JP2922111B2 - Method for diagnosing the life of oil-filled electric equipment and centrifuge container used for the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for diagnosing the life of oil-filled electrical equipment and a centrifuge container used for the method, and
The present invention relates to a method for diagnosing the life of an oil-filled electric device such as an oil-filled transformer and an oil-filled reactor, and a centrifuge container used in the method.

[0002]

2. Description of the Related Art The life of oil-filled electrical equipment such as oil-filled transformers and oil-filled reactors is generally estimated by the degree of deterioration of insulating paper. The degree of deterioration of the insulating paper is determined by measuring the tensile strength and the degree of polymerization of the insulating paper itself. In addition, it has been studied to perform a diagnosis of the deterioration and life of the insulating paper using furfurals and furans such as furancarboxylic acid and aldehydes such as acetaldehyde and formaldehyde, which are products generated by the deterioration of the insulating paper.

However, the diagnosis of the life of the insulating paper from the tensile strength and the degree of polymerization can be performed only at the occasion of an internal inspection in which the insulating paper can be collected from the oil-filled electrical equipment. In this case, the degree of polymerization of the insulating paper, that is, the press board used as the structural material of the oil-filled electrical device is obtained, and the life of the oil-filled electrical device is estimated. On the other hand, when insulating paper used in oil-filled electrical equipment is decomposed due to deterioration, as shown in FIG. 4, cellulose as a constituent material of the insulating paper is thermally decomposed and oxidized, thereby obtaining furfural (also referred to as furaldehyde). ) And furfural derivatives such as hydroxymethylfurfural are produced and dissolved in insulating oil. Therefore, the life of oil-filled electrical equipment is estimated by estimating the degree of polymerization of the press board from the amount of furfural or the like dissolved in insulating oil and the amounts of insulating paper and insulating oil known in advance. Can be. However, furfural dissolves in insulating oil and is absorbed by insulating paper.
As described in Japanese Patent No. 41407, the adsorption ratio of furfural to insulating paper is constant at about 15%, so that the amount of furfural generated is about 6.7 times the amount of furfural in insulating oil. Good.

Conventionally, furfural has been extracted from insulating oil by contacting an insulating oil such as mineral oil with an extraction liquid.
The liquid extraction method and the solidification of contacting insulating oil with solids such as silica
A liquid extraction method is known (IEC (International Ele
ctrotechnical Commission), 1198, 1993
Year). In the liquid-liquid extraction method, methanol, acetonitrile, water / methanol,
Water / acetonitrile and the like are used. A high-performance liquid chromatograph is used as a method for separating and analyzing the extracted furfural, and an ultraviolet photometer is used as a detector. With such a separation and analysis device, furfural in the insulating oil is quantified, and the life of the oil-filled electric device is diagnosed.

FIG. 5 is a flowchart showing a conventional method for diagnosing the life of an oil-filled electrical device by a liquid-liquid extraction method. As shown in the figure, the insulating oil sample and the organic liquid are mixed and shaken sufficiently. Next, a predetermined amount of the organic liquid is collected, the concentration of furfural or the like extracted from the insulating oil into the organic liquid is quantified by, for example, a high-performance liquid chromatograph, and the life of the oil-filled electric device is diagnosed.

[0006]

According to the above-described method for diagnosing the life of an oil-filled electrical device, in the case of the liquid-liquid extraction method, insulating oil remains in the organic liquid as the extract, and the organic liquid is allowed to stand by standing. When it is attempted to separate a layer from an insulating oil layer, it is difficult to separate the layers into two layers, so a long time of about 8 to 20 hours is required. There was a problem that it became an obstacle. Further, in the case of the solid-liquid extraction method, although there is almost no insulating oil remaining in the extract, there is a problem that the operation is complicated. The present invention has been made in order to solve such problems, and it is possible to quantitatively determine furfural in insulating oil by a simple operation and to accurately diagnose the life of an oil-filled electrical device. It is an object of the present invention to obtain a method for diagnosing the life of a sphere and a centrifuge container used for the method.

[0007]

According to a first aspect of the present invention, there is provided a method for diagnosing the life of an oil-filled electric device, comprising mixing an organic liquid for dissolving furfural and its derivatives with an insulating oil sample and shaking the mixture. The shaken mixed solution was allowed to stand to separate the organic liquid layer and the insulating oil layer, and the separated organic liquid layer was collected and centrifuged to remove the insulating oil component from the organic liquid layer, and then centrifuged. The separated organic liquid layer is collected to analyze furfural and its derivatives in the organic liquid layer.

