Residual-free mixed insulation gas charging device and charging amount calculation method

Abstract

The application relates to a residual-free mixed insulation gas charging device and a charging quantity calculation method, and belongs to the technical field of electrical equipment insulation gas, which solves the problems of inaccurate charging quantity calculation and excessive residual mixed gas in the device after the completion of the charging in the prior art. A first air inlet pipeline, a second air inlet pipeline and a mixing tank are connected through a three-way pipeline, the mixing tank is connected with a buffer tank, a first density relay and a comprehensive detection module are installed between the mixing tank and the buffer tank, a second compressor is connected with a vacuum compressor in parallel and then connected with a flowmeter through a hose, the flowmeter is connected with a charging port, and a second density relay is installed between the flowmeter and the charging port. In the application, almost no residual mixed gas exists in the device after the completion of the charging, the cost of the insulation gas is saved, the influence of the insulation gas on the environment is avoided, the charging quantity can be accurately measured, and the application has a positive effect on the carbon emission accounting and management of power grid enterprises.

Description

Technical Field

[0001] This invention belongs to the field of electrical equipment insulating gas technology, and relates to a device for replenishing residual mixed insulating gas and a method for calculating the replenishment volume. Background Technology

[0002] As an essential part of power system operation and maintenance, accurate measurement of gas replenishment for electrical equipment plays a positive role in the carbon emission accounting and management of power grid companies.

[0003] The basic principle of the mixed gas replenishment device currently used in power systems is to obtain the replenishment gas volume through a built-in mass flow controller (MFC) and an algorithm based on flow and time integration.

[0004] To ensure the uniformity of the charging gas mixture, a large-capacity mixing tank (generally no less than 100L) is usually designed at the rear end of the MFC in the device, and a buffer tank is added at the front end of the compressor to ensure stable front-end pressure. When the existing charging gas device charges the gas chamber of the electrical equipment, it stops charging after reaching the rated gas pressure of the gas chamber; therefore, a large amount of mixed gas residue will remain in the mixing tank, buffer tank, as well as inside the charging gas device and the connecting pipeline to the electrical equipment.

[0005] This causes two problems: 1) If the amount of mixed gas measured by MFC is used directly as the amount of replenishment gas, there will be a large error, resulting in inaccurate calculation of the replenishment gas amount; 2) From the perspective of environmental protection and cost (C4F7N pure gas is expensive, generally not less than 5,000 yuan / kg), a large amount of residual mixed gas (generally 0.1MPa) is usually kept inside for direct use during the next replenishment. Considering that the internal pipeline of the entire replenishment device is intricate and there are many welded and bolted connections, gas leakage is inevitable. Since the replenishment frequency is not high, the leakage over a long period of time cannot be ignored. Summary of the Invention

[0006] This invention addresses the problems of inaccurate calculation of the amount of gas to be added and the presence of a large amount of mixed gas remaining inside the device after the gas filling process in existing gas filling devices.

[0007] The present invention solves the above-mentioned technical problems through the following technical solutions: A residual-free mixed insulating gas filling device includes: a first inlet pipe, a second inlet pipe, a mixing tank (8), a first density relay (9), a comprehensive detection module (10), a buffer tank (11), a second compressor (12), a vacuum compressor (13), a hose (14), a flow meter (15), a second density relay (16), and a filling port (17); the first inlet pipe and the second inlet pipe are connected in parallel, and the output end of the first inlet pipe, the output end of the second inlet pipe, and the input end of the mixing tank (8) are sealed and connected by a three-way pipe; the output end of the mixing tank (8) and the input end of the buffer tank (11) are sealed and connected by a pipe, and the first density relay (9) is sealed and installed on the pipe between the mixing tank (8) and the buffer tank (11). The integrated detection module (10) is sealed and installed on the pipeline between the mixing tank (8) and the buffer tank (11) along the airflow direction. The output end of the buffer tank (11) is sealed and connected to the input end of the second compressor (12) through a pipeline. The input end of the vacuum compressor (13) is sealed and connected to the input end of the second compressor (12) through a pipeline. The output end of the vacuum compressor (13) is sealed and connected to the output end of the second compressor (12) through a pipeline. The output end of the second compressor (12) is sealed and connected to the input end of the flow meter (15) through a hose (14). The output end of the flow meter (15) is sealed and connected to the filling port (17) through a pipeline. The second density relay (16) is sealed and installed on the pipeline between the flow meter (15) and the filling port (17).

