Device and method for in situ irregular container volume measurement

Abstract

The present application relates to a device and method for measuring the volume of irregular containers in situ. Based on the principle of partial pressure, a certain amount of SF6 gas is extracted into another partial pressure container, and when equilibrium is reached, the effective volume of the measured container is calculated. Through the measurement of the effective volume of the measured container, combined with pressure and temperature sensors, the weight of the in-service SF6 gas can be evaluated in real time.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of insulation gas electrical equipment gas management, and particularly relates to a device and method for measuring the volume of an irregular container on site. BACKGROUND

[0002] Sulfur hexafluoride is an excellent insulating and arc extinguishing medium and has been widely used in the power industry. With the increasing number of sulfur hexafluoride electrical equipment, the amount of sulfur hexafluoride gas is increasing, and the complexity of technical supervision is stronger. Sulfur hexafluoride has a high greenhouse effect and can easily cause climate warming, which poses a serious threat to the human living environment. Controlling greenhouse gas emission reduction is an important way to respond to climate change and slow global warming. Since 2006, State Grid Corporation of China has taken a series of independent sulfur hexafluoride gas emission reduction measures. By 2015, 26 provincial sulfur hexafluoride gas recycling and processing centers have been built in the company system, realizing sulfur hexafluoride gas recycling and recycling and effectively reducing sulfur hexafluoride gas emissions.

[0003] Sulfur hexafluoride has been rapidly reduced by independent emission reduction to a mandatory emission reduction stage, and there are more severe challenges in the potential emission reduction of sulfur hexafluoride gas and control. Sulfur hexafluoride gas comes from multiple sources and is used in multiple stages such as construction, operation and maintenance, overhaul and retirement, purification treatment and recycling. It is difficult to verify the data of the recycling process of sulfur hexafluoride in multiple stages, and there is still a certain gap from the carbon market supervision requirements.

[0004] Accurate statistics of sulfur hexafluoride gas in the gas chamber of high-voltage electrical equipment is the basis for in-service gas management. Due to the operation of electrical equipment, it is impossible to extract the gas for weight determination, and it is also impossible to accurately determine the gas consumption.

[0005] Although a certain amount of gas is injected into the newly operated high-voltage electrical equipment, and the gas weight (kg) is marked on the body label, it is only a reference value, and there are processes such as gas leakage and gas supplement during operation. The precise content of gas in each gas chamber is unknown. There are many methods for determining the weight of gas in high-voltage electrical equipment, one of which is to directly calculate the weight of gas by the effective volume V of the gas chamber, according to the pressure P and density p. The pressure P can be obtained by a pressure gauge, and the density p is known data when the pressure and temperature are constant. Therefore, the determination of the effective volume of the gas chamber is the key.

[0006] At present, the determination of the effective volume of the gas chamber of an electrical device is a great technical problem, and the difficulties are as follows: 1. There are many types of electrical devices, and the internal gas chambers of circuit breakers, GIS and GIL are mostly irregular structures, which makes the mass / weight of the gas in the internal gas chambers indeterminable; 2. Although the newly-operated electrical device is marked with the rated pressure and weight of the gas on the label of the device body, the information is effective only when the device is newly-operated, but it can only be used as a reference after several years of operation; 3. The in-service electrical device has been operated for many years, even for decades, and the gas volume / mass / weight of each gas chamber is still unknown during the maintenance such as gas supplement and gas leakage. SUMMARY

[0007] The purpose of the present application is to provide a device and method for measuring the volume of an irregular container on site, which calculates the effective volume of the gas chamber of the electrical device to be measured by extracting a certain amount of SF6 gas through the principle of partial pressure.

[0008] To achieve the above purpose, the technical scheme of the present application is as follows: a device for measuring the volume of an irregular container on site, comprising a gas partial pressure container with a known volume, the gas partial pressure container is provided with an inlet and an outlet, the inlet and the outlet of the gas partial pressure container are respectively provided with a gas pipeline and a vacuum pipeline, and a stop valve is arranged on each of the gas pipeline and the vacuum pipeline;

[0009] A back-filling module and a back-filling pipeline are further provided, the back-filling module is connected in series in the back-filling pipeline, one end of the back-filling pipeline is connected to the inlet and the outlet of the gas partial pressure container, and the other end is connected to the gas inlet of the gas chamber of the electrical device to be measured, and the back-filling module back-fills the gas in the gas partial pressure container into the gas chamber of the electrical device to be measured after the measurement is completed;

[0010] A pressure gauge / pressure sensor is arranged on the irregular container to be measured in the gas chamber of the electrical device to be measured;

[0011] The vacuum pipeline is connected to the back-filling pipeline at the same time, and the gas partial pressure container and the back-filling pipeline are vacuumized, and a first stop valve is arranged between the vacuum pipeline and the back-filling pipeline.

