Air pressure dynamic compensation control system for environmentally friendly gas insulated switchgear

Abstract

The application discloses an air pressure dynamic compensation control system for an environmentally-friendly gas insulated switch cabinet, relates to the dry air pressure dynamic compensation control technical field of the environmentally-friendly gas insulated switch cabinet, and aims to solve the technical problem of waterproof failure caused by the breathing effect, and comprises a dry air storage tank communicated with a gas chamber of the switch cabinet, a pressure detection unit arranged in the gas chamber, and an electromagnetic valve arranged on a pipeline communicated between the storage tank and the gas chamber. The application is characterized in that the multi-point water level detection unit is arranged at different positions on the bottom of the switch cabinet, and the controller compares the water depth difference values of the positions to identify the non-uniform water immersion state caused by the ground inclination, and then determines the exhaust area, so that the precise positioning of the leakage gap in the area is realized. By actively reducing the pressure in the cabinet to a controlled negative pressure state lower than the external atmospheric pressure, a directional pressure difference from outside to inside is formed between the inside and outside of the cabinet, and the suspended impurities carried by the external accumulated water are guided to directionally penetrate into the micro gap of the exhaust area and are filled.

Description

Technical Field

[0001] This invention relates to the field of dynamic compensation control technology for dry air pressure in environmentally friendly gas-insulated switchgear, and more specifically, to a dynamic compensation control system for air pressure in environmentally friendly gas-insulated switchgear. Background Technology

[0002] Environmentally friendly gas-insulated switchgear uses dry air as the insulating medium. It maintains a slight positive pressure inside the gas chamber to prevent external moisture and dust from entering, thus ensuring insulation strength. Underground substation floors are not perfectly flat; the switchgear base is usually raised by channel steel. However, after years of operation, uneven ground settlement creates a small, sloping gap at the bottom of the cabinet. When water slowly rises, it first submerges the cable entry / exit seals on one side of the cabinet bottom, while the other side, being slightly higher, remains exposed to air. This difference in external water level is not instantaneous but forms naturally as the water gradually rises. At the submerged seals, due to water pressure, external moisture tends to penetrate into the cabinet. At the shallowest submerged side, where only the bottom of the seals is moistened by a thin layer of water, if the internal temperature rises slightly due to equipment operation, creating a slight positive pressure, air will escape.

[0003] Existing dynamic pressure compensation control systems, due to their reliance on water level detection at a single location at the bottom of the cabinet or their failure to differentiate water level differences across various locations, cannot identify uneven immersion caused by ground inclination. Furthermore, they cannot specifically block the breathing channel driven by water level differences. Consequently, the "pressurization upon contact with water" strategy not only fails to effectively waterproof in this scenario but may also exacerbate water vapor circulation by maintaining exhaust airflow, leading to continuous deterioration of weak sealing points. Therefore, this invention proposes an air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear. This system actively constructs a controlled negative pressure environment, guiding naturally occurring suspended impurities in the accumulated water to perform directional self-sealing of the breathing channel. Thus, we propose an air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art, adapt to practical needs, and provide an air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear to solve the technical problem of waterproof failure caused by the current breathing effect.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a dynamic compensation control system for air pressure in an environmentally friendly gas-insulated switchgear, comprising a dry air storage tank connected to the switchgear's air chamber, a pressure detection unit disposed within the air chamber, a replenishing solenoid valve, an exhaust solenoid valve, and a controller, characterized in that it further comprises: Multiple water level detection units are installed at different locations on the bottom of the switch cabinet; The controller is connected to the pressure detection unit, the air supply solenoid valve, the exhaust solenoid valve, and each water level detection unit. The controller determines a non-uniform immersion state when the difference between the maximum and minimum water depth exceeds a preset water depth difference threshold, and identifies the location with the minimum water depth as the exhaust zone. In a non-uniform immersion state, the controller closes the air supply solenoid valve and intermittently opens the exhaust solenoid valve to reduce the air chamber pressure to the target pressure. The target pressure is lower than the external atmospheric pressure, and the pressure difference between the target pressure and the external atmospheric pressure is greater than the external water pressure in the exhaust area. A directional pressure difference is formed between the air chamber and the exhaust area from the outside to the inside. Under the action of the directional pressure difference, the external water carries suspended impurities into the micro gaps in the exhaust area and forms a filling layer. If, after exhaust is stopped, the pressure fluctuation in the air chamber is less than the preset pressure fluctuation threshold and the humidity change is less than the preset humidity change threshold within the preset stable observation period, then the sealing is deemed effective. After the sealing is effective, the controller closes the exhaust solenoid valve and opens the replenishment solenoid valve to restore the air chamber pressure to the repressurization target pressure. The positive pressure difference between the repressurization target pressure and the external atmospheric pressure is lower than the ultimate pressure difference corresponding to the maximum static friction force of the impurity packing layer.

[0006] Preferably, the system has an external atmospheric pressure sensor located outside the cabinet, and the controller is connected to the external atmospheric pressure sensor. The target pressure satisfies: (Recorded as negative pressure amplitude); The total net driving pressure difference from the outside to the inside of the gap is the sum of the external atmospheric pressure and the static water pressure, minus the target pressure inside the cabinet. The total net pressure difference drives water and impurities to seep into the gaps. in, The real-time external atmospheric pressure is measured by an external atmospheric pressure sensor. The density of the accumulated water, It is the acceleration due to gravity. This represents the minimum water depth measured by multiple water level detection units. This is the preset negative pressure margin.

[0007] Preferably, the difference between the target pressure and the external atmospheric pressure is .

[0008] Preferably, the target pressure for the overpressure process satisfies: ; in, The real-time external atmospheric pressure is measured by an external atmospheric pressure sensor. For safety reasons, This refers to the static friction force per unit area between the impurity-filled layer and the gap wall. This refers to the contact area between the impurity-filling layer and the crevice wall. Let be the cross-sectional area of ​​the gap perpendicular to the pressure direction.

[0009] Preferably, the plurality of water level detection units are electrodes arranged at multiple preset positions on the bottom of the switch cabinet, with the lower end of each electrode flush with the mounting reference surface on the bottom of the cabinet, and the water depth resolution of the electrodes is not lower than a preset resolution threshold. The venting area corresponds to the cable inlet / outlet hole sealing component on the shallow submerged side of the bottom of the switch cabinet.

[0010] Preferably, if the rate of pressure drop in the air chamber exceeds a preset pressure drop rate threshold, the pressure reduction maintenance time is extended for a preset extension period for secondary plugging. If the rate of pressure drop in the air chamber still exceeds the preset pressure drop rate threshold after the extension, it is determined that there is a leak point in the exhaust area that exceeds the self-sealing capability and a sealing abnormality warning is issued.

[0011] Preferably, the controller pre-stores the material type information of the sealing components at each cable inlet and outlet hole. The material types include rubber rings and fireproof putty. The controller adjusts the pressure reduction depth and / or pressure reduction maintenance time during the pressure reduction process according to the material type of the sealing component corresponding to the exhaust area.