According to a second aspect of the present invention, there is provided a method for diagnosing the life of an oil-filled electrical device, the method comprising mixing a centrifugally separated organic liquid layer with a fluorescent labeling agent. The solution is analyzed by a fluorescence detector.

According to a third aspect of the present invention, there is provided a centrifugal separation container used in the method for diagnosing the life of an oil-filled electric device, comprising: a centrifuge container main body; It is provided with.

[0010]

According to the first aspect of the present invention, the insulating oil contained in the organic liquid layer is separated in a short time by centrifugation.

According to a second aspect of the present invention, furfural or the like is analyzed with high accuracy by a fluorescence detector.

According to the third aspect of the present invention, the lower organic liquid layer is collected without touching the upper insulating oil.

[0013]

【Example】

Embodiment 1 FIG. FIG. 1 is a flowchart showing an outline of a method for diagnosing the life of an oil-filled electric device according to Embodiment 1 of the present invention. In the drawings, the same reference numerals indicate the same or corresponding parts. In the figure, an insulating oil sample collected from an oil-filled electrical device and an organic liquid are mixed. As the organic liquid, for example, a liquid that dissolves methanol, acetonitrile, or water-methanol furfural and its derivatives can be suitably used. After sufficiently shaking the mixed liquid of the insulating oil and the organic liquid, an organic liquid layer as an extract is collected. This organic liquid is centrifuged by a centrifuge. FIG. 6 shows a conventional centrifugal separation vessel 1 which contains an organic liquid and is used in a centrifugal separation apparatus. Sinks in the lower part. By performing centrifugation using the centrifugal separation container 1, the insulating oil contained in the organic liquid layer is settled in, for example, about 10 to 20 minutes. Therefore, there is an advantage that the insulating oil mixed in the organic liquid can be removed in a short time and the operation time can be greatly reduced.

Next, after collecting the organic liquid with a microsyringe, furfural and its derivative such as hydroxymethylfurfural are separated by high performance liquid chromatography, and quantitative analysis is performed by, for example, an ultraviolet ray detector. At that time, in the insulating oil, 2 equivalent to furfural
An aromatic compound having ultraviolet absorption near 73 nm is contained, and becomes a hindrance component in the analysis of trace amounts of furfural. However, since the insulating oil has been removed from the organic liquid layer,
Noise can be prevented from entering the detector, and measurement accuracy can be improved.

By the above-mentioned method, the separation of furfural from insulating oil can be improved, and the amount of furfural can be accurately obtained by a simple method.
Further, the life diagnosis of the oil-filled electric device can be performed as follows. That is, there is a good correlation between the amount of furfural and the like generated from the insulating paper and the degree of polymerization of the insulating paper, which indicates the degree of deterioration of the insulating paper. Therefore, the amount of furfural produced per gram of insulating paper is calculated from the amount of furfural adsorbed on the insulating paper and the amount of insulating paper in the highest temperature part of the oil-filled electric device. Next, the degree of polymerization degree remaining is obtained from the relationship between the amount of furfural produced and the degree of polymerization degree remaining, and the degree of deterioration of the insulating paper can be diagnosed.

Embodiment 2 FIG. FIG. 2 is a flowchart showing an outline of a method for diagnosing the life of an oil-filled electric device according to Embodiment 2 of the present invention. As shown in FIG. 2, a mixed solution of 20% water and 80% methanol (hereinafter referred to as 80% methanol aqueous solution) is prepared as an organic liquid as an extract. After mixing this 80% methanol aqueous solution with the insulating oil sample, it is shaken sufficiently and allowed to stand. Since the 80% aqueous methanol solution obtained by extracting and dissolving furfural or the like has a lower specific gravity than insulating oil, it floats in the upper layer, and the insulating oil sample sinks in the lower layer. Next, by centrifuging the solution after standing, the insulating oil remaining in the 80% aqueous methanol solution precipitates and moves into the insulating oil.

Next, a predetermined amount of an 80% aqueous methanol solution is collected by a microsyringe, and a 1 × 10 ⁻⁴ molar concentration (M) of a fluorescent labeling agent such as 2,2-dithiobis (1-aminonaphthalene) ( (Hereinafter referred to as DTAN) and allowed to react at 70 ° C. for 1 hour. Acetone as a fluorescence stabilizer and a 2 M aqueous sodium acetate solution are mixed with the reaction solution. The reaction solution thus obtained is separated using a high performance liquid chromatograph, and can be quantified with a fluorescence detector with high accuracy. By using a fluorescent labeling agent, a trace amount of furfural or the like, for example, about 1 ppb can be detected. The life of the oil-filled electrical device can be diagnosed in the same manner as in Example 1 from the amount of furfural or the like thus obtained.

