SF6 mixed gas leakage automatic replenishment system

Abstract

The application belongs to the technical field of electrical equipment safety, and specifically discloses an SF6 mixed gas leakage automatic replenishment system, which comprises a premixing buffer tank, a storage tank, a pressurizing electromagnetic valve, a compressor set and a charging one-way valve connected in sequence through pipelines at the exhaust end of the premixing buffer tank, and a SF6 interface connected through a pipeline at the gas inlet end of the No.1 mass flowmeter connected with a three-way joint at the gas inlet end of the premixing buffer tank, and an N2 / CF4 interface connected through a pipeline at the gas inlet end of the No.2 mass flowmeter. SF6 gas and N2(CF4) gas are filled into the storage tank first, and then the storage tank is used to automatically replenish gas for a plurality of SF6 electrical equipment in need of gas replenishment. The gas pressure in the storage tank is slightly greater than the standard gas pressure in the circuit breaker gas chamber, and the gas pressure difference between the storage tank and the circuit breaker gas chamber can be reduced, so that the gas flow rate during gas charging is prevented from being too large.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical equipment safety, in particular to a SF6 mixed gas leakage automatic replenishment system. BACKGROUND

[0002] SF6 electrical equipment promotes the rapid development of the power industry, and in the current power system, the application of SF6 electrical equipment is also more and more widely. Ensuring the reliable operation of SF6 electrical equipment has become one of the important tasks of the power department. SF6 circuit breaker and GIS equipment are important components in the power system, in which SF6 gas mainly plays the role of insulation and arc extinguishing, and SF6 must be at a certain density to meet the needs of insulation and arc extinguishing of the circuit breaker. Once SF6 gas leaks, it will greatly reduce the insulation strength of the electrical equipment, and in severe cases, it will also cause the circuit breaker to fail to complete the opening and closing operation, thereby expanding the scope of the accident and causing serious consequences.

[0003] When SF6 gas leaks, in order to prevent insufficient arc extinguishing ability, the circuit breaker will cut off the load or fault current and start the opening locking relay of the circuit breaker, so that the auxiliary contact in series on the opening circuit is disconnected, thereby achieving the purpose of locking the opening of the circuit breaker. However, after the opening locking signal of the circuit breaker appears, when the fault in the line protection range cannot be normally cut off by the line circuit breaker, the line protection action will fail, thereby causing the power outage range of the fault to expand.

[0004] External damage (including natural disasters), equipment quality, operating life, etc. can cause the sealing element of SF6 electrical equipment to age and deform, which in turn can cause SF6 leakage. In the prior art, artificial gas replenishment is mainly used, which has the following shortcomings:

[0005] 1. Artificial filling of SF6 cannot accurately control the filling pressure. Unstable filling pressure can cause instantaneous impact on the circuit breaker chamber, causing particle suspension and dust oscillation in the chamber, which in turn can affect the safe operation of the equipment.

[0006] 2. Artificial filling of SF6 is difficult to control the filling speed. When the filling speed is too fast, the steel cylinder will freeze due to the excessive heat carried away by SF6 gas, and SF6 gas will also liquefy at low temperature, which in turn will affect the filling of SF6 gas.

[0007] 3. It is difficult to accurately control the amount of SF6 used when filling the leaked equipment artificially. In order to ensure sufficient SF6, overfilling is usually performed, which will cause gas waste.

[0008] Four, in the case of unable to accurately find the leakage point or has found the leakage point but unable to carry out the electrified processing, and the equipment cannot be powered off in the short term, frequent air filling operation is needed, and manual filling of SF6 will cause great waste of manpower; and in the case of long time manual filling work in extreme climate or at night, not only the work efficiency is low, but also the personal safety of the greenhouse inspection personnel is affected.

[0009] Therefore, we propose a SF6 mixed gas leakage automatic filling system for intelligent filling of SF6 electrical equipment in the case of general leakage of circuit breakers or GIS tanks and inability to promptly carry out power-off maintenance. SUMMARY

[0010] The purpose of the present application is to provide a SF6 mixed gas leakage automatic filling system to solve the problem of difficulty in accurately controlling the filling pressure, filling speed and filling amount when filling SF6 mixed gas in the existing SF6 electrical equipment as described in the background.

[0011] To achieve the above purpose, the present application provides the following technical scheme: a SF6 mixed gas leakage automatic filling system, comprising:

[0012] A premixing buffer tank, the gas inlet end of the premixing buffer tank is connected with a first mass flow meter and a second mass flow meter through a tee joint, the gas inlet end of the first mass flow meter is connected with an SF6 interface through a pipeline, and the gas inlet end of the second mass flow meter is connected with an N2 / CF4 interface through a pipeline;

[0013] A storage tank, the gas outlet end of the premixing buffer tank is connected with a pressurizing electromagnetic valve, a compressor unit and a gas filling check valve in sequence through a pipeline, and the other end of the gas filling check valve is connected with the gas inlet end of the storage tank through a pipeline;

[0014] The gas outlet end of the storage tank is connected with an inlet pressure reducing valve and a sampling electromagnetic valve which are connected with each other in parallel through a pipeline; the other end of the inlet pressure reducing valve is connected with a molecular sieve, an inlet electromagnetic valve, an inlet check valve and a switch interface in sequence through a pipeline; and the other end of the sampling electromagnetic valve is connected with an analysis pressure reducing valve, an analysis sensor and an exhaust port in sequence through a pipeline.

[0015] The gas inlet end of the switch interface is connected with a gas discharge electromagnetic valve, and the other end of the gas discharge electromagnetic valve is connected with the gas inlet end of the analysis pressure reducing valve through a pipeline;

[0016] A gas storage pressure sensor is arranged on the outside of the storage tank, and the gas storage pressure sensor is electrically connected with the compressor unit and the pressurizing electromagnetic valve;

[0017] A gas chamber pressure sensor is arranged at the gas inlet end of the switch interface, and the gas chamber pressure sensor is electrically connected with the inlet electromagnetic valve.