[0012] Preferably, the controller receives humidity sensor data in real time during the pressure reduction process. When the humidity rises above the baseline before pressure reduction by more than a preset humidity safety threshold, it immediately closes the exhaust solenoid valve, opens the replenishment solenoid valve to restore positive pressure, and outputs an alarm signal. The difference between the target pressure and the external atmospheric pressure is less than a preset safe negative pressure threshold.

[0013] Preferably, the system further includes a temperature and humidity coupling correction unit, a pressure threshold dynamic adaptation unit, and a solenoid valve drive control unit. The input of the temperature and humidity coupling correction unit is connected to the temperature sensor and humidity sensor in the air chamber. The temperature and humidity coupling correction unit has a built-in temperature and humidity-pressure deviation mapping table. The temperature and humidity-pressure deviation mapping table has multiple sets of temperature and humidity sampling points generated by environmental simulation test calibration and corresponding pressure compensation offsets. The temperature and humidity coupling correction unit matches the real-time temperature data and real-time humidity data with the temperature and humidity-pressure deviation mapping table. The pressure threshold dynamic adaptation unit superimposes the standard air pressure reference value with the pressure correction offset to obtain a dynamic pressure trigger threshold. The solenoid valve drive control unit compares the real-time pressure value with the dynamic pressure trigger threshold and outputs a control signal to the air supply solenoid valve or the exhaust solenoid valve.

[0014] Preferably, the solenoid valve drive control unit has a built-in delay anti-shake module, which has a preset delay anti-shake duration. The valve opening control signal or valve closing control signal is output only when the comparison result continuously meets the triggering condition to reach the preset delay anti-shake duration.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention designs multi-point water level detection units arranged at different locations on the bottom of the switchgear. A controller compares the water depth differences at each location to identify uneven immersion caused by ground inclination, thereby determining the venting area and accurately locating leaks in that area. Based on this, by actively reducing the pressure inside the cabinet to a controlled negative pressure state below the external atmospheric pressure, with the negative pressure amplitude limited by a preset safe negative pressure threshold, a directional pressure difference is created from the outside inwards. This guides suspended impurities carried by external water to seep into and fill the micro-gap in the venting area. Simultaneously, the humidity interlock protection mechanism of this invention can immediately terminate the voltage reduction operation when humidity abnormally increases, ensuring insulation safety.

[0016] 2. This invention employs a sealing effect verification mechanism and coordinated control during the repressurization and reinforcement stage. After depressurization and sealing, it continuously monitors the pressure stability and humidity changes within the cabinet to determine sealing effectiveness. Once sealing is effective, the target pressure value for repressurization is calculated based on the maximum static friction of the impurity-filled layer within the gap. A safety factor is introduced to ensure the repressurization pressure remains below the theoretical tolerance limit of the impurity layer, achieving the effect of compacting and solidifying the impurity-filled layer without it being pushed back out. Simultaneously, this invention includes a sealing failure judgment and exit mechanism. When the pressure or humidity indicators are abnormal after repressurization, it automatically exits the sealing mode and triggers an alarm, avoiding risks associated with unreliable impurity sealing.

[0017] 3. This invention designs a controller that pre-stores the material type information of the sealing components at each cable inlet and outlet hole, and adjusts the pressure reduction depth and pressure reduction maintenance time according to whether the sealing component is a rubber ring or fireproof putty during the pressure reduction operation, so as to achieve differentiated matching between the pressure reduction parameters and the characteristics of the sealing material. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the system hardware configuration of the present invention; Figure 2 This is a flowchart of the pressure dynamic compensation control under normal conditions according to the present invention; Figure 3 This is the main control flowchart for "directional sealing of the breathing hole" under immersion conditions according to the present invention; Figure 4 This is a flowchart of the differential control sub-process for sealing materials in this invention. Detailed Implementation

[0019] Example 1, Reference Figure 1-4This invention provides a dynamic air pressure compensation control system for environmentally friendly gas-insulated switchgear. Its overall structure includes a dry air storage tank connected to the switchgear's air chamber, a pressure detection unit installed inside the air chamber, and solenoid valves installed on the connecting pipeline between the storage tank and the air chamber. The solenoid valves include a replenishment solenoid valve and an exhaust solenoid valve. The dry air storage tank provides dry air to replenish the air chamber; the dew point temperature of the gas inside should be lower than the minimum temperature required for the switchgear's operating environment to ensure the dryness of the replenished gas. The pressure detection unit monitors the absolute pressure inside the air chamber in real time and outputs the real-time pressure value to the subsequent processing unit. The solenoid valves, installed on the connecting pipeline between the storage tank and the air chamber, receive control signals to open and close the pipeline, thereby controlling the start and stop of the replenishment operation.

[0020] The system integrates a temperature and humidity coupling correction unit, a pressure threshold dynamic adaptation unit, and a solenoid valve drive control unit. These three functional units work together.

[0021] The specific connection relationship is as follows: The input terminal of the temperature and humidity coupling correction unit is connected to the real-time temperature data output by the temperature sensor installed in the air chamber and the real-time humidity data output by the humidity sensor. After performing coupling analysis on these two types of environmental parameters, the output terminal of the temperature and humidity coupling correction unit is connected to the correction parameter input terminal of the pressure threshold dynamic adaptation unit, providing it with the pressure correction offset under the current operating conditions.

[0022] The reference input of the pressure threshold dynamic adaptation unit is connected to a preset standard air pressure reference value. This standard air pressure reference value is the ideal working pressure value of the air chamber pre-calibrated by the switchgear manufacturer based on the circuit breaker's opening and closing characteristics and insulation requirements. It is usually set and stored in the controller at the factory. The pressure threshold dynamic adaptation unit integrates the standard air pressure reference value with the received pressure correction offset and generates a dynamic pressure trigger threshold at its output. This output is connected to the trigger threshold input of the solenoid valve drive control unit.

[0023] The signal input terminal of the solenoid valve drive control unit is connected to the real-time pressure output terminal of the pressure detection unit to obtain the current real-time pressure value in the air chamber. The output terminal of the solenoid valve drive control unit is connected to the control terminal of the solenoid valve. By comparing the real-time pressure value with the dynamic pressure trigger threshold, the corresponding valve opening or closing control signal is output, thereby achieving closed-loop dynamic compensation of the dry air pressure in the air chamber based on the dynamic pressure threshold after temperature and humidity correction.

[0024] In addition, a pressure reducing valve is installed on the connecting pipeline between the dry air storage tank and the air chamber to reduce the pressure of the high-pressure gas in the storage tank to a pressure range suitable for replenishing the air chamber, so as to avoid the high-pressure gas directly impacting the air chamber and causing pressure overshoot or damage to the seals.

[0025] Temperature and humidity coupling correction and dynamic pressure threshold generation under normal operation: During normal operation without ground flooding or other special conditions, the system mainly achieves precise dynamic control of the air chamber pressure through the coordinated work of the temperature and humidity coupling correction unit and the pressure threshold dynamic adaptation unit.

