JP5239193B2 - Abnormality diagnosis method for oil-filled electrical equipment - Google Patents

Description

  The present invention relates to an abnormality diagnosis method for an interior of an oil-filled electrical device, particularly a transformer main body using a conservator.

  Conservators used in oil-filled electrical equipment can be broadly classified into the types in which transformer body insulating oil and switching switch chamber oil are partitioned by a partition rubber film, transformer body insulating oil and switching switch chamber oil. There is a type that is partitioned by partition walls other than the rubber-like film. For example, as shown in FIG. 1, the former conservator is installed in the upper part of the transformer main body, and when the main body insulating oil 11 in the transformer expands and contracts due to load fluctuation, the partition rubber film inside the conservator 10 The movement of 12 absorbs the volume increase / decrease of the insulating oil and prevents deterioration due to contact between the outside air and the main body insulating oil 11. The partition rubber-like film 12 serves as a partition that partitions the transformer body insulating oil 11 and the switching switch chamber oil 13. For this reason, the partition rubber-like film 12 has stretchability that responds to expansion and contraction, gas impermeability and oil resistance that prevents gas permeation from the switching switch chamber oil 13 and maintains the cleanliness of the main body insulating oil 11. Excellent material is used.

  For example, as shown in FIG. 2, the latter conservator is installed in the upper part of the transformer main body, and communicates with the outside air in the conservator 20 when the main body insulating oil 21 in the transformer expands and contracts due to load fluctuations. The rubber cell 22 reacts to absorb the volume increase / decrease of the insulating oil and prevent deterioration due to contact between the outside air and the main body insulating oil 21.

  In any of the conservators 10 and 20, the switching switch chamber oils 13 and 23 are arced when the taps are switched, so that they are gradually fouled during use, resulting in a decrease in insulation, acetylene, methylvinylacetylene, Gas components such as 2-methyl-1,3-butadiene increase. On the other hand, when an abnormality such as discharge or overheating occurs in the transformer body insulating oil, gas components such as acetylene, methylvinylacetylene, 2-methyl-1,3-butadiene increase. Further, the conservators 10 and 20 are arranged in the transformer body insulating oil 11 and 21 in a liquid-tight manner in the transformer body insulating oil 11 and 21 on the transformer body side. Gas components contained in the oils 13 and 23 may move to the transformer body insulating oil 21 side.

  As an effective method for maintenance management of oil-filled electrical equipment, maintenance management based on oil-in-gas analysis has been adopted by many electric power companies and other users and is useful for preventing accidents (for example, Non-Patent Document 1). Abnormality diagnosis by gas analysis in oil collects insulating oil without stopping the equipment, extracts and analyzes the gas components dissolved in the oil, and early detects abnormalities such as discharge and overheating from the amount and type of gas It is a technology to discover.

Internal abnormality diagnosis of oil-filled electrical equipment was initially reported in Electrical Cooperative Research, Vol. 54, No. 5 (1999) on several types of low-boiling gases such as ethylene gas and acetylene gas dissolved in insulating oil. Analysis method (hereinafter referred to as “Denki Kyoken method”). In recent years, with the advancement of analytical technology, a new analysis method in oil (hereinafter referred to as “high-sensitivity oil-in-gas”) that analyzes high-boiling trace gases such as methylvinylacetylene and 2-methyl-1,3-butadiene with high sensitivity. "Analysis method" is proposed (Patent Document 1). If the internal abnormality diagnosis of oil-filled electrical equipment is performed by this high-sensitivity oil-in-gas analysis method, components that are characteristically detected due to damage to various insulating materials and components that are detected during the discharge of main body insulating oil and overheat decomposition are detected. It is possible to identify and accurately identify a damaged material, a damaged site, and an abnormal aspect, and further accurately determine whether or not to continue operation (for example, Patent Document 2).
Electric Cooperative Research, Vol. 54, No. 5 (1999) JP-A-9-72892 JP 2002-350426 A

  However, even if low boiling point gases such as acetylene gas are detected by gas analysis in oil by the electric cooperative research method, and there is a suspicion of internal abnormality, abnormalities may not be confirmed inside the equipment as a result of multifaceted follow-up investigation. there were. In addition, there were cases where abnormalities were confirmed inside the equipment even though acetylene gas was not detected by gas analysis in oil by the electric cooperative research method. In addition, it has been desired to disclose an abnormality diagnosis method that can determine whether or not an abnormal part can be continuously used even if it cannot be identified.

