JP2005308424A - Dielectric deterioration diagnosing method of electric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric deterioration diagnosing method of an electric device capable of simply and properly grasping the degree of hydrolysis by an efficient procedure. <P>SOLUTION: When the dielectric deterioration of a material to be tested is diagnosed from the amount of the hydrolytic product of the material to be tested due to an accelerated test, the degree of advance of dielectric deterioration is judged on the basis of each of the size of the surface precipitate of the material to be tested to an accelerated test time, the acid production concentration of organic matter per a unit sample, absorbancy ratio and a pH value or a combination of an arbitrary number of the measured values. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an insulation degradation diagnosis method for electrical equipment.

In electrical equipment such as rotating machines, when a failure occurs due to insulation deterioration, a large social loss occurs in addition to the time and cost required to restore the equipment. Deterioration diagnostic methods are being developed.
Especially in electrical equipment, it takes a lot of time and money to replace the windings of a rotating machine. Therefore, it is important to properly predict the life of the windings and update them systematically.
The insulation deterioration of a rotating machine is represented by the sum of physical deterioration and chemical deterioration. Here, the physical deterioration factors include mechanical ones associated with heat cycles and electromagnetic vibrations, and electric ones due to corona. Further, chemical deterioration factors include the environment due to moisture absorption and hydrolysis and thermal factors.

Diagnosis is performed based on the above-described insulation deterioration condition. As a non-destructive test for the stator winding of the rotating machine, there is a stator winding non-destructive insulation deterioration diagnosis test (hereinafter referred to as a conventional test method). Moreover, the thing like a nonpatent literature 1 and the patent document 1 is well-known. The thing of this patent document 1 detects the degradation state of an insulating layer by measuring the amount of hydrolysis products of the resin which comprises an insulating layer by an ion chromatograph analysis or an infrared absorption analysis, and is a nonpatent literature. No. 1 shows the result of examination focusing on the polarization index, dielectric loss tangent, maximum discharge charge amount, and the like.
JP 2003-107075 A 2001 IEEJ National Conference 2-082

FIG. 9 shows a correlation diagram between the insulation diagnosis items by the conventional method and the deterioration phenomenon.
As is clear from the figure, physical deterioration such as voids and peeling of the insulating material can be detected by a conventional method, but chemical deterioration such as material alteration cannot be grasped.
In addition, as described in each document, in recent years, it has been considered that the problem of diagnosis of insulation deterioration of rotating machines in relation to these is evaluated by the conventional method when physical deterioration progresses alone. However, if physical and chemical degradation progress simultaneously, the chemical degradation will affect the physical degradation index (Qmax. △ tanδ. △ I), resulting in an underestimation over the true progress of degradation. It may become.
In particular, the impregnating resin for a rotating machine using a polyester resin is deteriorated by hydrolysis and degradation due to water and heat, so that the function of the insulating material is not satisfied, and the equipment is eventually destroyed. For this reason, there is a strong demand for the development of a method for appropriately grasping the degree of progress of deterioration.

  Therefore, an object of the present invention is to provide an insulation deterioration diagnosis method capable of easily and appropriately grasping the degree of hydrolysis by an efficient procedure.

The first of the present invention uses polyester resin as a material to be tested, and diagnoses the degree of insulation deterioration from the amount of hydrolysis product of the material to be tested by an accelerated test.
While measuring the size of the white precipitate deposited on the surface of the material to be tested with respect to the accelerated test time, a criterion is prepared in advance based on the relationship between the retention rate and time by the dielectric breakdown voltage test. Based on the size of the precipitate, the degree of progress of the insulation deterioration is determined.

  In the second aspect of the present invention, the maximum diameter of the precipitate is 0.02 mm or less, the degree of deterioration is small, and the maximum diameter of the precipitate is 0.02 to 0.1 mm, while the maximum diameter of the precipitate is 0.1 mm or more. Is characterized by determining that the degree of deterioration is large.

In the third aspect of the present invention, a polyester resin is used as a material to be tested, and the degree of insulation deterioration is diagnosed from the amount of hydrolysis products of the material to be tested by an accelerated test.
The organic acid generation concentration per unit sample (mg / L) with respect to the accelerated test time is measured by IC, and a determination criterion is created in advance based on the relationship between the retention rate and time in the dielectric breakdown voltage test. The degree of progress of insulation deterioration is determined based on the organic acid concentration (mg / L) measured from the beginning.

  In the fourth aspect of the present invention, the measured amount of organic acid (mg / L) is 0.15 or less, the degree of deterioration is small, and the amount of organic acid 0.15 to 1.0 is the degree of deterioration, while the amount of organic acid is 1.0 or more. Is characterized by determining that the degree of deterioration is large.

In the fifth aspect of the present invention, a polyester resin is used as a material to be tested, and the degree of insulation deterioration is diagnosed from the amount of hydrolysis products of the material to be tested by an acceleration test.
Obtain the absorbance ratio of the material to be tested based on the measurement results in the FT-IR, obtain the absorbance ratio with respect to the accelerated test time, and create a criterion based on the relationship between retention rate and time in the dielectric breakdown voltage test in advance. In addition, the degree of progress of insulation deterioration is determined based on the magnitude of the absorbance ratio measured based on this determination criterion.