[0026] The temperature and humidity coupling correction unit has a built-in preset temperature and humidity-pressure deviation mapping table. The pressure of the dry air in the chamber is affected by both temperature and humidity. Increased temperature causes thermal expansion of the gas, leading to an increase in pressure, while decreased temperature causes a decrease in pressure. Simultaneously, trace amounts of residual moisture in the chamber exist in gaseous or liquid form at different temperatures, affecting the total gas volume and indirectly altering the pressure reading. Relying solely on the pressure value to determine whether additional air needs to be added, without considering the impact of current temperature and humidity on the pressure baseline, can easily lead to incorrect or insufficient air addition.

[0027] To establish this mapping table, multiple sets of environmental simulation tests can be conducted before the equipment leaves the factory. Each test is conducted under a combination of temperature and humidity sampling points, recording the actual deviation between the chamber pressure and the standard atmospheric pressure reference value under this condition. This deviation is the pressure compensation offset for the corresponding temperature and humidity combination. A large amount of test data constitutes a mapping table covering the expected operating temperature and humidity range of the equipment. During actual system operation, the temperature and humidity coupling correction unit matches the received real-time temperature and humidity data with the mapping table, calculates the pressure correction offset corresponding to the current operating condition using lookup or interpolation, and outputs it to the pressure threshold dynamic adaptation unit.

[0028] The dynamic pressure threshold adaptation unit receives the standard air pressure reference value and the pressure correction offset, and then calculates the dynamic pressure trigger threshold corresponding to the current operating condition by superimposing the two values. This dynamic pressure trigger threshold includes an upper limit threshold and a lower limit threshold. The upper limit threshold is the standard air pressure reference value plus the pressure correction offset, plus a preset allowable positive deviation range. The lower limit threshold is the standard air pressure reference value plus the pressure correction offset, minus a preset allowable negative deviation range. The allowable positive and negative deviation ranges can be set according to the pressure-bearing capacity of the switchgear seals and the circuit breaker's minimum functional pressure requirements.

[0029] The solenoid valve drive control unit continuously compares the real-time pressure value output by the pressure detection unit with the connected dynamic pressure trigger threshold. When the real-time pressure value is lower than the lower threshold, it indicates insufficient air chamber pressure, requiring the replenishment of dry air to restore insulation margin. The solenoid valve drive control unit outputs an opening control signal to the solenoid valve, and dry air from the air tank is injected into the air chamber through the pressure reducing valve. When the real-time pressure value is higher than the upper threshold, it indicates excessive air chamber pressure, which may place an additional burden on the seals. The solenoid valve drive control unit can output a closing control signal to stop air replenishment, or release a small amount of gas through an independent exhaust circuit. Through this closed-loop control, the air chamber pressure is always maintained within a reasonable range that matches the current temperature and humidity conditions, avoiding pressure regulation deviations caused by neglecting the influence of temperature and humidity.

[0030] Anti-jitter and early warning mechanism for solenoid valve drive: To avoid frequent start-stop of the solenoid valve due to instantaneous fluctuations in airflow within the chamber or occasional jumps in pressure sensor readings, the solenoid valve drive control unit incorporates an adjustable delay anti-jitter module. The working principle of this delay anti-jitter module is as follows: the valve opening control signal or valve closing control signal is only output when the comparison result continuously meets the trigger condition for a duration set by the delay anti-jitter module. For example, if the delay anti-jitter module is set to 5 seconds, the valve opening control signal will only be output when the real-time pressure value remains below the lower threshold for more than 5 seconds; similarly, the valve closing control signal will only be output when the real-time pressure value remains above the upper threshold for more than 5 seconds. This mechanism effectively filters out transient interference and extends the service life of the solenoid valve.

[0031] Furthermore, the solenoid valve drive control unit is also connected to an audible and visual warning unit installed on the outer wall of the switchgear cabinet. The system continuously accumulates the duration of each solenoid valve opening. When the cumulative opening duration exceeds a preset threshold and the real-time pressure value still has not reached the upper limit threshold, it indicates that there may be a leak exceeding the normal range, and simply relying on air replenishment cannot maintain the pressure to the target level. At this time, the solenoid valve drive control unit outputs a warning signal to the audible and visual warning unit, reminding on-site maintenance personnel to check the equipment sealing condition in a timely manner.

[0032] Special control procedures under ground flooding conditions: When the underground power distribution room experiences ground flooding due to heavy rain or seepage, and the floodwater submerges the bottom of the switch cabinet in a non-uniform manner, the system of this invention can execute a targeted "breathing hole directional sealing" control procedure on the basis of the above-mentioned normal control architecture to deal with the breathing effect caused by the water level difference at the bottom of the cabinet.

[0033] Multiple water level detection units are arranged at different locations on the outer side of the cabinet bottom. These units are electrodes positioned at multiple preset locations on the cabinet bottom, with the lower end of each electrode flush with the mounting reference surface. The water depth resolution of each electrode is not lower than a preset resolution threshold. As the water level rises, each detection unit simultaneously collects the water depth value at its corresponding location. The controller compares these water depth values, and when the difference between the maximum and minimum water depth exceeds a preset threshold (e.g., 5mm), the cabinet bottom is determined to be in a non-uniform immersion state. In this state, the location with the lowest water depth is identified as the venting area, which corresponds to the cable inlet / outlet sealing piece on the shallow submerged side of the switchgear bottom. Multiple water level detection units employ multi-stage conductive electrode arrays to acquire water depth data. Each electrode array consists of an insulated epoxy support, a 304 stainless steel common grounding main electrode, and multiple layers of independent detection sub-electrodes. The vertical spacing between adjacent detection sub-electrodes is equal to the system's preset water depth resolution. The bottom of the lowest layer of detection sub-electrodes is attached to the mounting reference surface at the bottom of the cabinet, while the highest layer matches the maximum water accumulation detection range at the bottom of the cabinet. The controller has a built-in low-voltage constant-voltage detection circuit that continuously transmits signals to the common grounding system. The grounded main electrode outputs a safe DC detection signal. When there is no water accumulation, the electrode circuit insulation is broken. When the water rises and submerges any sub-electrode, a conductive path is formed and a feedback current is generated. The controller calculates the accurate water depth based on the layer number of the conductive electrodes at each point. The water depth detection is achieved at a level not lower than the preset resolution threshold by relying on the stable spacing between the electrode layers. In addition to the layered conductive electrode array, this system can also be replaced with an analog liquid level probe that outputs a 4-20mA current signal as a water level detection unit. The continuous water depth is calculated linearly by the current value. Both structures can complete the acquisition of multi-point water depth difference and support the determination of non-uniform immersion state.

[0034] For this exhaust area, conventional pressurization strategies cannot prevent the gas driven by the water level difference from being discharged outwards; in fact, they may exacerbate water vapor circulation. Therefore, the system performs an active depressurization operation, guiding external accumulated water to carry impurities and fill the leaks in the exhaust area.

