Method for measuring the electrification tendency of SF6 gas

Abstract

The application discloses a kind of SF6 gas electric tendency determination method, comprising the following steps: measuring the humidity D1 of SF6 gas in gas chamber. Frost layer is established using SF6 gas without electricity and humidity D2. The first mixed gas obtained by mixing SF6 gas in gas chamber with SF6 gas without electricity and humidity D2 according to a set ratio is passed to the frost layer, and the time T required for the first mixed gas to change the thickness of the frost layer is measured. The second mixed gas obtained by mixing SF6 gas without electricity and humidity D1 with SF6 gas without electricity and humidity D2 according to a set ratio is passed to the frost layer, and the time T1 required for the second mixed gas to change the thickness of the frost layer is measured. Whether the SF6 gas in the gas chamber has an electric tendency is determined according to T and T1. The application uses the principle of combining SF6 ‑ with H2O after partial discharge, using SF6 gas with a certain humidity as reference gas, by measuring the elimination time of the reference gas cold mirror frost layer to a certain thickness, the electric tendency of the SF6 gas in the gas chamber can be determined.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of SF6 gas electrification tendency determination, and particularly to a SF6 gas electrification tendency determination method. BACKGROUND

[0002] Partial discharge is the main precursor of insulation failure of electrical equipment. When partial discharge occurs, it is often accompanied by physical characteristics such as pulse current, electromagnetic wave, ultrasonic wave, light signal, characteristic gas, etc. 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 pulse current method, electromagnetic wave and ultrasonic wave method are easy to be disturbed by environment, and have high false alarm probability; optical method has poor sensitivity, needs to be built-in in electrical equipment, and has poor operability; characteristic gas detection method is a commonly used electrical equipment state monitoring method, but the relationship between the content of characteristic gas and the discharge quantity is not clear, and the internal partial discharge intensity of the equipment cannot be reflected. SUMMARY

[0003] The present application provides a SF6 gas electrification tendency determination method, which can determine whether the SF6 gas has electrification tendency.

[0004] Embodiments of the present application provide a SF6 gas electrification tendency determination method, comprising the following steps: measuring the humidity D1 of the SF6 gas in the gas chamber. A frost layer is established by using SF6 gas without electrification and with humidity D2. A first mixed gas obtained by mixing the SF6 gas in the gas chamber and the SF6 gas without electrification and with humidity D2 according to a set proportion is introduced into the frost layer, and the time T required for the first mixed gas to change the thickness of the frost layer is measured. A second mixed gas obtained by mixing the SF6 gas without electrification and with humidity D1 and the SF6 gas without electrification and with humidity D2 according to a set proportion is introduced into the frost layer, and the time T1 required for the second mixed gas to change the thickness of the frost layer is measured. Whether the SF6 gas in the gas chamber has electrification tendency is determined according to T and T1.

[0005] In some embodiments, according to T and T1, whether the SF6 gas in the gas chamber has electrification tendency is determined, including: if T is less than T1, the SF6 gas in the gas chamber has electrification tendency. Otherwise, the SF6 gas in the gas chamber does not have electrification tendency.

[0006] In some embodiments, the humidity D1 of the SF6 gas in the gas chamber is measured, including: introducing the SF6 gas in the gas chamber into a dew point instrument, and measuring the humidity D1 of the SF6 gas in the gas chamber by the dew point instrument.

[0007] In some embodiments, D2 is greater than D1.

[0008] In some embodiments, the frost layer is established by using the uncharged SF6 gas with humidity D2, including: introducing the uncharged SF6 gas with humidity D2 into the dew point meter, measuring the dew point of the uncharged SF6 gas with humidity D2 by the dew point meter, and waiting for the dew point reading of the dew point meter to be stable, i.e. the frost layer is established on the mirror surface of the dew point meter.

[0009] In some embodiments, after the frost layer is established on the mirror surface of the dew point meter, the temperature of the mirror surface is controlled to remain unchanged at the dew point of the uncharged SF6 gas with humidity D2, so as to maintain the thickness of the frost layer unchanged.

[0010] In some embodiments, after the frost layer is established on the mirror surface of the dew point meter, the light energy L0 representing the current thickness of the frost layer displayed by the dew point meter is recorded.

[0011] In some embodiments, the first mixed gas obtained by mixing the SF6 gas in the gas chamber and the uncharged SF6 gas with humidity D2 in a set ratio is introduced into the frost layer, and the time T required for the first mixed gas to change the thickness of the frost layer is measured, including: mixing the SF6 gas in the gas chamber with a set flow rate and the uncharged SF6 gas with humidity D2 with a set flow rate to obtain the first mixed gas, then introducing the first mixed gas into the dew point meter, starting timing, stopping timing when the light energy displayed by the dew point meter reaches L1 representing a certain thickness of the frost layer, and obtaining the time T.

