JPH11354333A - Inside abnormality diagnostic method for gas insulated electric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to perform early detection of inner abnormality, by analizing the hydrocarbon-based gas in the insulation gas filled inside a gas insulated electric device. SOLUTION: In a gas insulated transformer using sulfer hexafluoride (SF6 ) gas for insulating gas, the insulation gas is picked up from a gas-insulated transformer in operation, and the hydrocarbon-based gas contained in the insulation gas is analyzed by gas chromatography. That is to say, when the abnormality such as discharge and overheat occurs in the gas-insulated transformer, the abnormal part becomes high in temperature. Therefore, the insulation material in the vicinity is broken down, and the gas, which is CH4 , C2 H4 , C3 H6 , C3 H8 , CO and CO2 , is remarkably generated. Since this gas is chemically stable, the gas is stored in the lapse of time even if the generated quantity is minute, and the detectable concentration is obtained after some time. Therefore, the quantity of each component is measured by component analysis, and the inner abnormality is securely detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for analyzing an insulating gas filled in a gas-insulated electrical device by analyzing the insulating gas.
The present invention relates to a method of diagnosing an internal abnormality of a gas-insulated electrical device.

[0002]

2. Description of the Related Art As a gas-insulated electric device, there are a gas-insulated transformer and a gas-insulated reactor using sulfur hexafluoride (SF ₆ ) gas as an insulating gas also serving as a cooling medium.
In such electrical equipment, when an abnormality occurs in the inside, the insulating gas is decomposed by the heat generated thereby,
For example, in the case of SF ₆ gas, sulfur-based or fluorine-based decomposition gas such as SF ₄ , SOF ₂ , SO ₂ is generated. Also,
If an insulating material is present in the vicinity of the abnormal location, that material will also decompose. In a gas-insulated transformer having a winding, the winding is covered with a thin-leaf plastic-based material, and a cellulosic material is arranged around the winding to provide insulation. When these decompose, gases such as CO and CO ₂ are generated. A technique has been put to practical use in which a trace component in an insulating gas is analyzed by paying attention to the above-mentioned decomposed gas, and an abnormality in an electric device is diagnosed based on its type and concentration. Such an internal abnormality diagnosis technique has a feature that diagnosis can be performed without stopping the operation of the electric device.

[0003]

The decomposition gas generated by decomposition of the insulating gas, such as SF ₄ or SOF ₂ , is very effective as an indicator of the internal abnormality of electric equipment,
Since it is a gas having hydrolyzability, the following reaction proceeds when moisture coexists. SF ₄ + H ₂ O → SOF ₂ + 2HF SOF ₂ + H ₂ O → SO ₂ + 2HF Therefore, the decomposition gas changes with time, and a phenomenon that the concentration is remarkably reduced with time is seen. For this reason, when a sulfur-based or fluorine-based decomposed gas is used as an indicator of abnormality, there is a problem that the above-described reaction occurs and it is difficult to detect even a small amount of gas generated in the initial stage of the internal abnormality. From the viewpoint of early detection of an internal abnormality, an object of the present invention is to obtain a highly accurate internal abnormality diagnosis method.

[0004]

According to a first aspect of the present invention, there is provided a method for diagnosing internal abnormality of a gas-insulated electric device, comprising analyzing a hydrocarbon-based gas in an insulating gas filled in the gas-insulated electric device, and analyzing the gas-insulated gas. This is for diagnosing an abnormality inside the electric equipment. According to a second aspect of the present invention, there is provided a method for diagnosing an internal abnormality of a gas-insulated electric device, which determines whether or not there is a discharge abnormality inside the gas-insulated electric device based on whether or not acetylene is detected in the insulating gas. The method for diagnosing internal abnormality of a gas-insulated electric device according to claim 3 is based on whether or not acetylene is detected in the insulating gas.
This is to determine whether or not there is a discharge abnormality in the coil portion inside the gas insulated electric device.