[0018] Preferably, the exhaust end of the storage tank is further connected with a suction electromagnetic valve through a pipeline, the other end of the suction electromagnetic valve is connected with a vacuum pump through a pipeline, and the exhaust end of the vacuum pump is connected with the exhaust port through a pipeline.

[0019] Preferably, the exhaust end of the premixing buffer tank is further connected with a direct charging electromagnetic valve through a pipeline, the other end of the direct charging electromagnetic valve is connected with a charging one-way valve through a pipeline, and the direct charging electromagnetic valve is a normally open electromagnetic valve.

[0020] Preferably, the compressor set comprises two compressors connected in parallel in the gas circuit, and the compressor set is connected in parallel with the direct charging electromagnetic valve in the gas circuit.

[0021] Preferably, the exhaust end of the SF6 interface is sequentially connected with a first pressure reducing valve and a first vaporizer through a pipeline, and the other end of the first vaporizer is connected with the gas inlet end of a first mass flow meter through a pipeline.

[0022] The exhaust end of the N2 / CF4 interface is sequentially connected with a second pressure reducing valve and a second vaporizer through a pipeline, and the other end of the second vaporizer is connected with the gas inlet end of a second mass flow meter through a pipeline.

[0023] Preferably, a first pressure sensor is arranged outside the first vaporizer, and a second pressure sensor is arranged outside the second vaporizer.

[0024] A third pressure sensor is arranged at the gas outlet end of the first mass flow meter, and a fourth pressure sensor is arranged at the gas outlet end of the second mass flow meter.

[0025] Preferably, a first electric control valve is arranged between the gas outlet end of the first mass flow meter and the gas inlet end of the premixing buffer tank, and a second electric control valve is arranged between the gas outlet end of the second mass flow meter and the gas inlet end of the premixing buffer tank.

[0026] The first pressure sensor and the third pressure sensor are electrically connected with the first electric control valve, and the second pressure sensor and the fourth pressure sensor are electrically connected with the second electric control valve.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] 1) The present application will first fill SF6 gas, N2(CF4) gas into the storage tank, and then the storage tank will automatically fill gas to several SF6 electrical equipment which need to be filled; the inlet pressure reducing valve and the inlet solenoid valve are arranged between the storage tank and the circuit breaker chamber, whether the SF6 mixture is added is controlled by the opening and closing of the inlet solenoid valve, the gas pressure is stabilized by the inlet pressure reducing valve, thereby avoiding the instantaneous impact on the circuit breaker chamber during gas filling; in addition, the gas pressure in the storage tank is slightly greater than the standard gas pressure in the circuit breaker chamber, which can also reduce the gas pressure difference between the storage tank and the circuit breaker chamber, thereby avoiding too large gas flow rate during gas filling;

[0029] 2) The present application uses a first mass flow meter to monitor and control the amount of SF6 gas, and a second mass flow meter to monitor and control the amount of N2(CF4) gas, and then uses a gas analysis sensor to monitor the content of SF6 gas in the mixed gas in the circuit breaker chamber and the storage tank; by controlling the precise amount of SF6 gas and N2(CF4), the content of SF6 gas in the mixed gas in the storage tank can be precisely controlled, thereby precisely gas distribution for the circuit breaker chamber;

[0030] 3) The present application monitors the pressure of the circuit breaker chamber through the chamber pressure sensor to determine the opening and closing of the inlet solenoid valve, and controls whether to fill gas to the circuit breaker chamber through the opening and closing of the inlet solenoid valve; the gas pressure in the storage tank is monitored through the storage pressure sensor, and then whether to fill gas to the storage tank is controlled by controlling the opening and closing of the pressure solenoid valve and whether the compressor set works, thereby realizing automatic gas distribution and filling, which can save manpower by avoiding manual gas filling operation;

[0031] 4) The amount of SF6 gas and N2(CF4) gas can be recorded through the statistics of the mass flow meter, and the replacement time of the gas cylinder can be accurately grasped by combining the starting and ending pressure values of the gas filling;

[0032] 5) The present application sets a premixing buffer tank between the compressor set and the mass flow meter, the buffer of the premixing buffer tank makes the instantaneous pressure difference in the pipeline not too large when the compressor set is working, and the stable pressure difference of the pipeline where the mass flow meter is located can also ensure the accuracy of the mass flow meter during measurement. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The structure connection diagram of the present application.

[0034] In the figure: 10 storage tank, 20 premixing buffer tank, 31 SF6 interface, 32 N2 / CF4 interface, 33 switch interface, 34 exhaust port, 41 first vaporizer, 42 second vaporizer, 50 compressor set, 60 molecular sieve, 70 gas analysis sensor, 80 vacuum pump;

[0035] P1 first pressure sensor, P2 second pressure sensor, P3 third pressure sensor, P4 fourth pressure sensor, P5 gas storage pressure sensor, P6 gas chamber pressure sensor;

[0036] V1 first electric control valve, V2 second electric control valve, V3 pressurizing solenoid valve, V4 inlet solenoid valve, V5 exhaust solenoid valve, V6 direct charging solenoid valve, V7 sampling solenoid valve, V8 exhaust solenoid valve;

[0037] C1 first pressure reducing valve, C2 second pressure reducing valve, C3 inlet pressure reducing valve, C4 analysis pressure reducing valve;

[0038] L1 gas charging one-way valve, L2 inlet one-way valve;

[0039] MFC1 first mass flow meter, MFC2 second mass flow meter. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0041] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0042] Embodiment:

[0043] Please refer to Figure 1 The present application provides a technical solution: a SF6 gas mixing leakage automatic replenishment system, comprising a storage tank 10, a premixing buffer tank 20, a gas analysis sensor 70, a first vaporizer 41, a second vaporizer 42, a first mass flow meter MFC1 and a second mass flow meter MFC2.

