SF6 electrification tendency determination method based on humidity variation

Abstract

The invention discloses an SF6 electrification tendency determination method based on humidity variation. The SF6 electrification tendency determination method comprises the following steps: detecting a humidity value D1 of SF6 gas in a gas chamber; and mixing the SF6 gas with the SF6 standard gas with the humidity value of D'according to a set proportion. And detecting the humidity value D2 of the mixed gas obtained by mixing. And according to D1 and D ', calculating a humidity value D3 of the mixed gas under the condition of no electrification tendency. And according to the D2 and the D3, judging whether the SF6 gas has an electrification tendency or not. According to the method, based on the principle that SF6 <-> and H2O are combined after partial discharge, the SF6 gas humidity in the gas chamber is detected, and the variation of the actually measured humidity value and the theoretical value after the SF6 insulating gas and the SF6 gas with the certain humidity are mixed according to the fixed proportion is analyzed, so that the electrification tendency of the SF6 gas is obtained, and technical support is provided for distinguishing the partial discharge degree based on the SF6 gas humidity.

Description

Technical Field

[0001] The present invention relates to the field of SF6 charging tendency measurement, and in particular to a method for measuring SF6 charging tendency based on humidity variation. Background Art

[0002] Partial discharge is the main precursor to insulation failure in electrical equipment. When partial discharge occurs, it is often accompanied by physical characteristics such as pulse current, electromagnetic waves, ultrasound, optical signals, and characteristic gases. Detecting these physical quantities can timely discover and warn of partial discharge defects inside the equipment to ensure equipment safety. However, the above detection methods all have certain limitations. For example, the pulse current method, electromagnetic wave and ultrasonic method are easily affected by environmental interference and have a high probability of false alarms. The optical method has poor sensitivity and requires the sensor to be built into the electrical equipment, which is not easy to operate. The characteristic gas detection method is currently a commonly used means of monitoring the status of electrical equipment, but the relationship between the characteristic gas content and the discharge amount is not clear, and it cannot reflect the intensity of partial discharge inside the equipment. Summary of the invention

[0003] The present invention provides a method for measuring the charging tendency of SF6 based on humidity variation, which can determine whether SF6 gas has a charging tendency.

[0004] 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 the SF6 gas in the gas chamber. Mixing the SF6 gas with the SF6 standard gas having a humidity value D' according to a set ratio. Detecting the humidity value D2 of the mixed gas. Based on D1 and D', calculating the humidity value D3 of the mixed gas without a charging tendency. Based on D2 and D3, judging whether the SF6 gas has a charging tendency.

[0005] In some embodiments, the SF6 gas is mixed with the SF6 standard gas having a humidity value of D' according to a set ratio, including: the SF6 gas and the SF6 standard gas having a humidity value of D' are mixed at a set flow rate.

[0006] In some embodiments, the humidity value D3 of the mixed gas without charging tendency is calculated based on D1 and D', including: using the following formula to calculate the humidity value D3 of the mixed gas without charging tendency: D3 = (D1 + D') / 2.

[0007] In some embodiments, judging whether the SF6 gas has a tendency to be charged based on D2 and D3 includes: calculating the difference ΔD between the measured humidity value and the theoretical humidity value of the mixed gas using the following formula: ΔD=D2-D3. Judging whether the SF6 gas has a tendency to be charged based on ΔD.

[0008] In some embodiments, whether the SF6 gas in the gas chamber has a charging tendency is determined based on ΔD, including: if ΔD<0, the SF6 gas has a charging tendency. Otherwise, the SF6 gas does not have a charging tendency.

[0009] In some of the embodiments, the SF6 gas is transported to the humidity detection module and flows out from the gas outlet, so that the humidity detection module detects the humidity value D1 of the SF6 gas.

[0010] In some embodiments, the mixed gas is delivered to the humidity detection module and flows out from the gas outlet, so that the humidity detection module detects the humidity value D2 of the mixed gas.

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

[0012] In some of the embodiments, SF6 gas and SF6 standard gas are delivered to the same point in the humidity detection pipeline on the side of the humidity detection module away from the gas outlet, so that 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 of the embodiments, SF6 gas and SF6 standard gas are respectively transported from two opposite sides of the humidity detection pipeline to the same location in the humidity detection pipeline.

[0014] According to an embodiment of the present invention, a method for determining the charging tendency of SF6 based on humidity change is provided, comprising the following steps: detecting the humidity value D1 of SF6 gas in the gas chamber. Mixing SF6 gas and SF6 standard gas with a humidity value D' according to a set ratio. Detecting the humidity value D2 of the mixed gas. Based on D1 and D', calculating the humidity value D3 of the mixed gas without charging tendency. Based on D2 and D3, judging whether SF6 gas has a charging tendency. The present invention utilizes SF6 after partial discharge to determine the humidity of the mixed gas. - Combined with the principle of H2O, the SF6 gas humidity in the gas chamber is detected, and the change in the measured humidity value and the theoretical value after the SF6 insulating gas and the SF6 gas with a certain humidity are mixed in a fixed ratio is analyzed to obtain the charging tendency of the SF6 gas, providing technical support for the determination of the degree of partial discharge based on the humidity of the SF6 gas. The present invention can determine whether the SF6 gas has a charging tendency by only analyzing the change in the gas humidity value, and further analyze the partial discharge amount, greatly reducing the technical complexity and cost of conventional electrical equipment status monitoring methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of 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 paying any creative work.