[0012] In an embodiment of the present application, the gas partial pressure container further comprises N parallel gas cylinders, and the inlets and outlets of the N parallel gas cylinders are respectively connected to the gas pipeline and the vacuum pipeline.

[0013] In an embodiment of the present application, the gas pipeline comprises N stop valves connected to the inlets of the N gas cylinders respectively, and the N stop valves are connected to the irregular container to be measured in the gas chamber of the electrical device to be measured through a ball valve and a three-way valve.

[0014] In an embodiment of the present application, the vacuum pipeline comprises N stop valves connected to the outlets of the N gas cylinders respectively, and the N stop valves are connected to the back-filling pipeline through the first stop valve.

[0015] The backfill pipeline further comprises a one-way valve, and the backfill module is connected with the three-way valve through the one-way valve.

[0016] The application further provides a method for measuring the volume of an irregular container on site based on the device for measuring the volume of an irregular container on site.

[0017] Firstly, the gas partial pressure container is vacuumized.

[0018] The vacuumizing pipeline of the gas partial pressure container is connected with the vacuum pump to vacuumize the gas partial pressure container.

[0019] Secondly, the gas pipeline of the gas partial pressure container is connected with the irregular container to be measured in the gas chamber of the electrical equipment to be measured, and the gas pressure P1 of the irregular container to be measured is recorded.

[0020] Thirdly, the stop valve on the gas pipeline is opened to make the gas in the gas partial pressure container and the irregular container to be measured reach a gas equilibrium state, and the equilibrium gas pressure P2 is recorded, wherein P2>low pressure alarm value.

[0021] Fourthly, the effective volume of the electrical equipment gas chamber is calculated.

[0022] The effective volume of the irregular container to be measured is V1, which is unknown, and the initial pressure of the irregular container to be measured is P1; the volume of the gas partial pressure container is V2, which is known, the equilibrium pressure is P2, and the pressure difference after equilibrium is ΔP=P1-P2; ΔP

[0023] The pressure difference between the equilibrium pressure P2 and the initial pressure P1 of the irregular container to be measured is not less than 2kPa, so as to ensure that the pressure drop of the gas chamber in the measurement process has no influence on the working state and the effectiveness of the data.

[0024] According to the ideal gas state equation, P1*V1=P2*(V1+V2), so

[0025] The effective volume V1 of the irregular container to be measured is P2V2 / (P1-P2)=P2V2 / ΔP (formula 1).

[0026] Fifthly, the gas in the gas partial pressure container is backfilled into the irregular container to be measured, or the gas in the gas partial pressure container is stored / recycled.

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

[0028] 1. The application provides a design scheme for measuring the volume of an irregular container on site, which is suitable for various electrical equipment, simple in method, strong in practicability, small in calculation amount and simple in operation.

[0029] 2. When the volume of the gas pressure vessel V2 involved in this invention is much smaller than the effective volume of the gas chamber of the electrical equipment V1, the gas in the gas pressure vessel V2 can be temporarily stored by means of storage and recycling. After all, the refilling equipment needs to have large components such as compressors, and it is inconvenient to bring these things to the site.

[0030] 3. A gas partial pressure vessel with a known volume V2 ( Figure 1 When the area within the dashed box represents a parallel combination of several gas cylinders, it is applicable to many electrical devices because it indicates that the volume V2 is variable. The effective volume of the gas chamber is 1000L, 300L, or even 40L. Furthermore, after the volume is measured, the gas can be temporarily stored by replacing the gas cylinders, which is simple and convenient. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a device for measuring the volume of irregular containers on-site, according to the present invention. Detailed Implementation

[0032] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0033] like Figure 1 As shown, the present invention provides a device for measuring the volume of irregular containers on site, comprising a gas partial pressure container with a known volume, an inlet and an outlet on the gas partial pressure container, and a gas pipeline and a vacuum pipeline connected in parallel to the inlet and outlet of the gas partial pressure container, both of which are equipped with shut-off valves.

[0034] The gas partial pressure container is also equipped with a recharge module and a recharge pipeline. The recharge module is connected in series in the recharge pipeline. One end of the recharge pipeline is the inlet and outlet of the gas partial pressure container, and the other end is connected to the air inlet of the gas chamber of the electrical equipment under test. After the measurement is completed, the recharge module recharges the gas in the gas partial pressure container into the gas chamber of the electrical equipment through the recharge pipeline.

[0035] A pressure gauge / pressure sensor is installed on the irregular container to be tested.

[0036] Gas partial pressure container with known volume ( Figure 1 The area within the dashed box represents a parallel combination of several gas cylinders.