  Therefore, the object of the present invention is to diagnose whether or not the transformer body of the oil-filled electrical equipment in which the transformer body insulating oil and the switching switch chamber oil are partitioned by the partition wall can be used continuously and in a simple manner. An object of the present invention is to provide an abnormality diagnosis method for oil-filled electrical equipment.

  Under such circumstances, the present inventors have conducted intensive studies, and as a result, (1) the partition rubber-like film that partitions the transformer main body insulating oil and the switching switch chamber oil is gas-impermeable. Permeates acetylene gas, but does not permeate methyl vinyl acetylene gas. (2) When acetylene gas is detected in the main body insulating oil from the gas analysis in oil by the electric cooperative research method, it is generated inside the transformer body. There are two cases: the case where the oil is passed through the rubber film from the switching switch chamber oil, and the generation source cannot be determined in general. (3) However, the acetylene gas is separated from the copper coil of the transformer body. Because it reacts to become copper acetylide, the presence or absence of acetylene gas cannot be used as an indicator for abnormality diagnosis such as discharge or overheating inside the transformer body. (4) On the other hand, methylvinylacetylene gas It does not react with copper coil of the transformer body, presence or absence of methylvinyl acetylene gas finds and can be used as an index of the abnormality diagnosis of the transformer body inside the discharge or overheating, thereby completing the present invention.

That is, the present invention is an abnormality diagnosis method for an oil-filled electrical device including a conservator partitioned by a partition wall which is a rubber-like film in which transformer body insulating oil and switching switch chamber oil do not permeate methylvinylacetylene gas. Oil-filled electrical equipment that determines the abnormality of the transformer body of oil-filled electrical equipment by collecting a sample of transformer body insulation oil from the oil-filled electrical equipment and analyzing the presence or absence of methyl vinyl acetylene in the sample oil An abnormality diagnosis method is provided.

  According to the present invention, methyl vinyl acetylene can be used as an indicator of discharge or barrier seal failure. For this reason, the transformer body of oil-filled electrical equipment having a conservator that partitions the transformer body insulating oil and the switchgear switch chamber oil with a partition wall by a simple method, without disassembling the equipment, can be used. Whether it is possible or not can be diagnosed. Conventionally, several types of gas analysis such as ethylene gas, acetylene gas, methyl vinyl acetylene gas and 2-methyl-1,3 butadiene dissolved in transformer body insulation oil have been performed. However, analysis of only methyl vinyl acetylene is sufficient. , Analysis burden and cost can be greatly reduced.

  In the abnormality diagnosis method for oil-filled electrical equipment according to the present invention (hereinafter, also simply referred to as “abnormality diagnosis method”), the partition wall separating the transformer body insulating oil and the switching switch chamber oil is located above the transformer body. A partition rubber-like film (hereinafter also simply referred to as “rubber film”) that partitions the transformer body insulating oil and the switching switch chamber oil in the located conservator, or a transformer located below the conservator The partition which has the seal | sticker part which divides the transformer main body insulating oil and the switching switch room oil in a transformer main body is said. Examples of the seal member used in the seal portion include NBR.

