SF6 electrically charged tendency determination method based on humidity change amount

Abstract

This invention discloses a method for determining the charging tendency of SF6 based on humidity changes. The method includes the following steps: detecting the humidity value D1 of SF6 gas in a gas chamber; mixing SF6 gas with SF6 standard gas of humidity value D' according to a set ratio; detecting the humidity value D2 of the resulting mixed gas; calculating the humidity value D3 of the mixed gas under no charging tendency based on D1 and D'; and determining whether SF6 gas has a charging tendency based on D2 and D3. This invention utilizes the effect of partial discharge on SF6... ‑ Based on the principle of combining with H2O, by detecting the humidity of SF6 gas in the gas chamber and analyzing the change between the measured humidity value and the theoretical value after mixing SF6 insulating gas and SF6 gas with a certain humidity in a fixed ratio, the charging tendency of SF6 gas is obtained, providing technical support for the determination of the degree of partial discharge based on the humidity of SF6 gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of SF6 electrification tendency determination, and particularly relates to an SF6 electrification tendency determination method based on humidity change amount. BACKGROUND

[0002] Partial discharge is the main precursor of insulation failure of electrical equipment. When partial discharge occurs, physical characteristics such as pulse current, electromagnetic wave, ultrasonic wave, light signal, characteristic gas, etc. often appear, and detecting these physical quantities can timely discover and warn the partial discharge defects existing in the equipment, so as to ensure the safety of the equipment. However, the above detection methods have certain limitations, such as the pulse current method, the electromagnetic wave and ultrasonic wave method are easily disturbed by the environment, and have a large false alarm probability; the optical method has poor sensitivity, and needs to be built-in in the electrical equipment, and has poor operability; the characteristic gas detection method is a commonly used electrical equipment state monitoring method, but the relationship between the characteristic gas content and the discharge amount is not clear, and the internal partial discharge intensity of the equipment cannot be reflected. SUMMARY

[0003] The present application provides an SF6 electrification tendency determination method based on humidity change amount, which can determine whether the SF6 gas has electrification tendency.

[0004] Embodiments of the present application provide an SF6 electrification tendency determination method based on humidity change amount, comprising the following steps: detecting the humidity value D1 of the SF6 gas in the gas chamber. Mixing the SF6 gas with SF6 standard gas with a humidity value of D' according to a set proportion. Detecting the humidity value D2 of the mixed gas. According to D1 and D', calculating the humidity value D3 of the mixed gas without electrification tendency. According to D2 and D3, judging whether the SF6 gas has electrification tendency.

[0005] In some embodiments, mixing the SF6 gas with the SF6 standard gas with a humidity value of D' according to a set proportion comprises: mixing the SF6 gas and the SF6 standard gas with a humidity value of D' according to a set flow rate.

[0006] In some embodiments, according to D1 and D', calculating the humidity value D3 of the mixed gas without electrification tendency comprises: calculating the humidity value D3 of the mixed gas without electrification tendency by using the following formula: D3=(D1+D') / 2.

[0007] In some embodiments, according to D2 and D3, judging whether the SF6 gas has electrification tendency comprises: calculating the difference ΔD between the measured humidity value and the theoretical value of the mixed gas by using the following formula: ΔD=D2-D3. According to ΔD, judging whether the SF6 gas has electrification tendency.

[0008] In some embodiments, determining whether the SF6 gas in the gas chamber has a tendency to become charged based on ΔD includes: if ΔD < 0, then the SF6 gas has a tendency to become charged; otherwise, the SF6 gas does not have a tendency to become charged.

[0009] In some embodiments, the humidity detection module detects the humidity value D1 of the SF6 gas by delivering SF6 gas to the humidity detection module and allowing it to flow out from the outlet.

[0010] In some embodiments, the humidity detection module detects the humidity value D2 of the mixed gas by delivering the mixed gas to the humidity detection module and allowing it to flow out from the outlet.

[0011] In some embodiments, the gas flowing out of the outlet is delivered to an exhaust gas treatment device.