[0012] In some embodiments, L1 is also set to be less than the light energy L2 corresponding to the dew point of the SF6 gas with humidity D1.

[0013] In some embodiments, the second mixed gas obtained by mixing the uncharged SF6 gas with humidity D1 and the uncharged SF6 gas with humidity D2 in a set ratio is introduced into the frost layer, and the time T1 required for the second mixed gas to change the thickness of the frost layer is measured, including: mixing the uncharged SF6 gas with humidity D1 with a set flow rate and the uncharged SF6 gas with humidity D2 with a set flow rate to obtain the second mixed gas, then introducing the second mixed gas into the dew point meter, starting timing, stopping timing when the light energy displayed by the dew point meter reaches L1, and obtaining the time T1.

[0014] The SF6 gas electrification tendency measuring method provided by the embodiment of the present application comprises the following steps: measuring the humidity D1 of the SF6 gas in the gas chamber. A frost layer is established by using the SF6 gas without electrification and with humidity D2. The first mixed gas obtained by mixing the SF6 gas in the gas chamber and the SF6 gas without electrification and with humidity D2 according to a set ratio is introduced into the frost layer, and the time T required for the first mixed gas to change the thickness of the frost layer is measured. The second mixed gas obtained by mixing the SF6 gas without electrification and with humidity D1 and the SF6 gas without electrification and with humidity D2 according to a set ratio is introduced into the frost layer, and the time T1 required for the second mixed gas to change the thickness of the frost layer is measured. Whether the SF6 gas in the gas chamber has electrification tendency is judged according to T and T1. The present application uses the principle of the combination of SF6 gas and H2O after partial discharge, takes the SF6 gas with certain humidity as the reference gas, and measures the elimination time of the frost layer of the reference gas to a certain thickness, so that the electrification tendency of the SF6 gas in the gas chamber can be measured, and technical support is provided for the partial discharge degree discrimination based on the humidity of the SF6 gas. The present application measures the elimination time instead of the humidity value, and does not need to wait for the thickness of the frost layer to be reduced to the thickness of the frost layer corresponding to the dew point temperature, so that the problem of long time consumption in the measurement of the dew point humidity of the gas, especially the low humidity gas, is solved, and the SF6 electrification tendency measuring time is shortened. The present application can realize the electrification tendency test while measuring the humidity value in daily operation and maintenance through the conventional dew point instrument, and does not need to additionally increase the instrument. - The SF6 gas electrification tendency measuring method provided by the embodiment of the present application comprises the following steps: measuring the humidity D1 of the SF6 gas in the gas chamber. A frost layer is established by using the SF6 gas without electrification and with humidity D2. The first mixed gas obtained by mixing the SF6 gas in the gas chamber and the SF6 gas without electrification and with humidity D2 according to a set ratio is introduced into the frost layer, and the time T required for the first mixed gas to change the thickness of the frost layer is measured. The second mixed gas obtained by mixing the SF6 gas without electrification and with humidity D1 and the SF6 gas without electrification and with humidity D2 according to a set ratio is introduced into the frost layer, and the time T1 required for the second mixed gas to change the thickness of the frost layer is measured. Whether the SF6 gas in the gas chamber has electrification tendency is judged according to T and T1. The present application uses the principle of the combination of SF6 gas and H2O after partial discharge, takes the SF6 gas with certain humidity as the reference gas, and measures the elimination time of the frost layer of the reference gas to a certain thickness, so that the electrification tendency of the SF6 gas in the gas chamber can be measured, and technical support is provided for the partial discharge degree discrimination based on the humidity of the SF6 gas. The present application measures the elimination time instead of the humidity value, and does not need to wait for the thickness of the frost layer to be reduced to the thickness of the frost layer corresponding to the dew point temperature, so that the problem of long time consumption in the measurement of the dew point humidity of the gas, especially the low humidity gas, is solved, and the SF6 electrification tendency measuring time is shortened. The present application can realize the electrification tendency test while measuring the humidity value in daily operation and maintenance through the conventional dew point instrument, and does not need to additionally increase the instrument. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, brief introductions will be given to the drawings needed to be used in the embodiments or prior art descriptions. Obviously, the drawings in the following description only represent some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0016] Figure 1 FIG. 1 is a schematic diagram of the SF6 gas electrification tendency measuring device in the embodiment of the present application. DETAILED DESCRIPTION

[0017] In order to make the objectives, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0018] Reference Figure 1 The embodiment of the present application provides an SF6 gas electrification tendency measuring device, which comprises a gas chamber 1, a reference gas cylinder 2, a first electromagnetic valve 3, a second electromagnetic valve 4, a first flow regulating valve 5, a second flow regulating valve 6 and a dew point instrument 7.