  An example of the structure of a conservator that partitions the transformer body insulating oil and the switching switch chamber oil with a rubber film will be described with reference to FIG. FIG. 1 is a simplified diagram showing the structure of a conservator for oil-filled electrical equipment. In FIG. 1, a conservator 10 is installed on an upper part of a transformer main body having a copper coil, and a rubber cell 121 filled with the transformer main body insulating oil 11 and an on-load tap changer are accommodated in the outer box 14. And a switching switch chamber 131 filled with switching switch chamber oil 13. The transformer body insulating oil 11 and the switching switch chamber oil 13 are partitioned by a rubber film 12, and the transformer body and the rubber cell 121 are connected by a connecting pipe 15. In the outer box, outside the rubber cell 121, there are a drain valve 17 for draining water accumulated in the water reservoir 18, and a dial oil level gauge 19 for displaying the liquid level from the position of the float 124. Yes. In addition, the code | symbol 123 is a breather connection pipe, 16 is a partition plate, 122 is an air vent plug. The switchgear chamber oil 13 of such a conservator 10 is gradually fouled during use due to arc discharge generated at the time of tap switching, resulting in a decrease in insulation, and acetylene, methylvinylacetylene, 2-methyl- Gas components such as 1,3 butadiene increase. For this reason, it becomes a problem whether the gas permeation phenomenon with respect to the rubber film 12 of the gas component in the switching switch chamber oil 13 arises, and the leak from the pinhole produced in the rubber film 12 becomes a problem. Note that, on the transformer main body side (the lower portion of the conservator 10 not shown in FIG. 1), the switching switch chamber 23 is liquid-tightly arranged in the transformer main body insulating oil 11 with a seal member such as NBR, Diffusion of the gas component in the switching switch chamber oil 13 due to the sealing failure of the seal portion into the transformer body insulating oil 11 becomes a problem.

  An example of the structure of the conservator that partitions the transformer main body insulating oil and the switching switch chamber oil with partition walls that are not rubber-like films will be described with reference to FIG. FIG. 2 is a simplified diagram showing another structure of the oil-filled electrical equipment conservator. In FIG. 2, the conservator 20 is installed on the upper part of the transformer main body having a copper coil, and the outer box 32 includes an insulating oil sealing chamber 33 filled with the transformer main body insulating oil 21 and a load tap changer. And a switching switch chamber 34 filled with switching switch chamber oil 23 to be accommodated. A rubber cell 22 through which outside air enters and exits through the breather 30 is installed in the insulating oil sealing chamber 33. The transformer body insulating oil 21 and the switching switch chamber oil 23 are partitioned by a partition wall 24, and the transformer body and the insulating oil sealing chamber 33 are separated. Are connected by a connecting pipe 25. Each of the insulating oil sealing chamber 33 and the switching switch chamber 34 has a dial oil level gauge 31 for displaying the liquid level from the position of the float. Reference numeral 26 is an oil discharge valve, and 27 is an oil supply valve. Note that, on the transformer main body side (the lower portion of the conservator 20 (not shown in FIG. 2)), the switching switch chamber 34 is liquid-tightly arranged in the transformer main body insulating oil 21 with a seal member such as NBR, Diffusion of the gas component in the switching switch chamber oil 23 due to the sealing failure of the seal portion into the transformer body insulating oil 21 becomes a problem.

  The switchgear chamber oils 13 and 23 of such conservators 10 and 20 are gradually damaged during use due to arc discharge generated at the time of tap switching, resulting in a decrease in insulation, and acetylene, methylvinylacetylene, Gas components such as 2-methyl-1,3-butadiene increase. For this reason, in the conservator 10, it becomes a problem whether the gas permeation phenomenon with respect to the rubber film 12 of the gas component in the switching switch chamber oil 13 arises. Further, when a pinhole is generated in the rubber film 12, the gas component in the switching switch chamber oil 13 diffuses into the transformer body insulating oil 11. In the conservators 10 and 20, when a seal member such as NBR on the transformer main body side becomes defective, the gas component in the switching switch chamber oil 13 moves to the transformer main body insulating oil 11.

  The partition rubber-like film is not particularly limited. For example, as shown in FIG. 3, a polyvinyl alcohol (PVA) film 341 is used as a core, and an adhesive layer 331 and polyamide fibers 321 are formed from the core toward both outer sides. And a seven-layer film in which nitrile rubber 311 is laminated. There is also a five-layered film in which the core material and the adhesive layer are replaced with nitrile rubber (NBR) in contrast to the seven-layered film.

