation system for an electric power facility, based on the functional section type noise reduction ventilation system for an electric power facility, comprising the following steps:

[0021] Periodic detection is performed by a temperature sensor set in the noise reduction ventilation system. When the detection result of the temperature sensor does not exceed the set threshold, the temperature sensor continues to perform periodic detection; when the detection result of the temperature sensor exceeds the set threshold, the smoke sensor detection is started;

[0022] When the detection result of the smoke sensor does not exceed the set threshold, the fan runs at low or medium speed;

[0023] When the smoke sensor detection result exceeds the set threshold, the fan runs at high speed, the foam fire extinguishing device is started, the forced exhaust ventilation damper pops open, and the oxygen content sensor starts detection;

[0024] When the detection result of the oxygen content sensor meets the requirements for personnel entry, the temperature sensor continues to perform periodic detection;

[0025] When the detection result of the oxygen content sensor does not meet the requirements for personnel entry, the fan continues to run at a high speed until the detection result of the oxygen content sensor meets the requirements for personnel entry.

[0026] Compared with the prior art, the beneficial effects of the present invention include at least:

[0027] This application solves the problem of controlling the noise of the turbine fan and the main transformer and the rapid ventilation and smoke exhaust when the turbine fan is used to control the temperature of the main transformer room during the high temperature and high load period of the substation in summer by setting different functional sections;

[0028] When the temperature in the main transformer room is too high but there is no fire, the present application realizes low noise and efficient ventilation and heat dissipation in the main transformer room, wherein the sound absorption and noise reduction section effectively realizes efficient absorption of the frequency components with larger amplitudes in the transformer body noise, transformer accessory fan noise and turbine fan noise by setting the porosity of the silicone rubber micro-perforated sound absorption board, the thickness of the micro-perforated sound absorption board, the position and distance of the sound absorption board, and the direction of the air outlet can be arbitrarily adjusted through the direction adjustment section to avoid the factory boundary on the side with a higher risk of exceeding the noise standard, thereby reducing the risk of exceeding the noise level at the factory boundary;

[0029] When there is a fire hazard or fire in the main transformer room, the forced exhaust ventilation section can realize automatic control detection, fire extinguishing linkage, and open the forced exhaust ventilation baffle, shorten the ventilation path, and perform forced exhaust ventilation through the combination of sensors. At the same time, it can be linked to the foam spray fire extinguishing device to achieve spray fire extinguishing. After the fire hazard is eliminated, the smoke content and oxygen content in the main transformer room can be continuously detected to provide life-saving data support for the entry of firefighting and operation and maintenance personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall structure of the noise reduction ventilation system;

[0031] Figure 2 It is a structural diagram of the forced exhaust ventilation section (including sensors and spraying devices);

[0032] Figure 3 The side view (left) and top view (right) of the spiral square hole channel in the sound absorption and noise reduction section;

[0033] Figure 4 The top view and side view of the A-type partially square-hole silicone rubber micro-perforated sound-absorbing panel in the sound absorption and noise reduction section (left) and the top view and side view of the B-type partially square-hole silicone rubber micro-perforated sound-absorbing panel (right);

[0034] Figure 5 It is a schematic diagram of the structure of the orientation adjustment section;

[0035] Figure 6 It is a top view of the orientation adjustment effect;

[0036] Figure 7 It is the control logic flow chart of the forced exhaust ventilation section;

[0037] In the figure: 1. Main transformer room; 2. Forced exhaust ventilation section; 21. Oxygen content sensor; 22. Temperature sensor; 23. Smoke sensor; 24. Foam fire extinguishing sprinkler device; 25. Turbine fan; 26. Executive motor; 27. Forced exhaust ventilation baffle; 28. Pull ring; 3. Sound absorption and noise reduction section; 31. Partial square hole silicone rubber micro-perforated sound absorption board; 4. Direction adjustment section; 41. Sound insulation rubber; 42. Extension section; 43. Direction adjustment structure; 44. Air outlet; 5. Fastening support structure. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0039] like Figure 1 As shown, embodiment 1 of the present invention provides a functional section type noise reduction ventilation system for electric power facilities, including a forced exhaust ventilation section 2, a sound absorption and noise reduction section 3 and a direction adjustment section 4.