[0019] The gas chamber 1 has SF6 gas.

[0020] The reference gas bottle 2 has reference gas. Since the SF6 gas in the electrical equipment is usually less than 500 ppm, the SF6 gas with humidity content of 500 ppm can be selected as the reference gas.

[0021] The first electromagnetic valve 3 is connected with the gas outlet of the gas chamber 1.

[0022] The second electromagnetic valve 4 is connected with the gas outlet of the reference gas bottle 2.

[0023] The first flow regulating valve 5 is connected with the first electromagnetic valve 4.

[0024] The second flow regulating valve 6 is connected with the second electromagnetic valve 4.

[0025] The dew point meter 7 is connected with the first flow regulating valve 5 and the second flow regulating valve 6. The dew point meter 7 has an exhaust port 8.

[0026] The embodiment of the present application provides a SF6 gas electrification tendency measuring method, which can adopt the SF6 gas electrification tendency measuring device.

[0027] (1) Measure the humidity D1 of the SF6 gas in the gas chamber 1.

[0028] The above step can be specifically: open the first electromagnetic valve 3, adjust the flow of the first flow regulating valve 5 to Q1 (such as 200 mL / min), pass the SF6 gas in the gas chamber 1 into the dew point meter, measure the humidity D1 of the SF6 gas in the gas chamber 1 through the dew point meter 7, and close the first electromagnetic valve 3.

[0029] (2) Establish a frost layer by using the SF6 gas without electrification and with humidity D2.

[0030] In the above step, D2 is greater than D1. The above step can be specifically: open the second electromagnetic valve 4, adjust the flow of the second flow regulating valve 6 to Q2 (such as 200 mL / min), pass the SF6 gas without electrification and with humidity D2 into the dew point meter 7 as the reference gas, measure the dew point of the reference gas through the dew point meter 7, and wait for the dew point of the dew point meter 7 to be stable, that is, a certain thickness of frost layer has been established on the mirror surface of the dew point meter 7.

[0031] After a certain thickness of frost layer is established on the mirror surface of the dew point meter 7, the temperature of the mirror surface is controlled by the dew point meter 7 to keep the dew point of the reference gas unchanged, so as to maintain the thickness of the frost layer unchanged.

[0032] After a certain thickness of frost layer is established on the mirror surface of the dew point meter 7, the light energy L0 displayed by the dew point meter 7 is recorded, which represents the thickness of the frost layer at this time.

[0033] (3) The first mixed gas obtained by mixing the SF6 gas in the gas chamber with the non-charged SF6 gas with a humidity of D2 in a set ratio is passed to the frost layer, and the time T required for the first mixed gas to change the thickness of the frost layer is measured.

[0034] In the above steps, the change in the thickness of the frost layer can be a decrease in the thickness of the frost layer. At this time, the time is the dew-eliminating time. Dew-eliminating reduces the thickness of the frost layer, which can also be called defrosting. The above steps can be specifically as follows: keep the second solenoid valve 4 open and the flow of the second flow regulating valve at Q2, open the first solenoid valve 3, adjust the flow of the first flow regulating valve 5 to Q2 (such as 200mL / min), mix the SF6 gas and the reference gas in the gas chamber 1 to obtain a first mixed gas, and then introduce the dew point meter 7, start timing, because the humidity D1 of the SF6 gas in the gas chamber 1 is lower than the humidity D2 of the reference gas, that is, lower than the refrigeration humidity of the dew point meter 7, so the humidity of the first mixed gas is lower than the refrigeration humidity of the dew point meter 7, and the thickness of the frost layer condensed on the mirror surface As the temperature begins to decrease and the light energy increases, the change in light energy displayed by the dew point meter is observed. When the light energy displayed by the dew point meter 7 reaches L1, which represents a specific frost layer thickness (L1 is set to be greater than L0 and less than the light energy L2 corresponding to the dew point of SF6 gas at a humidity of D1 (i.e., the light energy displayed by the dew point meter after the dew point of SF6 gas at a humidity of D1 stabilizes), that is, L2>L1>L0 (at this time, the frost layer at the dew point of gas with a humidity ≤D1 can reach a specific thickness. It should be noted that the lower the humidity, the greater the light energy), the timing is stopped to obtain the time T. The above process only measures the time when the frost layer thickness drops to light energy L1. The frost layer thickness has not yet dropped to the frost layer thickness corresponding to the dew point, so that the measured dew-clearing time is less than the time required to measure the humidity, thereby shortening the measurement time.

