Emergency air supply device for electrical equipment

Abstract

The invention discloses an emergency gas supplementing device for electrical equipment, which is characterized in that a multi-way joint is arranged to be respectively connected with an SF6 gas cylinder, a nitrogen cylinder and the electrical equipment, so that the supplementary supply of mixed gas of SF6 gas and nitrogen in the electrical equipment is realized, and a pressure sensor and a temperature sensor are arranged in the multi-way joint to measure the pressure of the mixed gas in the electrical equipment; the mixing ratio of mixed gas in the electrical equipment is measured through the mixing ratio tester, and the single-chip microcomputer firstly calculates the total amount of the mixed gas needing to be supplemented according to the initial pressure value and the target pressure value of the mixed gas in the electrical equipment; the proportion of the SF6 gas and the nitrogen needing to be supplemented is calculated according to the initial mixing ratio and the target mixing ratio of the mixed gas in the electrical equipment, and finally the SF6 gas cylinder and the nitrogen cylinder are controlled to fill the corresponding SF6 gas and nitrogen into the electrical equipment respectively, so that automatic gas supplementation of the mixed gas of the SF6 gas and the nitrogen in the electrical equipment without power failure is achieved. And safe operation of equipment in a power grid is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of electrical equipment and relates to an air replenishing device, in particular to an emergency air replenishing device for electrical equipment. Background Art

[0002] At present, SF6 gas is widely used in power systems, mainly in high-voltage circuit breakers and GIS combined electrical equipment. Circuit breakers are used for breaking and arc extinguishing during operation. Since SF6 gas has a high capacity in current breaking and arc extinguishing in electrical equipment, the remaining gas chambers mainly play an insulating role. According to the requirements of environmental protection and greenhouse gas emissions, new products and new energy combinations are used to reduce the use of SF6 gas. SF6 gas and nitrogen mixed gas are specially selected for use, which can improve green environmental protection and meet national requirements to enhance environmental protection awareness.

[0003] At present, SF6 gas is used in busbars, lightning arresters, voltage transformers, current transformers and cable outlets in GIS equipment, which requires a large amount of gas. Various tests have shown that GIS busbar gas chambers can use 30% SF6 gas mixed with 70% nitrogen to form a mixed gas, which can reduce the use of a large amount of SF6 gas overall. The use of mixed gas can not only ensure the normal operation of the equipment, but also reduce the pollution to the atmosphere, improve the stable operation of the equipment and the environmental protection effect.

[0004] However, during the operation of the power grid, due to various reasons, the mixed gas in the electrical equipment is prone to leakage, affecting the safe use of the electrical equipment. In addition, the power grid cannot be shut down for maintenance during many major events. Therefore, a device is needed that can automatically replenish gas according to the pressure changes inside the electrical equipment without shutting down the power grid to ensure the safe operation of the equipment in the power grid. Summary of the invention

[0005] In order to solve the technical problems existing in the background technology, the present invention proposes an emergency gas replenishment device for electrical equipment, which realizes automatic gas replenishment of a mixed gas of SF6 gas and nitrogen in the electrical equipment without power outage, thereby ensuring the safe operation of the equipment in the power grid.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] An emergency gas replenishment device for electrical equipment comprises a multi-way joint, an SF6 gas cylinder and a nitrogen gas cylinder. The multi-way joint is connected to the electrical equipment through a first pipeline. A pressure sensor P and a temperature sensor T are installed in the multi-way joint to measure the pressure of the mixed gas in the electrical equipment. The SF6 gas cylinder is connected to the multi-way joint through a second pipeline to replenish SF6 gas into the electrical equipment. The nitrogen gas cylinder is connected to the multi-way joint through a third pipeline to replenish nitrogen into the electrical equipment. A first solenoid valve DF1 is installed on the second pipeline, and a second solenoid valve DF2 is installed on the third pipeline to respectively control the replenishment amount of SF6 gas and nitrogen.