[0040] The strong exhaust ventilation section 2, the sound absorption and noise reduction section 3 and the orientation adjustment section 4 are connected in sequence from bottom to top through the sound insulation rubber 41, wherein the strong exhaust ventilation section 2 is connected to the air vent of the main transformer room 1, and each section is fixed to the outer wall of the main transformer room 1 through the fastening support structure 5.

[0041] like Figure 2 As shown, an oxygen content sensor 21, a temperature sensor 22, a smoke sensor 23 and a foam fire extinguishing spray device 24 are provided in the forced exhaust ventilation section 2. The oxygen content sensor 21, the temperature sensor 22, the smoke sensor 23 and the foam fire extinguishing spray device 24 are linked to detect and extinguish fires in the substation.

[0042] The forced exhaust ventilation section 2 also includes a turbine fan 25, an executive motor 26, a forced exhaust ventilation damper 27 and a pull ring 28. The turbine fan 25 is arranged at the ventilation port of the main transformer room 1, and the executive motor 26 is arranged on the inner side of the forced exhaust ventilation damper 27. When a fire occurs, according to the control logic, the executive motor 26 can control the forced exhaust ventilation damper 27 to pop open, so as to ensure the forced ventilation and smoke exhaust effect;

[0043] In a preferred but non-limiting embodiment of the present invention, the pull ring 28 is arranged on the outside of the forced exhaust ventilation baffle 27, so that when the execution motor 26 or its control system is damaged, the operation and maintenance personnel can manually pull open the baffle with the help of an insulating operating rod to ensure the ventilation and smoke exhaust effect.

[0044] like Figure 3 , 4 As shown, a partially square-hole-shaped silicone rubber micro-perforated sound-absorbing plate 31 is fixed inside the sound-absorbing and noise-reducing section 3, and the micro-perforated structure is used to ensure the sound absorption effect. The partially square-hole-shaped silicone rubber micro-perforated sound-absorbing plate 31 includes two types, A and B. Type A is a square hole set at a right angle of the sound-absorbing plate, and type B is a square hole set in the middle of one side of the sound-absorbing plate.

[0045] In a preferred but non-restrictive embodiment of the present invention, there are 8 plates in total of type A and type B, whose micro-perforated structures have different porosities and unequal distances between plates. They are staggered and rotated in the sound absorption and noise reduction section 3 to form a spiral square hole channel for ventilation, thereby forming a noise reduction cavity, and at the same time, the peak frequency of the acoustic transmission loss is made to coincide with or be close to the frequency band with larger amplitude in the spectrum of the transformer body noise, the transformer accessory fan noise, and the turbine fan noise, so as to achieve preferential and effective absorption of the frequency components with larger amplitudes in the three noises, that is, first absorb the high-decibel frequency band with larger amplitude in the sound spectrum, grasp the main contradiction, and eliminate the main sound source, while the remaining frequency components with small amplitudes have been greatly reduced by the natural attenuation of the air and the adjustment of the direction of the air duct outlet (avoiding the factory boundary with a higher risk of exceeding the standard), and then meet the requirements of the factory boundary noise standard limit (GB 12348).

[0046] It is worth noting that the applicant of the present invention has noticed that the unequal-distance design is related to the absorption of sounds of different frequencies. Therefore, a series of special acoustic designs performed here are all aimed at making the peak frequency of acoustic transmission loss coincide with or be close to the frequency band with larger amplitude in the spectrum of transformer body noise, transformer accessory fan noise, and turbine fan noise. In particular, regarding the distance between plates, if an equidistant design is used, it is equivalent to losing one adjustment parameter, and the dynamic adjustment range will become smaller. The design of 8 plates is to construct a more suitable silencing cavity structure, and secondly, when the total thickness is constant, the thickness of a single micro-perforated plate can be reduced, thereby reducing the load-bearing capacity of the single plate's own structure to improve durability.

[0047] like Figure 5As shown, the direction adjustment section 4 includes an extension section 42, a direction adjustment structure 43 and an air outlet 44. The extension section 42 can adjust its length to adapt to the height of the main transformer room 1 according to the height of the main transformer room 1. The direction adjustment structure 43 is a retractable structure made of sound insulation sealing rubber, which is convenient for adjusting the direction of the air outlet of the noise reduction air duct system to avoid the direction of the sensitive point outside the factory boundary on a specific side or the factory boundary on a side with a higher risk of exceeding the standard, so as to reduce the risk of exceeding the factory boundary noise level. The direction adjustment effect is as follows: Figure 6 shown.