[0016] Figure 1 Schematic diagram of a device for measuring SF6 charging tendency in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

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

[0019] The first air intake line 1 has a first air intake port 11, a first pressure regulating valve 12, a first solenoid valve 13 and a first flow controller 14. The first air intake port 11, the first pressure regulating valve 12, the first solenoid valve 13 and the first flow controller 14 are sequentially arranged along the gas flow direction of the first air intake line 1. The first air intake port 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 sequentially arranged along the gas flow direction of the second air inlet line 2. The second air inlet 21 is connected to a SF6 standard gas cylinder with an internal gas humidity value of D' (such as 200ppm).

[0021] The humidity detection pipeline 3 is connected to the first air inlet pipeline 1 and the second air inlet pipeline 2. The humidity detection pipeline 3 is provided with a humidity detection module 31 and an air outlet 32. The humidity detection module 31 and the air outlet 32 ​​are arranged in sequence along the gas flow direction of the humidity detection pipeline 3. The humidity detection pipeline 3 intersects with the first air inlet pipeline 1 and the second air inlet pipeline 2 at one point. The first air inlet pipeline 1 and the second air inlet pipeline 2 are both vertically connected to the humidity detection pipeline 3. The connection point between the first air inlet pipeline 1 and the humidity detection pipeline 3 and the connection point between the second air inlet pipeline 2 and the humidity detection pipeline 3 are arranged oppositely. The air outlet 32 ​​is connected to the exhaust gas treatment device.

[0022] An embodiment of the present invention provides a method for measuring SF6 charging tendency using the above-mentioned 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: connect the first air inlet 11 to the air chamber, adjust the pressure of the first pressure regulating valve 12 to P1 (such as 0.2MPa), the flow rate of the first flow controller 14 to Q1 (such as 200mL / min), open the first solenoid valve 13, and allow the SF6 gas in the air chamber to flow through the first air 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 air outlet 32. The humidity detection module 31 detects the humidity of the SF6 gas in the air chamber, which is recorded as D1. In the above process, by conveying the SF6 gas to the humidity detection module 31 and flowing out from the air outlet 32, the humidity detection module 31 detects the humidity value D1 of the SF6 gas. In addition, the gas flowing out of the air outlet 32 ​​is conveyed to the exhaust gas treatment device.

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

[0026] The above steps can be: connect the second air inlet 21 to the SF6 standard gas cylinder with an internal gas humidity value of D' (such as 200ppm), adjust the pressure of the second pressure regulating valve 22 to P2 (such as 0.2MPa), the flow rate of the second flow controller 24 to Q2 (such as 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, and mixes with the SF6 gas in the gas chamber. In the above process, the SF6 gas and the SF6 standard gas with a humidity value of D' (such as 200ppm) are mixed at a set flow rate (such as 200mL / min). In the above process, by transporting the SF6 gas and the SF6 standard gas to the same place in the humidity detection pipeline 3 on the side of the humidity detection module 31 away from the gas outlet 32, the SF6 gas and the SF6 standard gas are mixed in the humidity detection pipeline 3, and the mixed gas is transported to the humidity detection module 3. Moreover, the SF6 gas and the SF6 standard gas are respectively transported from two opposite sides of the humidity detection pipeline 3 to the same place in 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' (such as 200 ppm), adjust the pressure of the second pressure regulating valve 22 to P2 (such as 0.2 MPa), and the flow rate of the second flow controller 24 to Q2 (such as 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 after mixing with the SF6 gas in the gas chamber, it flows through the humidity detection module 31 and the air outlet 32. The humidity detection module 31 detects the humidity of the mixed gas obtained, denoted as D2. In the above process, by transporting the mixed gas to the humidity detection module 31 and flowing out from the air outlet 32, the humidity detection module 31 detects the humidity value D2 of the mixed gas. In addition, the gas flowing out from the air outlet 32 is transported to the tail gas treatment device.

[0029] (4) Calculate the humidity value D3 of the mixed gas without the tendency of electrification according to D1 and D'.

[0030] The above steps can be as follows: Use the following formula to calculate the humidity value D3 of the mixed gas without the tendency of electrification: D3 = (D1 + D') / 2. When D' is 200 ppm, D3 = (D1 + 200) / 2.

[0031] (5) Judge whether the SF6 gas has the tendency of electrification according to D2 and D3.