[0008] Furthermore, the first air intake pipeline includes: a first air intake (1), a first solenoid valve (3), and a first mass flow controller (5); the first air intake (1) and one end of the first solenoid valve (3) are sealed together by a pipeline, the other end of the first solenoid valve (3) is sealed together with the input end of the first mass flow controller (5) by a pipeline, and the output end of the first mass flow controller (5) is sealed together with the input end of the mixing tank (8) by a pipeline.

[0009] Furthermore, the second air intake pipeline includes: a second air intake (2), a second solenoid valve (4), and a second mass flow controller (6). The second air inlet (2) is sealed to one end of the second solenoid valve (4) through a pipe, the other end of the second solenoid valve (4) is sealed to the input end of the second mass flow controller (6) through a pipe, and the output end of the second mass flow controller (6) is sealed to the input end of the mixing tank (8) through a pipe.

[0010] Furthermore, the residual-free mixed insulating gas replenishment device also includes: a first compressor (7), the input end of the first compressor (7) is sealed and installed on the top of the mixing tank (8) through a pipe, and the output end of the first compressor (7) is sealed and installed on the bottom of the mixing tank (8) through a pipe.

[0011] Furthermore, the first density relay (9) and the second density relay (16) are TP-PT-oL type mixed gas digital density relays.

[0012] Furthermore, the integrated detection module (10) adopts the TSTP1002PRO thermal conductivity detection type mixing ratio detection module.

[0013] Furthermore, the working process of the residue-free mixed insulating gas replenishment device is as follows: S1. Set the air flow rate of the first air inlet pipe and the second air inlet pipe, and output the gas from the first air inlet pipe and the second air inlet pipe to the mixing tank (8) for mixing. S2. Open the output end of the mixing tank (8) and let the mixed gas flow into the buffer tank (11) at the rear end. The integrated detection module (10) detects the mixing ratio of the mixed gas in real time. S3. Start the second compressor (12) and fill the gas mixture into the gas chamber of the electrical equipment through the hose (14), flow meter (15) and filling port (17). When the input pressure of the second compressor (12) is lower than 0.1MPa, the second compressor (12) stops working. S4. When the first and second air inlet pipes stop outputting gas, start the vacuum compressor (13) to fill the electrical equipment with the mixed gas from the mixing tank (8) and the buffer tank (11). When the second density relay (16) detects that the gas chamber pressure of the electrical equipment is equal to the rated pressure... Stop when the time comes.

[0014] A method for calculating the replenishment gas volume based on the aforementioned residue-free mixed insulating gas replenishment device includes the following steps: 1) During the inflation process, the first density relay (9) and the second density relay (16) monitor the pressure P1 of the mixing tank (8) and the pressure P2 of the electrical equipment gas chamber in real time, and the flow meter (15) measures the gas flow rate as Q3. 2) Record the pressure P2 of the electrical equipment's gas chamber before charging as P 20 When the value of P2 changes to P 21 P 21 =P 20 At +0.03MPa, the gas volume currently being charged into the electrical equipment is calculated based on the flow rate Q3 of the flow meter (15). as follows: (1) In the formula, The volume of gas introduced when the pressure in the gas chamber of electrical equipment increases by 0.03 MPa. 1 represents the time taken for the pressure in the air chamber of the electrical equipment to increase by 0.03 MPa; 3) During the process of the pressure in the gas chamber of the electrical equipment increasing by 0.03 MPa, the value of the first density relay (9) is monitored and recorded every 10 seconds, and denoted as P. 11 P 12 ... P 1n Then calculate the average pressure during this stage. for: (2) According to the ideal gas law, when the gas quantity, temperature, and relative molecular mass are the same, the gas pressure and volume are directly proportional. Therefore, the gas volume in the mixing tank (8) is... The conversion formula under a pressure of 0.1 MPa and a temperature of 20°C is as follows: (3) In the formula, The volume of the mixing tank (8) is a known quantity; 4) Let the gas volume be... The mixed gas pressurizes the electrical equipment to ,but: (4) After an initial pre-charge and pressurization of 0.03 MPa, the pressure of the electrical equipment is monitored in real time as P. 2z When P is detected 2z satisfy When the gas distribution stops and no more gas is output, the first solenoid valve (3) and the second solenoid valve (4) are closed, and the vacuum compressor (13) is started to fill the electrical equipment with the residual mixed gas in the mixing tank (8) and the buffer tank (11); 5) The total gas volume V during the entire filling process is calculated as follows: (5) Where t is the total duration of the gas filling process; 6) The filling gas volume m is calculated as follows: (6) Given the mixing ratios C1 and C2 of the mixed gases, the volumes of the two gas components are V1 = C1V and V2 = C2V, respectively. Based on the densities of the different gas components at a pressure of 0.1 MPa and a temperature of 20℃... and .