[0048] The air outlet 44 is designed as an oblique cut, with the upper side longer than the lower side, which can prevent rainwater from entering the noise reduction air duct.

[0049] In a preferred but non-limiting embodiment of the present invention, the outer wall of each section of the noise reduction ventilation system is made of rust-resistant sound-insulating materials such as hot-dip galvanized steel plates or stainless steel plates, and each section is fixed to the outer wall of the main structure of the power facility by expansion bolts.

[0050] The above is a noise reduction ventilation system based on a substation as an example, which can also be applied to power facilities such as generators and transformers. Figure 7 As shown, embodiment 2 of the present invention discloses a control method for a functional section type noise reduction ventilation system for a power facility, comprising the following steps:

[0051] Periodic detection is performed by a temperature sensor set in the noise reduction ventilation system. When the detection result of the temperature sensor does not exceed the set threshold, the temperature sensor continues to perform periodic detection; when the detection result of the temperature sensor exceeds the set threshold, the smoke sensor detection is started;

[0052] When the detection result of the smoke sensor does not exceed the set threshold, the fan runs at low or medium speed;

[0053] When the detection result of the smoke sensor exceeds the set threshold, the fan runs at high speed, the foam fire extinguishing device is started, the forced exhaust ventilation damper pops open, and the oxygen content sensor starts detection;

[0054] When the detection result of the oxygen content sensor meets the requirements for personnel entry, the temperature sensor continues to perform periodic detection;

[0055] When the detection result of the oxygen content sensor does not meet the requirements for personnel entry, the fan continues to run at a high speed until the detection result of the oxygen content sensor meets the requirements for personnel entry.

[0056] Compared with the prior art, the beneficial effects of the present invention include at least:

[0057] This application solves the problem of controlling the noise of the turbine fan and the main transformer and the rapid ventilation and smoke exhaust when the turbine fan is used to control the temperature of the main transformer room during the high temperature and high load period of the substation in summer by setting different functional sections;

[0058] When the temperature in the main transformer room is too high but there is no fire, the present application realizes low noise and efficient ventilation and heat dissipation in the main transformer room, wherein the sound absorption and noise reduction section effectively realizes efficient absorption of the frequency components with larger amplitudes in the transformer body noise, transformer accessory fan noise and turbine fan noise by setting the porosity of the silicone rubber micro-perforated sound absorption board, the thickness of the micro-perforated sound absorption board, the position and distance of the sound absorption board, and the direction of the air outlet can be arbitrarily adjusted through the direction adjustment section to avoid the factory boundary on the side with a higher risk of exceeding the noise standard, thereby reducing the risk of exceeding the noise level at the factory boundary;

[0059] When there is a fire hazard or fire in the main transformer room, the forced exhaust ventilation section can realize automatic control detection, fire extinguishing linkage, and open the forced exhaust ventilation baffle, shorten the ventilation path, and perform forced exhaust ventilation through the combination of sensors. At the same time, it can be linked to the foam spray fire extinguishing device to achieve spray fire extinguishing. After the fire hazard is eliminated, the smoke content and oxygen content in the main transformer room can be continuously detected to provide life-saving data support for the entry of firefighting and operation and maintenance personnel.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A functional section type noise reduction ventilation system for power facilities, characterized in that: include: A strong exhaust ventilation section (2), a sound absorption and noise reduction section (3) and a direction adjustment section (4); the strong exhaust ventilation section (2), the sound absorption and noise reduction section (3) and the direction adjustment section (4) are connected in sequence from bottom to top through sound insulation sealing rubber (41), wherein the strong exhaust ventilation section (2) is connected to the vent of the main transformer chamber (1), and each section is fixed to the outer wall of the main transformer chamber (1) through a fastening support structure (5); The forced exhaust ventilation section (2) comprises: a turbine fan (25), an executive motor (26) and a forced exhaust ventilation damper (27), wherein the turbine fan (25) is arranged at the ventilation opening of the main transformer room (1), and the executive motor (26) is arranged on the inner side of the forced exhaust ventilation damper (27), and the executive motor (26) can control the forced exhaust ventilation damper (27) to pop open, so as to achieve forced ventilation and smoke exhaust; A partially square-hole-shaped silicone rubber micro-perforated sound-absorbing plate (31) is fixed inside the sound-absorbing and noise-reducing section (3) to absorb noise; The orientation adjustment section (4) comprises an extension section (42), an orientation adjustment structure (43) and an air outlet (44), and is used to adapt to the height of the main transformer room (1) and adjust the orientation of the air outlet of the noise reduction ventilation system.