[0044] The storage tank 10 is used for temporarily storing the mixed gas to facilitate the measurement of the concentration ratio of the final mixed gas. The storage tank 10 is initially designed to have a volume of 1L, a pressure resistance of 1.5MPa, and a stainless steel material. The storage tank 10 is provided with a gas storage pressure sensor P5 for detecting the gas pressure inside the storage tank 10. The pressurizing electromagnetic valve V3 is electrically connected with the gas storage pressure sensor P5 and the compressor set 50. When the gas pressure in the storage tank 10 is less than 0.7MPa, the pressurizing electromagnetic valve V3 is powered on to open the gas path, and the compressor set 50 draws the mixed gas into the storage tank 10. When the gas pressure in the storage tank 10 reaches 1.0MPa, the pressurizing electromagnetic valve V3 is powered off to close the gas path, and the compressor set 50 stops supplying gas to the storage tank 10. The gas outlet end of the storage tank 10 is also connected with the gas analysis sensor 70 through a pipeline. The gas analysis sensor 70 adopts an SF6 sensor for detecting the content of SF6 in the mixed gas passing through the gas analysis sensor 70. The gas analysis sensor 70 is also provided with an analysis pressure reducing valve C4 and a sampling electromagnetic valve V7 between the gas analysis sensor 70 and the storage tank 10. After the sampling electromagnetic valve V7 is opened, the gas in the storage tank 10 enters the gas analysis sensor 70 through the sampling electromagnetic valve V7 and the analysis pressure reducing valve C4 in sequence. The analysis pressure reducing valve C4 is used to reduce the pressure of the gas discharged from the storage tank 10, so that the mixed gas entering the gas analysis sensor 70 maintains a constant pressure, thereby ensuring the accuracy of the measurement results of the gas analysis sensor 70. The gas outlet end of the gas analysis sensor 70 is connected with the gas outlet 34 through a pipeline.

[0045] The exhaust end of the storage tank 10 is connected with a four-way through a pipeline, three outlets of the four-way are connected with a sampling electromagnetic valve V7, an inlet pressure reducing valve C3 and an exhaust electromagnetic valve V5 through pipelines respectively; the other end of the inlet pressure reducing valve C3 is connected with a molecular sieve 60, an inlet electromagnetic valve V4 and an inlet check valve L2 in sequence through pipelines, the other end of the inlet check valve L2 is connected with a switch interface 33 through a pipeline; the number of the switch interface 33 can be increased or decreased according to the number of SF6 electrical equipment, and each switch interface 33 needs to be equipped with an inlet electromagnetic valve V4, an inlet check valve L2 and a gas chamber pressure sensor P6; the other end of the switch interface 33 is connected with a circuit breaker gas chamber or a GIS tank body gas chamber in SF6 electrical equipment (in the following content, the circuit breaker gas chamber is described). The inlet check valve L2 is used to reduce the gas pressure of the exhaust gas of the storage tank 10 and keep the gas pressure of the exhaust gas of the storage tank 10 constant. The molecular sieve 60 is composed of F-03, activated alumina, 13X, 3A and 5A adsorbents, and is used to adsorb moisture in the gas, so as to ensure the dryness of the gas filled into the circuit breaker gas chamber; wherein, the F-03 adsorbent can remove trace low fluorides, acidic substances and moisture in SF6 mixed gas; the activated alumina has many microporous channels and large specific surface area, and can be used as an air adsorbent, a dehydration drying agent and a catalyst carrier, etc., has strong affinity to water, oxide, acetic acid, alkali, etc., is a micro-water deep drying agent, and is also an adsorbent for adsorbing polar molecules, and the chemical molecular formula is Al2O3·nH2O; the pore size of the 13X type molecular sieve is 10A, and any molecule larger than 3.64A and smaller than 10A can be adsorbed, and can be used for catalyst carrier, water and carbon dioxide co-adsorption, water and hydrogen sulfide gas co-adsorption, and the static water adsorption capacity can reach 25%; the main function of the 3A type molecular sieve is also to adsorb moisture, and the size of the adsorbed particles is different according to the different pore sizes; the 5A molecular sieve can adsorb any molecule smaller than the pore size, and is generally called calcium molecular sieve, which has the functions of 3A and 4A molecular sieves, and can also adsorb C3-C4 normal alkanes, chloroethane, bromoethane, butanol, etc., and can be applied to normal and isomeric hydrocarbon separation, pressure swing adsorption separation and water and carbon dioxide co-adsorption. The inlet check valve L2 is used to prevent the backflow of SF6 mixed gas in the circuit breaker gas chamber.

