JP7152178B2 - Deterioration diagnosis method for oil-filled electrical equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for diagnosing the state of deterioration of an oil-filled electrical device such as a transformer during maintenance or the like, and a method for creating a reference necessary for the deterioration diagnosis.

Deterioration diagnosis of oil-filled electrical equipment such as transformers is performed by measuring the concentration of gases such as carbon monoxide and carbon dioxide in the insulating oil, which are the decomposition products of insulating paper, and measuring the concentration of furfural in the insulating oil. However, these measurements had to be performed with a gas-in-oil measuring device (gas chromatograph) or furfural measuring device (liquid chromatograph) installed in the analysis room, so the The extracted insulating oil had to be brought to the analysis room once, which prevented rapid analysis.

On the other hand, as a means for solving such problems, an apparatus has been proposed in which an insulating material is irradiated with light of multiple wavelengths and the deterioration of the insulating paper is determined using the difference or ratio of reflection absorbance ( See Patent Document 1 below). Since the device is portable, it can be brought to the site where the transformer or the like is installed and the degree of deterioration can be analyzed directly.

Patent No. 3440759

However, the device described in Patent Document 1 uses an optical fiber sensor to diagnose the degree of deterioration of the material (insulating material) from the difference in the reflection absorbance between two wavelengths, so its configuration is special and general. has the problem of being expensive.

SUMMARY OF THE INVENTION The present invention is intended to solve the aforementioned problems, and to provide a method for quickly diagnosing deterioration of an oil-filled electrical device without using an expensive device.

According to the first aspect of the invention, insulating oil and insulating oil are placed in a stainless steel container that can simulate the deterioration prevention specifications of oil-filled electrical equipment by providing a vent hole and a valve for removing air and enclosing inert gas. Insulating paper is hermetically housed and the container is heated, a part of the insulating paper is sampled every time the predetermined heating time elapses, and after cooling a part of the sampled insulating paper, a part of the insulating paper is The average degree of polymerization is measured using a part, and the remainder of the sampled insulating paper is degreased to clarify the hue and used as a color sample in the measured value of the average degree of polymerization, and the hue of the color sample and the average degree of polymerization as a color difference standard, and remove the insulating oil from the oil-filled electrical equipment that is the target of deterioration diagnosis, or lift the electrical equipment body, or extract a part and expose the insulating paper to the atmosphere. Then, the insulating paper is measured for color difference between the oil-immersed states of the color sample or between the non-oil-immersed states after the degreasing treatment, and the average degree of polymerization is estimated from the color difference standard using the color difference. have

In the invention of claim 2, an image of the insulating paper of claim 1 is adjusted with a white color reference and the white balance is adjusted, and the photographed image and the color sample are compared, and the average of the color samples with similar hues is obtained. It is characterized in that the degree of polymerization is determined using the color difference criteria.

According to the invention of claim 3, the insulating paper of claim 1 is photographed under the same conditions as the new insulating paper, and the color difference between the insulating paper and the new insulating paper is compared with the color difference standard, so that the oil-filled electricity It is characterized by diagnosing the degree of deterioration of equipment.

According to the first aspect of the invention, equipment used for diagnosing deterioration of oil-filled electrical equipment can be constructed at low cost. In addition, by using stainless steel for the container constituting the equipment, corrosion does not occur even during storage or when heated in a constant temperature bath. Furthermore, the deterioration state of the oil-filled electrical equipment can be easily grasped by using the color sample and the color difference standard. In addition , it is possible to easily simulate the deterioration prevention specifications of oil-filled electrical equipment, and it is possible to unify the oil-immersed and non-oil-immersed states of the insulating paper and color samples that make up the oil-filled electrical equipment, improving the accuracy of deterioration diagnosis. be able to. In particular, by degreasing the insulating paper and the color sample so that they are not immersed in oil, the hue becomes clearer and the accuracy of deterioration diagnosis can be further improved.