[0008] Furthermore, the pressure sensor P, the temperature sensor T, the first solenoid valve DF1, and the second solenoid valve DF2 are all communicatively connected to the single chip microcomputer, and the single chip microcomputer is connected to a keyboard, which is used to input a pressure threshold and a target mixing ratio into the single chip microcomputer. The pressure sensor P and the temperature sensor T measure the initial pressure value of the mixed gas in the electrical equipment and upload it to the single chip microcomputer for comparison with the pressure threshold. If the initial pressure value of the mixed gas is less than the pressure threshold, the single chip microcomputer calculates the ratio of SF6 gas and nitrogen that needs to be supplemented into the electrical equipment according to the target mixing ratio, and then obtains a second pressure value p2 for supplementing SF6 gas and a third pressure value p3 for supplementing nitrogen. The single chip microcomputer opens the first solenoid valve DF1 to supplement SF6 gas into the electrical equipment. When the pressure of the mixed gas reaches the second pressure value p2, the single chip microcomputer closes the first solenoid valve DF1 and opens the second solenoid valve DF2 to supplement nitrogen into the electrical equipment. When the pressure of the mixed gas reaches the third pressure value p3, the single chip microcomputer closes the second solenoid valve DF2.

[0009] Furthermore, an electrically controlled three-way valve STF is provided on the first pipeline, and the electrically controlled three-way valve STF is connected to a mixing ratio tester through a fourth pipeline to measure the mixing ratio of the mixed gas in the electrical equipment.

[0010] Furthermore, the electric three-way valve STF and the mixing ratio tester are both communicatively connected to the single-chip microcomputer. When the single-chip microcomputer controls the electric three-way valve STF to connect the mixing ratio tester and the electrical equipment, the current mixing ratio of the mixed gas in the electrical equipment is measured by the mixing ratio tester. The single-chip microcomputer calculates the ratio of SF6 gas and nitrogen that needs to be added to the electrical equipment based on the current mixing ratio of the mixed gas and the target mixing ratio.

[0011] Furthermore, a first hand valve F1 is installed in series on the second pipeline on the first solenoid valve DF1 side, a second hand valve F2 is installed in series on the third pipeline on the second solenoid valve DF2 side, and a third hand valve F3 is installed in series on the first pipeline between the electric three-way valve STF and the multi-way connector.

[0012] Furthermore, a first self-sealing valve ZFF1 is installed in series on the second pipeline between the first solenoid valve DF1 / first manual valve F1 and the SF6 gas cylinder, a second self-sealing valve ZFF2 is installed in series on the third pipeline between the second solenoid valve DF2 / second manual valve F2 and the nitrogen cylinder, a third self-sealing valve ZFF3 is installed in series on the first pipeline between the third manual valve F3 and the electrically controlled three-way valve STF, and a fourth self-sealing valve ZFF4 is installed at the connection between the first pipeline and the electrical equipment.

[0013] Furthermore, the multi-way connector is connected to a micro vacuum pump via a fifth pipe. The micro vacuum pump is used to evacuate the multi-way connector and the first pipe, the second pipe, the third pipe and the fifth pipe to check the air tightness of the device. A fourth manual valve F4 is installed on the fifth pipe.

[0014] Furthermore, when the micro vacuum pump is started, the fourth manual valve F4 is opened to evacuate each gas circuit. When the pressure sensor P data is below zero, the micro vacuum pump and the fourth manual valve F4 are closed. After waiting for a predetermined time, if the pressure sensor P data does not return to zero, it indicates that the device has good air tightness.

[0015] Furthermore, a first pressure reducing valve JYF1 is installed at the connection between the second pipeline and the SF6 gas cylinder, and a second pressure reducing valve JYF2 is installed at the connection between the third pipeline and the nitrogen gas cylinder.

[0016] Beneficial effects of the present invention: The emergency gas replenishment device for electrical equipment provided by the present invention realizes the supplementary supply of the mixed gas of SF6 gas and nitrogen in the electrical equipment by arranging a multi-way joint to respectively connect the SF6 gas cylinder, the nitrogen cylinder and the electrical equipment, and measures the pressure of the mixed gas in the electrical equipment by arranging a pressure sensor and a temperature sensor in the multi-way joint, and measures the mixing ratio of the mixed gas in the electrical equipment by a mixing ratio tester. The single-chip microcomputer first calculates the total amount of the mixed gas that needs to be replenished according to the initial pressure value and the target pressure value of the mixed gas in the electrical equipment, and then calculates the ratio of SF6 gas and nitrogen that needs to be replenished according to the initial mixing ratio and the target mixing ratio of the mixed gas in the electrical equipment, and finally controls the SF6 gas cylinder and the nitrogen cylinder to fill the corresponding SF6 gas and nitrogen into the respective electrical equipment, thereby realizing the automatic gas replenishment of the mixed gas of SF6 gas and nitrogen in the electrical equipment without power outage, and ensuring the safe operation of the equipment in the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the gas replenishment system of the present invention.