[0046] After the opening of the intake solenoid valve V4, the mixed gas in the storage tank 10 passes through the intake pressure reducing valve C3, the molecular sieve 60, the intake solenoid valve V4 and the intake check valve L2, and then enters the breaker chamber from the switch interface 33 to fill the SF6 mixed gas. The intake end of the switch interface 33 is provided with a chamber pressure sensor P6 for detecting the gas pressure of the mixed gas in the breaker chamber, and the chamber pressure sensor P6 is electrically connected with the intake solenoid valve V4. When the internal pressure of the breaker chamber is lower than the protection pressure, the intake solenoid valve V4 is opened for filling and air supplementing operation. When the internal pressure of the breaker chamber reaches the operating pressure, the intake solenoid valve V4 is closed. The intake end of the switch interface 33 is also connected with a three-way pipe. One outlet of the three-way pipe is directly connected with the intake check valve L2 through a pipeline, and the other outlet of the three-way pipe is connected with a gas discharge solenoid valve V8 through a pipeline. The other end of the gas discharge solenoid valve V8 is also connected with a sampling solenoid valve V7 through a three-way pipe, and the remaining end of the three-way pipe is connected with an analysis pressure reducing valve C4 through a pipeline. When the gas pressure of the breaker chamber is too high or the mixed gas composition in the breaker chamber needs to be detected, the gas discharge solenoid valve V8 is opened. The mixed gas in the breaker chamber passes through the switch interface 33, the gas discharge solenoid valve V8 and the analysis pressure reducing valve C4, enters the gas analysis sensor 70, and then is discharged from the exhaust port 34. The exhaust port 34 can also be provided with a recovery device for recovering the discharged mixed gas, so as to avoid the pollution of the discharged mixed gas to the environment. The exhaust end of the premixing buffer tank 20 is connected with a pressurizing solenoid valve V3, a compressor set 50 and a charging check valve L1 in sequence through pipelines, and the other end of the charging check valve L1 is connected with the intake end of the storage tank 10 through a pipeline. The pressurizing solenoid valve V3, the intake solenoid valve V4 and the gas suction solenoid valve V5 are all normally closed solenoid valves, which are closed when not powered and opened when powered. The charging check valve L1 is used to prevent the gas in the storage tank 10 from flowing back to the premixing buffer tank 20. The compressor set 50 is composed of two parallel compressors, which is used to suck the mixed gas in the premixing buffer tank 20 into the storage tank 10. The main function of the compressor set 50 is to continuously pressurize the gas in the premixing buffer tank 20 to the next stage for compression until the gas is compressed into the storage tank 10. The compressor is equipped with a maximum model 52 direct current brush motor on the market, and the compressor set 50 adopts a double-compressor form to increase the gas distribution flow. Since the pipeline volume is too small and the compressor set 50 has a large suction force when working, the instantaneous pressure difference in the pipeline will be too high. Therefore, the premixing buffer tank 20 is placed in the front stage of the compressor set 50 to avoid large pressure difference at the intake end of the premixing buffer tank 20, so as to ensure the stability of the gas flow. The premixing buffer tank 20 has a design volume of 500 ml and a pressure resistance of 0.8 MPa (the actual operating pressure range is 0-0.2 MPa), and is made of stainless steel.The storage tank 10 is about 0 in the internal air pressure before inflation, when the first inflation is carried out, the early mixed gas can be automatically filled into the premixing buffer tank 20 under the action of air pressure. In order to facilitate the automatic filling of mixed gas, a pipeline is additionally arranged between the inflation one-way valve L1 and the exhaust end of the premixing buffer tank 20, and a direct charging solenoid valve V6 is arranged on the pipeline. The pipeline at the gas outlet end of the compressor set 50 also communicates with the direct charging solenoid valve V6. When the compressor set 50 charges the storage tank 10, the excess gas can also be discharged from the storage tank 10 back to the premixing buffer tank 20, so as to prevent the mixed gas in the storage tank 10 from being filled with too high air pressure. In use, it is sometimes necessary to empty the gas in the premixing buffer tank 20 and the storage tank 10 (for example, replacing N2 with CF4, the internal mixed gas composition of the premixing buffer tank 20 is uncertain, etc.), so it is also necessary to connect the exhaust end of the premixing buffer tank 20 with the exhaust port 34 through a pipeline, and the exhaust end of the storage tank 10 is sequentially connected with a gas extraction solenoid valve V5 and a vacuum pump 80 through a pipeline, and the other end of the vacuum pump 80 is connected with the exhaust port 34 through a pipeline; the vacuum pump 80 is an oil-free vacuum pump, the vacuum rate is 10L / min, and the final negative pressure during operation is-65KPa; after the gas extraction solenoid valve V5 is opened, the mixed gas in the premixing buffer tank 20 and the storage tank 10 can be extracted by starting the vacuum pump 80.

[0047] The gas inlet of the premixing buffer tank 20 is connected with two pipelines, and the other ends of the two pipelines are respectively connected with an SF6 interface 31 and an N2 / CF4 interface 32; the SF6 interface 31 is connected with a high-purity sulfur hexafluoride gas cylinder outside, and the N2 / CF4 interface 32 is connected with a nitrogen gas cylinder or a carbon tetrafluoride gas cylinder outside. When the SF6 mixed gas is SF6 and N2, the N2 / CF4 interface 32 is connected with the nitrogen gas cylinder, and when the SF6 mixed gas is SF6 and N2, the N2 / CF4 interface 32 is connected with the carbon tetrafluoride gas cylinder. In the pipeline where the SF6 interface 31 is located, the SF6 interface 31 is sequentially connected with a first pressure reducing valve C1, a first vaporizer 41, a first mass flow meter MFC1 and a first electric control valve V1 through a pipeline, and the other end of the first electric control valve V1 is connected with the gas inlet of the premixing buffer tank 20 through a pipeline. In the pipeline where the N2 / CF4 interface 32 is located, the N2 / CF4 interface 32 is sequentially connected with a second pressure reducing valve C2, a second vaporizer 42, a second mass flow meter MFC2 and a second electric control valve V2 through a pipeline, and the other end of the second electric control valve V2 is also connected with the gas inlet of the premixing buffer tank 20 through a pipeline.

[0048] Because the gas pressure of the steel bottle is too high (the pressure of the full bottle of sulfur hexafluoride is 3 MPa, the pressure of high-purity nitrogen is 13.5 MPa, and the pressure of carbon tetrafluoride is about 5 MPa), a first pressure reducing valve C1, a second pressure reducing valve C2 and an external pipeline are needed to control the pressure, the first pressure reducing valve C1 and the second pressure reducing valve C2 are brass high-pressure pressure reducing valves, the flow rate is 15-30 Nm 3 / h, the pressure after the valve can be adjusted in the range of 0-0.8 MPa, in combination with the selection of the mass flow meter, the standard pressure here is 0.35 MPa, and the other main function of the first pressure reducing valve C1 and the second pressure reducing valve C2 is to stabilize the pressure, when the pressure of the steel bottle is higher than 0.6 MPa, the pressure after the valve can be stably controlled to be kept at 0.35 MPa.