According to the second aspect of the invention, by adjusting the white balance, the hue of the insulating paper constituting the oil-filled electrical equipment can be accurately captured without being affected by differences in illumination and weather.

According to the third aspect of the invention, by using the color difference standard, it is possible to determine the degree of deterioration of the oil-filled electrical equipment from the insulating paper constituting the oil-filled electrical equipment and the new insulating paper.

1 is a cross-sectional view of a color sample maker according to an embodiment of the present invention; FIG. FIG. 5 is a scatter diagram showing the correlation between the average degree of polymerization and hue of insulating paper for each heating time according to the example of the present invention.

Embodiment 1 of the present invention will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 shows a color sample maker A according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a container that constitutes a fabricator A. The container 1 contains insulating paper 2 and insulating oil 3 of the same type as those used in the oil-filled electrical equipment to be diagnosed for deterioration. there is

Reference numeral 4 denotes a through hole formed in the flange portion 5 of the storage container 1, and 6 a lid for closing the upper opening of the storage container 1. As shown in FIG. 7 is a through hole of the lid 6 opened at a position corresponding to the through hole 4 of the flange portion 5, and 8 is sandwiched between the lid 6 and the flange portion 5 to keep the container 1 sealed. It is a packing such as a ring.

Reference numeral 9 denotes a bolt to be passed through the through holes 4 and 7, 10 denotes a plate washer, and 11 denotes a spring washer. A nut 12 is screwed onto the bolt 9 and fastens the container 1 and the lid 2 .

Reference numeral 13 denotes a plurality of vent holes in the lid 2 for removing air from the storage container 1 and enclosing inert gas therein; 14 is a vent pipe attached to the vent hole 13; is a valve attached to the tip of the

Next, a method of manufacturing equipment (color difference standard) used for deterioration diagnosis of oil-filled electrical equipment using the manufacturing device A having the above configuration will be described.

The preparation device A having the above configuration has a structure that can seal the inside of the container 1 by the presence of the packing 8. By connecting a vacuum pump (not shown) to the valve 15 and operating it for a certain period of time, the space inside the container 1 is to a vacuum.

Here, if the oil-filled electrical equipment to be diagnosed for deterioration contains an inert gas, the same kind of inert gas is contained through the ventilation pipe 14 after the inside of the container 1 is evacuated. By enclosing it in the container 1, the same environment as in the case of the oil-filled electrical equipment to be diagnosed for deterioration is created. In the case of pressureless sealing, the top space is kept under vacuum. In the case of the airtight type, the air is sealed.

In this state, the preparation device A is placed in a constant temperature bath (not shown) and heated at, for example, 120 to 140 ° C. for a predetermined time (time expected to obtain the degree of polymerization as a deterioration diagnostic index according to past empirical rules). Each time , the preparation device A is taken out from the constant temperature bath and cooled to room temperature. The containing container 1 and the lid 6 may be made of metal, but considering that they will be heated in a constant temperature bath, they are preferably made of stainless steel so that the containing container does not corrode during storage or under the influence of heating.

The nut 12 and bolt 9 are removed from the preparation device A taken out of the constant temperature bath, the lid 6 is opened, and the amount of insulating paper necessary for measuring the average degree of polymerization is taken out from the insulating paper 2 in the container 1 .

After taking out the required amount, the container 1 is covered with the lid 6 again, and the lid 6 is fastened to the container 1 with the bolt 9 and the nut 12 . After that, by activating a vacuum pump (not shown), the inside of the container 1 is again evacuated, the insulating paper 2 and the insulating oil 3 in the container 1 are degassed, and in addition to this, the oil-filled If the electrical equipment is filled with an inert gas, fill it with the same type of inert gas.

After that, the preparation device A is again placed in the constant temperature bath and heated, and after a predetermined time (the time expected to obtain the degree of polymerization as a deterioration diagnostic index based on past empirical rules) has passed, the preparation device A is kept at a constant temperature. After removing from the bath, the same operation as described above is repeated.