[0018] Figure 2 It is a schematic diagram of the control system of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figure 1 As shown, the present invention provides an emergency gas supply device for electrical equipment, comprising a multi-way connector 1, a SF6 gas cylinder 2 and a nitrogen gas cylinder 3. The multi-way connector 1 is connected to the electrical equipment 4 through a first pipeline 5. A pressure sensor P and a temperature sensor T are installed in the multi-way connector 1 to measure the pressure and temperature of the mixed gas in the electrical equipment 4. According to the ideal gas state equation: In the formula, M is the mass of the gas, μ is the mass of 1 mole of gas, V is the volume of the gas, R is the gas constant, t is the gas temperature, and p is the gas pressure. It can be seen from the above formula that the pressure p of the mixed gas in the electrical equipment 4 is a two-variable function of the gas density M / pV and the gas temperature t. The pressure change caused by the gas temperature t can be accurately compensated according to the SF6 gas pressure-temperature change isoclinic line to obtain the pressure of the mixed gas in the electrical equipment 4 at the standard temperature. And when the initial pressure value of the mixed gas in the electrical equipment 4 is lower than the preset pressure threshold, it is necessary to add SF6 gas and nitrogen to the electrical equipment 4 according to the preset target mixing ratio.

[0021] The SF6 gas cylinder 2 is connected to the multi-way connector 1 through the second pipeline 6 to replenish SF6 gas into the electrical equipment 4. The nitrogen gas cylinder 3 is connected to the multi-way connector 1 through the third pipeline 7 to replenish nitrogen into the electrical equipment 4. A first solenoid valve DF1 is installed on the second pipeline 6, and a second solenoid valve DF2 is installed on the third pipeline 7 to control the replenishment amount of SF6 gas and nitrogen respectively.

[0022] like Figure 2As shown, the pressure sensor P, the temperature sensor T, the first solenoid valve DF1, and the second solenoid valve DF2 are all connected to the single-chip microcomputer for communication. The single-chip microcomputer is connected to a keyboard, and the keyboard is used for the staff to input the pressure threshold, the target pressure value, and the target mixing ratio to the single-chip microcomputer in advance. The pressure sensor P and the temperature sensor T measure the initial pressure value of the mixed gas in the electrical equipment 4 and upload it to the single-chip microcomputer for comparison with the pressure threshold. If the initial pressure value of the mixed gas is less than the pressure threshold, SF6 gas and nitrogen need to be added to the electrical equipment 4 to make the pressure of the mixed gas reach the target pressure value. The single-chip microcomputer calculates the ratio of SF6 gas and nitrogen that needs to be added to the electrical equipment 4 according to the target mixing ratio, and calculates the ratio between the initial pressure value of the mixed gas in the electrical equipment and the target pressure value. The pressure difference is divided into a first pressure interval and a second pressure interval according to the replenishment ratio of SF6 gas and nitrogen. The first pressure interval is from the first pressure value p1 to the second pressure value p2, and the second pressure interval is from the second pressure value p2 to the third pressure value p3. Among them, the first pressure value p1 is the initial pressure value of the mixed gas inside the electrical equipment, and the third pressure value p3 is the target pressure value of the mixed gas inside the electrical equipment. The single-chip microcomputer opens the first solenoid valve DF1 to replenish SF6 gas into the electrical equipment 4. When the pressure of the mixed gas reaches the second pressure value p2, the single-chip microcomputer closes the first solenoid valve DF1 and opens the second solenoid valve DF2 to replenish nitrogen into the electrical equipment 4. When the pressure of the mixed gas reaches the third pressure value p3, the single-chip microcomputer closes the second solenoid valve DF2.

[0023] The first pipeline 5 is provided with an electrically controlled three-way valve STF, which is connected to a mixing ratio tester 9 through a fourth pipeline 8 to measure the mixing ratio of the mixed gas in the electrical equipment 4. The electrically controlled three-way valve STF and the mixing ratio tester 9 are both connected to a single-chip microcomputer for communication. When the single-chip microcomputer controls the electrically controlled three-way valve STF to connect the mixing ratio tester 9 and the electrical equipment 4, the initial mixing ratio of the mixed gas in the electrical equipment 4 is measured by the mixing ratio tester 9. The single-chip microcomputer calculates the ratio of SF6 gas and nitrogen that needs to be added to the electrical equipment 4 based on the initial mixing ratio and the target mixing ratio of the mixed gas. The mixing ratio tester 9 uses the LX-3100M portable SF6 mixed gas (mixed gas ratio) detector, which can realize the quantitative analysis of the mixing ratio of the two mixed insulating gases SF6 / N2 and SF6 / CF4 without changing the analysis conditions, and monitor the oxygen concentration at the same time.