[0032] The above steps can be as follows: Use the following formula to calculate the difference ΔD between the measured value and the theoretical value of the humidity of the mixed gas: ΔD = D2 - D3. Judge whether the SF6 gas has the tendency of electrification according to ΔD. Among them, if ΔD < 0, the SF6 gas has the tendency of electrification, that is, partial discharge has occurred. Otherwise, the SF6 gas does not have the tendency of electrification. The higher the partial discharge energy, the greater the tendency of the SF6 gas to be electrified, that is, the more SF6- combines with free water molecules, and the smaller ΔD. Therefore, the degree of partial discharge can be reflected by the value of |ΔD|.

[0033] The humidity of the insulating gas is an important detection index for the daily operation and maintenance of electrical equipment. At present, there is no research on the corresponding relationship between gas humidity, discharge faults, and discharge amounts. After partial discharge occurs in electrical equipment, the internal insulating gas SF6 will carry a certain amount of negative charge and become SF6 - , SF6 - will combine with free water molecules in the gas to form SF6 - ·H2O polymer, resulting in a decrease in free water molecules in the gas. Therefore, taking the H2O content as a fulcrum, the electrification tendency of SF6 can be analyzed by detecting the change of the insulating gas humidity value, so as to diagnose the discharge fault and discharge degree of the SF6 switchgear.

[0034] The method of the present invention uses the H2O content in the insulating gas as a fulcrum to analyze the discharge fault of the electrical equipment, and uses the change in the measured humidity value and the theoretical humidity value after the insulating gas is mixed with a certain humidity SF6 gas to determine whether the SF6 gas has a tendency to be charged, thereby further analyzing the discharge fault of the electrical equipment. The present invention can determine whether the SF6 gas has a tendency to be charged by only analyzing the change in gas humidity, and further analyze the partial discharge amount, greatly reducing the technical complexity and cost of conventional electrical equipment status monitoring methods.

[0035] In summary, the present invention utilizes SF6 after partial discharge - Combined with the principle of H2O, the SF6 gas humidity in the gas chamber is detected, and the change in the measured humidity value and the theoretical value after the SF6 insulating gas and the SF6 gas with a certain humidity are mixed in a fixed ratio is analyzed to obtain the charging tendency of the SF6 gas, providing technical support for the determination of the degree of partial discharge based on the humidity of the SF6 gas. The present invention provides new ideas and new solutions for partial discharge detection of electrical equipment, and discharge detection can be achieved based on the humidity value, a daily operation and maintenance detection indicator, saving costs and manpower.

[0036] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0037] The above description is only 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 in the protection scope of the present invention.

Claims

1. A method for measuring SF6 charging tendency based on humidity change, characterized in that: The following steps are involved: Detect the humidity value D1 of SF6 gas in the gas chamber; Mixing the SF6 gas with SF6 standard gas having a humidity value of D' according to a set ratio; Detecting the humidity value D2 of the mixed gas obtained by mixing; According to D1 and D', calculate the humidity value D3 of the mixed gas without charging tendency; According to D2 and D3, it is determined whether the SF6 gas has a tendency to be charged.

2. The method for measuring SF6 charging tendency according to claim 1, characterized in that: The SF6 gas is mixed with SF6 standard gas having a humidity value of D' according to 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 measuring SF6 charging tendency according to claim 2, characterized in that: According to D1 and D', the humidity value D3 of the mixed gas without charging tendency is calculated, including: The humidity value D3 of the mixed gas without charging tendency is calculated using the following formula: D3 = (D1 + D') / 2.

4. The method for measuring SF6 charging tendency according to claim 1, characterized in that: According to D2 and D3, judging whether the SF6 gas has a tendency to be charged includes: The difference ΔD between the measured humidity value and the theoretical humidity value of the mixed gas is calculated using the following formula: ΔD=D2-D3; According to ΔD, it is determined whether the SF6 gas has a tendency to be charged.

5. The method for measuring SF6 charging tendency according to claim 4, characterized in that: According to ΔD, judging whether the SF6 gas in the gas chamber has a tendency to be charged includes: If ΔD<0, the SF6 gas has a tendency to be charged; otherwise, the SF6 gas has no tendency to be charged.

6. The method for measuring SF6 charging tendency according to claim 1, characterized in that: The SF6 gas is transported to the humidity detection module and flows out from the gas outlet, so that the humidity detection module detects the humidity value D1 of the SF6 gas.

7. The method for measuring SF6 charging tendency according to claim 6, characterized in that: The mixed gas is delivered to the humidity detection module and flows out from the gas outlet, so that the humidity detection module detects the humidity value D2 of the mixed gas.

8. The method for measuring SF6 charging tendency according to claim 6, characterized in that: The gas flowing out of the gas outlet is transported to the tail gas treatment device.

9. The method for measuring SF6 charging tendency according to claim 6, characterized in that: By conveying the SF6 gas and the SF6 standard gas to the same point in the humidity detection pipeline on the side of the humidity detection module away from the gas outlet, the SF6 gas and the SF6 standard gas are mixed in the humidity detection pipeline, and the mixed gas is conveyed to the humidity detection module.

10. The method for measuring SF6 charging tendency according to claim 9, characterized in that: The SF6 gas and the SF6 standard gas are respectively transported from two opposite sides of the humidity detection pipeline to the same place in the humidity detection pipeline.

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