Method for measuring recovery rate and recovering sulfur hexafluoride gas

Abstract

The application relates to a method for measuring the quantity and recovery rate of sulfur hexafluoride gas recovery, which comprises pressure and temperature sensors and a mass flow meter, characterized in that the mass flow meter is connected in series in a recovery pipeline between a gas chamber to be recovered and a recovery device, the pressure and temperature sensors are arranged at a sampling port of the gas chamber to be recovered or in the recovery pipeline in series between the mass flow meter and the gas chamber to be recovered, the mass of the recovered gas is m = rho (nu t) * k (P), wherein m is the mass of the recovered gas, rho is the gas density under standard conditions, nu is the gas flow, i.e. the output flow of the mass flow meter, t is the recovery time, and k is a function of the pressure P, the pressure data being obtained from the pressure sensor; and the recovery rate of the sulfur hexafluoride gas is 1 - (P1T0) / (P0T1) * 100%, wherein P0 and T0 are the initial gas pressure and temperature, and P1 and T1 are the real-time gas pressure and temperature. The application is suitable for the measurement of the quantity and recovery rate of gas recovery of different insulating gas electrical devices.

Description

Technical Field

[0001] This invention belongs to the field of electrical equipment insulating gas recovery technology, and relates to a method for metering and determining the recovery rate of sulfur hexafluoride gas. Background Technology

[0002] The State Grid Corporation of China requires a sulfur hexafluoride (SF6) recovery rate of 96.5%. Therefore, the recovered gas mass (weight) is a crucial piece of data. Currently, the only method for detecting the mass (weight) of SF6 gas in recovery operations is weighing, which requires the gas to be collected in cylinders or storage tanks. This makes it difficult to guarantee the real-time nature of the recovered mass (weight). Furthermore, the original weight of the gas inside SF6 insulating electrical equipment is not known, making it difficult to measure the recovery rate of a single operation. How to obtain relevant data through daily operations is a topic worthy of in-depth research. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method for metering and determining the recovery rate of sulfur hexafluoride gas.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A method for metering and determining the recovery rate of sulfur hexafluoride gas recovery, characterized in that a mass flow meter is connected in series in the recovery pipeline between the gas chamber to be recovered and the recovery device, and pressure and temperature sensors are set at the sampling port of the gas chamber to be recovered or connected in series in the recovery pipeline between the mass flow meter and the gas chamber to be recovered.

[0006] The mass of the recovered gas is m = ρ(νt) * k(P) (Formula 1)

[0007] Where m is the mass of the recovered gas, ρ is the gas density under standard conditions, ν is the gas flow rate, i.e. the output flow rate of mass flow meter 1, t is the recovery time, and k is a function of pressure P, the pressure data of which can be obtained from the pressure sensor;

[0008] Sulfur hexafluoride gas recovery rate = 1 - (P1T0) / (P0T1) * 100% (Formula 2)

[0009] Where P0 and T0 are the initial gas pressure and temperature, and P1 and T1 are the final (real-time) gas pressure and temperature.

[0010] The inner diameter of the mass flow meter is consistent with the main recovery pipeline of the recovery device.

[0011] The inner diameter of the mass flow meter and the inner diameter of the main recovery pipeline of the recovery device are both DN20.

[0012] A mass flow meter, connected in series in the recovery pipeline, is characterized by its inner diameter being identical to that of the main recovery pipeline. This allows for real-time monitoring of the gas mass flow rate while ensuring normal gas recovery speed. By connecting the mass flow meter in series, gas mass flow data can be obtained more directly and accurately. Then, based on gas density and time, the gas mass during the recovery process can be calculated, obtaining the gas mass for each recovery operation. The specific algorithm is shown in Formula (I). This enables the metering and accumulation of sulfur hexafluoride gas recovery on-site.

[0013] According to m = ρ * (ν * t), where ρ is the known gas density under standard conditions, ν is the gas flow rate under standard conditions (i.e., the output flow rate of mass flow meter 1), and t is time. Considering that the gas flow rate may be affected by the gas pressure, an influence factor k is added for mass flow rate correction. Therefore, m = ρ(νt) * k(P), where k is a function of pressure P.

[0014] The k(P) function can be obtained through experiments and methods, as detailed below.