[0035] (4) A second mixed gas obtained by mixing uncharged SF6 gas with a humidity of D1 and uncharged SF6 gas with a humidity of D2 in a set ratio is passed to the frost layer, and the time T1 required for the second mixed gas to change the thickness of the frost layer is measured.

[0036] In the above steps, the change in the thickness of the frost layer can be a decrease in the thickness of the frost layer. In this case, the time is the dew-eliminating time. Dew-eliminating reduces the thickness of the frost layer, which can also be called defrosting. The above steps can be specifically as follows: in the preliminary test process, a non-charged SF6 gas with a flow rate of Q2 (such as 200 mL / min) and a humidity of D1 is mixed with a non-charged SF6 gas with a flow rate of Q2 (such as 200 mL / min) and a humidity of D2 to obtain a second mixed gas, which is then introduced into the dew point meter 7 and timing is started. Since the humidity of the second mixed gas is also lower than the refrigeration humidity of the dew point meter 7, the thickness of the frost layer condensed on the mirror surface begins to decrease, and the light energy increases. When the light energy displayed by the dew point meter 7 reaches L1, the timing is stopped to obtain time T1.

[0037] (5) According to T and T1, whether the SF6 gas in the gas chamber 1 has a charging tendency is judged.

[0038] The above steps can be: if the SF6 gas in the gas chamber 1 has a charging tendency, the SF6 - in the SF6 gas will combine with water molecules to form SF6 - ·H2O polymer, accelerate the frost layer to reveal speed, shorten the reveal time. Therefore, if T is less than T1, the SF6 gas in the gas chamber 1 has a charging tendency, that is, partial discharge occurs in the gas chamber 1. Otherwise, the SF6 gas in the gas chamber 1 does not have a charging tendency. The greater the difference between T and T1, the more obvious the charging tendency of the SF6 gas in the gas chamber 1, that is, the more severe the discharge.

[0039] The humidity of the insulating gas is an important detection index for the daily operation and maintenance of electrical equipment, and there is currently no research on the corresponding relationship between gas humidity and discharge fault and discharge amount. After partial discharge occurs in electrical equipment, negative ions SF6 - will be generated, and the degree of discharge fault will affect the number of negative ions SF6 - . SF6 - will combine with H2O to form SF6 - ·H2O polymer, resulting in a decrease in gas humidity, so the concentration of H2O can be used as a reference point to determine the charging tendency of SF6. The stronger the charging tendency of the SF6 gas in the gas chamber 1, the more SF6 - it carries, and the stronger its ability to combine with water. The stronger the ability to eliminate the frost layer formed when measuring the reference gas, the shorter the time it takes for the frost layer to reach a certain thickness, so the reveal time can reflect whether the SF6 has a gas charging tendency and the strength of the charging tendency, thereby diagnosing the severity of the partial discharge fault. Since conventional gas dew point humidity measurement requires water in the gas to condense on the cold mirror surface to form a frost layer of a certain thickness, it takes a long time to measure low-humidity gas. Moreover, after measuring high-humidity gas, it takes a long time to obtain accurate low-humidity dew point values (longer than measuring low-humidity gas first and then measuring high-humidity gas).

[0040] The method of the present application takes the H2O content in the insulating gas as the reference point, takes SF6 gas with a certain humidity as the reference gas, and measures the elimination time of the reference gas frost layer caused by the SF6 gas of the electrical equipment to a certain thickness during the dew point measurement, thereby further analyzing the discharge fault of the electrical equipment. The present application can determine whether the SF6 gas has a charging tendency by only daily operation and maintenance humidity detection, further analyze the amount of partial discharge, and replace humidity measurement with reveal time measurement, thereby solving the problem of long time consumption in gas, especially low-humidity gas, dew point humidity detection, shortening the SF6 charging tendency determination time, and greatly reducing the technical complexity and cost of conventional electrical equipment state monitoring methods.

[0041] In summary, the present application utilizes SF6 - With the combination principle of H2O, the SF6 gas with certain humidity is used as reference gas, the elimination time of the reference gas cold mirror frost layer reducing to a certain thickness is measured, the charged tendency of SF6 gas is determined, technical support is provided for the partial discharge degree discrimination based on the humidity of SF6 gas. The present application measures the elimination time instead of the humidity value, does not need to wait for the frost layer thickness to reduce to the frost layer thickness corresponding to the dew point temperature, solves the problem of long time consumption in the dew point humidity measurement of gas, especially low humidity gas, shortens the charged tendency determination time of SF6. The present application can realize the charged tendency test while measuring the humidity value in daily operation and maintenance through the conventional dew point instrument, without additional instruments.

