Dynamic frost layer regulation-based test method and device for temperature and humidity of gas chamber of ring main unit

Abstract

The present application relates to the technical field of power distribution equipment, and particularly relates to a ring main unit gas chamber temperature and humidity test method and device based on dynamic frost layer regulation. The method tests the ring main unit gas chamber at multiple temperature points in a high-low temperature test chamber, and dynamically regulates the thickness of the frost layer formed by a mirror surface humidity detection unit during dew point measurement to achieve rapid and accurate adjustment of the humidity in the gas chamber, thereby avoiding the traditional inefficient gas replacement process, allowing the entire humidity adjustment process to be completed within 10 minutes, greatly shortening the multi-working-condition temperature and humidity test cycle. The control terminal automatically coordinates the high-low temperature test chamber, electromagnetic valve, pump set and detection unit to achieve full closed-loop operation from temperature regulation, humidity measurement to frost layer regulation, supports 24-hour continuous operation, avoids operation errors and data fluctuations caused by manual intervention, and significantly improves the reliability and repeatability of test data.

Description

Technical Field

[0001] This invention relates to the field of power distribution equipment technology, and in particular to a method and apparatus for testing the ambient temperature and humidity of a ring main unit based on dynamic frost layer control. Background Technology

[0002] Ring main units (RNBs) are critical equipment in medium-voltage power distribution networks, and their insulation performance directly affects the safety and reliability of the power grid operation. In recent years, with increasingly stringent environmental protection requirements, RNBs using dry air instead of sulfur hexafluoride (SF6) as the insulating medium have been gradually adopted. In these devices, the humidity of the insulating gas inside the gas chamber is one of the key indicators monitored during operation and maintenance. Excessive humidity may lead to decreased insulation performance and even partial discharge or flashover faults; while excessively low humidity may affect the aging characteristics of the materials. Therefore, accurately assessing the humidity status of the gas chamber is of great significance for ensuring the long-term stable operation of the RNB.

[0003] Due to factors such as the hydrophobicity of insulating materials and the hydrophilicity of desiccants, the humidity value in the air chamber is positively correlated with temperature. Therefore, humidity detection values ​​generally need to be converted to a uniform 20℃ value for quantitative analysis. Currently, the humidity detection results of dry-air ring main units under different temperature conditions are mainly converted using the temperature conversion table for SF6 gas humidity detection results in standard DL / T 506-2018. However, because the insulating medium, gas pressure, insulating materials, and desiccants of dry-air ring main units differ significantly from those of SF6 gas electrical equipment, this temperature conversion table is no longer applicable. Therefore, a new temperature conversion table needs to be developed specifically for dry-air ring main units to facilitate the uniform conversion of humidity detection values ​​at different temperatures to humidity values ​​at 20℃ for analysis of whether humidity exceeds the standard.

[0004] The development of the temperature conversion table requires changing the chamber temperature under initial humidity conditions (humidity value at a stable temperature of 20℃) and measuring the humidity value when the temperature stabilizes. Since this experiment needs to be conducted under multiple initial humidity conditions, and humidity values ​​need to be measured at multiple temperature points under each initial humidity condition, it is difficult to achieve 24-hour uninterrupted operation if done manually throughout. Furthermore, variations in operator skill levels can lead to fluctuations in experimental error, affecting data reliability. Additionally, to achieve multiple initial humidity conditions, traditional methods require first evacuating the original gas from the chamber using a vacuum pump, and then re-injecting the target humidity gas using a low-flow humidity generator. Considering that the chamber volume of a ring main unit is typically several hundred liters, while the output flow rate of commercial humidity generators is limited (generally only a few liters / minute), a single gas replacement can take several hours, severely slowing down the overall experimental progress.

[0005] In addition, although cold mirror dew point meters have been widely used for high-precision humidity measurement, dew or frost will form on the cooled mirror during the measurement process. However, this physical phenomenon has long been regarded as a detection byproduct and has not been effectively utilized for active humidity control.

[0006] Therefore, this case is brought. Summary of the Invention

[0007] The purpose of this invention is to provide a method and apparatus for testing the room temperature and humidity of a ring main unit based on dynamic frost layer control. This method can perform multi-temperature and multi-humidity point tests and utilize the frost layer formed during dew point measurement by the mirror humidity detection unit. By controlling the thickness of the frost layer, the humidity of the gas inside the ring main unit can be quickly adjusted to support the scientific formulation of a dedicated temperature-humidity conversion table and ensure the safe and reliable operation of the ring main unit equipment.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] A method for testing the room temperature and humidity of a ring main unit based on dynamic frost layer control includes the following steps:

[0010] S1. Place the ring main unit's air chamber in the high and low temperature test chamber, set the initial temperature of the high and low temperature test chamber, and fill the air chamber with the set humidity after the dry air in the gas cylinder passes through the humidity generating unit until the pressure in the air chamber stabilizes at the rated pressure and then stop filling.

[0011] S2. After standing, the humidity in the air chamber is measured by the mirror humidity detection unit and the humidity is adjusted to the initial humidity target value;

[0012] S3. Control the high and low temperature test chamber to adjust to multiple temperature set points according to the preset program, and keep it at each temperature set point until the temperature of the air chamber stabilizes, and then detect the humidity of the dry air in the air chamber.

[0013] S4. By using the frost layer formed on the mirror surface during the dew point detection process by the mirror humidity detection unit, the humidity of the gas in the air chamber is adjusted by dynamically controlling the thickness of the frost layer;

[0014] The temperature of the high and low temperature test chamber is restored to the initial temperature.

[0015] S5. After settling, measure the humidity in the air chamber and adjust the humidity to the next initial target humidity value;

[0016] S6. Repeat steps S3 to S5 until all initial humidity target values ​​are covered.

[0017] Furthermore, in step S1, the air chamber of the ring network cabinet contains an adsorbent, and the humidity value set by the humidity generating unit needs to take into account the amount of water adsorbed by the adsorbent. The humidity generated by the humidity generating unit is set to the sum of the maximum test humidity limit and the amount of water adsorbed by the adsorbent.

[0018] Furthermore, the humidity adjustment in step S2 involves using a vacuum pump and a humidity generating unit to replace part of the gas in the air chamber to achieve humidity regulation, including the following processes:

[0019] S21a. Measure the humidity value inside the air chamber using the mirror humidity detection unit;

[0020] If the current humidity value is not equal to the maximum test humidity limit, proceed to step S22;

[0021] If the current humidity value is equal to the maximum test humidity limit, proceed to step S24a;

[0022] S22a. Extract some gas from the air chamber, reduce the pressure in the air chamber, and adjust the humidity generated by the humidity generating unit at the same time;

[0023] The dry air in the gas cylinder passes through the humidity generating unit and then enters the gas chamber until the pressure in the gas chamber reaches the rated pressure.