  A method for collecting a sample of the transformer body insulating oil from the oil-filled electrical device may be performed in the same manner as in the past. Moreover, the analysis of methyl vinyl acetylene in the sample oil of the transformer body insulating oil collected from the oil-filled electrical device may be performed in accordance with a highly sensitive gas analysis method in oil. Methyl vinyl acetylene is known to be a gas component detected in oil by arc discharge or by overheating of 700 ° C. or higher in insulating oil, and is an effective index for diagnosing abnormalities inside transformers. Is. A high-sensitivity analysis method is reported in detail in JP-A-9-72892. Although a high-sensitivity analysis method is well-known but not well-known, it will be described below.

  FIG. 4 shows the configuration of an apparatus used in the high sensitivity gas analysis method. In FIG. 4, 51 is a sample oil container for storing sample oil, 52 is an inlet of the sample oil container 51, 53 is an outlet of the sample oil container 51, 54 is a discharge valve, 55 is sample oil, and 56 is an inert gas. Is a carrier gas supply pipe for bubbling as a carrier gas, 57 is a heater for heating sample oil, 58 is a carrier gas injection pipe for injecting carrier gas, 59 is a carrier gas flow control valve, 60 is a two-way cock, 61 Is a carrier gas supply pipe, 62 is a gas extraction pipe for extracting the extraction gas extracted by bubbling, 63 is an extraction gas ventilation pipe for ventilating the extraction gas together with the carrier gas, 64 is a three-way cock, 65 is a cold trap container, 65a, 65b Is a supply port and a discharge port of a cooling medium such as liquid nitrogen in the cold trap container 65, and 66 is decomposed by cooling to about -130 ° C. A cold trap for condensing and trapping 67, a heater for heating the cold trap 66, 68 for a three-way cock, 69 for a gas supply pipe for supplying a carrier gas, 70 for a gas cylinder filled with a carrier gas such as helium gas, and 71 for a flow rate A control valve, 72 is a three-way cock, 73 is a gas chromatograph analyzer, and is composed of a column 73a and a detector 73b. Reference numeral 27 denotes a cooling medium container, 75 denotes a cooling medium, 76 denotes a pressurizing pipe for applying pressure to the cooling medium container 74 to supply the cooling medium 75, 77 denotes a cooling medium supply pipe, and 78 denotes a flow rate adjusting valve.

  Next, a method for analyzing gas in oil using the analyzer 50 will be described. First, the two-way cock 60 and the discharge valve 54 are opened, the carrier gas is adjusted from the carrier gas supply pipe 61 by the flow rate adjusting valve 59, and the flow is made to flow through the flow channel on the sample oil container 51 side, and the air in the flow channel is blown out. To do. Next, the three-way cocks 64 and 72 are opened to the gas chromatograph analyzer 73 side, and the air in the cold trap 66 and the gas chromatograph analyzer 73 is blown out. Pressure is applied from the pressurizing pipe 76 of the cooling medium container 74 to guide the cooling medium (liquid nitrogen) 75 to the cold trap container 65 and cool to about −130 ° C. Several milliliters of sample oil is collected with a syringe or the like and injected into the sample oil container 51 from the injection port 52 of the sample oil container 51. The three-way cock 64 is switched to the sample oil container 51 side, the sample oil container 51 is heated by the heater 57 at a temperature at which the vapor pressure becomes 53 Pa, the two-way cock 60 is opened, the flow rate is adjusted by the pressure control valve 59, and the bubbling pipe A carrier gas is supplied to 56, and a gas component dissolved in the sample oil is extracted by bubbling for several minutes. The extracted gas component is introduced into the inner diameter portion of the cold trap 66 in the cold trap container 65 together with the carrier gas, and the gas component is condensed and captured in the cold trap 66. The cold trap 66 is rapidly heated to 200 ° C. or more by the heater 67, the condensed and trapped gas component is vaporized, and the carrier gas is introduced into the gas chromatograph analyzer 73b for analysis.