[0012] In some embodiments, SF6 gas and SF6 standard gas are both delivered to the same location in the humidity detection pipeline on the side of the humidity detection module away from the outlet, so that the SF6 gas and SF6 standard gas are mixed in the humidity detection pipeline and the mixed gas is delivered to the humidity detection module.

[0013] In some embodiments, SF6 gas and SF6 standard gas are respectively delivered from opposite sides of the humidity detection pipeline to the same point inside the humidity detection pipeline.

[0014] An embodiment of the present invention provides a method for determining the charging tendency of SF6 based on humidity change, comprising the following steps: detecting the humidity value D1 of SF6 gas in a gas chamber; mixing SF6 gas with SF6 standard gas of humidity value D' according to a set ratio; detecting the humidity value D2 of the resulting mixed gas; calculating the humidity value D3 of the mixed gas under no charging tendency based on D1 and D'; and determining whether SF6 gas has a charging tendency based on D2 and D3. The present invention utilizes the effect of partial discharge on SF6... - Based on the principle of H2O, this invention detects the humidity of SF6 gas in a gas chamber and analyzes the change between the measured humidity value and the theoretical value of a mixture of SF6 insulating gas and SF6 gas with a certain humidity in a fixed ratio. This analysis reveals the charging tendency of SF6 gas, providing technical support for determining the degree of partial discharge based on SF6 gas humidity. This invention can determine whether SF6 gas has a charging tendency simply by analyzing changes in gas humidity, and further analyze the amount of partial discharge, significantly reducing the technical complexity and cost of conventional electrical equipment condition monitoring methods. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the SF6 charge tendency measuring device in an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] See Figure 1 An embodiment of the present invention provides an SF6 charging tendency measuring device based on humidity change, including a first air inlet line 1, a second air inlet line 2 and a humidity detection line 3.

[0019] The first air intake line 1 has a first air inlet 11, a first pressure regulating valve 12, a first solenoid valve 13, and a first flow controller 14. The first air inlet 11, the first pressure regulating valve 12, the first solenoid valve 13, and the first flow controller 14 are arranged sequentially along the gas flow direction of the first air intake line 1. The first air inlet 11 is connected to the air chamber.

[0020] The second air inlet line 2 has a second air inlet 21, a second pressure regulating valve 22, a second solenoid valve 23, and a second flow controller 24. The second air inlet 21, the second pressure regulating valve 22, the second solenoid valve 23, and the second flow controller 24 are arranged sequentially along the gas flow direction of the second air inlet line 2. The second air inlet 21 is connected to an SF6 standard gas cylinder with an internal gas humidity value of D' (e.g., 200ppm).

[0021] Humidity detection pipeline 3 is connected to the first air inlet pipeline 1 and the second air inlet pipeline 2. A humidity detection module 31 and an air outlet 32 ​​are installed on humidity detection pipeline 3. The humidity detection module 31 and the air outlet 32 ​​are arranged sequentially along the gas flow direction of humidity detection pipeline 3. Humidity detection pipeline 3 intersects with the first air inlet pipeline 1 and the second air inlet pipeline 2 at one point. Both the first air inlet pipeline 1 and the second air inlet pipeline 2 are perpendicularly connected to humidity detection pipeline 3. The connection points of the first air inlet pipeline 1 and the humidity detection pipeline 3, and the second air inlet pipeline 2 and the humidity detection pipeline 3, are positioned opposite each other. The air outlet 32 ​​is connected to an exhaust gas treatment device.

[0022] An embodiment of the present invention provides a method for determining the SF6 charging tendency using the above-described SF6 charging tendency measuring device, comprising the following steps:

[0023] (1) Detect the humidity value D1 of SF6 gas in the gas chamber.

[0024] The above steps can be as follows: Connect the first inlet 11 to the gas chamber; adjust the pressure of the first pressure regulating valve 12 to P1 (e.g., 0.2 MPa) and the flow rate of the first flow controller 14 to Q1 (e.g., 200 mL / min); open the first solenoid valve 13, allowing the SF6 gas in the gas chamber to flow through the first inlet 11, the first pressure regulating valve 12, the first solenoid valve 13, the first flow controller 14, the humidity detection module 31, and the outlet 32. The humidity detection module 31 detects the humidity of the SF6 gas in the gas chamber and records it as D1. During this process, by delivering the SF6 gas to the humidity detection module 31 and allowing it to flow out from the outlet 32, the humidity detection module 31 detects the humidity value D1 of the SF6 gas. Furthermore, the gas flowing out of the outlet 32 ​​is delivered to the exhaust gas treatment device.