[0024] S23a. After standing, measure the humidity in the air chamber. If the absolute value of the difference between the current measurement result and the maximum test humidity limit is not less than the first permissible error, repeat step S22a; otherwise, proceed to step S24a.

[0025] S24a. Record the current humidity value in the air chamber as the initial humidity target value.

[0026] Furthermore, in step S3, the high and low temperature test chamber is controlled to adjust to multiple temperature set points sequentially from low to high according to a preset program;

[0027] The humidity adjustment in step S4 includes the following processes:

[0028] S41. After the measurement stabilizes at the last temperature set point, start adjusting the thickness of the frost layer on the mirror in the mirror humidity detection unit. The thickness of the frost layer is achieved by controlling the mirror cooling temperature and monitoring the energy of the reflected light from the mirror.

[0029] S42. Pass the dry air from the gas cylinder through the mirror humidity detection unit into the buffer tank until there is no more frost on the mirror surface.

[0030] Furthermore, in step S1, the air chamber of the ring network cabinet contains an adsorbent, and the humidity value set by the humidity generating unit needs to take into account the amount of water adsorbed by the adsorbent. The humidity generated by the humidity generating unit is set to the sum of the minimum test humidity limit and the amount of water adsorbed by the adsorbent.

[0031] Furthermore, the humidity adjustment in step S2 involves using a vacuum pump and a humidity generating unit to replace part of the gas in the air chamber to achieve humidity regulation, including the following processes:

[0032] S21b. Measure the humidity value inside the air chamber using the mirror humidity detection unit;

[0033] If the current humidity value is not equal to the minimum test humidity limit, proceed to step S22b;

[0034] If the current humidity value is equal to the minimum test humidity limit, proceed to step S24b;

[0035] S22b. Extract some gas from the air chamber to reduce the pressure in the air chamber and adjust the humidity generated by the humidity generating unit;

[0036] The dry air in the gas cylinder passes through the humidity generating unit and then enters the gas chamber until the pressure in the gas chamber reaches the rated pressure.

[0037] S23b. After standing, measure the humidity in the air chamber. If the absolute value of the difference between the measurement result and the minimum test humidity limit is not less than the first permissible error, repeat step S22b; otherwise, proceed to step S24b.

[0038] S24b. Record the current humidity value in the air chamber as the initial humidity target value.

[0039] Furthermore, the humidity adjustment in step S4 includes the following processes:

[0040] S41. Start the humidity generating unit and the mirror humidity detection unit. Dry air in the gas cylinder flows through the humidity generating unit and the mirror humidity detection unit in sequence and then enters the buffer tank, causing the mirror surface of the mirror humidity detection unit to frost. The thickness of the frost layer is controlled by controlling the mirror cooling temperature and monitoring the mirror reflected light energy.

[0041] S42. The dry air in the ring main unit's air chamber is circulated back into the air chamber after passing through the mirror humidity detection unit until there is no more frost on the mirror surface.

[0042] Furthermore, step S5 includes the following processes:

[0043] S51. After standing, measure the humidity in the air chamber;

[0044] S52. If the absolute value of the difference between the current humidity and the humidity adjusted in step S4 is not less than the second allowable error, the frost layer formed on the mirror surface during the dew point detection process by the mirror humidity detection unit is used again to adjust the humidity of the gas in the air chamber by dynamically adjusting the thickness of the frost layer, and then the process returns to S51.

[0045] The second allowable error is greater than the first allowable error;

[0046] If the absolute value of the difference between the current humidity and the humidity adjusted in step S4 is less than the second allowable error and greater than or equal to the first allowable error, then the vacuum pump and humidity generating unit are used again to replace part of the gas in the air chamber to achieve humidity adjustment, and then the process returns to S51.

[0047] If the absolute value of the difference between the current humidity and the humidity adjusted in step S4 is less than the first allowable error, then the humidity is considered to meet the requirements, and the current humidity is used as the next initial humidity target value.

[0048] The ring main unit air temperature and humidity test device based on dynamic frost layer control for the above method includes:

[0049] High and low temperature test chambers are used to provide different temperature environments;

[0050] The ring network cabinet air chamber is placed inside the high and low temperature test chamber. The air chamber is used to fill dry air and contains an adsorbent.

[0051] The air chamber environment monitoring unit is used to monitor and display the air pressure and temperature inside the air chamber in real time.

[0052] A mirror-like humidity detection unit is used to measure the humidity inside the air chamber and to form a frost layer.

[0053] The humidity generating unit provides the set humidity to the dry air;

[0054] Buffer tanks are used to store treated, dry air;

[0055] A booster pump is used to provide the power for the flow of gas within a pipeline.

[0056] Vacuum pump, used to extract dry air from the air chamber of the ring main unit;

[0057] Several solenoid valves are used to control the opening and closing of pipelines;

[0058] Gas cylinders, used in conjunction with pressure reducing valves, are used to provide dry air;

[0059] The control terminal is used to receive various monitoring or detection feedback signals and issue control strategies.

[0060] Furthermore, the solenoid valves include solenoid valve one, solenoid valve two, solenoid valve three, solenoid valve four, solenoid valve five, solenoid valve six, solenoid valve seven and solenoid valve eight.

[0061] The solenoid valve 2, solenoid valve 3, mirror humidity detection unit, solenoid valve 7, booster pump and solenoid valve 8 are connected in series, and the output end of solenoid valve 8 is connected to the air inlet of the ring network cabinet air chamber, and the air outlet of the ring network cabinet air chamber is connected to the input end of solenoid valve 2.

[0062] The input end of the first solenoid valve is connected to the pipeline between the second solenoid valve and the air chamber of the ring main unit, and the output end of the first solenoid valve is connected to the input end of the vacuum pump.

[0063] The input end of the humidity generating unit is connected to the pipeline between solenoid valve two and solenoid valve three, and the output end of the humidity generating unit is connected to the pipeline between solenoid valve three and the mirror humidity detection unit through solenoid valve four.

[0064] The gas cylinder is connected to the input end of the solenoid valve and the humidity generating unit via a pressure reducing valve;

[0065] The input end of the buffer tank is connected to the pipeline between the solenoid valve seven and the mirror humidity detection unit via solenoid valve five, and the output end of the buffer tank is connected to the pipeline between the solenoid valve seven and the booster pump via solenoid valve six.

[0066] The advantages of this invention are:

[0067] 1. Significantly improved testing efficiency: Traditional methods rely on a low-flow humidity generator in conjunction with a vacuum pump for gas replacement, and a single humidity switch takes several hours; this solution innovatively utilizes the frost layer that forms naturally during the humidity detection process on the mirror surface, and achieves rapid humidification or dehumidification by dynamically adjusting its thickness. The entire humidity adjustment process can be completed within 10 minutes, greatly shortening the test cycle for multi-condition temperature and humidity.