[0024] A first hand valve F1 is installed in series on the second pipeline 6 on one side of the first solenoid valve DF1, a second hand valve F2 is installed in series on the third pipeline 7 on one side of the second solenoid valve DF2, and a third hand valve F3 is installed in series on the first pipeline 5 between the electric three-way valve STF and the multi-way connector 1. The hand valves are all installed at the inlet of the solenoid valve. When the hand valve is in the open state, the solenoid valve will be activated, and the gas can flow through the pipeline through the solenoid valve. When the hand valve is closed, the solenoid valve loses the activation signal, thereby cutting off the pipeline flow. Through the series connection of the hand valve and the solenoid valve, the opening and closing of the valve can be controlled by manual operation, and the opening and closing of the solenoid valve can also be controlled by the single-chip microcomputer, realizing the function of combining manual operation and automatic control, which can not only meet the manual control needs of the operator, but also reduce the burden of the operator, improve the accuracy and stability of the automatic control, and when the solenoid valve fails, the power fails or other problems occur in the single-chip microcomputer, the hand valve can be manually operated to cut off the pipeline flow by physical means, thereby ensuring safety.

[0025] The first self-sealing valve ZFF1 is installed in series on the second pipeline 6 between the first solenoid valve DF1 / first hand valve F1 and the SF6 gas cylinder 2, the second self-sealing valve ZFF2 is installed in series on the third pipeline 7 between the second solenoid valve DF2 / second hand valve F2 and the nitrogen gas cylinder 3, the third self-sealing valve ZFF3 is installed in series on the first pipeline 5 between the third hand valve F3 and the electric-controlled three-way valve STF, and the fourth self-sealing valve ZFF4 is installed at the connection between the first pipeline 5 and the electrical equipment 4. The self-sealing valve has a self-sealing function, and when the equipment or connector is removed from the self-sealing valve, it can be automatically sealed to ensure that the SF6 gas will not leak.

[0026] The multi-way connector 1 is connected to a micro vacuum pump 11 through a fifth pipe 10. The micro vacuum pump 11 is used to evacuate the multi-way connector 1 and the first pipe 5, the second pipe 6, the third pipe 7, and the fifth pipe 10 to check the air tightness of the device. A fourth hand valve F4 is installed on the fifth pipe 10. When the micro vacuum pump 11 is started, the fourth hand valve F4 is opened to evacuate each gas path. When the pressure sensor P data is below zero, the micro vacuum pump 11 and the fourth hand valve F4 are closed. After waiting for a predetermined time, if the pressure sensor P data does not return to zero, it indicates that the air tightness of the device is good.

[0027] The first pressure reducing valve JYF1 is installed at the connection between the second pipeline 6 and the SF6 gas cylinder 2, and the second pressure reducing valve JYF2 is installed at the connection between the third pipeline 7 and the nitrogen gas cylinder 3. By setting the pressure reducing valve, the pressure at the outlet of the SF6 gas cylinder 2 and the nitrogen gas cylinder 3 is reduced to the preset pressure and output to the second pipeline 6 and the third pipeline 7, so that the pressure in the second pipeline 6 and the third pipeline 7 is kept stable.

[0028] The specific use process of the present invention is as follows:

[0029] The first step is to check the air tightness of the device;

[0030] Close the first solenoid valve DF1, the first hand valve F1, the second solenoid valve DF2, the second hand valve F2 and the third hand valve F3, open the fourth hand valve F4 and start the micro vacuum pump 11, evacuate the multi-way connector 1 and the first pipe 5, the second pipe 6, the third pipe 7 and the fifth pipe 10, when the pressure sensor P data is below zero, close the micro vacuum pump 11 and the fourth hand valve F4, wait for 30 minutes, if the pressure sensor P data does not return to zero, it means that the device is airtight.

[0031] The second step is to measure the initial mixing ratio of the mixed gas in the electrical device 4;

[0032] The single chip microcomputer controls the electrically controlled three-way valve STF to connect the mixing ratio tester 9 and the electrical equipment 4. The initial mixing ratio of the mixed gas in the electrical equipment 4 measured by the mixing ratio tester 9 is 60% SF6 gas and 40% nitrogen.