2. The functional section type noise reduction ventilation system for electric power facilities according to claim 1 is characterized in that: The forced exhaust ventilation section (2) further comprises: an oxygen content sensor (21), a temperature sensor (22), a smoke sensor (23) and a foam fire extinguishing spray device (24); the oxygen content sensor (21), the temperature sensor (22), the smoke sensor (23) and the foam fire extinguishing spray device (24) are linked to detect and extinguish fire in the main transformer room (1).

3. The functional section type noise reduction ventilation system for electric power facilities according to claim 1, characterized in that: The forced exhaust ventilation section (2) further comprises a pull ring (28), which is arranged on the outer side of the forced exhaust ventilation baffle (27) and is used for the operation and maintenance personnel to manually open the baffle with the aid of an insulating operating rod to ensure ventilation and smoke exhaust when the execution motor (26) or its control system is damaged.

4. The functional section type noise reduction ventilation system for electric power facilities according to claim 1, characterized in that: The partially square hole-shaped silicone rubber micro-perforated sound absorbing plate (31) includes two types, A and B. Type A is a partially square hole-shaped silicone rubber micro-perforated sound absorbing plate with square holes arranged at right angles to the sound absorbing plate, and type B is a partially square hole-shaped silicone rubber micro-perforated sound absorbing plate with square holes arranged in the middle of one side of the sound absorbing plate.

5. The functional section type noise reduction ventilation system for electric power facilities according to claim 4 is characterized in that: The two types A and B of partially square-hole silicone rubber micro-perforated sound-absorbing panels have unequal distances between the panels and are installed in a staggered rotation in the sound-absorbing and noise-reducing section (3) to form a spiral square-hole channel for ventilation.

6. The functional section type noise reduction ventilation system for electric power facilities according to claim 1, characterized in that: The length of the extension section (42) can be adjusted accordingly according to the height of the main transformer room (1) to adapt to the height of the main transformer room.

7. The functional section type noise reduction ventilation system for electric power facilities according to claim 1, characterized in that: The direction adjustment structure (43) is a retractable structure made of sound-insulating sealing rubber material, and is used to adjust the direction of the air outlet of the noise reduction air duct system.

8. The functional section type noise reduction ventilation system for electric power facilities according to claim 1, characterized in that: The air outlet (44) is designed as an oblique cutout to prevent rainwater from entering the noise reduction air duct.

9. The functional section type noise reduction ventilation system for electric power facilities according to claim 1, characterized in that: The outer wall of each section of the noise reduction ventilation system is made of corrosion-resistant sound insulation material, and each section is fixed to the outer wall of the main structure of the power facility via expansion bolts.

10. A control method for a functional sectional noise reduction ventilation system for electric power facilities, based on the functional sectional noise reduction ventilation system for electric power facilities according to any one of claims 1 to 9, characterized in that: The following steps are involved: Periodic detection is performed by a temperature sensor set in the noise reduction ventilation system. When the detection result of the temperature sensor does not exceed the set threshold, the temperature sensor continues to perform periodic detection; when the detection result of the temperature sensor exceeds the set threshold, the smoke sensor detection is started; When the detection result of the smoke sensor does not exceed the set threshold, the fan runs at low or medium speed; When the smoke sensor detection result exceeds the set threshold, the fan runs at high speed, the foam fire extinguishing device is started, the forced exhaust ventilation damper pops open, and the oxygen content sensor starts detection; When the detection result of the oxygen content sensor meets the requirements for personnel entry, the temperature sensor continues to perform periodic detection; When the detection result of the oxygen content sensor does not meet the requirements for personnel entry, the fan continues to run at a high speed until the detection result of the oxygen content sensor meets the requirements for personnel entry.

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