[0068] 2. Fully intelligent and unmanned operation: The control terminal automatically coordinates the high and low temperature test chamber, solenoid valves, pump groups and detection units to realize a closed-loop operation from temperature regulation and humidity measurement to frost control. It supports continuous operation for 24 hours, avoids operation errors and data fluctuations caused by manual intervention, and significantly improves the reliability and repeatability of test data.

[0069] 3. High reusability of technology and low cost: The mirror humidity detection unit (also known as a cold mirror dew point meter), which was originally only used for detection, is cleverly "dual-purpose", so that it can simultaneously perform humidity sensing and active humidity regulation functions without the need for additional complex humidification / dehumidification equipment; the frost layer thickness is achieved by controlling the mirror cooling temperature and monitoring the mirror reflection light energy, realizing quantitative control of trace moisture, balancing accuracy and practicality. Attached Figure Description

[0070] Figure 1 This is a schematic diagram of the frame of the experimental apparatus in Example 1;

[0071] Figure 2 This is a schematic diagram of the dew point condensation dehumidification process in Example 1;

[0072] Figure 3 This is a schematic diagram of the dew point condensation humidification process in Example 2;

[0073] Label Explanation

[0074] 1. Gas cylinder; 2. High and low temperature test chamber; 3. Ring main unit gas chamber; 4. Adsorbent; 501. Pressure gauge; 502. Thermometer; 601. Solenoid valve one; 602. Solenoid valve two; 603. Solenoid valve three; 604. Solenoid valve four; 605. Solenoid valve five; 606. Solenoid valve six; 607. Solenoid valve seven; 608. Solenoid valve eight; 7. Mirror humidity detection unit; 8. Humidity generation unit; 9. Vacuum pump; 10. Booster pump; 11. Buffer tank; 12. Pressure reducing valve. Detailed Implementation

[0075] The present invention will be further described in detail below with reference to embodiments. It should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., used in this document indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0076] Example 1: This example proposes a method for testing the temperature and humidity of a ring main unit's gas chamber based on dynamic frost layer control. A fully automated intelligent operating platform automatically adjusts the temperature of the gas chamber 3 within the ring main unit. After the gas temperature stabilizes, the humidity value at that temperature is automatically detected. The frost layer formed on the mirror surface of the mirror humidity detection unit 7 is used to adjust the gas humidity in the chamber. The entire humidity adjustment process can be completed within 10 minutes, allowing for the next initial humidity test, significantly shortening the multi-condition temperature and humidity test cycle. This test method can also be used to create temperature conversion tables for humidity monitoring results of other insulating gases.

[0077] The mirror humidity detection unit 7 in this embodiment, also known as a cold mirror dew point meter or frost point detection unit, is a high-precision humidity sensing device based on the cold mirror method. Its core is a high-gloss mirror that can be actively cooled. By monitoring the change in reflected light energy caused by water vapor condensing into dew or frost on the mirror surface, combined with mirror temperature measurement, the dew point or frost point of the gas is accurately determined, thereby calculating the humidity value. In this embodiment, this unit is not only used for humidity detection but also for dynamically controlling the thickness of the frost layer formed on the mirror surface. By controlling the cooling temperature and providing real-time feedback of reflected light energy, combined with a pre-calibrated mapping relationship between light energy and frost thickness, quantitative capture or release of moisture in the air chamber is achieved, thereby completing rapid and accurate humidity regulation and significantly improving the efficiency of temperature and humidity testing in the ring main unit.

[0078] like Figure 1 As shown, the operating platform mainly consists of a high and low temperature test chamber 2, a ring network cabinet air chamber 3, a thermometer 502, a pressure gauge 501, a humidity generating unit 8, a mirror humidity detection unit 7, a buffer tank 11, a gas cylinder 1, a booster pump 10, a vacuum pump 9, a pressure reducing valve 12, several solenoid valves, and a control terminal (not shown in the figure). The system includes a high and low temperature test chamber 2 to provide different temperature environments; a ring main unit air chamber 3 located inside the high and low temperature test chamber 2, which is filled with dry air and contains an adsorbent 4; a thermometer 502 and a pressure gauge 501 to monitor and display the air pressure and temperature inside the air chamber in real time; a mirror humidity detection unit 7 to measure the humidity inside the air chamber and form a frost layer; a humidity generating unit 8 to provide the set humidity for the dry air; a buffer tank 11 to store the treated dry air; a booster pump 10 to provide the power for gas flow in the pipeline; a vacuum pump 9 to extract the dry air from the ring main unit air chamber 3; several solenoid valves to control the opening and closing of the pipeline; a gas cylinder 1 and a pressure reducing valve 12 to provide dry air; and a control terminal to receive various monitoring or detection feedback signals and issue control strategies to achieve fully automatic testing.

[0079] Specifically, the solenoid valves include solenoid valve 601, solenoid valve 602, solenoid valve 603, solenoid valve 604, solenoid valve 605, solenoid valve 606, solenoid valve 607, and solenoid valve 608. Solenoid valve 602, solenoid valve 603, the mirror humidity detection unit 7, solenoid valve 607, the booster pump 10, and solenoid valve 608 are connected in series. The output of solenoid valve 608 is connected to the air inlet of the ring main unit's air chamber 3, and the air outlet of the ring main unit's air chamber 3 is connected to the input of solenoid valve 602. The input of solenoid valve 601 is connected to the pipeline between solenoid valve 602 and the ring main unit's air chamber 3, and the output of solenoid valve 601 is connected to the input of the vacuum pump 9. The input end of the humidity generating unit 8 is connected to the pipeline between solenoid valve 2 (602) and solenoid valve 3 (603). The output end of the humidity generating unit 8 is connected to the pipeline between solenoid valve 3 (603) and mirror humidity detection unit 7 via solenoid valve 4 (604). The gas cylinder 1 is connected to the input end of the humidity generating unit 8 via pressure reducing valve 12. The input end of the buffer tank 11 is connected to the pipeline between solenoid valve 7 (607) and mirror humidity detection unit 7 via solenoid valve 5 (605). The output end of the buffer tank 11 is connected to the pipeline between solenoid valve 7 (607) and booster pump 10 via solenoid valve 6 (606).

[0080] The air chamber contains adsorbent 4, which is commonly used in dry air ring main units. Real ring main units are usually equipped with similar adsorbent materials to maintain a dry internal environment. When conducting temperature and humidity tests on the operating platform of this embodiment, placing adsorbent 4 can better simulate the situation of the ring main unit in actual power grid operation.