On the other hand, a part of the insulation paper taken out in the necessary amount was degreased and bleached, dissolved in copper ethylenediamine or cuprammonium solution as a sample, and the average degree of polymerization was measured by the viscosity method. It guides the relationship of degrees. A method such as GPC (liquid chromatograph) or light scattering may be used to measure the average degree of polymerization of the insulating paper.

In this way, the required amount of the insulating paper 2 is taken out every time a predetermined time (the time expected to obtain the degree of polymerization as a deterioration diagnosis index according to past empirical rules) has passed, and each time, after degreasing, the average Since the degree of polymerization is measured, the relationship between the hue of the insulating paper 2 and the average degree of polymerization according to the heating time until it is taken out of the preparation device A can be derived.

Insulating paper from which a part of the sample was removed (hereinafter referred to as residual insulating paper) is used as a color sample for deterioration diagnosis. In JEM1463 "Evaluation Standards for Average Degree of Polymerization of Insulating Paper for Transformers", there is a criterion that an average degree of polymerization of 450 or less for insulating paper is a life level, and an average degree of polymerization of 250 or less is a dangerous level. Therefore, by preparing color samples with an average degree of polymerization of 250 and an average degree of polymerization of 450 and using them for deterioration diagnosis, it is possible to determine the usage limit of the oil-filled electrical equipment. By degreasing the remaining insulating paper, the hue of the remaining insulating paper can be made clear.

Here, an explanation will be given of how the insulating paper 2 changes in hue as heat deterioration progresses. The insulating paper 2, which was light yellow at first, changes from dark yellow to brown as the heat deterioration progresses. , and when the deterioration progresses further, it changes to a dark color.

The scatter diagram of FIG. 2 shows the correlation between the average degree of polymerization of insulating paper and the amount of hue change (the color difference between new insulating paper and the color sample is called color difference). As shown in FIG. 2, the correlation is clear, so if the insulating paper constituting the oil-filled electrical equipment to be diagnosed for deterioration is colorimetrically measured with a colorimeter, the scatter diagram of FIG. It becomes possible to determine the degree of deterioration of the incoming electrical equipment.

At this time, the relationship between the insulating paper of the oil-filled electrical equipment and the color sample is as follows: (1) when the insulating paper is oil-immersed and the color sample is not oil-immersed, (2) when the insulating paper is oil-immersed and the color sample is also In the case of oil immersion, (3) the insulating paper is not immersed in oil and the color sample is also not immersed in oil, and (4) the insulating paper is not immersed in oil and the color sample is oil immersed. Since the insulating paper is in a state of being soaked in the insulating oil of the oil-filled electrical equipment, the diagnosis is generally made using the color difference relationship in case (1) or (2). If the situation permits, the insulation paper of the transformer and the color sample are degreased and both are not immersed in oil, so that the hue becomes clear and the color difference between the two becomes clear, so the accuracy of deterioration diagnosis is further improved. be able to.

Next, a specific example of the deterioration diagnosis method according to the second embodiment of the oil-filled electrical equipment, which is the object of deterioration diagnosis, will be described. First, remove the insulating oil from the oil-filled electrical equipment to be diagnosed for deterioration, lift the main body of the electrical equipment, extract a part, etc. to expose the insulator. Arrange the color samples (JIS Z8102 "color name of the object color", etc.), and use shooting equipment such as a digital camera to adjust the white balance while adjusting the color tone so that the white color sample appears in the correct whiteness. Shoot after compensating for

White balance may be adjusted using the preset white balance of the digital camera, or manual white balance that is set manually may be used. By adjusting the white balance, it is possible to accurately capture the hue of the insulators that make up the oil-filled electrical equipment without being affected by differences in lighting and weather.

If the insulating object to be photographed exists in a narrow area, photographing equipment such as an endoscope fiberscope may be used to photograph it.