[0033] The third step is to measure the initial pressure value of the mixed gas in the electrical device 4;

[0034] The single chip microcomputer controls the electrically controlled three-way valve STF to connect the multi-way connector 1 with the electrical device 4, opens the third manual valve F3, and measures the initial pressure value of the mixed gas in the electrical device 4 to be 5 through the pressure sensor P and the temperature sensor T.

[0035] Step 4: Calculate the second pressure value p2 that needs to be reached for replenishing SF6 gas;

[0036] The single chip microcomputer compares the initial pressure value 5 of the mixed gas with the pressure threshold value 10, and obtains that SF6 gas and nitrogen need to be supplemented into the electrical equipment 4 to make the pressure of the mixed gas reach the target pressure value 15, and then obtains that the amount of mixed gas supplemented is twice the current amount of mixed gas. The single chip microcomputer then calculates that the ratio of SF6 gas and nitrogen that needs to be supplemented into the electrical equipment 4 is 9 / 1 based on the initial mixing ratio of the mixed gas (60% SF6 gas and 40% nitrogen) and the target mixing ratio (80% SF6 gas and 20% nitrogen), and then calculates the second pressure value p2 to be 14.

[0037] Step 5, replenishing SF6 gas and nitrogen into the electrical equipment 4 respectively;

[0038] Open the first manual valve F1 and the second manual valve F2, the single chip microcomputer controls the first solenoid valve DF1 to open, so as to add SF6 gas into the electrical equipment 4; when the pressure sensor P and the temperature sensor T measure the current pressure value of the mixed gas in the electrical equipment 4 to reach 14, the single chip microcomputer controls the first solenoid valve DF1 to close, and controls the second solenoid valve DF2 to open, so as to add nitrogen into the electrical equipment 4; when the pressure sensor P and the temperature sensor T measure the current pressure value of the mixed gas in the electrical equipment 4 to reach 15, the single chip microcomputer controls the second solenoid valve DF2 to close.

[0039] Step 6, measuring the current mixing ratio of the mixed gas in the electrical device 4 again;

[0040] After the SF6 gas and nitrogen are replenished into the electrical equipment 4 respectively, wait for 30 minutes, close the third manual valve F3, and the single chip microcomputer controls the electronically controlled three-way valve STF to connect the mixing ratio tester 9 with the electrical equipment 4. The current mixing ratio of the mixed gas in the electrical equipment 4 is measured again by the mixing ratio tester 9. If the proportion of SF6 gas in the current mixing ratio of the mixed gas is lower than the proportion of SF6 gas in the target mixing ratio, the single chip microcomputer controls the electronically controlled three-way valve STF to connect the multi-way connector 1 with the electrical equipment 4, open the third manual valve F3, and the single chip microcomputer controls the first solenoid valve DF1 to open, and continue to replenish the electrical equipment 4. SF6 gas is supplemented in the equipment 4 so that the proportion of SF6 gas in the mixed gas exceeds the proportion of SF6 gas in the target mixing ratio. When the current mixing ratio of the mixed gas reaches the preset target mixing ratio, the connection between the electrically controlled three-way valve STF and the electrical equipment 4 is disconnected from the fourth self-sealing valve ZFF4, the connection between the multi-way connector 1 and the electrically controlled three-way valve STF is disconnected from the third self-sealing valve ZFF3, the connection between the nitrogen cylinder 3 and the multi-way connector 1 is disconnected from the second self-sealing valve ZFF2, the connection between the SF6 cylinder 2 and the multi-way connector 1 is disconnected from the first self-sealing valve ZFF1, and the gas replenishing device is retracted.

[0041] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. An emergency air supply device for electrical equipment, characterized in that: The invention comprises a multi-way connector (1), an SF6 gas cylinder (2) and a nitrogen gas cylinder (3); the multi-way connector (1) is connected to an electrical device (4) via a first pipeline (5); a pressure sensor P and a temperature sensor T are installed in the multi-way connector (1) to measure the pressure of a mixed gas in the electrical device (4); the SF6 gas cylinder (2) is connected to the multi-way connector (1) via a second pipeline (6) to replenish SF6 gas into the electrical device (4); the nitrogen gas cylinder (3) is connected to the multi-way connector (1) via a third pipeline (7) to replenish nitrogen into the electrical device (4); a first electromagnetic valve DF1 is installed on the second pipeline (6); and a second electromagnetic valve DF2 is installed on the third pipeline (7) to control the replenishment amount of SF6 gas and nitrogen respectively.