[0015] The advantages of this invention are: The device of the present invention leaves almost no residual mixed gas inside after the gas filling is completed, which saves the cost of insulating gas and avoids the environmental impact of insulating gas. At the same time, the method of the present invention can accurately measure the amount of gas filling, which has a positive effect on the carbon emission accounting and management of power grid companies. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structural principle of the residue-free mixed insulating gas replenishment device according to an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments: Example 1 like Figure 1 As shown, a residual mixed insulating gas filling device includes: a first air inlet (1), a second air inlet (2), a first solenoid valve (3), a second solenoid valve (4), a first mass flow controller (5), a second mass flow controller (6), a first compressor (7), a mixing tank (8), a first density relay (9), a comprehensive detection module (10), a buffer tank (11), a second compressor (12), a vacuum compressor (13), a hose (14), a flow meter (15), a second density relay (16), and a filling port (17).

[0019] The first air inlet (1) is sealed to one end of the first solenoid valve (3) through a pipe, and the other end of the first solenoid valve (3) is sealed to the input end of the first mass flow controller (5) through a pipe. The second air inlet (2) is sealed to one end of the second solenoid valve (4) through a pipe, and the other end of the second solenoid valve (4) is sealed to the input end of the second mass flow controller (6) through a pipe. The output end of the first mass flow controller (5), the output end of the second mass flow controller (6), and the input end of the mixing tank (8) are sealed to each other through a three-way pipe. The input end of the first compressor (7) is sealed to the top of the mixing tank (8) through a pipe, and the output end of the first compressor (7) is sealed to the bottom of the mixing tank (8) through a pipe. The output end of the mixing tank (8) is sealed to the input end of the buffer tank (11) through a pipe. A density relay (9) is sealed and installed on the pipeline between the mixing tank (8) and the buffer tank (11). The integrated detection module (10) is sealed and installed on the pipeline between the mixing tank (8) and the buffer tank (11) along the airflow direction. The output end of the buffer tank (11) is sealed and connected to the input end of the second compressor (12) through a pipeline. The input end of the vacuum compressor (13) is sealed and connected to the input end of the second compressor (12) through a pipeline. The output end of the vacuum compressor (13) is sealed and connected to the output end of the second compressor (12) through a pipeline. The output end of the second compressor (12) is sealed and connected to the input end of the flow meter (15) through a hose (14). The output end of the flow meter (15) is sealed and connected to the filling port (17) through a pipeline. The second density relay (16) is sealed and installed on the pipeline between the flow meter (15) and the filling port (17).

[0020] The first density relay (9) and the second density relay (16) are TP-PT-oL type mixed gas digital density relays. The comprehensive detection module (10) is a TSTP1002PRO thermal conductivity detection type mixing ratio detection module. This comprehensive detection module has the function of detecting the mixing ratio of two environmentally friendly mixed gases, SF6 / N2 and C4F7N / CO2, and can automatically select the corresponding detection program according to the type of gas being filled.

[0021] Device Working Process The device of this invention can carry out gas replenishment operations and gas volume measurement for two mixed insulating gases, SF6 / N2 and C4F7N / CO2. The following description takes the SF6 / N2 gas replenishment operation as an example.

[0022] 1) Open the first solenoid valve (3) and the second solenoid valve (4), and set the flow rates Q1 and Q2 of the first mass flow controller (5) and the second mass flow controller (6) (values ​​at pressure of 0.1MPa and temperature of 20℃); SF6 and N2 are input from the first air inlet (1) and the second air inlet (2) respectively, and then output to the mixing tank (8) for mixing after passing through the first mass flow controller (5) and the second mass flow controller (6) respectively; when mixing, start the first compressor (7), and the first compressor (7) draws the gas in the mixing tank (8) from the top and fills it from the bottom to promote the mixing of SF6 and N2 and improve the mixing performance; 2) Open the output end of the mixing tank (8) and let the mixed gas flow into the buffer tank (11) at the rear end. The integrated detection module (10) detects the mixing ratio of the mixed gas in real time. 3) Turn on the second compressor (12) and fill the gas mixture into the gas chamber of the electrical equipment through the hose (14), flow meter (15) and filling port (17). When the input pressure of the second compressor (12) is lower than 0.1MPa (about one standard atmosphere), the second compressor (12) stops working. 4) When the first mass flow controller (5) and the second mass flow controller (6) at the front end no longer output gas, close the first solenoid valve (3) and the second solenoid valve (4), and start the vacuum compressor (13) to charge the mixed gas in the mixing tank (8) and the buffer tank (11) into the electrical equipment. When the second density relay (16) detects that the gas chamber pressure of the electrical equipment is the rated pressure, Stop when the time comes.