Embodiment 3 FIG. As an organic liquid that is an extract,
When the specific gravity of the insulating oil is higher than about 0.88 to 0.89, for example, water alone or a water-methanol mixed solution having a high mixing ratio of water is used, the organic liquid layer is formed in the lower part of the centrifugal separation container. Sinks. If the organic liquid layer is collected with a micro syringe in this state, the insulating oil in the upper layer portion is taken in, and this is undesirable because it causes noise at the time of detection.

In such a case, as shown in FIG. 3, a centrifugal separation container 1A provided with a silicon rubber stopper 4 as a stopper at the bottom can be suitably used. Centrifuge container 1A
Comprises a centrifuge container main body 10 and a silicone rubber stopper 4 provided at the bottom thereof. By inserting a micro syringe or a syringe into the silicone rubber stopper 4, it is possible to collect the liquid in the lower layer without touching the insulating oil in the upper layer. The silicone rubber stopper 4 hardly contains additives such as a plasticizer and does not elute components that interfere with analysis. Further, the silicone rubber stopper 4 has a large restoring force, and can be suitably used without leaking liquid even after a micro syringe or the like is inserted. The size and shape of the silicone rubber stopper are not particularly limited, and various sizes and shapes of the silicone rubber stopper can be used according to the size and shape of the centrifugal separator body 10.

[0020]

As described above, according to the first aspect of the present invention, an organic liquid for dissolving furfural and its derivatives and an insulating oil sample are mixed and shaken, and the shaken mixed solution is allowed to stand still. The organic liquid layer and the insulating oil layer are separated from each other, and the separated organic liquid layer is collected and centrifuged to remove the insulating oil component from the organic liquid layer, and then the centrifuged organic liquid layer is collected. Since furfural and its derivatives in the organic liquid layer are analyzed, the effect is obtained that the insulating oil contained in the organic liquid layer can be separated in a short time by centrifugation and the analysis time can be shortened. Also,
Since the insulating oil is removed from the organic liquid layer, it is possible to prevent noise from entering the detector, and it is possible to improve the measurement accuracy.

According to a second aspect of the present invention, in the first aspect, a fluorescent labeling agent is mixed with the centrifugally separated organic liquid layer, and the obtained solution is analyzed by a fluorescence detector. And the like can be detected.

According to a third aspect of the present invention, since the centrifugal separation container is provided with a silicone rubber plug member provided at the bottom of the centrifuge container main body, the lower organic liquid layer can be replaced with the upper organic layer. It is possible to collect the sample without touching the insulating oil, and it is possible to prevent the generation of noise when detecting furfural or the like.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an outline of a method for diagnosing the life of an oil-filled electric device according to Embodiment 1 of the present invention.

FIG. 2 is a flowchart showing an outline of a method of diagnosing the life of an oil-filled electric device according to Embodiment 2 of the present invention.

FIG. 3 is a schematic sectional side view of a centrifuge container according to Embodiment 3 of the present invention.

FIG. 4 is a structural formula showing a state in which cellulose is decomposed to produce furfural and hydroxymethylfurfural.

FIG. 5 is a flowchart showing an outline of a conventional method for diagnosing the life of an oil-filled electric device.

FIG. 6 is a schematic side sectional view of a conventional centrifuge container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Centrifuge container 2 Organic liquid layer 3 Insulating oil layer 4 Silicon rubber stopper 10 Centrifuge container main body

Claims (3)

(57) [Claims] An organic oil for dissolving furfural and its derivative and an insulating oil sample are mixed and shaken, and the shaken mixed solution is allowed to stand to separate the organic liquid layer and the insulating oil layer. Collecting the separated organic liquid layer and centrifuging to remove insulating oil from the organic liquid layer, and then collecting the centrifuged organic liquid layer and analyzing furfural and its derivatives in the organic liquid layer. Life diagnosis method for oil-filled electrical equipment. 2. The life diagnosis of an oil-filled electrical device according to claim 1, wherein a fluorescent labeling agent is mixed into the organic liquid layer separated by centrifugation, and the obtained solution is analyzed by a fluorescence detector. Method. 3. A centrifuge container for use in a method for diagnosing the life of an oil-filled electrical device, comprising: a centrifuge container main body; and a silicone rubber stopper member provided at a bottom of the centrifuge container main body.