[0025] (2) Mix SF6 gas with SF6 standard gas with a humidity value of D' according to the set ratio.

[0026] The above steps can be as follows: Connect the second air inlet 21 to an SF6 standard gas cylinder with an internal gas humidity value of D' (e.g., 200ppm), adjust the pressure of the second pressure regulating valve 22 to P2 (e.g., 0.2MPa), and the flow rate of the second flow controller 24 to Q2 (e.g., 200mL / min), open the second solenoid valve 23, and the SF6 standard gas flows through the second air inlet 21, the second pressure regulating valve 22, the second solenoid valve 23, and the second flow controller 24, mixing with the SF6 gas in the gas chamber. During this process, the SF6 gas and the SF6 standard gas with a humidity value of D' (e.g., 200ppm) are mixed at a set flow rate (e.g., 200mL / min). During this process, by supplying both the SF6 gas and the SF6 standard gas to the same location within the humidity detection pipeline 3 on the side of the humidity detection module 3 opposite to the air outlet 32, the SF6 gas and the SF6 standard gas are mixed within the humidity detection pipeline 3, and the mixed gas is then supplied to the humidity detection module 3. Furthermore, SF6 gas and SF6 standard gas are respectively transported from opposite sides of the humidity detection pipeline 3 to the same point inside the humidity detection pipeline 3.

[0027] (3) Detect the humidity value D2 of the mixed gas obtained by mixing.

[0028] The above steps can be as follows: Connect the second air inlet 21 to an SF6 standard gas cylinder with an internal gas humidity value of D' (e.g., 200 ppm); adjust the pressure of the second pressure regulating valve 22 to P2 (e.g., 0.2 MPa) and the flow rate of the second flow controller 24 to Q2 (e.g., 200 mL / min); open the second solenoid valve 23; the SF6 standard gas flows through the second air inlet 21, the second pressure regulating valve 22, the second solenoid valve 23, and the second flow controller 24, and mixes with the SF6 gas in the gas chamber. The mixture then flows through the humidity detection module 31 and the air outlet 32. The humidity detection module 31 detects the humidity of the mixed gas and records it as D2. In this process, by delivering the mixed gas to the humidity detection module 31 and allowing it to flow out from the air outlet 32, the humidity detection module 31 detects the humidity value D2 of the mixed gas. Furthermore, the gas flowing out of the air outlet 32 ​​is delivered to the exhaust gas treatment device.

[0029] (4) Calculate the humidity value D3 of the mixed gas under the condition of no tendency to be charged, based on D1 and D'.

[0030] The above steps can be performed as follows: Calculate the humidity value D3 of the mixed gas under no-charge tendency using the following formula: D3=(D1+D') / 2. When D' is 200ppm, D3=(D1+200) / 2.

[0031] (5) Based on D2 and D3, determine whether SF6 gas has a tendency to be charged.

[0032] The above steps can be as follows: Calculate the difference ΔD between the measured and theoretical humidity values ​​of the mixed gas using the following formula: ΔD = D² - D³. Based on ΔD, determine whether the SF6 gas has a tendency to become charged. If ΔD < 0, the SF6 gas has a tendency to become charged, indicating partial discharge. Otherwise, the SF6 gas does not have a tendency to become charged. The higher the partial discharge energy, the greater the tendency of the SF6 gas to become charged, meaning more SF6⁻ molecules combine with free water molecules, and the smaller ΔD. Therefore, the degree of partial discharge can be reflected by the |ΔD| value.

[0033] Insulating gas humidity is an important monitoring indicator for the daily operation and maintenance of electrical equipment. Currently, there is no research on the correlation between gas humidity and discharge faults and discharge magnitude. After partial discharge occurs in electrical equipment, the internal insulating gas SF6 will acquire a certain negative charge and transform into SF6. - SF6 - It can combine with free water molecules in the gas to form SF6. - • H2O polymers cause a decrease in free water molecules in the gas. Therefore, the H2O content can be used as a fulcrum to analyze the charging tendency of SF6 by detecting changes in the humidity value of the insulating gas, thereby diagnosing discharge faults and the degree of discharge in SF6 switchgear.