The image taken in this way is compared with the aforementioned color samples to identify the color sample that matches or is closest in hue. Next, the average degree of polymerization corresponding to the specified color sample is determined using the color difference standard described above. By obtaining the average degree of polymerization of the insulator in this way, it is possible to diagnose the degree of deterioration of the oil-filled electrical equipment.

Next, a specific example of the method for diagnosing deterioration according to the third embodiment of the oil-filled electrical equipment to be diagnosed for deterioration will be described. First, remove the insulating oil from the oil-filled electrical equipment to be diagnosed for deterioration, lift the electrical equipment body, extract a part, etc. to expose the insulating material, and photograph the new insulating paper under the same conditions with a digital camera, etc. Take pictures with equipment.

In the photographed images, the color difference in hue between the insulating paper of the oil-filled electrical equipment and the new insulating paper is compared, and from the scatter diagram showing the correlation between the average degree of polymerization and the hue created by claim 2, the insulation that applies to the color difference By obtaining the average degree of polymerization of the product, it becomes possible to determine the degree of deterioration of the oil-filled electrical equipment.

As described above, according to the method of diagnosing deterioration of the present invention, it is not necessary to bring the insulating oil extracted from the oil-filled electrical equipment back to the analysis room and diagnose the deterioration using a gas chromatograph or a liquid chromatograph, unlike the conventional method. , it is possible to quickly diagnose deterioration at the site where oil-filled electrical equipment is installed.

In addition, the deterioration diagnosis described above only requires a fabricating device comprising a container for insulating paper and insulating oil, a lid for sealing the container, and a constant temperature bath for heating the device. The configuration is simple and can be configured at low cost.

Furthermore, since the inside of the preparation device A of the present invention can be set to be almost the same environment as the inside of the case of the oil-filled electrical device to be diagnosed for deterioration, the color sample produced in the preparation device A can be used for the oil-filled electrical device to be diagnosed for deterioration. In this case, the hue and color difference are similar to those of the deteriorated insulating paper, and the accuracy of deterioration diagnosis can be improved.

1 Storage Container 2 Insulating Paper 3 Insulating Oil 4, 7 Through Hole 5 Flange Part 6 Lid 8 Packing 9 Bolt 10 Plate Washer 11 Spring Washer 12 Nut 13 Vent Hole 14 Ventilation Pipe 15 Valve A Color Sample Producer

Claims (3)

Insulating oil and insulating paper are hermetically housed in a stainless steel container that can mimic the anti-degradation specifications of oil-filled electrical equipment by providing vents and valves for removing air and enclosing inert gas. Heat the container, collect a part of the insulating paper each time the scheduled heating time has passed, cool a part of the collected insulating paper, and then use a part of the insulating paper to measure the average degree of polymerization. is measured, and the remainder of the sampled insulating paper is degreased to clarify the hue and used as a color sample for the measured value of the average degree of polymerization, and the correlation between the hue of the color sample and the average degree of polymerization The insulating paper is exposed to the atmosphere by extracting the insulating oil from the oil-filled electrical equipment that is used as a color difference standard and is the target of deterioration diagnosis, or by lifting the main body of the electrical equipment, or extracting a part of it, and then removing the insulating paper . Deterioration of oil-filled electrical equipment characterized by measuring the color difference between color samples in oil-immersed states or between non-oil-immersed states after degreasing, and estimating the average degree of polymerization from the color difference standard using the color difference. diagnostic method. The insulating paper is photographed together with a white color reference after adjusting the white balance, the photographed image and the color sample are compared, and the average degree of polymerization of the color sample having a similar hue is grasped using the color difference reference. 2. The method for diagnosing deterioration of an oil-filled electrical device according to claim 1, wherein the degree of deterioration of the oil-filled electrical device is diagnosed by means of the oil-filled electrical device. The insulating paper is photographed under the same conditions as the new insulating paper, and the color difference between the insulating material and the new insulating paper is compared with the color difference standard, thereby diagnosing the degree of deterioration of the oil-filled electrical equipment. The method for diagnosing deterioration of an oil-filled electrical device according to claim 1 .

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