SF6 gas self-adaptive flow rate control method and combined device

Abstract

The invention relates to the technical field of SF6 gas filling equipment, and discloses an SF6 gas self-adaptive flow rate control method and a combined device. According to the method, the pressure Pdevice of an equipment air chamber and the pressure Pout of a device outlet are obtained in real time, the dynamic target pressure Ptarget = Pdevice + delta P is calculated, the opening degree of a pressure reducing valve is dynamically adjusted by comparing the Pout with the Ptarget, and the Pout approaches the Ptarget to maintain the dynamic pressure difference. The device comprises a pressure-bearing pipeline, a pressure reducing valve connected to the pressure-bearing pipeline in series, an inlet pressure sensor and an outlet pressure sensor which are arranged on the inlet side and the outlet side of the pressure reducing valve respectively, a control module and an electric actuator. And the control module is configured to execute the steps of the method to realize self-adaptive precise control. The pressure reducing valve is automatically adjusted through closed-loop control, the pressure difference is intelligently adjusted according to the inflation stage, a safety protection mechanism is combined, and the problems that traditional manual operation is low in efficiency and poor in stability, and potential safety hazards exist are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of SF6 gas filling equipment, in particular to a SF6 gas self-adaptive flow rate control method and a combined device. BACKGROUND

[0002] Sulfur hexafluoride (SF6) gas is widely used in circuit breakers, combined electrical apparatus and other high-voltage electrical equipment in substations due to its excellent insulation and arc extinguishing performance. In order to ensure the normal operation of these devices, it is necessary to periodically supplement SF6 gas to the device gas chamber, i.e. gas supplement operation.

[0003] At present, in the SF6 gas supplement operation of substations, the commonly used operation mode is to connect the SF6 gas cylinder and the electrical equipment by using a special filling hose, and then manually adjust the pressure reducing valve installed on the pipeline by the operator to control the filling pressure and flow rate. However, since the initial pressure in the SF6 gas cylinder is usually much higher than the rated working pressure of the electrical equipment gas chamber, and the cylinder pressure will continue to drop during the entire gas supplement process, the operator must continuously and finely manually adjust the pressure reducing valve according to his own experience, so as to control the outlet pressure in a narrow and dynamically changing appropriate range slightly higher than the device gas chamber pressure. This method not only completely depends on the personal experience and concentration of the operator, resulting in low operation efficiency and high labor intensity, but also makes it difficult to ensure the stability of the filling pressure and flow rate. If the output pressure is too low, the gas cannot be effectively filled, and if the pressure is too high or the flow rate is too fast, it may cause impact on the internal components of the device, which poses a safety hazard, and the stability and safety of the entire filling process cannot be effectively guaranteed. SUMMARY

[0004] (I) Technical problems solved In view of the deficiencies of the prior art, the present application provides a SF6 gas self-adaptive flow rate control method and a combined device, which has the advantages of full-automatic and accurate adjustment of the SF6 filling process, and solves the problems of traditional manual operation depending on experience, low efficiency, poor stability and safety hazards.

[0005] (II) Technical solutions In order to achieve the purpose of full-automatic and accurate adjustment of the SF6 filling process, the present application provides the following technical solutions: In one aspect, the present application provides a SF6 gas self-adaptive flow rate control method, comprising the following steps: Real-time acquisition of device gas chamber pressure P device and device outlet pressure P out ; Calculation of dynamic target pressure P target , wherein P target =P device +ΔP, ΔP is a preset pressure difference; By comparing P out With P target Dynamically adjust the opening of the pressure reducing valve to make P out Approaching the dynamically changing P target This is to maintain a dynamic pressure differential for continuous inflation.

[0006] The "dynamic adjustment" step includes: If P out <P target If so, increase the opening of the pressure reducing valve; If P out >P target +δ, where δ is the pressure tolerance, then the opening of the pressure reducing valve is reduced.