[0023] Method for calculating replenishment gas volume 1) During the inflation process, the first density relay (9) and the second density relay (16) monitor the pressure P1 of the mixing tank (8) and the pressure P2 of the electrical equipment gas chamber in real time, and the flow meter (15) measures the gas flow rate as Q3 (the value at a pressure of 0.1MPa and a temperature of 20℃).

[0024] 2) Record the pressure P2 of the electrical equipment's gas chamber before charging as P 20 When the value of P2 changes to P 21 P 21 =P 20 When the pressure is +0.03MPa (since the amount of gas replenished each time is generally higher than 0.05MPa, a pre-charge of 0.03MPa is performed first), the gas volume currently being filled into the electrical equipment is calculated based on the flow rate Q3 of the flow meter (15). (Values ​​at pressure of 0.1 MPa and temperature of 20°C): (1) In the formula, The volume of gas introduced when the pressure in the gas chamber of electrical equipment increases by 0.03 MPa. 1 represents the time taken for the pressure in the gas chamber of the electrical equipment to increase by 0.03 MPa.

[0025] 3) During the process of the pressure in the gas chamber of the electrical equipment increasing by 0.03 MPa, the value of the first density relay (9) is monitored and recorded every 10 seconds, and denoted as P. 11 P 12 ... P 1n (Pressure value at 20℃), then calculate the average pressure during this stage. for: (2) From the ideal gas law It can be seen that, given the gas quantity m, temperature T, and relative molecular mass M (the average relative molecular mass of the mixed gas is taken as m), ,in, and The relative molecular mass and volume fraction of SF6 are given. and When the relative molecular mass and volume percentage of N2 are the same, the gas pressure and volume (at the same temperature) are directly proportional. Therefore, the gas volume in the mixing tank (8) is... The conversion formula under a pressure of 0.1 MPa and a temperature of 20°C is as follows: (3) In the formula, The volume of the mixing vessel (8) is a known quantity. Since the mixing vessel (8) has a relatively large volume, therefore... It can be approximated as the total gas volume inside the device.

[0026] 4) Let the gas volume be... The mixture of gases can pressurize electrical equipment to ,but: (4) After an initial pre-charge and pressurization of 0.03 MPa, the electrical equipment pressure is monitored in real time as P. 2z When P is detected 2z satisfy When the first mass flow controller (5) and the second mass flow controller (6) at the front end of the device stop gas distribution and no longer output gas, at this time, the first solenoid valve (3) and the second solenoid valve (4) are closed, and the vacuum compressor (13) is started to fill the electrical equipment with the residual mixed gas in the mixing tank (8) and the buffer tank (11); The value can be set based on experience, taking into account that the vacuum compressor cannot completely remove the residual gas. Due to factors such as estimated values ​​and slower inflation rates under low pressure, it is recommended that... The value range is [1.1~1.2].

[0027] This method ensures that the gas prepared by the first mass flow controller (5) and the second mass flow controller (6) is exactly or slightly more than the amount of gas required for replenishment.

[0028] 5) The total gas volume V during the entire filling process is calculated as follows: (5) In the formula, t is the total duration of the gas filling process; Further calculations of the charge gas volume m are performed. Given the mixing ratios C1 and C2, the volumes of the two gas components are V1 = C1V and V2 = C2V, respectively. Based on the densities of the different gas components at a pressure of 0.1 MPa and a temperature of 20°C... and The filling gas volume m is calculated as follows: (6) At a pressure of 0.1 MPa and a temperature of 20℃, the densities of SF6, N2, C4F7N, and CO2 are respectively 6.08 kg / m³. 3 1.25kg / m 3 8.29kg / m 3 1.99kg / m 3 .