[0081] The following describes the application process of the platform using specific experimental methods. The experimental method in this embodiment is to first select the highest humidity, and then obtain all the humidity required for the experiment by dehumidification.

[0082] Parameter selection: Based on relevant standards and on-site operation and maintenance experience for dry air ring main units, the test humidity range was selected as 500–1500 μL / L, and the temperature range as 10–40℃. This test selected the highest humidity of 1500 μL / L as the initial humidity. To ensure the accuracy of the initial humidity, a humidity generator was used to generate this humidity. Subsequent tests were conducted to shorten the test time, using a frost layer for dehumidification.

[0083] like Figure 2 As shown, the experimental steps are as follows.

[0084] Step S1. Set the high and low temperature test chamber to 20℃, and set the humidity generator to D0, where D0 = (1500 + ΔD1) μL / L, and ΔD1 is the theoretical moisture adsorption capacity of the adsorbent. Open solenoid valves four, five, six, and eight, adjust the pressure reducing valve to 0.2MPa, and start the humidity generating unit, mirror humidity detection unit, and booster pump. Dry air from the gas cylinder is introduced into the gas chamber through the humidity generating unit, mirror humidity detection unit, buffer tank, and booster pump until the pressure in the gas chamber reaches the rated pressure P0. Then close solenoid valves four, five, six, eight, and the pressure reducing valve.

[0085] Step S2. After standing for 12 hours, open solenoid valves 2, 3, 7 and 8, start the mirror humidity detection unit and booster pump, measure the humidity in the air chamber, and record the detection result as D1. After the detection is completed, close solenoid valves 2, 3, 7 and 8.

[0086] Determine if test result D1 meets the requirements. If not, use a vacuum pump and humidity generator to replace part of the gas in the chamber, for example, replacing low-humidity gas with high-humidity gas or vice versa, to achieve humidity regulation. The specific process is as follows:

[0087] S21a. If D1≠1500μL / L, then proceed to step S22a;

[0088] If D1 = 1500 μL / L, proceed to step S24a;

[0089] S22a. Open solenoid valve one, start the vacuum pump, extract some gas from the gas chamber, making the pressure in the gas chamber P1, then close solenoid valve one. P1 is:

[0090] ;

[0091] Set the humidity generated by the humidity generating unit to D2, that is:

[0092] ;

[0093] Open solenoid valves four, five, six and eight, adjust the pressure reducing valve to 0.2MPa, start the humidity generating unit, the mirror humidity detection unit and the booster pump, so that the dry air in the gas cylinder becomes moist after passing through the humidity generating unit, and then enters the gas chamber until the rated pressure in the gas chamber reaches P0 and then stops. Close solenoid valves four, five, six and eight and the pressure reducing valve.

[0094] S23a. After standing for four hours, open solenoid valves 2, 3, 7, and 8 to start the mirror humidity detection unit and booster pump. Measure the humidity in the air chamber and record the result as D3. If |D3-D H If |≥△D1, repeat step S22a; otherwise, proceed to step S24a. △D1 is the first allowable error, which can be set by the user.

[0095] S24a. Record the current humidity value in the air chamber as the initial humidity target value D. S .

[0096] Step S3. Set the high and low temperature test chamber to a programmed test. The temperature settings are 10℃, 12℃, 14℃, 16℃, 18℃, 24℃, 28℃, 32℃, 36℃, and 40℃, with each temperature setting lasting for 5 hours. After 5 hours, measure the gas temperature in the chamber. When the gas temperature in the chamber reaches the set temperature and remains unchanged for 20 minutes, the temperature in the chamber is considered stable at the set value. Open solenoid valves 2, 3, 7, and 8, start the mirror humidity detection unit, and start the booster pump to measure humidity at each temperature point. After the measurement is completed, close and open solenoid valves 2, 3, 7, and 8.

[0097] Step S4. Utilizing the frost layer formed on the mirror surface during dew point detection by the mirror humidity detection unit, the humidity of the gas in the air chamber is adjusted by dynamically controlling the thickness of the frost layer. Specifically:

[0098] Step S41. After humidity detection at each temperature point, by controlling the mirror's cooling temperature and monitoring the reflected light energy, frost can condense on the mirror surface when dry air in the air chamber flows through it, thereby reducing the humidity of the dry air in the air chamber. Experiments show that at 40℃, the adsorbent releases a large amount of moisture, significantly increasing the humidity in the air chamber, which is more conducive to frost condensation. Therefore, this embodiment selects to conduct experiments from low to high temperatures, and begins adjusting the frost thickness after the temperature at the last temperature point (40℃) has stabilized. This further improves experimental efficiency.

[0099] The thickness of the frost layer is adjusted as follows:

[0100] Define the humidity of the gas after dehumidification in the air chamber as D4, and the amount of water W condensed on the mirror surface in the mirror humidity detection unit as:

[0101] ;

[0102] In the formula, The volume of the ring main unit's air chamber. At an atmospheric pressure of 0.1 MPa, The density of gaseous water at atmospheric pressure. The density of liquid water;

[0103] Let the area of ​​the mirror be S, and the preset frost thickness H corresponding to the water content W of the frost layer is:

[0104] ;

[0105] Based on the pre-defined mapping relationship between frost thickness and light energy (this mapping relationship is a well-known technique that can be obtained experimentally and presented in the form of a table or function), the corresponding light energy L is obtained;

[0106] The calculated mirror cooling temperature T when the frost layer thickness is H is:

[0107] ;

[0108] In the formula, e is the partial pressure of water vapor corresponding to humidity D4, i.e., e = D4 × 0.1 MPa;

[0109] When the mirror cooling temperature is set to T and the light energy remains stable at L, the frost layer thickness on the mirror is considered to be stable at the preset frost layer thickness H.

[0110] S42. After the frost layer thickness is adjusted, the temperature of the high and low temperature test chamber can be adjusted back to 20℃ in time; at the same time, open solenoid valve three and solenoid valve five, adjust the pressure reducing valve to 0.2MPa, and the dry air in the gas cylinder is introduced into the buffer tank through the mirror humidity detection unit. At this time, the mirror is no longer cooled, and the dry air is used to remove the moisture of the frost layer. When the light energy is restored to 100%, it is considered that there is no longer a frost layer on the mirror surface, and all the moisture has been carried into the buffer tank.

[0111] S5. Measure the humidity in the air chamber and adjust the humidity to the next initial target humidity value, as follows.

[0112] S51. After standing for a certain period of time (e.g., 4 hours), open solenoid valves 2, 3, 7 and 8, start the mirror humidity detection unit and booster pump, measure the humidity in the air chamber, and record the measurement result as D5.