According to a fourth aspect of the present invention, there is provided a method for diagnosing an internal abnormality of a gas-insulated electric device, wherein the temperature of the internal abnormality of the gas-insulated electric device is estimated based on a ratio of an acetylene concentration to a total concentration of hydrocarbon gas components. . According to a fifth aspect of the present invention, there is provided a method for diagnosing an internal abnormality of a gas-insulated electric device by detecting benzene in an insulating gas. The method for diagnosing internal abnormality of a gas-insulated electrical device according to claim 6 is based on a comparison between a component of a hydrocarbon-based gas in the insulating gas and a component resulting from decomposition of sulfur hexafluoride gas. Diagnosis of the presence of insulating material in

According to a seventh aspect of the present invention, there is provided a method of diagnosing an internal abnormality of a gas-insulated electric device, wherein an insulating material is disposed at a specific portion of the gas-insulated electric device filled with an insulating gas, and the gas is generated from the insulating material. By detecting such a decomposed gas from the insulating gas, the position of the internal abnormality of the gas-insulated electric device is determined.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 As an example of a gas-insulated electric device, a gas-insulated transformer using sulfur hexafluoride (SF ₆ ) gas as an insulating gas will be described. The insulating gas was collected from the operating gas insulating transformer, and the hydrocarbon-based gas contained therein was analyzed by gas chromatography. FIG. 1 is a table showing the analysis results. The detected component is C
H _4, a _{C 2 H 4, C 3 H} 6, C 3 H 8, CO, CO 2. It is considered that these components are generated due to deterioration of the internal insulating material over time due to heat loss during operation of the gas insulating transformer. It should be noted that the term “insulating material” in this specification does not include an insulating gas and means a solid insulating material.

When an abnormality such as electric discharge or overheating occurs in the gas insulating transformer, the temperature of the abnormal part becomes high, so that the insulating material in the vicinity thereof is decomposed, and the above-mentioned gases are significantly generated. . Since the above-mentioned gas is chemically stable, even if the amount of generation is very small, it accumulates over time and reaches a detectable concentration after a certain time, so the amount of each component is measured by component analysis, Internal abnormalities can be reliably detected.

The decomposition temperature of SF ₆ gas when an insulating material coexists may be considered to be about 250 ° C. When a decomposition gas from SF ₆ gas, for example, SF ₄ , SOF _2, etc. The following internal abnormalities are difficult to detect. When a hydrocarbon-based gas such as the above component is used as an indicator of abnormality, a lower temperature internal abnormality can be detected, and SF ₄ , SOF ₂
Since there is no hydrolytic property as described above, the generated components can be detected reliably, and the accuracy of detecting abnormalities is improved.

Embodiment 2 In this embodiment, a case will be described in which acetylene (C ₂ H ₂ ) is used as an index of abnormality. A 50 mm thick polyethylene terephthalate (PET) film or a polyphenylene sulfide (PP) is placed on a rectangular copper wire 10 mm wide and 2.4 mm thick.
S) Two conductors wound with a film were brought into close contact with each other, and the conductors were placed in a container filled with SF ₆ gas as an insulating gas, and then a voltage was applied between the conductors to cause dielectric breakdown. FIGS. 2 and 3 show the results of analysis of the insulating gas by gas chromatography at this time. 2 shows the case where the conductor insulation is a PET film, and FIG. 3 shows the case where the conductor insulation is a PPS film.

The components detected by the analysis are H ₂ , C ₂ H ₂ ,
_{CH 4, C 2 H 6,} C 2 H 4, C 3 H 6, C 3 H 8, CO, CO 2
It is. These are considered as decomposition gases from PET and PPS films. H ₂ , CO, C
O ₂ does not appear in FIGS. 2 and 3 but is detected separately by analysis. As shown in Embodiment 1, C ₂ H ₂ is not detected from the gas-insulated transformer during normal operation, and thus is characteristic due to dielectric breakdown (abnormal discharge) of the PET film and the PPS film. Is considered to be a decomposed gas. Therefore, by using C ₂ H ₂ as the index component of the abnormality, it is possible to accurately detect the abnormal discharge inside the electric device.