[0049] After the gas is discharged from the steel bottle, the high-purity nitrogen is definitely gaseous, but the carbon tetrafluoride and sulfur hexafluoride can be partially liquid, in order to discharge the interference of this aspect on the gas distribution accuracy and the mass flowmeter, a vaporizer 41 and a vaporizer 42 are arranged in the pipeline; the main role of the vaporizer 41 and the vaporizer 42 is to heat the passing gas to a certain temperature, so that it is completely gasified, and the gas is rapidly heated to the standard temperature; the gas is heated to 20 DEG C after passing through the vaporizer 41 and the vaporizer 42, and the gas enters the mass flowmeter and the subsequent pipeline in the form of 20 DEG C pure gas. The vaporizer is designed as a small container, which is wrapped outside by a heating belt, and the heating belt is provided with a temperature sensor, so that the temperature of the vaporizer can be set and controlled through the sensor and a temperature control element. The vaporizer 41 is provided with a first pressure sensor P1 outside, and the first pressure sensor P1 is used for monitoring the gas pressure in the inner cavity of the vaporizer 41; the vaporizer 42 is provided with a second pressure sensor P2 outside, and the second pressure sensor P2 is used for monitoring the gas pressure in the inner cavity of the vaporizer 42; the range of the first pressure sensor P1 and the second pressure sensor P2 is 0-1 MPa, and the display accuracy is 0.01 MPa; the values returned by the first pressure sensor P1 and the second pressure sensor P2 are monitored in real time through the sensor, so that the gas pressure in the vaporizer 41 and the vaporizer 42 can be monitored in real time, that is, the front stage pressure of the mass flowmeter can be monitored in real time, so as to ensure that the front stage pressure of the first mass flowmeter MFC1 and the second mass flowmeter MFC2 is 0.35 MPa. The first mass flowmeter MFC1 and the second mass flowmeter MFC2 select CS200-A type MFC / MFM, and the CS200-A type MFC / MFM adopts unique technology in the driving of the sensor, the control of zero drift and valve control, and many other aspects, so as to provide high accuracy and high reliability for the control and measurement of gas mass flow. In the standard state, the density of the gas is a constant, and the mass number is the product of the gas density and the volume in the standard state, so the volume flow in the standard state is equivalent to the mass flow, and the flow rate of the MFC can control the proportion of the two gases. The present application stabilizes the gas pressure of SF6 through a first pressure reducing valve C1, stabilizes the gas pressure of N2 or CF4 through a second pressure reducing valve C2, stabilizes the temperature of SF6 through the vaporizer 41, and stabilizes the temperature of N2 or CF4 through the vaporizer 42, so that the filled gas is in the standard state, and then the accurate measurement of the first mass flowmeter MFC1 and the second mass flowmeter MFC2 is facilitated.Since the pressure difference before and after the mass flow meter must be kept within a certain range (≤0.02 MPa), only when kept within the range, the flow rate ratio can be more accurate, therefore, a pressure difference sensor is needed to control the pressure difference before and after the mass flow meter; a third pressure sensor P3 is arranged at the exhaust end of the first mass flow meter MFC1, and a fourth pressure sensor P4 is arranged at the exhaust end of the second mass flow meter MFC2; the first pressure sensor P1 and the third pressure sensor P3 are electrically connected with the first electric control valve V1; the second pressure sensor P2 and the fourth pressure sensor P4 are electrically connected with the second electric control valve V2; the first electric control valve V1 and the second electric control valve V2 are equal proportion regulating valves, which control the electric actuator through analog quantity equal percentage, and then complete the proportion of valve opening through the electric actuator; the first pressure sensor P1, the third pressure sensor P3 and the first electric control valve V1 constitute a pressure difference sensor, which is used to keep the pressure difference before and after the first mass flow meter MFC1 stable; the second pressure sensor P2, the fourth pressure sensor P4 and the second electric control valve V2 constitute another pressure difference sensor, which is used to keep the pressure difference before and after the second mass flow meter MFC2 stable; the stability of the pressure difference before and after the mass flow meter can more accurately control and measure the flow rate of various gases; when the difference between the first pressure sensor P1 and the third pressure sensor P3 is too large during the adjustment of the pressure difference, the flow rate of the first electric control valve V1 can be adjusted small; similarly, when the difference between the second pressure sensor P2 and the fourth pressure sensor P4 is too large, the flow rate of the second electric control valve V2 can be adjusted small.

[0050] The gas supplement pressure range during the gas supplement is generally within 0.1 MPa, the gas density changes very small and can be ignored, therefore, the mass flow meter can calculate and provide the cumulative flow rate, which is finally converted into the gas volume.

[0051] When SF6 gas and N2 gas are mixed and filled:

[0052] The filling weight = SF6 density × SF6 supplement volume + N2 density × N2 supplement volume.

[0053] When SF6 gas and CF4 gas are mixed and filled:

[0054] The filling weight = SF6 density × SF6 supplement volume + CF4 density × or CF4 supplement volume.

[0055] The compressor set 50, the gas analysis sensor 70, the vacuum pump 80, the first pressure sensor P1, the second pressure sensor P2, the third pressure sensor P3, the fourth pressure sensor P4, the gas storage pressure sensor P5, the gas chamber pressure sensor P6, the first electric control valve V1, the second electric control valve V2, the pressurizing electromagnetic valve V3, the air inlet electromagnetic valve V4, the air extraction electromagnetic valve V5, the direct charging electromagnetic valve V6, the sampling electromagnetic valve V7, the air release electromagnetic valve V8, the first mass flowmeter MFC1 and the second mass flowmeter MFC2 are electrically connected with an industrial computer with a Linux operating system, and the electrical components in the above structure are controlled through the industrial computer; the CPU processor of the industrial computer uses an Intel i3 processor, and can process data at high speed; the Linux system industrial computer on the market generally has a 4g communication module, and the Linux system industrial computer with the 4g communication module is used in the application, and when the 5g signal is weak, the 4g signal can be automatically switched for data transmission; at the same time, an industrial 5G-CPE device is added to the industrial computer, and 5G is converted into other communication modes such as a network port or wifi, so as to facilitate the control of the SF6 gas leakage automatic replenishment system on the network. The industrial computer is network-connected with the public network, when the device of the application runs or the device fails, the running data or fault data in the SF6 gas leakage automatic replenishment system are uploaded to a cloud platform through the communication module, the cloud platform responds to the uploaded data and sends the running data or fault data to the mobile phone of the operator through email or short message, so that the operator can know the running of the device and the fault factors of the device in time.