[0113] S52. Determine whether the test result D5 meets the requirements.

[0114] If |D5-D4|≥△D2, where △D2 is the second allowable error, and △D1<△D2, then the humidity is adjusted again using the mirror frost layer, specifically in two cases: D5>D4 and D4>D5.

[0115] When D5 is greater than D4, dehumidification is required;

[0116] Open solenoid valves 2, 3, 7 and 8 to start the mirror humidity detection unit and the booster pump. By controlling the mirror cooling temperature and monitoring the mirror reflected light energy, when the dry air in the air chamber flows through the mirror, frost can condense on the mirror, thereby reducing the humidity of the dry air in the air chamber (during this process, the temperature of the high and low temperature test chamber can be appropriately increased to improve the frost condensation efficiency).

[0117] The amount of water W condensed on the mirror surface in the mirror humidity detection unit is:

[0118] ;

[0119] In the formula, The volume of the ring main unit's air chamber. At an atmospheric pressure of 0.1 MPa, The density of gaseous water at atmospheric pressure. The density of liquid water;

[0120] Let the area of ​​the mirror be S, and the preset frost thickness H corresponding to the water content W of the frost layer is:

[0121] ;

[0122] Based on the pre-defined mapping relationship between frost thickness and light energy (this mapping relationship is a well-known technique that can be obtained experimentally and presented in the form of a table or function), the corresponding light energy L is obtained;

[0123] The calculated mirror cooling temperature T when the frost layer thickness is H is:

[0124] ;

[0125] In the formula, e is the partial pressure of water vapor corresponding to humidity D4, i.e., e = D4 × 0.1 MPa;

[0126] When the mirror cooling temperature is set to T and the light energy remains stable at L, the frost layer thickness on the mirror is considered to be stable at the preset frost layer thickness H.

[0127] After the frost layer thickness is adjusted, the temperature of the high and low temperature test chamber can be adjusted back to 20℃ in time; at the same time, open solenoid valve three and solenoid valve five, adjust the pressure reducing valve to 0.2MPa, and the dry air in the gas cylinder is introduced into the buffer tank through the mirror humidity detection unit. At this time, the mirror is no longer cooled, and the dry air is used to remove the moisture of the frost layer. When the light energy is restored to 100%, it is considered that there is no longer a frost layer on the mirror surface, and all the moisture has been carried into the buffer tank.

[0128] After adjustment, it returns to S51.

[0129] When D4 is greater than D5, humidification is required;

[0130] Open solenoid valves four and five, adjust the pressure reducing valve to 0.2MPa, start the humidity generating unit and the mirror humidity detection unit, and adjust the humidity of the humidity generating unit to, for example, 2000μL / L. At this time, the dry air in the gas cylinder flows through the humidity generating unit and the mirror humidity detection unit in sequence before entering the buffer tank, causing frost to form on the mirror surface of the mirror humidity detection unit.

[0131] The amount of water W condensed on the mirror surface in the mirror humidity detection unit is:

[0132] ;

[0133] In the formula, The volume of the ring main unit's air chamber. At an atmospheric pressure of 0.1 MPa, The density of gaseous water at atmospheric pressure. The density of liquid water;

[0134] Let the area of ​​the mirror be S, and the preset frost thickness H corresponding to the water content W of the frost layer is:

[0135] ;

[0136] Based on the pre-defined mapping relationship between frost thickness and light energy, the corresponding light energy L is obtained;

[0137] The calculated mirror cooling temperature T when the frost layer thickness is H is:

[0138] ;

[0139] In the formula, e is the partial pressure of water vapor corresponding to humidity D4, i.e., e = D4 × 0.1 MPa;

[0140] When the mirror cooling temperature is set to T and the light energy remains stable at L, the frost layer thickness on the mirror surface will remain stable at the preset frost layer thickness H.

[0141] Open solenoid valves 2, 3, 7, and 8 to start the booster pump. At this time, the mirror will no longer be cooled. The gas in the air chamber will continuously circulate back to the air chamber through the mirror humidity detection unit, fully carrying the moisture of the frost into the air chamber. When the light energy is restored to 100%, it is considered that there is no longer any frost on the mirror surface and all the moisture has been carried into the air chamber. Then close solenoid valves 2, 3, 7, and 8 and the booster pump.

[0142] If △D1≤|D5-D4|<△D2, then the vacuum pump and humidity generating unit are used again to replace part of the gas in the air chamber to achieve humidity regulation;

[0143] Extracting some gas from the chamber causes the pressure in the chamber to become P1, i.e.:

[0144] ;

[0145] Set the humidity generated by the humidity generating unit to D6, that is:

[0146] ;

[0147] The dry air in the gas cylinder enters the gas chamber after passing through the humidity generating unit until the rated pressure in the gas chamber reaches P0.

[0148] After adjustment, it returns to S51;

[0149] If |D5-D4|<△D1, then the humidity is considered to have met the requirements, and D5 is taken as the next initial humidity target value.

[0150] S6. Repeat steps S3 to S5 until all initial humidity target values ​​are covered.

[0151] Example 2: This example uses the same platform design as Example 1. The difference is that Example 1 sets a higher initial humidity value and then dehumidifies to complete the test for all humidity values, while this example sets a lower humidity value and then humidifies to complete the test for all humidity values. The specific process is as follows.

[0152] Parameter selection: Based on relevant standards and on-site operation and maintenance experience for dry air ring main units, the test humidity range was selected as 500–1500 μL / L, and the temperature range as 10–40℃. This test selected the lowest humidity of 500 μL / L as the initial humidity. To ensure the accuracy of the initial humidity, a humidity generator was used to generate this humidity. Subsequent humidification using a frost layer was employed to shorten the test time.

[0153] like Figure 3 As shown, the experimental steps are as follows.

[0154] Step S1. Set the high and low temperature test chamber to 20℃, and set the humidity generator to D0, where D0 = (500 + ΔD1) μL / L, and ΔD1 is the theoretical moisture adsorption capacity of the adsorbent. Open solenoid valves four, five, six, and eight, adjust the pressure reducing valve to 0.2MPa, and start the humidity generating unit, mirror humidity detection unit, and booster pump. Dry air from the gas cylinder is introduced into the gas chamber through the humidity generating unit, mirror humidity detection unit, buffer tank, and booster pump until the pressure in the gas chamber reaches the rated pressure P0, then stop. Close solenoid valves four, five, six, eight, and the pressure reducing valve.

[0155] Step S2. After standing for 12 hours, open solenoid valves 2, 3, 7 and 8, start the mirror humidity detection unit and booster pump, measure the humidity in the air chamber, and record the detection result as D1. After the detection is completed, close solenoid valves 2, 3, 7 and 8.