[0035] Here, the pressure reduction operation requires determining a safe and effective lower limit for pressure reduction. The target pressure for the lower limit is... The calculation logic is based on the following physical analysis: For external water to seep into the micro-gap between the sealing component and the cable sheath, it must overcome the capillary resistance of the gap itself. Only when the suction force provided by the negative pressure inside the cabinet and the external water head pressure are greater than the capillary resistance of the gap can the water carrying impurities enter the gap slowly and controllably, rather than rushing in violently. If the pressure drop is too deep, it may cause a large amount of water to enter the air chamber and damage the insulation; if the pressure drop is too shallow, it is insufficient to guide the water flow to effectively fill the gap.

[0036] Based on the above analysis, the target pressure for the lower limit of pressure reduction is... It can be determined according to the following relationship: ; in, The external atmospheric pressure is measured in real time by an external atmospheric pressure sensor, and the unit is Pascal (Pa). ρ is the density of the accumulated water, taken as the density of clean water under normal conditions, in kilograms per cubic meter; ρ is the acceleration due to gravity, taken as the standard value, in meters per second squared. The minimum water depth value measured by multiple water level detection units, in meters; This is a preset additional negative pressure margin, measured in Pascals (Pa), ranging from 100Pa to 300Pa. It is used to provide additional suction force sufficient to overcome the capillary resistance of the gap, while ensuring that the negative pressure does not exceed the safe pressure threshold of the switchgear air chamber.

[0037] The physical meaning of the above relationship is: target pressure inside the cabinet. Lower than the external atmospheric pressure The difference between the two (i.e., the negative pressure amplitude) is equal to the hydrostatic pressure generated by the water accumulation in the exhaust area. With additional negative pressure margin The sum of these. Therefore, the net pressure difference between the inside and outside of the cabinet is... The direction is from the outside to the inside, which is enough to drive the external water carrying impurities to seep into the gap in a directional manner.

[0038] The values ​​used in this embodiment are as follows: (Measured in real time by an external atmospheric pressure sensor); ; ; (The water depth on the west side is 3mm, which is the minimum water depth measured by multiple water level detection units.) (The preset negative pressure margin falls within the range of 100Pa to 300Pa, balancing driving performance and safety margin).

[0039] Substitute into the calculation: ; ; At this time, the negative pressure amplitude between the pressure inside the cabinet (101095.6 Pa) and the external atmospheric pressure (101325 Pa) is 229.4 Pa; the water accumulation in the western exhaust area generates a hydrostatic pressure of 29.4 Pa. The total pressure outside the gap is the sum of atmospheric pressure and the hydrostatic pressure of the accumulated water, i.e., 101325 + 29.4 = 101354.4 Pa; the total net driving pressure difference of the gap = total pressure outside - target pressure inside the cabinet = 101354.4 - 101095.6 = 258.8 Pa. This total pressure difference drives the water containing impurities to slowly seep into the gap from the outside in. The negative pressure amplitude of 229.4 Pa is only the pressure difference between the inside and outside of the cabinet and is not equivalent to the driving force for gap seepage. The negative pressure amplitude is much smaller than the pressure safety margin of the switchgear air chamber (usually not less than...). And below the system's preset safe negative pressure threshold. It will not damage the cabinet structure, nor will it cause a large amount of liquid water to flow into the air chamber.

[0040] It should be noted that the water depth on the east side... For use only with Comparison to determine non-uniform immersion conditions (difference between the two) Exceeding the preset threshold value The hydrostatic pressure generated by this pressure acts on the sealing component on the east side and does not participate in the pressure difference calculation for the directional fluid drive at the gap in the west venting area. The driving force at the gap on the west side originates entirely from the negative pressure inside the cabinet. ) and local water head pressure on the west side ( The superposition of ) The net pressure difference from the outside to the inside.

[0041] To prevent unexpected large-scale water ingress during depressurization, this system implements multiple safety protections simultaneously during the depressurization process:

[0042] First, the difference between the target pressure and the external atmospheric pressure ( (less than the preset safe negative pressure threshold) This ensures that the amount of water seeping in is only in the trace.

[0043] Second, during the depressurization period, the humidity sensor inside the chamber continuously monitors the humidity inside the cabinet. Once the humidity rises above a preset safety threshold (such as the baseline before depressurization), the system will detect the rise. rise %to The controller immediately terminates the pressure reduction operation, closes the exhaust solenoid valve and opens the replenishment solenoid valve to restore positive pressure, and outputs an alarm signal at the same time.

[0044] Third, the exhaust solenoid valve adopts an intermittent opening mode, opening for 1 to 2 seconds each time and then closing to avoid uncontrollable water ingress caused by continuous suction.

[0045] Provided that the above safety conditions are met, the controller closes the air supply solenoid valve and allows air to pass through the flow path. The exhaust solenoid valve exhausts air intermittently, to approximately to The traffic is in approximately Within seconds, the pressure inside the cabinet increased from approximately the normal level. Down to Nearby, then maintain the depressurization window. Second.

[0046] this Within seconds, water accumulated on the west side (water depth) (The bottom edge of the sealing component was not yet reached) inside and outside the cabinet. Driven by the directional net pressure difference (direction from outside to inside), suspended impurities such as mud, sand, and rust with a particle size of micrometers are slowly seeped inward along the micrometer-sized gap between the rubber ring and the cable. This pressure difference is actively constructed within the cabinet. Negative pressure and localized areas on the west side The superposition of water head pressure results in a seepage rate of approximately to It flows in via capillary action rather than free flow. Impurities are present in the narrowest part of the gap (the gap width is approximately...). They are mechanically intercepted and gradually accumulate, forming a physical blockage layer. A pressure reduction duration of a few seconds allows water containing impurities to flow through the gap for approximately [time period missing]. to Sufficient to cover the thickness of the rubber ring (approximately) to The main leakage path is as follows: Due to the limited negative pressure amplitude and the use of intermittent venting, the amount of water seeping into the air chamber is only trace: the humidity sensor monitors and displays the humidity in real time. % rose to %, the change range is %, much smaller The preset humidity safety threshold indicates that no dangerous situation has occurred where a large amount of liquid water has entered the air chamber.

[0047] Blocking effect verification: The controller performs a voltage reduction operation and maintains the preset voltage reduction time window (in this embodiment, ...). Within seconds, the controller continuously monitors the readings of the pressure sensor and humidity sensor inside the cabinet to determine the effectiveness of the seal. The specific logic is as follows: if the pressure inside the cabinet stabilizes on its own after venting stops and no longer continues to decrease, it indicates that external gas and liquid can no longer enter the cabinet through the original leak gap, and a seal has been formed. Simultaneously, if the humidity sensor inside the cabinet does not detect a significant increase in humidity, it indicates that the trace amount of moisture that has seeped into the cabinet is minimal and has not substantially affected the dryness inside the chamber. When both conditions are met, the controller determines that the seal is effective.

[0048] If the pressure continues to drop during the pressure reduction maintenance time, it indicates that the leak is large and the initial pressure reduction failed to effectively seal the leak. In this case, the controller can extend the pressure reduction maintenance time (e.g., extend...). (Seconds) allow more impurities to enter the gap with the water flow for secondary sealing. If the pressure still cannot be stabilized after extending the pressure reduction, the controller determines that there is a large leak point that exceeds the self-sealing capacity of the system, and immediately issues a sealing abnormality warning, prompting maintenance personnel to conduct manual inspection.