[0042] The same or similar reference numerals in the drawings of the embodiments correspond to the same or similar components; in the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary illustration, and cannot be understood as a limitation on the present application, for those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0043] The above only describes the preferred embodiments of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method of measuring the electrical charge tendency of SF6 gas, characterized by, The method comprises the following steps: measuring the humidity D1 of SF6 gas in a gas chamber; establishing a frost layer with SF6 gas which is not electrified and has humidity D2; D2 is greater than D1; feeding first mixed gas obtained by mixing SF6 gas in the gas chamber and SF6 gas which is not electrified and has humidity D2 according to a set ratio to the frost layer, and measuring the time T required for the first mixed gas to change the thickness of the frost layer; feeding second mixed gas obtained by mixing SF6 gas which is not electrified and has humidity D1 and SF6 gas which is not electrified and has humidity D2 according to the set ratio to the frost layer, and measuring the time T1 required for the second mixed gas to change the thickness of the frost layer; judging whether the SF6 gas in the gas chamber has electrification tendency according to T and T1; wherein judging whether the SF6 gas in the gas chamber has electrification tendency according to T and T1 comprises: if T is less than T1, the SF6 gas in the gas chamber has electrification tendency; otherwise, the SF6 gas in the gas chamber does not have electrification tendency; after establishing the frost layer on the mirror surface of the dew point meter, recording the light energy L0 displayed by the dew point meter which represents the current thickness of the frost layer; feeding first mixed gas obtained by mixing SF6 gas in the gas chamber and SF6 gas which is not electrified and has humidity D2 according to a set ratio to the frost layer, and measuring the time T required for the first mixed gas to change the thickness of the frost layer, comprises: mixing the SF6 gas in the gas chamber and the SF6 gas which is not electrified and has humidity D2 according to a set ratio to obtain first mixed gas, then feeding the first mixed gas to the dew point meter, starting timing, when the light energy displayed by the dew point meter reaches L1 which represents a certain thickness of the frost layer, L1 is set to be greater than L0, stopping timing, and obtaining the time T.

2. The method according to claim 1, wherein measuring the humidity D1 of SF6 gas in a gas chamber comprises: feeding the SF6 gas in the gas chamber to the dew point meter, and measuring the humidity D1 of the SF6 gas in the gas chamber by the dew point meter.

3. The method according to claim 1, wherein establishing a frost layer with SF6 gas which is not electrified and has humidity D2 comprises: feeding the SF6 gas which is not electrified and has humidity D2 to the dew point meter, measuring the dew point of the SF6 gas which is not electrified and has humidity D2 by the dew point meter, and waiting for the dew point displayed by the dew point meter to be stable, i.e. the frost layer has been established on the mirror surface of the dew point meter.

4. The method according to claim 3, wherein after establishing the frost layer on the mirror surface of the dew point meter, the temperature of the mirror surface is controlled to remain unchanged at the dew point of the SF6 gas which is not electrified and has humidity D2, so as to maintain the thickness of the frost layer unchanged.

5. The method according to claim 1, wherein L1 is also set to be less than the light energy L2 corresponding to the dew point of SF6 gas with humidity D1.

6. The method according to claim 1, wherein ​ ​ ​ ​ The second mixed gas obtained by mixing the uncharged SF6 gas with humidity D1 and the uncharged SF6 gas with humidity D2 according to the set ratio is introduced into the frost layer, and the time T1 required for the second mixed gas to change the thickness of the frost layer is measured, including: The second mixed gas obtained by mixing the uncharged SF6 gas with humidity D1 and the uncharged SF6 gas with humidity D2 according to the set ratio is introduced into the frost layer, and the time T1 required for the second mixed gas to change the thickness of the frost layer is measured, including: The second mixed gas obtained by mixing the uncharged SF6 gas with humidity D1 and the uncharged SF6 gas with humidity D2 according to the set ratio is introduced into the frost layer, and the time T1 required for the second mixed gas to change the thickness of the frost layer is measured, including: The second mixed gas obtained by mixing the uncharged SF6 gas with humidity D1 and the uncharged SF6 gas with humidity D2 according to the set ratio is introduced into the frost layer, and the time T1 required for the second mixed gas to change the thickness of the frost layer is measured, including: The second mixed gas obtained by mixing the uncharged SF6 gas with humidity D1 and the uncharged SF6 gas with humidity D2 according to the set ratio is introduced into the frost layer, and the time T1 required for the second mixed gas to change the thickness of the frost layer is measured, including: The second mixed gas obtained by mixing the uncharged

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