[0015] A standard mass flow meter and a measuring mass flow meter are connected in series. Gas at a constant pressure is passed through both, and the gas is eventually collected in a storage container. Assuming the gas flow pressure through the standard and measuring mass flow meters is constant (P1), the flow time is t, and the flow velocities are respectively... 1标 And ν1, the corresponding recovered mass m1=ρ(ν) 1标 *t)=ρ(ν1*t)*k1, then k1=ν 1标 / ν1,

[0016] If the ventilation pressure is adjusted to P2 and kept constant, then k2 = ν 2标 / ν2,

[0017] If the ventilation pressure is adjusted to P3 and kept constant, then k3 = ν 3标 / ν3,

[0018] By applying pressure covering the vacuum to the maximum chamber pressure of insulated circuit breakers and GIS combined electrical / GIL electrical equipment, multiple sets of data for pressure P and k can be obtained. A curve of k versus pressure P can be obtained on the coordinate axis. By using data fitting methods, the functional relationship between k and pressure P can be obtained.

[0019] Pressure and temperature sensors are installed at the sampling port of the gas chamber to be recovered and connected in series in the recovery pipeline for real-time measurement of the recovery rate. The recovery rate can be obtained by acquiring only the initial pressure P0 and temperature T0 of the recovered gas chamber, and the real-time pressure P and temperature T.

[0020] Sulfur hexafluoride gas recovery rate = 1 - (P1T0) / (P0T1)*100% (Formula 2).

[0021] Where P0 and T0 are the initial gas pressure and temperature, and P1 and T1 are the final (real-time) gas pressure and temperature.

[0022] For detailed methods for determining the recovery rate of sulfur hexafluoride gas, please refer to patent technology CN202022771379.X, "A device and method for measuring the recovery rate of sulfur hexafluoride gas".

[0023] Of course, the measurement data of the recycled mass (weight) and the determination data of the recycling rate can be easily calculated using various modern electronic computing methods or data transmission, such as on-site microprocessors, monitoring systems on recycling devices, or host computer PC software.

[0024] In summary, this invention can simultaneously obtain gas recovery rate and gas mass (kg) in a single recycling operation, and is also applicable to the recovery measurement and recovery rate calculation of different insulating gases in electrical equipment, such as pure SF6 gas and SF6 / N2 mixed gases. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the gas path structure of the present invention. Detailed Implementation

[0026] Figure 1 In the diagram, 1 represents the mass flow meter, 2 represents the main recovery pipeline of the recovery device, and the arrow indicates the airflow direction.

[0027] like Figure 1 As shown, the method for metering and determining the recovery rate of sulfur hexafluoride gas recovery is characterized in that a mass flow meter 1 is connected in series in the recovery pipeline 2 between the gas chamber to be recovered and the recovery device, and pressure and temperature sensors are set at the sampling port of the gas chamber to be recovered or connected in series in the recovery pipeline 2 between the mass flow meter 1 and the gas chamber to be recovered.

[0028] The mass of the recovered gas is m = ρ(νt) * k(P) (Formula 1)

[0029] Where m is the mass of the recovered gas, ρ is the gas density under standard conditions, ν is the gas flow rate, i.e. the output flow rate of mass flow meter 1, t is the recovery time, and k is a function of pressure P, the pressure data of which can be obtained from the pressure sensor;

[0030] Sulfur hexafluoride gas recovery rate = 1 - (P1T0) / (P0T1) * 100% (Formula 2)

[0031] Where P0 and T0 are the initial gas pressure and temperature, and P1 and T1 are the final (real-time) gas pressure and temperature.

[0032] The inner diameter of mass flow meter 1 is consistent with the main recovery pipeline 2 of the recovery device.

[0033] The inner diameter of mass flow meter 1 is DN20, which is the same as the inner diameter of the main recovery pipeline 2 of the recovery device.

[0034] Mass flow meter 1, connected in series in the recovery pipeline 2, is characterized by its inner diameter being identical to that of the main recovery pipeline 2. While ensuring the normal gas recovery rate, it monitors the gas mass flow rate in real time. By connecting mass flow meter 1 in series, gas mass flow rate data can be obtained more directly and accurately. Then, based on gas density and time, the gas mass during the gas recovery process can be calculated, obtaining the gas mass for each recovery operation. The specific algorithm is shown in formula (I). This achieves the metering and accumulation of sulfur hexafluoride gas recovery on-site.

[0035] According to m = ρ * (ν * t), where ρ is the known gas density under standard conditions, ν is the gas flow rate (i.e., the output flow rate of mass flow meter 1), and t is time. Considering that the gas flow rate may be affected by the gas pressure, an influence factor k is added for mass flow rate correction. Therefore, m = ρ(νt) * k(P), where k is a function of pressure P.

[0036] The k(P) function can be verified through experiments and algorithms, as detailed below.