[0049] In this control scheme, the driving force that guides impurities to directionally infiltrate into the micro-gap of the exhaust area originates from the superposition of only two factors: the controlled negative pressure actively constructed inside the cabinet (i.e., Below (partial area); local water accumulation depth in the exhaust area The resulting hydrostatic pressure. The sum of the two. This constitutes the net driving pressure difference from the outside in.

[0050] The net driving pressure difference only applies to the area with the lowest water depth identified by the water level detection unit (i.e., the venting area). Water depth differences in other areas (such as the east, south, and north sides) are only used to trigger the judgment logic for non-uniform immersion and do not participate in the fluid dynamics driving calculation at the venting area gaps. The correctness of the above physical relationship has been verified in the numerical calculations of this embodiment: cabinet pressure External water pressure on the west side Net pressure difference The direction is from the outside to the inside, which satisfies the physical conditions for driving water containing impurities to flow inward.

[0051] Restoring positive pressure and reinforcing the seal: Once the controller determines the seal is effective, immediately close the exhaust solenoid valve and open the replenishment solenoid valve to supply dry air from the dry air source into the air chamber, restoring the pressure inside the chamber from a slightly negative pressure state to a positive pressure state. Compared to the normal positive pressure value before depressurization, the target positive pressure value at this stage is set higher. The purpose is to apply an outward compressive force to the impurity sealing layer that has filled the gaps, making its structure more compact. However, this compressive force should not be too high: if the pressure is too high, it may push the impurity layer that has not yet fully solidified out of the gaps, causing the seal to fail.

[0052] To resolve this contradiction, the target pressure during the re-pressure reinforcement phase... It can be determined according to the following relationship: ; in, This is the external atmospheric pressure, measured in Pascals (Pa). Safety factor (range of values) In this embodiment, ); The static friction force per unit area between the impurity filling layer and the crevice wall is denoted as , and is a dimensionless empirical constant calibrated experimentally (a conservative value is taken from experiments in this embodiment). Actual measurement range to ); The contact area between the impurity filling layer and the crack wall is estimated by multiplying the crack perimeter by the filling depth, and the unit is square meters. The cross-sectional area of ​​the gap perpendicular to the pressure direction is expressed in square meters. This is the maximum static friction force that the impurity-filled layer can withstand within the gap, measured in Newtons; this maximum static friction force divided by the cross-sectional area. This gives the ultimate pressure difference that a unit area can withstand, measured in Pascals (Pa).

[0053] The calculation logic for the above relationship is as follows: the physical meaning of the right side of the inequality is the external atmospheric pressure plus the product of the ultimate pressure difference that the impurity packing layer can withstand per unit area and the safety factor. The sum of these two is the theoretical upper limit of the pressure that can be applied inside the cabinet without damaging the packing layer. After calculating this upper limit, the controller takes a value slightly lower than this upper limit as the target pressure for the re-pressure reinforcement stage. This ensures that the impurity layer is compacted without being pushed out, achieving the dual goals of sealing and reinforcement as well as sealing and maintaining.

[0054] The calculation for the double-pressure reinforcement in this embodiment is as follows: The circumference of the gap is taken as the average circumference of the cable and the rubber ring. The filling depth is taken as ( Therefore ; The cross-sectional area of ​​the gap perpendicular to the pressure direction is the average gap width after aging. , perimeter gap .

[0055] Substitute into the calculation:

[0056] ; This value ( ) lower than the theoretical tolerance limit of the impurity plugging layer ( ), left The safety margin ensures that the impurity layer is compacted without being pushed out.

[0057] The controller controls the air supply circuit to increase the pressure inside the cabinet to [a certain level]. ( And maintain the preset reinforcement time (in this embodiment, it is...) (seconds), allowing the impurity sealing layer to further compact and solidify under continuous pressure differential.

[0058] Blocking failure determination and exit mechanism: After the re-pressure is completed, the system continuously monitors the following two indicators: If the humidity inside the cabinet continues to rise and exceeds the preset threshold (such as the baseline before pressure reduction), rise to This indicates that external moisture is continuously entering the air chamber, indicating that the seal has failed. With the gas supply solenoid valve closed, if the pressure inside the cabinet continues to drop beyond a preset rate (e.g., exceeding...), This indicates that the sealing layer failed to effectively block the gas exchange channel, and the sealing was deemed to have failed.

[0059] When any of the above situations occur, the system automatically exits the blocking mode, switches back to the normal positive pressure maintenance mode, and issues an alarm signal through the audible and visual warning unit to prompt maintenance personnel to perform manual inspection and handling in a timely manner. If both indicators are normal, the system will resume normal dynamic pressure compensation control after the repressure reinforcement is completed.

[0060] The result after re-pressure in this embodiment: humidity stabilized at... %(rise less than (Threshold), pressure after the air supply solenoid valve closes Fluctuations within seconds not exceeding The blocking effect was good, and the system determined that the blocking was effective and resumed normal operation.

[0061] Supplementary notes on the differential control of sealing materials: In another embodiment of the invention, the controller also pre-stores material type information for the sealing components at each cable inlet and outlet, including rubber rings and fireproof putty. Since there are significant differences in the micro-gap morphology, elastic modulus, and capillary resistance characteristics between sealing components of different materials and the cable sheath, after determining the venting area based on water level detection, the controller further identifies the material type of the corresponding sealing component in that area and adjusts the control parameters during the pressure reduction process accordingly. Specifically: For rubber ring-type sealing components, their elastic recovery capability allows micro-gaps to tend to shrink under negative pressure, which is beneficial for impurity retention. Therefore, a shallower pressure reduction depth (corresponding to smaller...) can be used. Value, such as and a shorter duration of blood pressure reduction (e.g.) Second); For fireproof putty-type sealing components, which have strong plasticity and relatively stable micro-crack morphology, a large directional pressure difference is required to drive water containing impurities to fully penetrate deep into the cracks. Therefore, a larger... Value (e.g.) ) and a longer duration of blood pressure reduction (such as Second).

[0062] Through the above-mentioned differentiated control, the optimal match between the pressure reduction parameters and the characteristics of the sealing material was achieved, further improving the self-sealing success rate of various sealing components under non-uniform immersion conditions.

[0063] Data storage and remote communication functions: To facilitate the traceability and analysis of operational data and the remote monitoring of equipment status, this system also has data storage and remote communication functions.

[0064] The output of the pressure threshold dynamic adaptation unit is connected to a storage unit. This storage unit continuously records the corresponding data at preset sampling intervals (e.g., every 5 minutes), including the dynamic pressure trigger threshold, real-time temperature data, real-time humidity data, real-time pressure value, cumulative opening time of the air replenishment solenoid valve, and cumulative opening time of the exhaust solenoid valve. By retrieving this historical data, maintenance personnel can retrospectively analyze the changing trend of the air chamber pressure, the degree of influence of temperature and humidity on the pressure threshold, and the frequency and duration of air replenishment actions within any given time period, providing data support for judging the long-term evolution trend of the switchgear's sealing performance.