[0056] The Linux operating system of the industrial computer can also be linked with a remote monitoring system, and the operation sending instruction is sent to the cloud platform server through an intelligent terminal (including a mobile phone, a tablet computer, a computer and the like), the cloud platform server is transmitted to the CPE device or the 4g communication module in the industrial computer through the public network, and then is uploaded to the Linux system, and the Linux system sends the instruction to the PLC or the single-chip microcomputer, so as to control the SF6 gas leakage automatic replenishment system to work, and the contents of the remote control operation of the SF6 gas leakage automatic replenishment system include: mixed gas component detection in the air chamber of the circuit breaker, mixed gas component detection in the storage tank 10, automatic replenishment, special replenishment, system emptying and system vacuumizing. When the intelligent terminal logs in the cloud platform by inputting a special account password, the cloud platform only provides one account, so as to prevent cross operation of multiple accounts.

[0057] The application also carries out constant temperature arrangement; a heat conduction system is arranged outside the rest of pipelines and equipment except SF6 interface 31, N2 / CF4 interface 32, switch interface 33 and exhaust port 44, which is used for heat transfer to ensure the heat balance inside the system; then the rest of pipelines and equipment except SF6 interface 31, N2 / CF4 interface 32, switch interface 33 and exhaust port 44 are wrapped by using aluminum silicate heat preservation film outside the heat conduction system; the heat conduction system uniformly distributes the heat generated by the equipment during operation to different positions to realize uniform heating, thereby avoiding the uneven heating phenomenon in the pipeline; meanwhile, the temperature is stable, which is also beneficial to calculating the quality of the gas through pressure, volume and temperature.

[0058] Working principle:

[0059] Detection of mixed gas components in the circuit breaker gas chamber:

[0060] First, open the exhaust electromagnetic valve V8, and the mixed gas in the circuit breaker gas chamber enters the gas analysis sensor 70 in turn through the switch interface 33, the exhaust electromagnetic valve V8 and the analysis pressure reducing valve C4, the gas analysis sensor 70 analyzes the content of SF6 gas in the mixed gas, and closes the exhaust electromagnetic valve V8 after detection.

[0061] Detection of mixed gas components in the storage tank 10:

[0062] First, open the sampling electromagnetic valve V7, and the mixed gas in the storage tank 10 enters the gas analysis sensor 70 in turn through the sampling electromagnetic valve V7 and the analysis pressure reducing valve C4, the gas analysis sensor 70 analyzes the content of SF6 gas in the mixed gas, and closes the exhaust electromagnetic valve V8 after detection.

[0063] Pressure difference compensation between two ends of the first mass flowmeter MFC1:

[0064] During the aeration process, the pressure difference between the first pressure sensor P1 and the third pressure sensor P3 is calculated; when the pressure difference between the first pressure sensor P1 and the third pressure sensor P3 is less than 0.02 MPa, the first electric control valve V1 does not adjust; when the pressure difference between the first pressure sensor P1 and the third pressure sensor P3 reaches 0.02 MPa, the first electric control valve V1 reduces the flow capacity by reducing the aperture to reduce the pressure difference; when the pressure difference between the first pressure sensor P1 and the third pressure sensor P3 is greater than 0.01 MPa, the first electric control valve V1 increases the flow capacity by increasing the aperture to increase the flow of gas; after the first aeration is completed, the first electric control valve V1 is automatically reset and closed.

[0065] Pressure difference compensation between two ends of the second mass flowmeter MFC2:

[0066] The pressure difference between the second pressure sensor P2 and the fourth pressure sensor P4 is calculated; when the pressure difference between the second pressure sensor P2 and the fourth pressure sensor P4 is less than 0.02 MPa, the second electric control valve V2 does not adjust; when the pressure difference between the second pressure sensor P2 and the fourth pressure sensor P4 reaches 0.02 MPa, the second electric control valve V2 reduces the flow by reducing the aperture to reduce the pressure difference; when the pressure difference between the second pressure sensor P2 and the fourth pressure sensor P4 is greater than 0.01 MPa, the second electric control valve V2 increases the flow by increasing the aperture to increase the flow of gas; after the primary gas supplement is completed, the second electric control valve V2 is automatically reset to close.

[0067] Automatic storage supplement process (both the first mass flow meter MFC1 and the second mass flow meter MFC2 have gas passing through) :

[0068] When the gas chamber pressure sensor P6 detects that the gas pressure inside the circuit breaker gas chamber is insufficient, the inlet electromagnetic valve V4 is powered on to open the gas path, and the mixed gas in the storage tank 10 passes through the inlet pressure reducing valve C3, the molecular sieve 60, the inlet electromagnetic valve V4, the inlet check valve L2 and the switch interface 33 in sequence under the action of gas pressure, and enters the circuit breaker gas chamber; when the gas chamber pressure sensor P6 detects that the gas pressure in the circuit breaker gas chamber reaches the requirement, the power supply of the inlet electromagnetic valve V4 is automatically disconnected;

[0069] When the storage pressure sensor P5 detects that the gas pressure in the storage tank 10 is insufficient, the pressurizing electromagnetic valve V3 is powered on to open the gas path, and the compressor set 50 starts to work and draws the mixed gas in the premixing buffer tank 20 into the storage tank 10; at the same time, the first electric control valve V1 and the second electric control valve V2 are opened, and the SF6 gas and the N2 / CF4 gas are filled into the premixing buffer tank 20 according to the target ratio; when the storage pressure sensor P5 detects that the gas pressure in the storage tank 10 reaches 1 MPa, the compressor set 50 and the pressurizing electromagnetic valve V3 are closed.