Further, since C ₂ H ₂ is a decomposed gas originating from the above-mentioned film, there is a high possibility that the location of an internal abnormality can be specified by detecting C ₂ H ₂ . PET film and P
Since the PS film is wound around a conductor as an insulating material of the coil, when C ₂ H ₂ is detected, it can be determined that the discharge of the coil is abnormal.

Embodiment 3 High temperature (for example, 25
(0 ° C or higher) When an abnormality occurs in gas-insulated electrical equipment,
F ₆ gas is decomposed and SF ₄ , SOF ₂ , HF, SO ₂ , S
Decomposition gas such as O ₂ F ₂ is generated. When an insulating material is interposed in the internal abnormality, a hydrocarbon-based gas as described in the first embodiment is also generated. Therefore, SF
_When a sulfur-based or fluorine-based decomposed gas resulting from the decomposition of ₆ is detected, and the above-mentioned hydrocarbon-based gas is detected, an internal abnormality exists, and the abnormality is mediated by an insulating material. Can be determined. By comparing the two gases, it is possible to know the degree of the presence of the insulating material in the abnormality. The location where the insulating material is used in the electrical equipment is known by design, and thus can be a key to specifying an abnormal location.

Embodiment 4 If the insulating material is overheated due to an internal abnormality of the gas-insulated electric device, the total concentration of the hydrocarbon-based gas components described in the first embodiment increases. C ₂ H ₂ is not generated by a relatively low temperature internal abnormality, but is generated at a high temperature. Therefore, the ratio of the concentration of C ₂ H ₂ to the total concentration of hydrocarbon gas components in the insulating gas increases as the temperature of the abnormal part increases, and it is possible to estimate the temperature of the abnormal part based on this ratio. it can.

Embodiment 5 PET film and PP
When the S film decomposes, benzene is generated. FIG.
2 shows the relationship between the amount of benzene produced and the heating temperature when a PET film and a PPS film are thermally decomposed. The test was performed at a heating rate of 6 ° C./min by directly connecting an FID (hydrogen-based ionization detector) type gas chromatograph using a capillary column to a heat decomposition apparatus.

For any of the films, the higher the temperature, the higher the amount of the film produced. This indicates that the film has been overheated if the insulating gas is sampled from the electrical equipment and the gas is analyzed to detect benzene. In addition, PET film and PPS film are used as an insulating material of the coil. In such a case, it is possible to diagnose whether the film is overheated by detecting the presence of benzene which is a characteristic gas from these films. Yes, it is possible to diagnose the presence or absence of abnormalities in the coil part, which is important for the performance of electric equipment.

Embodiment 6 If an insulating material such as a plastic material that generates a characteristic gas when decomposed is placed in a specific location, for example, a functionally important location, when an abnormality occurs in this location, the characteristic gas is generated. Thus, an abnormality can be detected. Acetaldehyde is a characteristic decomposition gas in the case of a PET film, and hydrogen sulfide is a characteristic decomposition gas in the case of a PPS film. FIG. 5 shows the relationship between the amount of the decomposition gas generated and the heating temperature when the PET film and the PPS film are thermally decomposed. The test conditions are the same as in the case of the fifth embodiment.

Since the place where the plastics material is disposed is known in advance, if a characteristic decomposition gas is detected from the insulating gas, the abnormal place can be specified. In addition, if a plurality of types of plastics materials are used and the type of plastics material is changed depending on the location, the abnormal gas can be analyzed by analyzing the insulating gas for the decomposition gas characteristic of each material. The accuracy of the determination is improved. further,
If a plurality of types of insulating materials such as plastics materials having different decomposition temperatures are used, when an abnormality occurs, the temperature can be estimated.