[0065] In terms of communication, the temperature and humidity coupling correction unit, pressure threshold dynamic adaptation unit, and solenoid valve drive control unit are all connected to the local monitoring platform of the switchgear via CAN bus, enabling collaborative management with other intelligent devices within the station. Simultaneously, the system also connects to a remote operation and maintenance management platform via a 4G wireless communication module. The 4G wireless communication module reports data according to a preset reporting cycle (e.g., every 5 minutes), and alarms are immediately pushed to the local audible and visual warning unit and the remote operation and maintenance management platform. This allows maintenance personnel to remotely view the operating status of the switchgear, receive alarm information, and remotely adjust control parameters when necessary, significantly improving operation and maintenance efficiency and response speed.

[0066] Example 2: This example uses a prototype of a 10kV environmentally friendly gas-insulated switchgear installed in an underground smart grid distribution room as an example. The cabinet structure, sealing arrangement, gas chamber volume, insulating medium (dry air), and pressure control method of this prototype are all designed according to standard environmentally friendly gas-insulated switchgear. It should be noted that environmentally friendly gas-insulated metal-enclosed switchgear can be divided into two main categories according to its application function: ring main units and switchgear. The two are consistent in core technologies such as insulating gas chamber structure, sealing method, and gas pressure maintenance. The test platform used in this example is the same as the general test platform for ring main units, but the tested object and verification data are all derived from the switchgear itself.

[0067] Basic parameters of the switchgear and control system: The air chamber volume is 500 liters, filled with dry air as the insulating medium. The rated inflation pressure (standard air pressure reference value) is... (Absolute pressure, i.e.) The minimum functional pressure is (Absolute pressure, i.e.) ), the difference between the two This refers to the available margin for pressure compensation control. The dew point temperature at the outlet of the dry air receiver tank should not exceed [a certain value]. The extreme ambient temperature at the counter location in winter is no lower than Both The temperature difference margin ensures that no condensate will form in any part of the air chamber.

[0068] The pressure detection unit uses an absolute pressure sensor with a measurement range of [missing information]. Precision The air chamber is equipped with a temperature sensor (accuracy). ) and humidity sensor (accuracy) An atmospheric pressure sensor is installed outside the cabinet to collect real-time data on external atmospheric pressure. The system connects to the local monitoring platform via a CAN bus and reports data every 5 minutes via a 4G module, with alarms pushed out immediately.

[0069] A water level detection electrode is installed at each of the four positions on the bottom of the cabinet, with the lower end of the electrode flush with the mounting reference surface on the bottom of the cabinet. Cable inlet and outlet holes are sealed with rubber rings, and the cable outer diameter... Inner diameter of rubber ring This creates an over-compensation relationship.

[0070] Dynamic pressure compensation process under normal operation: At a certain moment, the temperature sensor measured The humidity sensor measured The pressure correction offset for this operating condition is obtained by interpolation in the mapping table using the temperature and humidity coupling correction unit. (A positive value indicates that the gas supply threshold needs to be adjusted upwards due to thermal expansion). The pressure threshold dynamic adaptation unit will adjust the standard gas pressure reference value. With offset Superimposed Then add or subtract respectively To obtain the upper limit threshold Lower threshold At this time, the pressure sensor measures the real-time pressure. If the air temperature falls below the lower threshold, the air replenishment condition is triggered. After the delay and anti-shake module confirms that this state lasts for 5 seconds, the solenoid valve opens, and dry air from the storage tank passes through the pressure reducing valve. The flow rate replenishes the air chamber. Approximately 46 seconds later, the pressure rises to the upper limit threshold. After a 5-second anti-shake confirmation, the solenoid valve closes. Throughout the entire process, the air chamber pressure remains higher than the minimum functional pressure. The circuit breaker's insulation and operating characteristics are stable.

[0071] In the above process, The selection criterion for allowable deviation is: greater than the sensor accuracy. To avoid false triggering by noise; and much smaller than Total margin ensures ample response time. The 5-second stabilization duration corresponds to approximately [missing information - likely a unit of measurement] per second during the air replenishment process. Pressure changes, accumulating over 5 seconds It will not mistakenly filter out normal pressure rises; while occasional sensor fluctuations, which are usually less than 2 seconds, can be effectively filtered out.

[0072] Procedure for "directional sealing of vents" under non-uniform ground immersion conditions: Heavy rain caused water accumulation in the power distribution room, and the area under the cabinets experienced uneven ground settlement (the eastern side settled approximately...). The water level is lower in the east and higher in the west. At a certain moment, the four electrodes measured the water depth: the east side, defined as south by the direction the switch cabinet door faces. ,South ,West ,north Maximum value (East), minimum value (West), difference Exceeding the preset threshold The area was determined to be in a non-uniform immersion state. The western side, where the water depth was the lowest, was designated as the venting zone. The threshold value is higher than the electrode. With its high resolution, it can reliably distinguish between uniform water accumulation and non-uniform water accumulation caused by tilting.

[0073] The controller then initiates active pressure reduction, using impurities to fill the breathing gap at the western sealing element. The target pressure for the lower limit of pressure reduction is... Determined according to the following formula: ; The values ​​of each parameter in the formula are as follows: The external atmospheric pressure is measured in real time by an external atmospheric pressure sensor. The value used in this embodiment is... ; For the density of the accumulated water, take... (Clear water); ; This embodiment represents the minimum water depth value among multiple water level detection units. (Water depth on the west side) ); As a preset additional negative pressure margin, this embodiment takes This value is sufficient to overcome the capillary resistance of the micro-slits and form an effective directional suction force.

[0074] Substitute into the calculation:

[0075] ; At this time, the pressure inside the cabinet ( ) lower than the external atmospheric pressure ( )about The cabinet is under a controlled, slightly negative pressure. Meanwhile, the external water pressure at the west exhaust area is: cabinet internal pressure ( The water pressure is lower than that on the west side. The net pressure difference is: (Direction from outside to inside).

[0076] Should The directional pressure difference is sufficient to drive external water carrying impurities to slowly seep inward along the micro-gap, while... The negative pressure amplitude is much smaller than the pressure safety margin of the switchgear air chamber (usually not less than...). This will not damage the cabinet structure.

[0077] It should be noted that the water depth on the east side... For use only with Comparison to determine non-uniform immersion conditions (difference between the two) Exceeding the preset threshold The hydrostatic pressure generated by this pressure acts on the sealing component on the east side and does not participate in the pressure difference calculation for the directional fluid drive at the gap in the west venting area. The driving force at the gap on the west side originates entirely from the negative pressure inside the cabinet. ) and local water head pressure on the west side ( The superposition of ) The net pressure difference from the outside to the inside.