[0070] In the automatic storage supplement process, the sampling electromagnetic valve V7 is opened at a certain time to measure the gas quality in the storage tank 10, for example, once every 1 minute, and the sampling electromagnetic valve V7 is closed when not detected; the automatic storage supplement process is a circulating storage supplement process, which monitors the pressure of the circuit breaker gas chamber in real time, and once the automatic storage supplement process is started, it enters the monitoring state, unless the automatic storage supplement process is manually stopped.

[0071] Special storage supplement process (only the first electric control valve V1 has gas passing through or only the second electric control valve V2 has gas passing through) :

[0072] Only the first electric control valve V1 has gas through, SF6 gas through SF6 interface 31, the first pressure reducing valve C1, the first vaporizer 41, the first mass flow meter MFC1, the first electric control valve V1 into the premix buffer tank 20 in turn; only the first electric control valve V1 has gas through, SF6 gas through SF6 interface 31, the first pressure reducing valve C1, the first vaporizer 41, the first mass flow meter MFC1, the first electric control valve V1 into the premix buffer tank 20 in turn;

[0073] Only the second electric control valve V2 has gas through, N2 / CF4 gas through N2 / CF4 interface 32, the second pressure reducing valve C2, the second vaporizer 42, the second mass flow meter MFC2, the second electric control valve V2 into the premix buffer tank 20 in turn;

[0074] The single gas in the premix buffer tank 20 passes through the pressure electromagnetic valve V3, the compressor set 50 and the charging one-way valve L1 into the storage tank 10 in turn; when the pressure of the storage tank 10 reaches 1MPa, stop gas distribution; then open the inlet electromagnetic valve V4, SF6 gas in the storage tank 10 passes through the inlet pressure reducing valve C3, the molecular sieve 60, the inlet electromagnetic valve V4, the inlet one-way valve L2 and the switch interface 33 into the circuit breaker gas chamber under the action of gas pressure, during which the composition of the mixed gas in the circuit breaker gas chamber is detected periodically until the composition of the mixed gas in the circuit breaker gas chamber is the same as the target ratio or the gas pressure of the circuit breaker gas chamber reaches the set upper limit.

[0075] When gas distribution, the first pressure sensor P1, the third pressure sensor P3 and the first electric control valve V1 automatically adjust the pressure difference between the two ends of the first mass flow meter MFC1; the second pressure sensor P2, the fourth pressure sensor P4 and the second electric control valve V2 automatically adjust the pressure difference between the two ends of the second mass flow meter MFC2;

[0076] The special replenishment process is a single process, after each replenishment process, gas measurement is carried out, if it is necessary to continue to replenish the missing gas to adjust the gas chamber ratio, the special process is started again, until the set replenishment ratio is reached, and the automatic replenishment process is started again, and the cycle is repeated.

[0077] System emptying process:

[0078] Open the sampling electromagnetic valve V7, the first electric control valve V1, the second electric control valve V2 and the pressure electromagnetic valve V3, and the gas is automatically discharged under the action of gas pressure.

[0079] System vacuumizing process:

[0080] Open the first electric control valve V1, the second electric control valve V2, the pressure electromagnetic valve V3 and the air suction electromagnetic valve V5, and then start the vacuum pump 80, and the vacuum pump 80 carries out system vacuumizing; before the system vacuumizing process, the system emptying process is carried out first.

[0081] Before the special replenishment process, the system emptying process and the system vacuum process are carried out, and the system emptying process and the system vacuum process are each carried out three times.

[0082] Selection of fixed ratio filling and calculated ratio filling:

[0083] First, the composition of the mixed gas in the circuit breaker chamber is detected, and then the difference between the actual content of SF6 gas in the mixed gas in the circuit breaker chamber and the target ratio (the theoretical range of the content of SF6 gas in the mixed gas in the circuit breaker chamber at the design time) is analyzed; when the actual content of SF6 gas in the mixed gas is within the target ratio, fixed ratio filling is selected; when the actual content of SF6 gas in the mixed gas exceeds the target ratio, calculated ratio filling is selected.

[0084] Fixed ratio filling:

[0085] First, the composition of the mixed gas in the storage tank 10 is detected; when the composition of the mixed gas in the storage tank 10 is the same as that of the mixed gas in the circuit breaker chamber, the gas electromagnetic valve V4 is directly opened, and the mixed gas in the storage tank 10 enters the circuit breaker chamber in sequence through the inlet pressure reducing valve C3, the molecular sieve 60, the inlet electromagnetic valve V4, the inlet check valve L2 and the switch interface 33 under the action of gas pressure; when the circuit breaker chamber pressure sensor P6 detects that the gas pressure in the circuit breaker chamber reaches the requirement, the gas electromagnetic valve V4 is disconnected.

[0086] When the components of the mixed gas in the storage tank 10 are different from the components of the mixed gas in the circuit breaker chamber, the mass of the mixed gas is calculated according to the pressure data measured by the gas storage pressure sensor P5 and the volume of the mixed gas in the storage tank 10, and then the mass of SF6 gas and N2 / CF4 gas in the mixed gas in the storage tank 10 is calculated according to the SF6 gas content measured by the gas analysis sensor 70; finally, the gas required for filling is calculated according to the proportion. For example, the mass of SF6 gas in the storage tank 10 is a grams and the mass of N2 gas is b grams, and the ratio of the mass of SF6 gas to the mass of N2 gas in the circuit breaker chamber is 3:7, at this time only m grams of gas can be filled into the storage tank 10, then when filling the gas, the mass of SF6 gas required for filling is 0.3(a+b+m)-a, and the mass of N2 gas required for filling is 0.7(a+b+m)-b, wherein the mass of SF6 gas required for filling and the mass of N2 gas required for filling are both greater than 0; when the mass of SF6 gas required for filling or the mass of N2 gas required for filling is less than 0, the sampling electromagnetic valve V7 is opened to discharge the mixed gas in the storage tank 10, and then the mass of SF6 gas required for filling and the mass of N2 gas required for filling are recalculated until both are greater than or equal to 0. After the components of the mixed gas in the storage tank 10 are the same as the components of the mixed gas in the circuit breaker chamber, the mixed gas in the storage tank 10 is introduced into the circuit breaker chamber; since there is a certain error in calculating the gas mass by pressure, therefore when filling the gas into the storage tank 10, the content of SF6 gas in the storage tank 10 needs to be detected regularly.