[0156] Determine if test result D1 meets the requirements. If not, use a vacuum pump and humidity generator to replace part of the gas in the chamber, for example, replacing low-humidity gas with high-humidity gas or vice versa, to achieve humidity regulation. The specific process is as follows:

[0157] S21b. If D1≠500μL / L, proceed to step S22b;

[0158] If D1 = 500 μL / L, proceed to step S24b;

[0159] S22b. Open solenoid valve one, start the vacuum pump, extract some gas from the gas chamber, making the pressure in the gas chamber P1, then close solenoid valve one. P1 is:

[0160] ;

[0161] Set the humidity generated by the humidity generating unit to D2, that is:

[0162] ;

[0163] Open solenoid valves four, five, six and eight, adjust the pressure reducing valve to 0.2MPa, start the humidity generating unit, the mirror humidity detection unit and the booster pump, so that the dry air in the gas cylinder becomes moist after passing through the humidity generating unit, and then enters the gas chamber until the rated pressure in the gas chamber reaches P0 and then stops. Close solenoid valves four, five, six and eight and the pressure reducing valve.

[0164] S23b. After standing for four hours, open solenoid valves two, three, seven, and eight to start the mirror humidity detection unit and booster pump. Measure the humidity in the air chamber and record the result as D3. If |D3-D L If |≥△D1, repeat step S22b; otherwise, proceed to step S24b. △D1 is the first allowable error, which can be set by the user.

[0165] S24b. Record the current humidity value in the air chamber as the initial humidity target value D. S .

[0166] Step S3. Set the high and low temperature test chamber to a programmed test. The temperature settings are 10℃, 12℃, 14℃, 16℃, 18℃, 24℃, 28℃, 32℃, 36℃, and 40℃, with each temperature setting lasting for 5 hours. After 5 hours, measure the gas temperature in the chamber. When the gas temperature in the chamber reaches the set temperature and remains unchanged for 20 minutes, the temperature in the chamber is considered stable at the set value. Open solenoid valves 2, 3, 7, and 8, start the mirror humidity detection unit, and start the booster pump to measure humidity at each temperature point. After the measurement is completed, close and open solenoid valves 2, 3, 7, and 8.

[0167] S4. By using the frost layer formed on the mirror surface during the dew point detection process using the mirror humidity detection unit, the humidity of the gas in the air chamber can be adjusted by dynamically controlling the thickness of the frost layer. During the humidification test, the temperature of the high and low temperature test chamber can be restored to 20°C in advance.

[0168] S41. Open solenoid valve four and solenoid valve five, adjust the pressure reducing valve to 0.2MPa, start the humidity generating unit and the mirror humidity detection unit. The dry air in the gas cylinder flows through the humidity generating unit and the mirror humidity detection unit in sequence and then enters the buffer tank, causing the mirror surface of the mirror humidity detection unit to frost. The thickness of the frost layer is achieved by controlling the mirror cooling temperature and monitoring the mirror reflected light energy.

[0169] Define the humidity of the gas after humidification in the air chamber as D4, and the amount of water W condensed on the mirror surface in the mirror humidity detection unit as:

[0170] ;

[0171] In the formula, The volume of the ring main unit's air chamber. At an atmospheric pressure of 0.1 MPa, The density of gaseous water at atmospheric pressure. The density of liquid water;

[0172] Let the area of ​​the mirror be S, and the preset frost thickness H corresponding to the water content W of the frost layer is:

[0173] ;

[0174] Based on the pre-defined mapping relationship between frost thickness and light energy, the corresponding light energy L is obtained;

[0175] The calculated mirror cooling temperature T when the frost layer thickness is H is:

[0176] ;

[0177] In the formula, e is the partial pressure of water vapor corresponding to humidity D4, i.e., e = D4 × 0.1 MPa;

[0178] When the mirror cooling temperature is set to T and the light energy remains stable at L, the frost layer thickness on the mirror surface will remain stable at the preset frost layer thickness H.

[0179] S42. Open solenoid valves 2, 3, 7, and 8 to start the booster pump. At this time, the mirror will no longer be cooled. The gas in the air chamber will continuously circulate back to the air chamber through the mirror humidity detection unit, fully carrying the moisture of the frost into the air chamber. When the light energy is restored to 100%, it is considered that there is no longer any frost on the mirror surface and all the moisture has been carried into the air chamber. Then close solenoid valves 2, 3, 7, and 8 and the booster pump.

[0180] S5. Measure the humidity in the air chamber and adjust the humidity to the next initial target humidity value, as follows.

[0181] S51. After standing for a certain period of time (e.g., 4 hours), open solenoid valves 2, 3, 7 and 8, start the mirror humidity detection unit and booster pump, measure the humidity in the air chamber, and record the measurement result as D5.

[0182] S52. Determine whether the test result D5 meets the requirements.

[0183] If |D5-D4|≥△D2, where △D2 is the second allowable error, and △D1<△D2, then the humidity is adjusted again using the mirror frost layer, specifically in two cases: D5>D4 and D4>D5.

[0184] When D5 is greater than D4, dehumidification is required;

[0185] Open solenoid valves 2, 3, 7 and 8 to start the mirror humidity detection unit and the booster pump. By controlling the mirror cooling temperature and monitoring the mirror reflected light energy, when the dry air in the air chamber flows through the mirror, frost can condense on the mirror, thereby reducing the humidity of the dry air in the air chamber (during this process, the temperature of the high and low temperature test chamber can be appropriately increased to improve the frost condensation efficiency).

[0186] The amount of water W condensed on the mirror surface in the mirror humidity detection unit is:

[0187] ;

[0188] In the formula, The volume of the ring main unit's air chamber. At an atmospheric pressure of 0.1 MPa, The density of gaseous water at atmospheric pressure. The density of liquid water;

[0189] Let the area of ​​the mirror be S, and the preset frost thickness H corresponding to the water content W of the frost layer is:

[0190] ;

[0191] Based on the pre-defined mapping relationship between frost thickness and light energy (this mapping relationship is a well-known technique that can be obtained experimentally and presented in the form of a table or function), the corresponding light energy L is obtained;

[0192] The calculated mirror cooling temperature T when the frost layer thickness is H is:

[0193] ;

[0194] In the formula, e is the partial pressure of water vapor corresponding to humidity D4, i.e., e = D4 × 0.1 MPa;

[0195] When the mirror cooling temperature is set to T and the light energy remains stable at L, the frost layer thickness on the mirror is considered to be stable at the preset frost layer thickness H.