[0078] To prevent unexpected large-scale water ingress during depressurization, this system implements multiple safety protections simultaneously during the depressurization process: The difference between the target pressure and the external atmospheric pressure ( (less than the preset safe negative pressure threshold) This ensures that the amount of water seeping in is only in the trace. During the depressurization period, the humidity sensor inside the chamber continuously monitors the humidity. Once the humidity rises above a preset safety threshold (e.g., compared to the baseline before depressurization), the system will detect the rise. rise to The controller immediately terminates the pressure reduction operation, closes the exhaust solenoid valve and opens the replenishment solenoid valve to restore positive pressure, and outputs an alarm signal at the same time. The exhaust solenoid valve opens intermittently, opening for 1 to 2 seconds each time before closing to prevent uncontrollable water ingress caused by continuous suction.

[0079] Provided that the above safety conditions are met, the controller closes the air supply solenoid valve and allows air to pass through the flow path. The exhaust solenoid valve exhausts air intermittently, to approximately to The traffic is in approximately Within seconds, the pressure inside the cabinet increased from approximately the normal level. Down to Nearby, then maintain the depressurization window. Second.

[0080] this Within seconds, water accumulated on the west side (water depth) (The bottom edge of the sealing component was not yet reached) inside and outside the cabinet. Driven by directional pressure difference, carrying particle size to Suspended impurities such as mud, sand, and rust slowly seep in through the micro-gap between the rubber ring and the cable, at a rate of approximately [missing information]. to Impurities are intercepted and accumulated in the narrow gaps, forming a physical sealing layer. The pressure drop duration of a few seconds ensures that impurities can penetrate deep into the gaps. to Sufficient to cover the thickness of the rubber ring (approximately) to The main leakage path. Because the negative pressure amplitude is controlled and venting is intermittent, the amount of water seeping in is only trace. The humidity sensor monitors and displays the humidity in real time as... % rose to %, change range %, much smaller The % safety threshold indicates that no large amount of liquid water has entered the gas chamber. Based on a gas chamber volume of 500L, this... The absolute moisture increment corresponding to the % safety threshold humidity increment is approximately 0.09g to 0.17g, which is less than one-thousandth of the long-term moisture accumulation (tens of grams) that the switchgear insulation system can withstand. Moreover, this trace amount of moisture is diluted by dry air after repressurization, and its impact on the dew point is less than 3°C, which is far below the design margin requirement of -40°C.

[0081] Verification of sealing effect: Pressure reduction and maintenance After the seconds are up, the controller stops exhausting and monitors the sealing effect: after exhausting stops... Within seconds, the pressure fluctuation inside the cabinet is less than (Depend on After slight fluctuations, it stabilized. (Nearby), indicating that external gas can no longer enter the cabinet through the original leak gap, and a sealing layer has been formed; at the same time, the humidity sensor reading changed from % becomes Changes in Within the accuracy range, no significant increase in humidity was detected. If both conditions are met, the controller determines the sealing is effective.

[0082] If the pressure continues to drop during the pressure reduction maintenance period, or if the humidity rises above the preset humidity safety threshold during the stable observation period after venting stops (e.g., ...), If the preset humidity safety threshold is not met, the controller determines that the sealing intervention has failed and immediately performs the following operations: closes the exhaust solenoid valve, opens the replenishment solenoid valve to restore the rated positive pressure, issues an alarm signal of "seal abnormality - manual inspection required", and does not repeat the pressure reduction sealing operation to avoid repeated introduction of moisture and cumulative insulation damage.

[0083] If the pressure continues to drop beyond a certain value after venting is stopped... (Right now Dropped more than within seconds If the pressure drop is too high, it indicates that the leak is too large or the supply of impurities is insufficient, and the initial pressure reduction failed to achieve effective sealing. In this case, the controller can extend the pressure reduction maintenance time. For several seconds, more impurities are allowed to enter the gaps with the water flow for secondary sealing. If the pressure still cannot be stabilized after extending the pressure reduction period, the controller determines that there is a large leak point that exceeds the system's self-sealing capacity, and immediately issues a sealing abnormality warning, prompting maintenance personnel to conduct manual inspection.

[0084] Re-pressure reinforcement stage: Once the controller determines the sealing is effective, immediately close the exhaust solenoid valve and open the replenishment solenoid valve to supply dry air from the dry air source into the air chamber, restoring the pressure inside the cabinet from a slightly negative pressure state to a positive pressure state. Target pressure for the re-pressure reinforcement stage. Determine using the following formula: ; in, For external atmospheric pressure, take the value. ; For safety reasons, this embodiment takes... ; The static friction force per unit area between the impurity filling layer and the gap wall is determined through experiments, using a conservative value. (Measurement range) to ); The contact area between the impurity-filling layer and the gap wall is the perimeter of the gap, which is the average circumference of the cable and the rubber ring. The filling depth is taken as ( Therefore ; The cross-sectional area of ​​the gap perpendicular to the pressure direction is the average gap width after aging. , perimeter gap .

[0085] Substitute into the calculation: ; ; This value ( ) lower than the theoretical tolerance limit of the impurity plugging layer ( ), left A safety margin is provided to ensure that the impurity layer is compacted without being pushed out. The controller controls the air supply circuit to maintain approximately [a certain level of safety]. Within seconds, the pressure inside the cabinet was reduced from Upgraded to and maintain The pressure difference lasts for several seconds, allowing the impurity sealing layer to further drain and solidify under continuous pressure difference, forming a stable seal.

[0086] Blocking failure determination and exit mechanism: After the re-pressure is completed, the system continuously monitors the following two indicators: If the humidity inside the cabinet continues to rise and exceeds the preset threshold (such as the baseline before pressure reduction), %rise to The percentage indicates that external moisture is continuously entering the air chamber, indicating that the seal has failed. With the gas supply solenoid valve closed, if the pressure inside the cabinet continues to drop beyond a preset rate (e.g., exceeding...), This indicates that the sealing layer failed to effectively block the gas exchange channel, and the sealing was deemed to have failed.

[0087] When any of the above situations occur, the system automatically exits the blocking mode, switches back to the normal positive pressure maintenance mode, and issues an alarm signal through the audible and visual warning unit to prompt maintenance personnel to perform manual inspection and handling in a timely manner. If both indicators are normal, the system will resume normal dynamic pressure compensation control after the repressure reinforcement is completed.

[0088] In this embodiment, the humidity stabilizes after repressurization. (rise less than (Threshold), pressure after the air supply solenoid valve closes Fluctuations within seconds not exceeding The blocking effect was good, and the system determined that the blocking was effective and resumed normal operation.

[0089] After a brief depressurization operation, the cabinet not only avoided uncontrollable water ingress, but also temporarily blocked the breathing channel using impurities carried in the water, buying valuable time for maintenance personnel to arrive on-site. Even if the impurity layer later partially detached due to environmental factors, it had already prevented continuous moisture exchange during the immersion period, avoiding the cumulative insulation degradation caused by the breathing effect.