  When the sample oil collected from the oil-filled electrical equipment is analyzed by the above analysis method, the extracted gas component is condensed and captured by the cold trap 66 and rapidly heated to 200 ° C. or more to evaporate and instantly gas chroma. Since it is introduced into the graph analyzer 73, it can be analyzed with high accuracy.

  In the present invention, the gas analysis of the sample oil of the transformer body insulating oil collected from the oil-filled electrical device may be performed only for the methyl vinyl acetylene gas, and the analysis of the acetylene gas is unnecessary. The reason is as follows. When an abnormality such as discharge or overheating occurs in the transformer body, acetylene, methylvinylacetylene, etc. are generated in the transformer body insulating oil. Thus, these gases in the transformer body insulating oil can be an index for diagnosing abnormalities in the transformer body. However, in oil-filled electrical equipment, the transformer body insulating oil is in contact with the copper coil, and acetylene reacts with copper and disappears. Therefore, acetylene cannot be an index for diagnosing abnormalities. On the other hand, since methyl vinyl acetylene does not permeate the rubber film and therefore cannot be mixed from the tap switching switch chamber, methyl vinyl acetylene can be an index for diagnosing abnormalities. In addition, because of the pinhole and seal failure of the rubber film, methyl vinyl acetylene in the tap switchgear chamber oil diffuses into the insulation oil of the transformer body. Can be an index for diagnosing.

  In the analysis of the gas component, if methyl vinyl acetylene is not detected, the inside of the main body of the oil-filled electrical device is determined to be normal.

  In the present invention, the abnormality of the transformer body of the oil-filled electrical equipment means the discharge phenomenon or overheating phenomenon that occurs in the transformer body, the occurrence of pinholes in the rubber film of the conservator, the transformer body insulation oil on the transformer body side The liquid-tight seal of the inside tap switchgear chamber is poor. Therefore, in the abnormality diagnosis method of the present invention, when methyl vinyl acetylene is detected as a result of the analysis of the gas component, it is found that any of the abnormalities listed above is present. If there is an abnormality, it is possible to stop the continuous use and further identify the abnormal part by multifaceted inspection such as disassembly of the oil-filled electrical equipment. Moreover, if it is normal, it can be determined that continuous use is possible.

  Next, the present invention will be described more specifically with reference to examples. However, this is merely an example and does not limit the present invention.

Reference example 1
(Reaction experiments between various gases and copper)
An airtight container 40 provided with the buffer bellows 43 shown in FIG. 5 was prepared, and the presence or absence of reaction between various gases and copper was examined under the following test conditions. The container 40 includes a sample supply pipe 42 and a sample collection pipe 44. Reference numeral 45 is sample oil, and 46 is a copper plate or a cigarette copper plate. The result is shown in FIG.

<Test conditions>
Insulated oil containing high concentrations of gases such as ethylene gas, acetylene gas, and methyl vinyl acetylene gas that have been subjected to dielectric breakdown in accordance with the dielectric breakdown voltage test method (JIS C 2101). A copper plate was sealed, and changes with time in the concentrations of various gases in oil at a predetermined oil temperature were confirmed. Copper was used by using two types, a bare copper plate and a cigarette copper plate.

  The acetylene concentration in the high-concentration gas-containing insulating oil before the start of the test was measured by the electric cooperative research method, and the methylvinylacetylene concentration was measured by the highly sensitive gas analysis method in the oil. As a result, the acetylene concentration was 45 ppm, and the methylvinylacetylene concentration was 152,000 counts (peak area value).

<Test conditions>
Test temperature: 80 ° C., test days: 60 days Oil amount: 2.2 liters Sampling interval: Every 20 days Minimum detection sensitivity: 0.1 ppm of acetylene, 100 counts of methylvinylacetylene Bare copper plate: 6.5 mm × A copper plate having a surface area of 1060 cm ² by superimposing 2.4 mm × 140 mm copper plates was used.
・ Copper copper sheet: Two sheets of 50μm thick paper are wound on the bare copper, and three sheets of 80μm thick paper are wound on top of each other, and an adhesive paper of 85μm in thickness is coated on the outermost layer. 2 were used, and a total thickness of 425 μm was used. The paper used was the same material that was actually used for the transformer.