[0196] After the frost layer thickness is adjusted, the temperature of the high and low temperature test chamber can be adjusted back to 20℃ in time; at the same time, open solenoid valve three and solenoid valve five, adjust the pressure reducing valve to 0.2MPa, and the dry air in the gas cylinder is introduced into the buffer tank through the mirror humidity detection unit. At this time, the mirror is no longer cooled, and the dry air is used to remove the moisture of the frost layer. When the light energy is restored to 100%, it is considered that there is no longer a frost layer on the mirror surface, and all the moisture has been carried into the buffer tank.

[0197] After adjustment, it returns to S51.

[0198] When D4 is greater than D5, humidification is required;

[0199] Open solenoid valves four and five, adjust the pressure reducing valve to 0.2MPa, start the humidity generating unit and the mirror humidity detection unit, and adjust the humidity of the humidity generating unit to, for example, 2000μL / L. At this time, the dry air in the gas cylinder flows through the humidity generating unit and the mirror humidity detection unit in sequence before entering the buffer tank, causing frost to form on the mirror surface of the mirror humidity detection unit.

[0200] The amount of water W condensed on the mirror surface in the mirror humidity detection unit is:

[0201] ;

[0202] In the formula, The volume of the ring main unit's air chamber. At an atmospheric pressure of 0.1 MPa, The density of gaseous water at atmospheric pressure. The density of liquid water;

[0203] Let the area of ​​the mirror be S, and the preset frost thickness H corresponding to the water content W of the frost layer is:

[0204] ;

[0205] Based on the pre-defined mapping relationship between frost thickness and light energy, the corresponding light energy L is obtained;

[0206] The calculated mirror cooling temperature T when the frost layer thickness is H is:

[0207] ;

[0208] In the formula, e is the partial pressure of water vapor corresponding to humidity D4, i.e., e = D4 × 0.1 MPa;

[0209] When the mirror cooling temperature is set to T and the light energy remains stable at L, the frost layer thickness on the mirror surface will remain stable at the preset frost layer thickness H.

[0210] Open solenoid valves 2, 3, 7, and 8 to start the booster pump. At this time, the mirror will no longer be cooled. The gas in the air chamber will continuously circulate back to the air chamber through the mirror humidity detection unit, fully carrying the moisture of the frost into the air chamber. When the light energy is restored to 100%, it is considered that there is no longer any frost on the mirror surface and all the moisture has been carried into the air chamber. Then close solenoid valves 2, 3, 7, and 8 and the booster pump.

[0211] If △D1≤|D5-D4|<△D2, then the vacuum pump and humidity generating unit are used again to replace part of the gas in the air chamber to achieve humidity regulation;

[0212] Extracting some gas from the chamber causes the pressure in the chamber to become P1, i.e.:

[0213] ;

[0214] Set the humidity generated by the humidity generating unit to D6, that is:

[0215] ;

[0216] The dry air in the gas cylinder enters the gas chamber after passing through the humidity generating unit until the rated pressure in the gas chamber reaches P0.

[0217] After adjustment, it returns to S51;

[0218] If |D5-D4|<△D1, then the humidity is considered to have met the requirements, and D5 is taken as the next initial humidity target value.

[0219] S6. Repeat steps S3 to S5 until all initial humidity target values ​​are covered.

[0220] Through the two embodiments described above, we can see that, compared to traditional methods, this solution innovatively utilizes the frost layer naturally formed during the mirror humidity detection process. By dynamically adjusting its thickness, it achieves rapid humidification or dehumidification, with the entire humidity adjustment process completed within 10 minutes, significantly shortening the multi-condition temperature and humidity test cycle. Simultaneously, the control terminal automatically coordinates the high and low temperature test chamber, solenoid valves, pump units, and detection units, achieving a fully closed-loop operation from temperature regulation and humidity measurement to frost layer control. This supports 24-hour continuous operation, avoiding operational errors and data fluctuations caused by manual intervention, and significantly improving the reliability and repeatability of test data. Furthermore, this solution cleverly integrates the mirror humidity detection unit (also known as a cold mirror dew point meter), originally used only for detection, into a dual-purpose unit, enabling it to simultaneously perform humidity sensing and active humidity adjustment functions without requiring additional complex humidification / dehumidification equipment. The frost layer thickness is controlled by adjusting the mirror cooling temperature and monitoring the mirror's reflected light energy, achieving quantitative control of trace moisture while maintaining both accuracy and practicality.

[0221] The above embodiments are only used to explain the concept of the present invention, and are not intended to limit the protection of the present invention. Any non-substantial modifications made to the present invention using this concept should fall within the protection scope of the present invention.

Claims

1. A method for testing the room temperature and humidity of a ring main unit based on dynamic frost layer control, characterized in that, Includes the following steps: S1. Place the ring main unit's air chamber in the high and low temperature test chamber, set the initial temperature of the high and low temperature test chamber, and fill the air chamber with the set humidity after the dry air in the gas cylinder passes through the humidity generating unit until the pressure in the air chamber stabilizes at the rated pressure and then stop filling. S2. After standing, the humidity in the air chamber is measured by the mirror humidity detection unit and the humidity is adjusted to the initial humidity target value; S3. Control the high and low temperature test chamber to adjust to multiple temperature set points according to the preset program, and keep it at each temperature set point until the temperature of the air chamber stabilizes, and then detect the humidity of the dry air in the air chamber; in step S3, control the high and low temperature test chamber to adjust to multiple temperature set points from low to high according to the preset program. S4. Utilizing the frost layer formed on the mirror surface during dew point detection by the mirror humidity detection unit, the humidity of the gas in the gas chamber is regulated by dynamically adjusting the thickness of the frost layer. The humidity regulation includes the following process: S41. After the measurement stabilizes at the last temperature set point, the thickness of the frost layer on the mirror surface in the mirror humidity detection unit is adjusted. The frost layer thickness is achieved by controlling the mirror cooling temperature and monitoring the reflected light energy of the mirror. When dry air in the gas chamber flows through the mirror, frost can condense on the mirror surface, thereby reducing the humidity of the dry air in the gas chamber; S42. After the frost layer thickness is adjusted, the dry air in the gas cylinder is introduced into the buffer tank through the mirror humidity detection unit. At this time, the mirror is no longer cooled, and the dry air carries away the moisture from the frost layer. When the light energy recovers to 100%, it is considered that there is no longer a frost layer on the mirror surface, and all the moisture has been carried into the buffer tank. The temperature of the high and low temperature test chamber is restored to the initial temperature. S5. After settling, measure the humidity in the air chamber and adjust the humidity to the next initial target humidity value; S6. Repeat steps S3 to S5 until all initial humidity target values ​​are covered.