[0007] Among them, according to P device The magnitude of the pressure difference ΔP is dynamically adjusted: When P device When the pressure is below the first pressure threshold, the first ΔP value is used; When P device When the pressure exceeds the second pressure threshold, a second ΔP value less than the first ΔP value is used.

[0008] This also includes security protection steps: when P is detected device The rate of decrease exceeds a preset threshold, or P out When the absolute safety pressure limit is exceeded, a safety protection action is triggered.

[0009] The system employs a PID control algorithm to generate instructions for adjusting the opening of the pressure reducing valve, and can dynamically tune the PID parameters according to the system status.

[0010] Another aspect of the present invention provides an SF6 gas adaptive flow rate control method and combined apparatus for implementing the method described in any one aspect, comprising: Pressure-bearing pipelines are used to connect SF6 gas cylinders and electrical equipment; Pressure reducing valve, installed in series on the pressure-bearing pipeline; An inlet pressure sensor and an outlet pressure sensor are respectively installed on the inlet side and the outlet side of the pressure reducing valve; The control module is connected to the inlet pressure sensor and the outlet pressure sensor. An electric actuator is electrically connected to the control module and driven by the regulating mechanism of the pressure reducing valve; The control module is configured to perform the method steps as described in any one of the aspects.

[0011] It also includes an audible and visual alarm and a safety relay, both of which are electrically connected to the control module and used to perform the safety protection actions.

[0012] It also includes a flow rate sensor, which is installed at the center of the main section of the pressure pipeline and is connected to the control module via a signal connection.

[0013] The electric actuator includes a stepper motor and a reduction gear set.

[0014] The pressure-bearing pipeline is a reinforced polyurethane flexible hose with quick connectors at both ends, and the pressure-bearing pipeline and the cables connecting the electrical components are integrated into a cable-pipeline composite bundle.

[0015] (III) Beneficial Effects Compared with the prior art, the present invention provides an SF6 gas adaptive flow rate control method and combined device, which has the following beneficial effects: This SF6 gas adaptive flow rate control method and combined device achieves adaptive and precise control throughout the entire inflation process by real-time monitoring of the equipment's gas chamber pressure and dynamic calculation of the optimal target pressure, and by automatically adjusting the pressure reducing valve opening using a closed-loop control system. This method intelligently adjusts the differential pressure parameter according to the inflation stage, effectively preventing pressure overshoot while ensuring inflation efficiency. Combined with multiple safety protection mechanisms, it significantly improves operational safety, stability, and automation, completely solving the problems of traditional manual operation, such as reliance on experience, poor adjustment accuracy, and potential safety hazards. Attached Figure Description

[0016] Figure 1 This is a diagram illustrating the method steps of the present invention; Figure 2 This is a schematic diagram of the process of the present invention; Figure 3 This is a schematic diagram of the structural principle of the present invention.

[0017] In the diagram: 1. Pressure-bearing pipeline; 2. Pressure reducing valve; 3. Inlet pressure sensor; 4. Outlet pressure sensor; 5. Control module; 6. Electric actuator; 7. Flow rate sensor; 8. Safety relay; 9. Audible and visual alarm. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0019] First Embodiment Please see Figure 1 and Figure 2 The first embodiment of the present invention provides an adaptive flow rate control method for SF6 gas, comprising the following steps: S101. System Initialization and Parameter Setting: After the device is powered on, the control module 5 first performs a system self-test, including status checks on each pressure sensor, electric actuator 6, and communication line. After completing the self-test, the system reads preset parameters, including the equipment's rated pressure P. rated (e.g., 0.5 MPa or 0.6 MPa), initial optimal pressure difference ΔP (e.g., 0.05 MPa), pressure tolerance δ (e.g., 0.02 MPa), upper limit of safe pressure (e.g., 0.7 MPa), and pressure change detection threshold.

[0020] S102, Real-time pressure data acquisition: Continuously acquires the equipment chamber pressure P through outlet pressure sensor 4. device The outlet pressure P of the device is continuously collected by the inlet pressure sensor 3. out The sampling frequency is set to 10Hz to ensure the control system can respond promptly to pressure changes. Both pressure sensors are equipped with temperature compensation to effectively eliminate the impact of ambient temperature changes on measurement accuracy.