[0037] The vacuuming line is also connected to the recharge line to evacuate the gas partial pressure container and the recharge line. A shut-off valve is installed on the vacuuming line.

[0038] The present invention also provides a method for measuring the volume of irregular containers on site, comprising the following steps:

[0039] The first step is to evacuate the gas partial pressure container;

[0040] The vacuum pipeline of the gas partial pressure container is connected to the vacuum pump to vacuumize the gas partial pressure container.

[0041] (The pressure change of the container to be measured is closely related to the actual volume of the partial pressure container. When the partial pressure container is relatively small, the partial pressure space can be increased by vacuumization. In actual use, the partial pressure container can have a certain pressure base. The vacuum degree is related to the lower limit and accuracy of the pressure sensor, and it is appropriate to ensure that the sensor can accurately measure.)

[0042] In the second step, the gas pipeline of the gas partial pressure container is connected to the gas chamber of the electrical equipment to be measured, and the gas pressure P1 of the electrical equipment to be measured is recorded.

[0043] In the third step, the stop valve on the gas pipeline is opened to achieve gas balance between the gas partial pressure container and the electrical equipment to be measured, and the balanced gas pressure P2 is recorded, P2>low pressure alarm value.

[0044] In the fourth step, the effective volume of the electrical equipment gas chamber is calculated.

[0045] The effective volume of the electrical equipment gas chamber is V1, which is unknown, and the initial pressure of the electrical equipment gas chamber is P1. The volume of the gas partial pressure container is V2, which is known, and the balanced pressure is P2. The pressure difference after balancing is ΔP=P1-P2. Although it is feasible when ΔP is too large, it has an impact on the insulation performance of the electrical equipment because the number of gas molecules per unit volume in the chamber will decrease when the pressure decreases, thereby affecting the insulation performance. Furthermore, when ΔP is too large, the electrical equipment will generate a low pressure alarm, which is not allowed in the field. Therefore, ΔP

[0046] The pressure difference between the balanced pressure P2 and the initial pressure P1 of the container to be measured is not less than 2kPa, which ensures the effectiveness of the measurement data. At the same time, attention should be paid to the fact that the pressure drop after the chamber has no effect on the working state of the equipment, i.e. the pressure after the pressure drop is not lower than the alarm point or the locking point.

[0047] According to the ideal gas state equation, P1×V1=P2×(V1+V2), then

[0048] The effective volume V1 of the electrical equipment gas chamber is P2V2 / (P1-P2)=P2V2 / ΔP (Formula 1)

[0049] In the fifth step, the gas in the gas partial pressure container is recharged into the electrical equipment, or the gas in the gas partial pressure container is stored / recycled.

[0050] The following is a specific embodiment of the present application.

[0051] Before large-scale application, the electrical equipment simulation device with known volume V1 is used to replace the electrical equipment chamber, and the method for measuring the volume of irregular container on site, i.e. the effective volume V1 of the electrical equipment chamber = P2V2 / (P1-P2) = P2V2 / ΔP formula 1, is implemented.

[0052] In example 1, the volume V1 of the electrical equipment simulation device is known to be 300L, SF6 gas is filled at about 0.48MPa, the volume of the gas partial pressure container is 8L, see table 1, the equilibrium pressure difference ΔP and the equilibrium time are changed, the gas partial pressure container uses multiple standard steel cylinders in parallel and is controlled by a manual ball valve to facilitate changing the size of the volume of the gas partial pressure container. The measurement is continuously measured twice, with an interval of 1 day each time, the maximum deviation is -8.3L, and the maximum value error is -2.76%. The application is met.

[0053] Table 1 Experimental data when the volume of the gas partial pressure container is 8L and the volume of the container to be measured is 300L

[0054]

[0055]

[0056] In example 2, the volume V1 of the electrical equipment simulation device is known to be 600L, SF6 gas is filled at about 0.48MPa, the volume of the gas partial pressure container is 40L, the equilibrium pressure difference ΔP and the equilibrium time are changed, and the gas partial pressure container uses multiple standard steel cylinders in parallel and is controlled by a manual ball valve to facilitate changing the size of the volume of the gas partial pressure container.

[0057] When the volume of the gas partial pressure container is 40L and ΔP is 0.03MPa, the measurement deviation under different equilibrium times is optimal, the maximum measurement deviation is -6.7L, and the corresponding maximum value error is -1.12%; the minimum measurement deviation is -1.9L, and the corresponding maximum value error is 0.32%; the application is met, see table 2.