[0029] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the replenishment gas volume based on a residual-free mixed insulating gas replenishment device, wherein the device is connected as follows: a first inlet pipe and a second inlet pipe are connected in parallel; the output ends of the first inlet pipe, the second inlet pipe, and the input end of the mixing tank are sealed together by a three-way pipe; the output end of the mixing tank and the input end of the buffer tank are sealed together by a pipe; a first density relay is sealed and installed on the pipe between the mixing tank and the buffer tank; a comprehensive detection module is sealed and installed on the pipe between the mixing tank and the buffer tank along the airflow direction; the output end of the buffer tank and the input end of the second compressor are sealed together by a pipe; the input end of the vacuum compressor and the input end of the second compressor are sealed together by a pipe; the output end of the vacuum compressor and the output end of the second compressor are sealed together by a pipe; the output end of the second compressor and the input end of the flow meter are sealed together by a hose; the output end of the flow meter and the replenishment gas port are sealed together by a pipe; and the second density relay is sealed and installed on the pipe between the flow meter and the replenishment gas port. The device's workflow is as follows: Set the air intake flow rate of the first air intake pipe and the second air intake pipe, and output the gas from the first air intake pipe and the second air intake pipe to the mixing tank for mixing. Open the output end of the mixing tank and let the mixed gas flow into the buffer tank at the rear end. The integrated detection module detects the mixing ratio of the mixed gas in real time. Turn on the second compressor and inject the mixed gas into the gas chamber of the electrical equipment through the hose, flow meter, and charging port. When the input pressure of the second compressor is lower than 0.1 MPa, the second compressor stops working. When the first and second inlet pipes stop outputting gas, the vacuum compressor is started to fill the electrical equipment with the mixed gas from the mixing tank and buffer tank. The electrical equipment is charged when the second density relay detects that the chamber pressure is at the rated pressure. Stop at this time; Its features are, The method for calculating the replenishment gas volume includes the following steps: During the inflation process, the first density relay and the second density relay monitor the pressure P1 of the mixing tank and the pressure P2 of the electrical equipment gas chamber in real time, and the flow meter measures the gas flow rate as Q3. The pressure P2 of the electrical equipment's gas chamber before filling with gas is denoted as P. 20 When the value of P2 changes to P 21 P 21 =P 20 At +0.03MPa, calculate the current gas volume being charged into the electrical equipment based on the flow rate Q3 measured by the flow meter. as follows: （1） In the formula, The volume of gas introduced when the pressure in the gas chamber of electrical equipment increases by 0.03 MPa. 1 represents the time taken for the pressure in the air chamber of the electrical equipment to increase by 0.03 MPa; During the process of the pressure in the gas chamber of the electrical equipment increasing by 0.03 MPa, the value of the first density relay is monitored and recorded every 10 seconds, and denoted as P. 11 P 12 ... P 1n Then calculate the average pressure during that stage. for: （2） According to the ideal gas law, when the gas quantity, temperature, and relative molecular mass are the same, the gas pressure and volume are directly proportional. Therefore, the gas volume in the mixing tank is... The conversion formula under a pressure of 0.1 MPa and a temperature of 20°C is as follows: （3） In the formula, Let be the volume of the mixing tank, which is a known quantity; Let the gas volume be The mixed gas pressurizes the electrical equipment to ,but: （4） After an initial pre-charge and pressurization of 0.03 MPa, the pressure of the electrical equipment is monitored in real time as P. 2z When P is detected 2z satisfy When the gas distribution stops and no more gas is output, close the first and second solenoid valves and start the vacuum compressor to fill the electrical equipment with the residual mixed gas in the mixing tank and buffer tank. The gas volume V during the entire filling process is calculated as follows: （5） Where t is the total duration of the gas filling process; The charge volume m is calculated as follows: （6） Given the mixing ratios C1 and C2 of the mixed gases, the volumes of the two gas components are V1 = C1V and V2 = C2V, respectively. Based on the densities of the different gas components at a pressure of 0.1 MPa and a temperature of 20℃... and .

2. The method for calculating the replenishment gas volume according to claim 1, characterized in that, The first air intake pipeline includes: a first air inlet, a first solenoid valve, and a first mass flow controller; the first air inlet is sealed to one end of the first solenoid valve through a pipeline, the other end of the first solenoid valve is sealed to the input end of the first mass flow controller through a pipeline, and the output end of the first mass flow controller is sealed to the input end of the mixing tank through a pipeline.

3. The method for calculating the replenishment gas volume according to claim 1, characterized in that, The second intake pipeline includes: a second intake port, a second solenoid valve, and a second mass flow controller; The second air inlet is sealed to one end of the second solenoid valve via a pipe, the other end of the second solenoid valve is sealed to the input end of the second mass flow controller via a pipe, and the output end of the second mass flow controller is sealed to the input end of the mixing tank via a pipe.

4. The method for calculating the replenishment gas volume according to claim 1, characterized in that, The device further includes: a first compressor, the input end of which is sealed and installed at the top of the mixing tank via a pipe, and the output end of which is sealed and installed at the bottom of the mixing tank via a pipe.

5. The method for calculating the replenishment gas volume according to claim 1, characterized in that, The first density relay and the second density relay are TP-PT-oL type mixed gas digital density relays.

6. The method for calculating the replenishment gas volume according to claim 1, characterized in that, The comprehensive detection module mentioned above uses the TSTP1002PRO thermal conductivity detection type mixing ratio detection module.

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