[0021] S103, Inflation completion judgment: Control module 5 compares the current P device With P rated If P device ≥P rated If the pressure remains stable (e.g., pressure fluctuation is less than 0.01 MPa for 10 seconds), then execute S104 to end the process; otherwise, execute S105 to continue the inflation process.

[0022] S104. End of inflation process: Control module 5 sends a command to electric actuator 6 to adjust the opening of pressure reducing valve 2 to the fully closed position (i.e., the stepper motor returns to zero). The system issues an audible and visual prompt of "inflation complete", records data such as inflation time and gas consumption, and generates an inflation report which is transmitted to the terminal device.

[0023] S105, Dynamic Target Pressure Calculation: Control module 5 calculates the target pressure based on real-time collected data. device Calculate the dynamic target pressure P target , where P target =P device +ΔP. The pressure difference ΔP is not a fixed value, but an adaptive parameter that is dynamically adjusted according to the inflation stage.

[0024] S106, Pressure Status Judgment and Adjustment Decision: Control module 5 will collect P data in real time... out With the calculated P target Compare the results and implement the corresponding adjustment strategy: if P out <P target This indicates insufficient outlet pressure and a risk of gas not being able to be introduced. Therefore, execute S107 to increase the opening of pressure reducing valve 2; if P out >Ptarget +δ indicates that the outlet pressure is too high, posing a risk of inefficiency or equipment impact. Therefore, execute S108 to reduce the opening of pressure reducing valve 2; if P out Located in [P target ,P target If the pressure is within the +δ] range, it indicates that the current pressure is in the optimal range, then execute S109 to maintain the current valve opening.

[0025] S107, Increase Valve Opening Operation: Control module 5 calculates the required increase in valve opening using a PID control algorithm and sends a forward rotation pulse signal to the stepper motor. The stepper motor drives the conical adjusting plug of the pressure reducing valve 2 via a reduction gear set, causing the valve opening to increase according to the calculated value. For example, in the initial inflation stage, when P... device When the pressure is 0 MPa, the system may rapidly increase the valve opening from 0 to 40% in order to quickly establish the initial pressure difference.

[0026] S108, Reducing Valve Opening: Control module 5 calculates the required reduction in valve opening using a PID control algorithm and sends a reverse pulse signal to the stepper motor. The stepper motor drives the conical adjusting plug of the pressure reducing valve 2 via a reduction gear set, causing the valve opening to decrease according to the calculated value. For example, in the later stages of inflation, when P... device When =0.45MPa, if P is detected out =0.53MPa>P target With a pressure of +δ=0.52MPa, the system slightly reduces the valve opening from 42% to 39%.

[0027] S109. Maintain current opening: Control module 5 maintains the current pulse signal output to the stepper motor, keeps the existing opening of pressure reducing valve 2 unchanged, and continuously monitors pressure changes.

[0028] S110, Dynamic Parameter Adjustment and Safety Verification: Control module 5 dynamically adjusts control parameters according to the system status, including: Adaptive differential pressure adjustment: when P device When P < 0.3 MPa, a larger ΔP = 0.07 MPa is used to quickly establish the flow; when P device When the pressure is >0.4MPa, a smaller ΔP = 0.03MPa is used to prevent overshoot; PID parameter self-tuning: when P target With P out When the error is large, the proportional effect is enhanced; when the error persists, the integral effect is enhanced; when P device When changes are rapid, enhance the differential action; safety protection verification: real-time monitoring of P. device If the rate of decrease exceeds 0.1 MPa per unit time, a leak is suspected, an audible and visual alarm is immediately triggered, and pressure reducing valve 2 is closed; simultaneously, P is monitored. out Ensure that it does not exceed the absolute safety limit of 0.7 MPa.