[0058] Table 2 Experimental data when the volume of the gas partial pressure container is 8L / 40L and the volume of the container to be measured is 600L

[0059]

[0060] In example 3, the volume V1 of the electrical equipment simulation device is known to be 1000L, and SF6 gas is filled at about 0.48MPa. The volume of the gas partial pressure container is 8L / 40L, respectively, the equilibrium pressure difference ΔP is changed, and the gas partial pressure container uses multiple standard steel cylinders in parallel and is controlled by a manual ball valve to facilitate changing the size of the volume of the gas partial pressure container.

[0061] When the gas partial pressure container volume is 8.03L, the pressure difference ΔP is 0.002MPa when balanced, the maximum measurement deviation is -31.5L, and the indication error is -3.15%; the basic application is met.

[0062] When the gas partial pressure container volume is 40L, the pressure difference ΔP is 0.018MPa when balanced, the maximum measurement deviation is 15.1L, and the indication error is 1.51%; the application is met, see Table 3.

[0063] Table 3 Experimental data when the gas partial pressure container is 8L, 40L, and the measured container is 1000L

[0064]

[0065]

[0066] The above is the preferred embodiment of the present application, any changes made according to the technical solutions of the present application, as long as the generated function does not exceed the scope of the technical solutions of the present application, belongs to the protection scope of the present application.

Claims

1. A device for in situ irregular container volume measurement, characterized by, The gas partial pressure container includes a gas partial pressure container with a known volume, an inlet and an outlet are arranged on the gas partial pressure container, a gas pipeline and a vacuum pipeline are arranged on the inlet and the outlet of the gas partial pressure container respectively, and stop valves are arranged on the gas pipeline and the vacuum pipeline; A backfill module and a backfill pipeline are further arranged, the backfill module is connected in series in the backfill pipeline, one end of the backfill pipeline is connected to the inlet and the outlet of the gas partial pressure container, and the other end is connected to the gas inlet of the gas chamber of the electrical equipment to be measured; after the measurement is completed, the backfill module backfills the gas in the gas partial pressure container into the gas chamber of the electrical equipment to be measured through the backfill pipeline; A pressure gauge / pressure sensor is arranged on the irregular container to be measured in the gas chamber of the electrical equipment to be measured; The vacuum pipeline is connected to the backfill pipeline, the gas partial pressure container and the backfill pipeline are vacuumized, and a first stop valve is arranged between the vacuum pipeline and the backfill pipeline; The gas partial pressure container further includes N gas cylinders connected in parallel, and the inlets and outlets of the N gas cylinders are connected to the gas pipeline and the vacuum pipeline respectively; The gas pipeline includes N stop valves connected to the inlets of the N gas cylinders respectively, and the N stop valves are connected to the irregular container to be measured in the gas chamber of the electrical equipment to be measured through a ball valve and a three-way valve.

2. The device for in situ irregular container volume measurement according to claim 1, characterized in that, The vacuum pipeline includes N stop valves connected to the outlets of the N gas cylinders respectively, and the N stop valves are connected to the backfill pipeline through the first stop valve.

3. The device for in situ irregular container volume measurement according to claim 1, characterized in that, The backfill pipeline further includes a one-way valve, and the backfill module is connected to the three-way valve through the one-way valve.

4. A method for on-site irregular container volume measurement based on the device according to any one of claims 1 to 3, characterized in that, The method includes the following steps: Firstly, the gas partial pressure container is vacuumized; The vacuum pipeline of the gas partial pressure container is connected to a vacuum pump to vacuumize the gas partial pressure container; Secondly, the gas pipeline of the gas partial pressure container is connected to the irregular container to be measured in the gas chamber of the electrical equipment to be measured, and the gas pressure P1 of the irregular container to be measured is recorded; Thirdly, the stop valve on the gas pipeline is opened, the gas partial pressure container and the irregular container to be measured reach a gas balance state, the balanced gas pressure P2 is recorded, and P2>low pressure alarm value; Fourthly, the effective volume of the gas chamber of the electrical equipment is calculated: The effective volume of the irregular container to be measured is V1, V1 is unknown, the initial pressure of the irregular container to be measured is P1, the volume of the gas partial pressure container is V2, V2 is known, the balanced pressure is P2, and the pressure difference after balancing is ΔP=P1-P2; ΔP The pressure difference between the balanced pressure P2 and the initial pressure P1 of the irregular container to be measured is not less than 2kPa, which ensures that the pressure drop of the gas chamber in the measurement process has no influence on the working state and the effectiveness of the data; According to the ideal gas state equation, P1×V1=P2×(V1+V2), then The effective volume V1 of the irregular container to be measured is P2V2 / (P1-P2)=P2V2 / ΔP Fifthly, the gas in the gas partial pressure container is backfilled into the irregular container to be measured, or the gas in the gas partial pressure container is stored / recycled.

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