[0037] A standard mass flow meter and a measuring mass flow meter are connected in series. Gas at a constant pressure is passed through both, and the gas is eventually collected in a storage container. Assuming the gas flow pressure through the standard and measuring mass flow meters is constant (P1), the flow time is t, and the flow velocities are respectively... 1标 And ν1, the corresponding recovered mass m1=ρ(ν) 1标 *t)=ρ(ν1*t)*k1, then k1=ν 1标 / ν1,

[0038] If the ventilation pressure is adjusted to P2 and kept constant, then k2 = ν 2标 / ν2,

[0039] If the ventilation pressure is adjusted to P3 and kept constant, then k3 = ν 3标 / ν3,

[0040] By applying pressure covering the vacuum to the maximum chamber pressure of insulated circuit breakers and GIS combined electrical / GIL electrical equipment, multiple sets of data for pressure P and k can be obtained. A curve of k versus pressure P can be obtained on the coordinate axis. By using data fitting methods, the functional relationship between k and pressure P can be obtained.

[0041] Pressure and temperature sensors are installed at the sampling port of the gas chamber to be recovered and connected in series in recovery pipeline 2 for real-time recovery rate measurement; the recovery rate can be obtained by acquiring only the initial pressure P0 and temperature T0 of the recovered gas chamber and the real-time pressure P and temperature T.

[0042] Sulfur hexafluoride gas recovery rate = 1 - (P1T0) / (P0T1)*100% (Formula 2).

[0043] Where P0 and T0 are the initial gas pressure and temperature, and P1 and T1 are the final (real-time) gas pressure and temperature.

[0044] For detailed methods for determining the recovery rate of sulfur hexafluoride gas, please refer to patent technology CN202022771379.X, "A device and method for measuring the recovery rate of sulfur hexafluoride gas".

[0045] Of course, the measurement data of the recycled mass (weight) and the determination data of the recycling rate can be easily calculated using various modern electronic computing methods or data transmission, such as on-site microprocessors, monitoring systems on recycling devices, or host computer PC software.

[0046] In summary, this invention can simultaneously obtain gas recovery rate and gas mass (kg) in a single recycling operation, and is also applicable to the recovery measurement and recovery rate calculation of different insulating gases in electrical equipment, such as pure SF6 gas and SF6 / N2 mixed gases.

[0047] This embodiment is not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for metering and determining the recovery rate of sulfur hexafluoride gas, characterized in that: The mass flow meter is connected in series in the recovery pipeline between the gas chamber to be recovered and the recovery device, and the pressure and temperature sensors are set at the sampling port of the gas chamber to be recovered or connected in series in the recovery pipeline between the mass flow meter and the gas chamber to be recovered. The mass of the recovered gas is m = ρ(νt) * k(P). Where m is the mass of the recovered gas, ρ is the gas density under standard conditions, ν is the gas flow rate, i.e., the output flow rate of the mass flow meter, t is the recovery time, and k is a function of pressure P, the pressure data of which can be obtained from the pressure sensor; The method for obtaining the k(P) function includes the following steps: The first step is to build an experimental platform and obtain experimental data. Specifically, a standard mass flow meter and a measuring mass flow meter are connected in series. Gas at a constant pressure is passed through both, and the gas is eventually collected in a storage container. Assuming that the gas flow pressure through the standard mass flow meter and the measuring mass flow meter is constant (P1), the gas flow time is t, and the flow velocities are respectively... 1标 And ν1, the corresponding recovered mass m1=ρ(ν) 1标 *t)=ρ(ν1*t)*k1, then k1=ν 1标 / ν1, If the ventilation pressure is adjusted to P2 and kept constant, then k2 = ν 2标 / ν2, If the ventilation pressure is adjusted to P3 and kept constant, then k3 = ν 3标 / ν3, …… By applying pressure covering the vacuum to the maximum gas chamber pressure of insulated equipment circuit breakers and GIS combined electrical / GIL electrical equipment, multiple sets of pressure P and k data are obtained. The second step is to obtain the curve of k with respect to pressure P on the coordinate axis. By using the data fitting method, the functional relationship between k and pressure P can be obtained. Sulfur hexafluoride gas recovery rate = 1 - (P1T0) / (P0T1) * 100% Where P0 and T0 are the initial gas pressure and temperature, and P1 and T1 are the real-time gas pressure and temperature.

2. The method for metering and determining the recovery rate of sulfur hexafluoride gas according to claim 1, characterized in that, The inner diameter of the mass flow meter is consistent with the main recovery pipeline of the recovery device.

3. The method for metering and determining the recovery rate of sulfur hexafluoride gas according to claim 1, characterized in that, The inner diameter of the mass flow meter and the inner diameter of the main recovery pipeline of the recovery device are both DN20.

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