[0090] Examples of differential control of sealing materials: In another embodiment of the invention, the controller pre-stores the material type information of the sealing components at each cable inlet and outlet. When the water level detection unit determines a non-uniform immersion state and identifies the venting area, the controller further identifies the material type of the sealing component corresponding to that area: If the sealing component corresponding to the exhaust area is a rubber ring, the controller will use it during the pressure reduction operation. Duration of blood pressure reduction Seconds. This is because the rubber ring has elastic recovery ability, and the micro-gap tends to shrink under negative pressure, which is conducive to the interception of impurities. A shallower pressure drop depth and a shorter maintenance time can achieve effective sealing; If the sealing material corresponding to the exhaust area is fireproof putty, then the controller adopts... Duration of blood pressure reduction Seconds. This is because fireproof putty has strong plasticity and relatively stable micro-crack morphology, requiring a large directional pressure difference to drive water containing impurities to fully penetrate into the depths of the cracks.

[0091] Through the above-mentioned differentiated control, the optimal match between the pressure reduction parameters and the characteristics of the sealing material was achieved, further improving the self-sealing success rate of various sealing components under non-uniform immersion conditions.

[0092] The above is a complete description of the specific embodiments of the present invention. It should be noted that the specific orientations, quantities, electrode arrangements, etc. involved in the above description are merely exemplary descriptions given to facilitate understanding of the concept of the present invention. In actual product implementation, adjustments can be made according to the specific size and structure of the switchgear. However, as long as the core control logic of "detecting water level difference to determine breathing gap, actively reducing pressure to utilize impurities for self-sealing, and then repressurizing and reinforcing" is adopted, it falls within the protection scope of the present invention.

[0093] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A dynamic air pressure compensation control system for environmentally friendly gas-insulated switchgear, comprising a dry air storage tank connected to the switchgear's air chamber, a pressure detection unit disposed within the air chamber, a replenishing solenoid valve, an exhaust solenoid valve, and a controller, characterized in that, Also includes: Multiple water level detection units are installed at different locations on the bottom of the switch cabinet; The controller is connected to the pressure detection unit, the air supply solenoid valve, the exhaust solenoid valve, and each water level detection unit. The controller determines a non-uniform immersion state when the difference between the maximum and minimum water depth exceeds a preset water depth difference threshold, and identifies the location with the minimum water depth as the exhaust zone. In a non-uniform immersion state, the controller closes the air supply solenoid valve and intermittently opens the exhaust solenoid valve to reduce the air chamber pressure to the target pressure. The target pressure is lower than the external atmospheric pressure, and the pressure difference between the target pressure and the external atmospheric pressure is greater than the external water pressure in the exhaust area. A directional pressure difference is formed between the air chamber and the exhaust area from the outside to the inside. Under the action of the directional pressure difference, the external water carries suspended impurities into the micro gaps in the exhaust area and forms a filling layer. If, after exhaust is stopped, the pressure fluctuation in the air chamber is less than the preset pressure fluctuation threshold and the humidity change is less than the preset humidity change threshold within the preset stable observation period, then the sealing is deemed effective. After the sealing is effective, the controller closes the exhaust solenoid valve and opens the replenishment solenoid valve to restore the air chamber pressure to the repressurization target pressure. The positive pressure difference between the repressurization target pressure and the external atmospheric pressure is lower than the ultimate pressure difference corresponding to the maximum static friction force of the impurity packing layer.

2. The air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear according to claim 1, characterized in that, The system has an external atmospheric pressure sensor located outside the cabinet, and the controller is connected to the external atmospheric pressure sensor. The target pressure satisfies: ； The total net driving pressure difference from the outside to the inside of the gap is the sum of the external atmospheric pressure and the static water pressure, minus the target pressure inside the cabinet. The total net pressure difference drives water and impurities to seep into the gaps. in, The real-time external atmospheric pressure is measured by an external atmospheric pressure sensor. The density of the accumulated water, It is the acceleration due to gravity. This represents the minimum water depth measured by multiple water level detection units. This is the preset negative pressure margin.

3. The air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear according to claim 2, characterized in that, The difference between the target pressure and the external atmospheric pressure is .

4. The air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear according to claim 3, characterized in that, The target pressure for the complex pressure meets the following requirements: ； in, The real-time external atmospheric pressure is measured by an external atmospheric pressure sensor. For safety reasons, This refers to the static friction force per unit area between the impurity filling layer and the gap wall. This refers to the contact area between the impurity-filling layer and the crevice wall. Let be the cross-sectional area of ​​the gap perpendicular to the pressure direction.

5. The air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear according to claim 1, characterized in that, The multiple water level detection units are electrodes, arranged in multiple preset positions on the bottom of the switch cabinet. The lower end of each electrode is flush with the mounting reference surface of the bottom of the cabinet. The water depth resolution of the electrodes is not lower than a preset resolution threshold. The exhaust area corresponds to the cable inlet and outlet hole sealing component on the shallow submerged side of the bottom of the switch cabinet.

6. The air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear according to claim 1, characterized in that, If the rate of pressure drop in the air chamber exceeds the preset pressure drop rate threshold, the pressure reduction maintenance time is extended for a preset extension period for secondary plugging. If the rate of pressure drop in the air chamber still exceeds the preset pressure drop rate threshold after the extension, it is determined that there is a leak point in the exhaust area that exceeds the self-sealing capability and a sealing abnormality warning is issued.

7. The air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear according to claim 6, characterized in that, The controller has pre-stored the material type information of the sealing parts at each cable inlet and outlet hole. The material types include rubber rings and fireproof putty. The controller adjusts the pressure reduction depth and / or pressure reduction maintenance time during the pressure reduction process according to the material type of the sealing part corresponding to the exhaust area.

8. The air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear according to claim 1, characterized in that, During the pressure reduction process, the controller receives humidity sensor data in real time. When the humidity rises above the baseline before pressure reduction and exceeds the preset humidity safety threshold, it immediately closes the exhaust solenoid valve, opens the replenishment solenoid valve to restore positive pressure, and outputs an alarm signal. The difference between the target pressure and the external atmospheric pressure is less than the preset safe negative pressure threshold.

9. The air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear according to claim 1, characterized in that, The system also includes a temperature and humidity coupling correction unit, a pressure threshold dynamic adaptation unit, and a solenoid valve drive control unit. The input of the temperature and humidity coupling correction unit is connected to the temperature sensor and humidity sensor in the air chamber. The temperature and humidity coupling correction unit has a built-in temperature and humidity-pressure deviation mapping table. The temperature and humidity-pressure deviation mapping table has multiple sets of temperature and humidity sampling points generated by environmental simulation test calibration and corresponding pressure compensation offsets. The temperature and humidity coupling correction unit matches the real-time temperature data and real-time humidity data with the temperature and humidity-pressure deviation mapping table. The pressure threshold dynamic adaptation unit superimposes the standard air pressure reference value with the pressure correction offset to obtain a dynamic pressure trigger threshold. The solenoid valve drive control unit compares the real-time pressure value with the dynamic pressure trigger threshold and outputs a control signal to the air supply solenoid valve or the exhaust solenoid valve.

10. The air pressure dynamic compensation control system for environmentally friendly gas-insulated switchgear according to claim 2, characterized in that, The solenoid valve drive control unit has a built-in delay anti-shake module. The delay anti-shake module has a preset delay anti-shake duration. The valve opening control signal or valve closing control signal is output only when the comparison result continuously meets the trigger condition to reach the preset delay anti-shake duration.

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