[0029] It should be noted that the specific rules for the self-tuning of the PID parameters are as follows: the control system determines the parameters based on the error e (e=P). target -P out The system uses different proportional coefficients P for different segments based on the absolute value of the error, achieving rapid adjustment when the error is large and stable and precise control when the error is small. For integral action, the system has error dead zone and duration conditions. Integral action, adapted to the error magnitude, is only introduced after the error has exceeded the dead zone for a certain period, effectively eliminating steady-state error while preventing integral saturation. Furthermore, the system also monitors the equipment's air chamber pressure P. device The changing trend, when the current rate of change is high, should be enhanced in advance to achieve proactive suppression of pressure overshoot.

[0030] After completing S110, the system returns to S102, forming a closed-loop control cycle until inflation is complete.

[0031] It should be noted that during the convergence phase of the inflation process, when the system determines P... device >0.9*P rated At this time, control module 5 automatically switches to "convergence control mode". In this mode, the system is based on P device The recent rate of increase predicts that it will reach P. rated Required time T p If the predicted time T p Less than the preset safe convergence time T safe (e.g., 15 seconds), the system will proactively and slightly reduce the opening of pressure reducing valve 2 in advance, so that P device It approaches and stabilizes at P with a gentle slope. rated This fundamentally prevents excessive pressure and achieves a "soft landing".

[0032] Second Embodiment Please see Figure 3 The second embodiment of the present invention provides an SF6 gas adaptive flow rate control combination device for implementing the method described in the first embodiment, comprising: The pressure-bearing pipeline 1 uses a reinforced polyurethane hose with a pressure-bearing capacity of not less than 10MPa, possessing excellent corrosion resistance and bending fatigue resistance. Quick couplings are integrated at both ends of the hose; the end near the gas cylinder is a standard CGA590 coupling, and the end near the equipment is a dedicated coupling suitable for electrical equipment interfaces. Both ends of the pressure-bearing pipeline 1 are sealed and mechanically connected to the quick couplings via stainless steel high-pressure ferrules, forming a complete gas passage from the gas cylinder to the equipment.

[0033] Pressure reducing valve 2 is connected in series on the pressure-bearing pipeline 1, located near the gas cylinder end. This pressure reducing valve 2 is an improved pilot-operated type, and its adjusting mechanism includes a conical adjusting plug with a taper of 1:5. It is made of a composite structure of PTFE and a stainless steel skeleton, providing good sealing and wear resistance, with a stroke range of 0-15mm. The valve body of pressure reducing valve 2 has NPT external thread interfaces at both ends, which connect in series with the corresponding pipe section of the pressure-bearing pipeline 1. A pressure measuring interface for installing a pressure sensor is provided on the valve body.

[0034] Inlet pressure sensor 3 and outlet pressure sensor 4 are respectively installed on the inlet and outlet sides of pressure reducing valve 2. Inlet pressure sensor 3 is installed at a distance of ≤200mm from the gas cylinder interface, and outlet pressure sensor 4 is installed at a distance of ≤300mm from the equipment interface. Both sensors have temperature compensation function to ensure accurate pressure data is provided under different ambient temperatures. Both inlet pressure sensor 3 and outlet pressure sensor 4 are vertically installed on the pressure measuring interface reserved on the valve body of pressure reducing valve 2 via G1 / 4 internal thread adapters, so that their sensing surfaces can directly sense the gas pressure in the flow channel.

[0035] Control module 5, serving as the system's control hub, utilizes an STM32 series microprocessor as its core and is housed within a sealed, waterproof control box. Control module 5 connects to various sensors and actuators via multi-core shielded cables, running embedded control programs to implement the various control logics and algorithms described in the first embodiment. Control module 5 achieves electrical connection to the multi-core shielded cables through soldered terminals on its PCB board and is secured to the internal frame of the waterproof control box using screws.