[0034] This invention uses the H2O content in insulating gas as a fulcrum to analyze electrical equipment discharge faults. It determines whether the SF6 gas has a tendency to become charged by comparing the measured humidity value with the theoretical humidity value after mixing the insulating gas with SF6 gas at a certain humidity level, thereby further analyzing the electrical equipment discharge faults. This invention can determine whether SF6 gas has a tendency to become charged and further analyze the partial discharge quantity simply by analyzing the change in gas humidity, greatly reducing the technical complexity and cost of conventional electrical equipment condition monitoring methods.

[0035] In summary, this invention utilizes SF6 after partial discharge. - Based on the principle of H2O, this invention detects the humidity of SF6 gas in a gas chamber and analyzes the change between the measured humidity value and the theoretical value of SF6 insulating gas mixed with SF6 gas of a certain humidity in a fixed proportion. This yields the charging tendency of SF6 gas, providing technical support for determining the degree of partial discharge based on SF6 gas humidity. This invention offers a new approach and solution for partial discharge detection in electrical equipment, enabling discharge quantity detection based on the routine maintenance and inspection indicator—humidity value—saving costs and manpower.

[0036] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this invention, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for determining the charging tendency of SF6 based on humidity changes, characterized in that, Includes the following steps: The humidity value D1 of SF6 gas in the detection chamber is measured. The SF6 gas is mixed with SF6 standard gas with a humidity value of D' in a set ratio; The humidity value D2 of the mixed gas is measured. Based on D1 and D', calculate the humidity value D3 of the mixed gas under the condition of no tendency to be charged; Based on D2 and D3, determine whether the SF6 gas has a tendency to become charged; The humidity value D3 of the mixed gas under the condition of no tendency to be charged is calculated based on D1 and D', including: The humidity value D3 of the gas mixture under conditions of no tendency to become charged is calculated using the following formula: D3 = (D1 + D') / 2; Based on D2 and D3, determining whether the SF6 gas has a tendency to become charged includes: The difference ∆D between the measured and theoretical humidity values ​​of the mixed gas is calculated using the following formula: ∆D = D2 - D3; Based on ∆D, determine whether the SF6 gas has a tendency to become charged; Based on ∆D, determining whether the SF6 gas in the gas chamber has a tendency to become charged includes: If ∆D < 0, then the SF6 gas has a tendency to become charged; otherwise, the SF6 gas does not have a tendency to become charged.

2. The method for determining the charging tendency of SF6 as described in claim 1, characterized in that, The SF6 gas is mixed with SF6 standard gas with a humidity value of D' in a set ratio, including: The SF6 gas and the SF6 standard gas with a humidity value of D' are mixed at a set flow rate.

3. The method for determining the charging tendency of SF6 as described in claim 1, characterized in that, The SF6 gas is delivered to the humidity detection module and flows out from the outlet, allowing the humidity detection module to detect the humidity value D1 of the SF6 gas.

4. The method for determining the SF6 charging tendency as described in claim 3, characterized in that, The mixed gas is delivered to the humidity detection module and flows out from the outlet, so that the humidity detection module detects the humidity value D2 of the mixed gas.

5. The method for determining the SF6 charging tendency as described in claim 3, characterized in that, The gas flowing out of the outlet is transported to the exhaust gas treatment device.

6. The method for determining the charging tendency of SF6 as described in claim 3, characterized in that, By supplying both the SF6 gas and the SF6 standard gas to the same location within the humidity detection pipeline on the side of the humidity detection module away from the outlet, the SF6 gas and the SF6 standard gas are mixed within the humidity detection pipeline, and the mixed gas is then supplied to the humidity detection module.

7. The method for determining the charging tendency of SF6 as described in claim 6, characterized in that, The SF6 gas and the SF6 standard gas are respectively delivered from opposite sides of the humidity detection pipeline to the same point inside the humidity detection pipeline.

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