[0087] Calculate the proportion of filling:

[0088] First, detect the components of the mixed gas in the storage tank 10, and then calculate how much corresponding gas needs to be filled into the storage tank 10 to make the mixed gas in the storage tank 10 and the mixed gas in the circuit breaker chamber meet the target proportion after mixing; for example: it is detected that there are a grams of mixed gas (SF6:N2=2:8) in the circuit breaker chamber, there are n grams of mixed gas (SF6:N2=4:6) in the storage tank 10, and the target proportion is SF6:N2=3:7; then m grams of SF6 or N2 needs to be filled in, (2a+4n) / (a+n+m)=0.3, when m is positive, SF6 is filled in, and when m is negative, N2 is filled in; then calculate whether the total amount of gas filled will cause the pressure in the circuit breaker chamber to exceed the standard, if not, directly fill in the corresponding gas, if yes, perform a special replenishment process;

[0089] After filling in enough corresponding gas, start to regularly detect the components of the mixed gas in the circuit breaker chamber until the components of the mixed gas are the same as the target components (in the case that the same components are not reached, continue to fill corresponding gas into the storage tank 10); then adjust the components of the mixed gas in the storage tank 10 to make the components of the mixed gas in the storage tank 10 the same as the target components.

[0090] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description. Therefore, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0091] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A SF6 gas mixture leakage automatic replenishment system, characterized in that, include: Premixed buffer tank (20); the air inlet of the premixed buffer tank (20) is connected to a first mass flow meter (MFC1) and a second mass flow meter (MFC2) via a tee. The air inlet of the first mass flow meter (MFC1) is connected to an SF6 interface (31) via a pipe. The air inlet of the second mass flow meter (MFC2) is connected to an N2 / CF4 interface (32) via a pipe. Storage tank (10); the exhaust end of the premixed buffer tank (20) is connected in sequence to a pressurizing solenoid valve (V3), a compressor unit (50) and an air filling check valve (L1) via a pipe; the other end of the air filling check valve (L1) is connected to the air inlet end of the storage tank (10) via a pipe; The exhaust end of the storage tank (10) is connected to an inlet pressure reducing valve (C3) and a sampling solenoid valve (V7) connected in parallel via a pipe; the other end of the inlet pressure reducing valve (C3) is connected in sequence via a pipe to a molecular sieve (60), an inlet solenoid valve (V4), an inlet check valve (L2), and a switch interface (33); the other end of the sampling solenoid valve (V7) is connected in sequence via a pipe to an analysis pressure reducing valve (C4), an analysis sensor (70), and an exhaust port (34); The air inlet of the switch interface (33) is connected to a venting solenoid valve (V8) via a pipe, and the other end of the venting solenoid valve (V8) is connected to the air inlet of the analysis pressure reducing valve (C4) via a pipe. A gas pressure sensor (P5) is provided on the outside of the storage tank (10), and the gas pressure sensor (P5) is electrically connected to the compressor unit (50) and the pressurization solenoid valve (V3). The air inlet of the switch interface (33) is provided with an air chamber pressure sensor (P6), which is electrically connected to the air inlet solenoid valve (V4).

2. The SF6 gas mixture leakage automatic replenishment system according to claim 1, characterized in that: The exhaust end of the storage tank (10) is also connected to a vacuum solenoid valve (V5) via a pipe. The other end of the vacuum solenoid valve (V5) is connected to a vacuum pump (80) via a pipe. The exhaust end of the vacuum pump (80) is connected to the exhaust port (34) via a pipe.

3. The SF6 gas mixture leakage automatic replenishment system according to claim 1, characterized in that: The exhaust end of the premixed buffer tank (20) is also connected to a direct-charge solenoid valve (V6) via a pipe. The other end of the direct-charge solenoid valve (V6) is connected to the inflation check valve (L1) via a pipe. The direct-charge solenoid valve (V6) is a normally open solenoid valve.

4. The SF6 gas mixture leakage automatic replenishment system according to claim 3, characterized in that: The compressor unit (50) includes two compressors connected in parallel in the gas path, and the compressor unit (50) is connected in parallel in the gas path with a direct-charge solenoid valve (V6).

5. The SF6 gas mixture leakage automatic replenishment system according to claim 1, characterized in that: The exhaust end of the SF6 interface (31) is connected in sequence to a pressure reducing valve (C1) and a vaporizer (41) via a pipe. The other end of the vaporizer (41) is connected to the inlet end of a mass flow meter (MFC1) via a pipe. The exhaust end of the N2 / CF4 interface (32) is connected in sequence to the second pressure reducing valve (C2) and the second vaporizer (42) via a pipe. The other end of the second vaporizer (42) is connected to the inlet end of the second mass flow meter (MFC2) via a pipe.

6. The SF6 gas mixture leakage automatic replenishment system according to claim 5, characterized in that: The outer side of the first vaporizer (41) is provided with a first pressure sensor (P1), and the outer side of the second vaporizer (42) is provided with a second pressure sensor (P2); The gas outlet end of the first mass flow meter (MFC1) is provided with a third pressure sensor (P3), and the gas outlet end of the second mass flow meter (MFC2) is provided with a fourth pressure sensor (P4).

7. The SF6 gas mixture leakage automatic replenishment system according to claim 6, characterized in that: A first electric control valve (V1) is arranged between the gas outlet end of the first mass flow meter (MFC1) and the gas inlet end of the premix buffer tank (20), and a second electric control valve (V2) is arranged between the gas outlet end of the second mass flow meter (MFC2) and the gas inlet end of the premix buffer tank (20). The first pressure sensor (P1) and the third pressure sensor (P3) are electrically connected with the first electric control valve (V1), and the second pressure sensor (P2) and the fourth pressure sensor (P4) are electrically connected with the second electric control valve (V2).

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