2. The method for testing the room temperature and humidity of a ring main unit based on dynamic frost layer control as described in claim 1, characterized in that, In step S1, the air chamber of the ring network cabinet contains an adsorbent. The humidity value set by the humidity generating unit needs to take into account the amount of water adsorbed by the adsorbent. The humidity generated by the humidity generating unit is set to the sum of the maximum test humidity limit and the amount of water adsorbed by the adsorbent.

3. The method for testing the room temperature and humidity of a ring main unit based on dynamic frost layer control as described in claim 2, characterized in that, The humidity adjustment in step S2 involves using a vacuum pump and a humidity generating unit to replace part of the gas in the air chamber to achieve humidity regulation, including the following processes: S21a. Measure the humidity value inside the air chamber using the mirror humidity detection unit; If the current humidity value is not equal to the maximum test humidity limit, proceed to step S22a; If the current humidity value is equal to the maximum test humidity limit, proceed to step S24a; S22a. Extract some gas from the air chamber, reduce the pressure in the air chamber, and adjust the humidity generated by the humidity generating unit at the same time; The dry air in the gas cylinder passes through the humidity generating unit and then enters the gas chamber until the pressure in the gas chamber reaches the rated pressure. S23a. After standing, measure the humidity in the air chamber. If the absolute value of the difference between the current measurement result and the maximum test humidity limit is not less than the first permissible error, then repeat step S22a. Conversely, proceed to step S24a; S24a. Record the current humidity value in the air chamber as the initial humidity target value.

4. The method for testing the room temperature and humidity of a ring main unit based on dynamic frost layer control as described in claim 1, characterized in that, In step S1, the air chamber of the ring network cabinet contains an adsorbent. The humidity value set by the humidity generating unit needs to take into account the amount of water adsorbed by the adsorbent. The humidity generated by the humidity generating unit is set to the sum of the minimum test humidity limit and the amount of water adsorbed by the adsorbent.

5. The method for testing the room temperature and humidity of a ring main unit based on dynamic frost layer control as described in claim 4, characterized in that, The humidity adjustment in step S2 involves using a vacuum pump and a humidity generating unit to replace part of the gas in the air chamber to achieve humidity regulation, including the following processes: S21b. Measure the humidity value inside the air chamber using the mirror humidity detection unit; If the current humidity value is not equal to the minimum test humidity limit, proceed to step S22; If the current humidity value is equal to the minimum test humidity limit, proceed to step S24; S22b. Extract some gas from the air chamber to reduce the pressure in the air chamber and adjust the humidity generated by the humidity generating unit; The dry air in the gas cylinder passes through the humidity generating unit and then enters the gas chamber until the pressure in the gas chamber reaches the rated pressure. S23b. After standing, measure the humidity in the air chamber. If the absolute value of the difference between the measurement result and the minimum test humidity limit is not less than the first allowable error, repeat step S22; otherwise, proceed to step S24. S24b. Record the current humidity value in the air chamber as the initial humidity target value.

6. The method for testing the room temperature and humidity of a ring main unit based on dynamic frost layer control as described in claim 5, characterized in that, The humidity adjustment in step S4 includes the following processes: S41. Start the humidity generating unit and the mirror humidity detection unit. Dry air in the gas cylinder flows through the humidity generating unit and the mirror humidity detection unit in sequence and then enters the buffer tank, causing the mirror surface of the mirror humidity detection unit to frost. The thickness of the frost layer is controlled by controlling the mirror cooling temperature and monitoring the mirror reflected light energy. S42. The dry air in the ring main unit's air chamber is circulated back into the air chamber after passing through the mirror humidity detection unit until there is no more frost on the mirror surface.

7. A method for testing the room temperature and humidity of a ring main unit based on dynamic frost layer control as described in claim 1 or 6, characterized in that, Step S5 Includes the following processes: S51. After standing, measure the humidity in the air chamber; S52. If the absolute value of the difference between the current humidity and the humidity adjusted in step S4 is not less than the second allowable error, the frost layer formed on the mirror surface during the dew point detection process by the mirror humidity detection unit is used again to adjust the humidity of the gas in the air chamber by dynamically adjusting the thickness of the frost layer, and then the process returns to S51. The second allowable error is greater than the first allowable error; If the absolute value of the difference between the current humidity and the humidity adjusted in step S4 is less than the second allowable error and greater than or equal to the first allowable error, then the vacuum pump and humidity generating unit are used again to replace part of the gas in the air chamber to achieve humidity adjustment, and then the process returns to S51. If the absolute value of the difference between the current humidity and the humidity adjusted in step S4 is less than the first allowable error, then the humidity is considered to meet the requirements, and the current humidity is used as the next initial humidity target value.

8. A ring main unit air temperature and humidity testing device based on dynamic frost layer control for use in any one of claims 1 to 7, characterized in that, include: High and low temperature test chambers are used to provide different temperature environments; The ring network cabinet air chamber is placed inside the high and low temperature test chamber. The air chamber is used to fill dry air and contains an adsorbent. The air chamber environment monitoring unit is used to monitor and display the air pressure and temperature inside the air chamber in real time. A mirror-like humidity detection unit is used to measure the humidity inside the air chamber and to form a frost layer. The humidity generating unit provides the set humidity to the dry air; Buffer tanks are used to store treated, dry air; A booster pump is used to provide the power for the flow of gas within a pipeline. Vacuum pump, used to extract dry air from the air chamber of the ring main unit; Several solenoid valves are used to control the opening and closing of pipelines; Gas cylinders, used in conjunction with pressure reducing valves, are used to provide dry air; The control terminal is used to receive various monitoring or detection feedback signals and to issue control strategies. The solenoid valves include solenoid valve one, solenoid valve two, solenoid valve three, solenoid valve four, solenoid valve five, solenoid valve six, solenoid valve seven and solenoid valve eight. The solenoid valve 2, solenoid valve 3, mirror humidity detection unit, solenoid valve 7, booster pump and solenoid valve 8 are connected in series, and the output end of solenoid valve 8 is connected to the air inlet of the ring network cabinet air chamber, and the air outlet of the ring network cabinet air chamber is connected to the input end of solenoid valve 2. The input end of the first solenoid valve is connected to the pipeline between the second solenoid valve and the air chamber of the ring main unit, and the output end of the first solenoid valve is connected to the input end of the vacuum pump. The input end of the humidity generating unit is connected to the pipeline between solenoid valve two and solenoid valve three, and the output end of the humidity generating unit is connected to the pipeline between solenoid valve three and the mirror humidity detection unit through solenoid valve four. The gas cylinder is connected to the input end of the solenoid valve and the humidity generating unit via a pressure reducing valve; The input end of the buffer tank is connected to the pipeline between the solenoid valve seven and the mirror humidity detection unit via solenoid valve five, and the output end of the buffer tank is connected to the pipeline between the solenoid valve seven and the booster pump via solenoid valve six.

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