[0019]

According to the method for diagnosing internal abnormality of a gas-insulated electric device according to the first to sixth aspects, a hydrocarbon-based gas in the insulating gas is analyzed to diagnose the internal abnormality. The target is a decomposition gas which is chemically more stable than the decomposed gas, and an abnormality at a relatively low temperature at which the insulating gas is not decomposed can also be detected. Therefore, a highly accurate abnormality detection can be performed.

Further, according to the method for diagnosing internal abnormality of a gas-insulated electric device according to the present invention, an insulating material is disposed at a specific location, and a characteristic decomposition gas from the material is detected. The location of the internal abnormality can be known by comparing the location of the internal abnormality.

[Brief description of the drawings]

FIG. 1 is a view for explaining a first embodiment of the present invention;
It is an analysis result table of the insulating gas collected from the transformer.

FIG. 2 is a view for explaining Embodiment 2 of the present invention;
It is an analysis result figure of the decomposition gas of a PET film.

FIG. 3 is a view for explaining Embodiment 2 of the present invention;
It is an analysis result figure of the decomposition gas of a PPS film.

FIG. 4 is a view for explaining Embodiment 5 of the present invention;
4 is a graph showing the relationship between the amount of benzene produced by thermal decomposition of a PET film and a PPS film and temperature.

FIG. 5 is a view for explaining Embodiment 6 of the present invention;
It is a graph which shows the relationship between the production amount of acetaldehyde and hydrogen sulfide by heat decomposition of a PET film and a PPS film, respectively, and temperature.

Claims (7)

[Claims] 1. A gas-insulated electric device characterized by analyzing a hydrocarbon gas in an insulating gas filled in the gas-insulated electric device to diagnose an abnormality in the gas-insulated electric device. Internal abnormality diagnosis method. 2. A method for diagnosing an internal abnormality of a gas-insulated electrical device using a polyethylene terephthalate film or a polyphenylene sulfide film as an internal insulating material, the method comprising the steps of: detecting whether or not acetylene is detected in an insulating gas; 2. The method for diagnosing an internal abnormality of a gas-insulated electric device according to claim 1, wherein the presence or absence of the abnormality is determined. 3. A method for diagnosing internal abnormality of a gas-insulated electric device having a coil portion using a conductor insulated by a polyethylene terephthalate film or a polyphenylene sulfide film, wherein the detection of acetylene in an insulating gas determines the presence of the gas. 3. The method for diagnosing internal abnormality of a gas-insulated electric device according to claim 2, wherein it is determined whether or not there is a discharge abnormality in the coil portion inside the insulated electric device. 4. A method for diagnosing internal abnormalities of a gas-insulated electric device using a polyethylene terephthalate film or a polyphenylene sulfide film as an internal insulating material, wherein the ratio of the acetylene concentration to the total concentration of hydrocarbon-based gas components is determined. 2. The method for diagnosing internal abnormality of a gas-insulated electric device according to claim 1, wherein the temperature of the internal abnormality of the device is estimated. 5. A method for diagnosing internal abnormality of a gas-insulated electric device using a polyethylene terephthalate film or a polyphenylene sulfide film as an internal insulating material, wherein the internal abnormality of the gas-insulated electric device is diagnosed by detecting benzene in an insulating gas. 2. The method for diagnosing internal abnormality of a gas-insulated electric device according to claim 1, wherein: 6. A method for diagnosing internal abnormality of a gas-insulated electric device using a sulfur hexafluoride gas as an insulating gas, wherein a component of a hydrocarbon-based gas in the insulating gas and a component resulting from decomposition of the sulfur hexafluoride gas. 2. The method for diagnosing internal abnormality of a gas-insulated electric device according to claim 1, wherein the diagnosis of the presence of an insulating material in the internal abnormality of the gas-insulated electric device is performed by comparing with the above. 7. An insulating material is disposed at a specific place of a gas-insulated electric device filled with an insulating gas, and a characteristic decomposition gas generated from the insulating material is detected from the insulating gas. A method for diagnosing an internal abnormality of a gas-insulated electric device, comprising determining a position of an internal abnormality of the gas-insulated electric device.