  As is clear from FIG. 6, it can be seen that the concentration of acetylene in the oil is remarkably lowered as time passes. On the other hand, it can be seen that methyl vinyl acetylene exhibits a gas concentration in oil almost equal to the initial concentration even after 60 days. From this, it was found that methyl vinyl acetylene remains in the oil without reacting with copper even under severe conditions of an oil temperature of 80 ° C.

  An operating transformer having a conservator having a structure in which the transformer body insulating oil and the switching switch chamber oil shown in FIG. 1 are partitioned by a rubber film, and the transformer body insulating oil and the switching switch chamber oil shown in FIG. Samples (A, B) of the transformer body insulating oil of one normal transformer were sampled for each of the transformers in operation having a conservator with a structure in which each was partitioned by a partition wall. Moreover, the sample (C, D) of the transformer main body insulating oil of one transformer each judged to be abnormal was collected. Subsequently, the sample oils A to D were examined for the presence or absence of dissolution of acetylene and methylvinylacetylene. Acetylene was analyzed by the electric cooperative research method, and methylvinylacetylene was analyzed by a highly sensitive gas analysis method in oil. As a result, neither acetylene nor methylvinylacetylene was detected in the insulation oil of normal transformers among the targeted transformers. Moreover, methyl vinyl acetylene was detected in the insulating oil of the abnormal transformer among the targeted transformers, but acetylene was not detected.

  According to the present invention, methyl vinyl acetylene can be used as an indicator of abnormalities such as discharge and partition seal failure. For this reason, the presence or absence of continuous use can be determined without performing disassembly investigation of the equipment. Previously, several types of gas analysis such as ethylene gas, acetylene gas, methyl vinyl acetylene gas and 2-methyl-1,3-butadiene dissolved in insulation oil in the transformer body were performed, greatly reducing the burden and cost of analysis. can do.

It is a simplified diagram showing the structure of a conservator for oil-filled electrical equipment. It is a simplified diagram showing the structure of another conservator of oil-filled electrical equipment. It is typical sectional drawing which shows the structure of the partition rubber-like film | membrane which divides transformer main body insulating oil and switching switch chamber oil. It is a flowchart of the analyzer used with a highly sensitive gas analysis method. It is the schematic of the apparatus used in the reaction experiment of various gas and copper. It is a figure which shows the reaction experiment result of various gas and copper.

Explanation of symbols

10, 20 Conservator 11, 21 Transformer body insulating oil 12 Bulkhead rubber-like film 13, 23 Switching switch chamber oil 14 Outer box 15 Connection pipe 16 Partition plate 19 Dial oil level gauge 24 Bulkhead 40 Container 50 Analytical device 311 Nitrile rubber 321 Polyamide fiber 331 Adhesive layer 341 Polyvinyl alcohol (PVA) film

Claims (3)

A method for diagnosing an abnormality in an oil-filled electrical device comprising a conservator partitioned by a partition wall made of a rubber-like film in which transformer body insulating oil and switching switch chamber oil do not transmit methyl vinyl acetylene gas. A sample of an oil-filled electrical device is characterized by taking a sample of the transformer body insulating oil and determining the abnormality of the transformer body of the oil-filled electrical device by analyzing the presence or absence of methyl vinyl acetylene in the sample oil. Abnormal diagnosis method.   2. The method for diagnosing an abnormality in an oil-filled electrical device according to claim 1, wherein when the methyl vinyl acetylene is not detected, the transformer body of the oil-filled electrical device is determined to be normal.   The method for diagnosing an abnormality in an oil-filled electrical device according to claim 1, wherein when methyl vinyl acetylene is detected, it is determined that the transformer body of the oil-filled electrical device is malfunctioning.

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