[0036] Electric actuator 6 is electrically connected to control module 5 and driven by the adjusting mechanism of pressure reducing valve 2. Electric actuator 6 includes a 42-stepper motor and a reduction gear set. The stepper motor drives the conical adjusting plug of pressure reducing valve 2 through the reduction gear set, achieving precise adjustment of the valve opening. The stepper motor has a step accuracy of 0.9° / step, which, combined with the reduction gear set, enables precise valve opening adjustment. Electric actuator 6 is fixed to the valve body of pressure reducing valve 2 by a mounting bracket. The output shaft of its stepper motor is connected to the input shaft of the reduction gear set via a flexible coupling, while the output end of the reduction gear set is directly coaxially connected to the drive rod of the conical adjusting plug of pressure reducing valve 2 via a threaded connecting sleeve, converting the rotational motion of the motor into the linear motion of the adjusting plug.

[0037] It should be noted that the mounting bracket is designed as a "C" shaped clamp structure, which is fastened to the valve body of the pressure reducing valve 2 by two bolts, and rubber shock-absorbing pads are provided at the corresponding mounting position of the stepper motor 61 to absorb the vibration and noise during motor start-up, shutdown and operation.

[0038] Both the audible and visual alarm 9 and the safety relay 8 are electrically connected to the control module 5. When the system detects an abnormal pressure, the control module 5 triggers the audible and visual alarm 9 to issue an audible and visual alarm, and simultaneously cuts off the safety circuit through the safety relay 8 to ensure system safety. The audible and visual alarm 9 is fixed to a reserved opening in the control box housing by clips, and its pins are soldered to the PCB board of the control module 5; the safety relay 8 is installed inside the control box via a guide rail, and its coil control terminal and contact output terminal are connected to the control module 5 and the controlled circuit respectively via wires.

[0039] The flow rate sensor 7 is installed at the center of the main section of the pressurized pipeline 1 and is connected to an external reading device via magnetic coupling. It is used to detect the real-time flow rate of SF6 gas and transmit the flow rate data to the control module 5, providing additional monitoring parameters for the system. The flow rate sensor 7 is connected in series in the pressurized pipeline 1 via a dedicated tee fitting located at the outlet side of the pressure reducing valve 2. One port of this tee fitting is connected to the upstream and downstream pipelines via a compression fitting, while the other two ports are respectively fitted with the probe body of the flow rate sensor 7 and a sealing plug for process blockage.

[0040] It should be noted that the control module 5 applies the data from the flow rate sensor 7 as follows: First, it calculates in real time the ratio of the actual flow rate to the theoretical maximum flow rate under the current pressure difference ΔP, which is used as the inflation efficiency coefficient η; when η remains below a set threshold (e.g., 0.85), the control module 5 ensures that P... out Without exceeding the limit, ΔP is automatically fine-tuned in steps of 0.01 MPa and locked near the optimal value that maximizes η. Secondly, the safety protection logic is linked to the flow rate and depth: when P is detected... device When the flow rate continues to rise while the flow rate continues to fall or suddenly drops to zero, the control module 5 determines that the gas chamber is full or the pipeline is blocked. It immediately overrides the pressure judgment logic and prioritizes the operation of closing the pressure reducing valve 2 and issuing a specific audible and visual alarm.

[0041] The cable-conduit composite bundle integrates a pressure-bearing conduit 1 with multi-core shielded cables connecting various electrical components through spiral winding or parallel wrapping. This ensures the system's neatness, robustness, and portability, effectively preventing entanglement and pulling damage to the lines and conduits during field operations. The specific integration method of the cable-conduit composite bundle is as follows: the multi-core shielded cables are placed parallel to each other against the outer wall of the pressure-bearing conduit 1, then bound spirally with high-strength nylon cable ties at equal intervals not exceeding 200mm, and finally covered with a flame-retardant PVC protective sleeve.

[0042] It should be noted that between the pressure-bearing pipeline 1 and the outer PVC protective sleeve, there is also a tensile reinforcement layer made of aramid fiber, which is used to significantly improve the overall tensile strength and bending fatigue resistance of the composite bundle.