2. The air supply device according to claim 1, characterized in that: The pressure sensor P, the temperature sensor T, the first solenoid valve DF1, and the second solenoid valve DF2 are all connected to the single chip microcomputer for communication. The single chip microcomputer is connected to a keyboard, and the keyboard is used to input a pressure threshold, a target pressure value, and a target mixing ratio into the single chip microcomputer. The pressure sensor P and the temperature sensor T measure the initial pressure value of the mixed gas in the electrical device (4) and upload it to the single chip microcomputer for comparison with the pressure threshold value. If the initial pressure value of the mixed gas is less than the pressure threshold value, SF6 gas and nitrogen need to be added to the electrical device 4 so that the pressure of the mixed gas reaches the target pressure value. The single chip microcomputer adjusts the pressure according to the pressure threshold. The target mixing ratio calculation requires the ratio of SF6 gas to nitrogen to be added to the electrical device (4), thereby obtaining a second pressure value p2 for adding SF6 gas and a third pressure value p3 for adding nitrogen. The single chip computer opens the first solenoid valve DF1 to add SF6 gas to the electrical device (4). When the pressure of the mixed gas reaches the second pressure value p2, the single chip computer closes the first solenoid valve DF1 and opens the second solenoid valve DF2 to add nitrogen to the electrical device (4). When the pressure of the mixed gas reaches the third pressure value p3, the single chip computer closes the second solenoid valve DF2.

3. The air replenishing device according to claim 2, characterized in that: An electrically controlled three-way valve STF is provided on the first pipeline (5), and the electrically controlled three-way valve STF is connected to a mixing ratio tester (9) via a fourth pipeline (8) to measure the mixing ratio of the mixed gas in the electrical equipment (4).

4. The air replenishing device according to claim 3, characterized in that: The electric-controlled three-way valve STF and the mixing ratio tester (9) are both communicatively connected to the single-chip microcomputer. When the single-chip microcomputer controls the electric-controlled three-way valve STF to connect the mixing ratio tester (9) and the electrical device (4), the mixing ratio tester (9) measures the initial mixing ratio of the mixed gas in the electrical device (4). The single-chip microcomputer calculates the ratio of SF6 gas and nitrogen that needs to be added to the electrical device (4) based on the initial mixing ratio and the target mixing ratio of the mixed gas.

5. The air replenishing device according to claim 4, characterized in that: A first hand valve F1 is installed in series on a second pipe (6) on one side of the first solenoid valve DF1, a second hand valve F2 is installed in series on a third pipe (7) on one side of the second solenoid valve DF2, and a third hand valve F3 is installed in series on a first pipe (5) between the electric-controlled three-way valve STF and the multi-way connector (1).

6. The air replenishing device according to claim 5, characterized in that: A first self-sealing valve ZFF1 is installed in series on the second pipeline (6) between the first solenoid valve DF1 / first manual valve F1 and the SF6 gas cylinder (2); a second self-sealing valve ZFF2 is installed in series on the third pipeline (7) between the second solenoid valve DF2 / second manual valve F2 and the nitrogen gas cylinder (3); a third self-sealing valve ZFF3 is installed in series on the first pipeline (5) between the third manual valve F3 and the electric-controlled three-way valve STF; and a fourth self-sealing valve ZFF4 is installed at the connection between the first pipeline (5) and the electrical equipment (4).

7. The air replenishing device according to claim 1, characterized in that: The multi-way connector (1) is connected to a micro vacuum pump (11) via a fifth pipeline (10). The micro vacuum pump (11) is used to evacuate the multi-way connector (1) and the first pipeline (5), the second pipeline (6), the third pipeline (7), and the fifth pipeline (10) to check the air tightness of the device. A fourth manual valve F4 is installed on the fifth pipeline (10).

8. The air replenishing device according to claim 7, characterized in that: When the micro vacuum pump (11) is started, the fourth manual valve F4 is opened to evacuate each gas path. When the pressure sensor P data is below zero, the micro vacuum pump (11) and the fourth manual valve F4 are closed. After waiting for a predetermined time, if the pressure sensor P data does not return to zero, it indicates that the air tightness of the device is good.

9. The air replenishing device according to claim 1, characterized in that: A first pressure reducing valve JYF1 is installed at the connection between the second pipeline (6) and the SF6 gas cylinder (2), and a second pressure reducing valve JYF2 is installed at the connection between the third pipeline (7) and the nitrogen gas cylinder (3).

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