[0043] The control box housing integrates an OLED display and simple buttons to display real-time parameters such as pressure, flow rate, and valve opening, and allows operators to set system parameters and start / stop the system. The entire system's electrical connections utilize aviation connectors to ensure quick and reliable connections. The OLED display is connected to the mainboard of control module 5 via an FPC cable, and its panel is attached to the display window within the control box housing using double-sided tape. The keycaps of the simple buttons pass through holes in the control box housing, while the microswitches below them are directly soldered to the PCB board of control module 5.

[0044] It should be noted that the waterproof control box adopts a double sealing structure of labyrinth groove and silicone sealing ring between the box body and the box cover. The aviation plug interface on its side wall is sealed with a compression nut with a pre-installed sealing rubber ring to ensure that the protection level reaches IP67.

[0045] In summary, this SF6 gas adaptive flow rate control method and combined device achieves adaptive and precise control throughout the entire inflation process by real-time monitoring of the equipment's gas chamber pressure and dynamic calculation of the optimal target pressure, and by automatically adjusting the opening of pressure reducing valve 2 using a closed-loop control system. This method intelligently adjusts the differential pressure parameter according to the inflation stage, effectively preventing pressure overshoot while ensuring inflation efficiency. Combined with multiple safety protection mechanisms, it significantly improves operational safety, stability, and automation, completely solving the problems of traditional manual operation, such as reliance on experience, poor adjustment accuracy, and potential safety hazards.

[0046] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for SF6 gas self-adaptive flow rate control, characterized in that, The method comprises the following steps: Real-time acquisition of device plenum pressure P device With device outlet pressure P out ; The dynamic target pressure P is calculated target where P target = P device + ΔP, ΔP being a preset pressure difference; By comparing P out with P target , the opening of the pressure reducing valve is dynamically adjusted to make P out tend to the dynamically changing P target to maintain a dynamic pressure difference for continuous inflation.

2. The method of claim 1, wherein, The "dynamic adjustment" step comprises: If P out If P target then increase the opening of the pressure reducing valve; If P out > P target + δ, δ is a pressure tolerance, then the opening of the pressure reducing valve is reduced.

3. The method of claim 1, wherein, According to P device dynamically adjusting the pressure difference ΔP: When P device below the first pressure threshold, the first ΔP value is employed; When P device A second ΔP value, smaller than said first ΔP value, is employed when the pressure is higher than a second pressure threshold.

4. The method of claim 1, wherein, Further comprising a safety protection step: When the rate of decrease of P device exceeds a preset threshold, or P out exceeds an absolute upper limit of safe pressure, a safety protection action is triggered.

5. The method of claim 1, wherein, A PID control algorithm is used to generate an instruction for adjusting the opening of the pressure reducing valve, and the PID parameters can be dynamically adjusted according to the system state.

6. A SF6 gas self-adapting flow rate control method and combination device for implementing the method of any one of claims 1-5, characterized in that, Comprise: A pressure pipeline (1) for connecting an SF6 gas cylinder and an electrical device; A pressure reducing valve (2) connected in series to the pressure pipeline (1); An inlet pressure sensor (3) and an outlet pressure sensor (4) arranged at the inlet side and the outlet side of the pressure reducing valve (2) respectively; A control module (5) connected to the inlet pressure sensor (3) and the outlet pressure sensor (4); An electric actuator (6) connected to the control module (5) and connected to the adjustment mechanism of the pressure reducing valve (2); The control module (5) is configured to perform the method steps of any one of claims 1-5.

7. The apparatus of claim 6, wherein, Further comprising: An audible and visual alarm (9) and a safety relay (8) both connected to the control module (5) for performing the safety protection action.

8. The apparatus of claim 6, wherein, Further comprising a flow rate sensor (7) installed at the center of the main pipe section of the pressure pipeline (1) and connected to the control module (5).

9. The apparatus of claim 6, wherein, The electric actuator (6) comprises a stepper motor and a speed reduction gear set.

10. The apparatus of claim 6, wherein, The pressure pipeline (1) is an enhanced polyurethane hose, both ends of which are provided with quick connectors, and the pressure pipeline (1) is integrated with cables connected to electrical components to form a cable-pipeline composite bundle.

Images