  In the sixth aspect of the present invention, the absorbance ratio is obtained by dividing the organic acid absorption spectrum 1710 cm −1 by the polyester absorption spectrum 1740 cm −1. 37 to 0.6 are characterized in that it is determined that the degree of deterioration is large when the absorbance ratio is 0.6 or more.

In the seventh aspect of the present invention, a polyester resin is used as a material to be tested, and the degree of insulation deterioration is diagnosed from the amount of hydrolysis products of the material under test by an accelerated test.
The pH value of the material to be tested with respect to the accelerated test time is measured, and a criterion is prepared in advance based on the relationship between the retention rate and the time in the dielectric breakdown voltage test, and the pH value measured based on the criterion is used. It is characterized by determining the progress of insulation deterioration.

  In the eighth aspect of the present invention, it is determined that the degree of deterioration is small when the pH value is 6.7 or less, the degree of deterioration is pH 6.7 to 6.5, and the degree of deterioration is high when the pH value is 6.5 or more. It is a feature.

The ninth of the present invention uses polyester resin as a material to be tested, and diagnoses the degree of insulation deterioration from the amount of hydrolysis products of the material to be tested by an accelerated test.
The progress of insulation degradation is determined by a combination of any number of the size of the surface precipitate of the material to be tested with respect to the accelerated test time, the organic acid generation concentration per unit sample, the absorbance ratio, and the pH value. It is a thing.

  As described above, according to the present invention, the progress of hydrolysis and the dielectric strength in each measurement of the size of the surface precipitate of the material to be tested, the organic acid production concentration per unit sample, the absorbance ratio, and the pH value, respectively. By clarifying the relationship, it is possible to determine the degree of progress of insulation deterioration by individual measurement, and it is possible to make a diagnosis in any combination that is most suitable for the current situation, taking time, cost, and accuracy into consideration, so it is easy The life can be judged efficiently.

In order to clarify the relationship between the degree of progress of hydrolysis and the dielectric strength, the present invention was subjected to the following accelerated test on the polyester resin.
The acceleration condition was a pressure cooker test (PCT; 121 ° C. 98% RH), and the test was a dielectric breakdown test. The test piece was impregnated with a polyester resin in a double glass winding (dimension 2.4 × 13 mm) in which a glass tape was wound in a single half wrap. The destruction condition was AC destruction in an air atmosphere.
As a measuring device used for hydrolysis, a microscope is used for surface observation, a Fourier transform infrared spectroscopic analyzer (FT-IR) and ion chromatography (IC) are used for analytical measurement, and a pH meter is used for pH. Each was used. 1 to 6 show the results.

Figure 1 shows BDV with dielectric breakdown retention (%) on the vertical axis and PCT time on the horizontal axis.
It is. Based on this FIG. 1, in order to discriminate the degree of deterioration, a judgment standard table as shown in FIG. 7 is set. That is, when the BDV retention rate is 75% or more, the degree of deterioration is small and the sound state is established. When the BDV retention rate is 75 to 50%, the deterioration degree is in progress, and the update plan is being created. When the BDV retention rate is 50% or less, the deterioration level is large and the life time is assumed. The BDV retention rate in the criteria table is IEC. pub. Based on the empirical rules of the applicant, the range of 75 to 50% and 75% or more was made based on 50% degradation degree of 216.
FIG. 2 shows the relationship between the PCT time during the surface observation and the precipitate size. When a certain time has passed since the start of the test, a white precipitate was confirmed on the surface of the test piece, and it was found that hydrolysis was progressing, and gradually increased with the passage of time. The diameter of the maximum precipitate is 0.02 mm in 8 hours of PCT time, and according to the judgment standard table shown in FIG. 7, this 8 hours is in the range of small deterioration degree with a retention rate of 75% or more.
That is, when the diameter of the deposited precipitate is 0.02 mm, a healthy state is obtained.
Next, for example, the size of the precipitate after 48 hours is 0.1 mm, and the BDV retention rate is in the vicinity of 50%. Therefore, when the precipitate has a large diameter of 0.1 mm, it corresponds to the update plan creation time.
Further, the time elapses. For example, when the time reaches 96, the precipitate diameter becomes 0.15 mm. The BDV retention rate in the 96th period is 50% or less, and it is diagnosed that the product has entered the life state when the precipitate diameter is 0.15 mm.

FIG. 3 is a graph showing the relationship between the organic acid production concentration per unit sample and the PCT time measured by IC. The organic acids here are maleic acid, malic acid, fumaric acid, glycolic acid, formic acid, carbonic acid, tartaric acid, lactic acid, etc. Especially, malic acid has a strong correlation with the degree of deterioration, so in the test the production of malic acid Concentration.
The generation concentration of the organic acid increases with time, 0.15 mg / L for PCT 8 hours, which is a small range of deterioration in the criteria table, and 0.53 mg / L and 1 for 16 hours or 48 hours, which is a medium range of deterioration, respectively. 0.0 mg / L. Moreover, it is 20.0 mg / L and 38.5 mg / L in 96 hours and 154 hours of a large deterioration degree. Therefore, it is possible to determine the progress state of the degree of deterioration depending on the amount of organic acid produced.

  FIG. 4 is an example based on an absorbance ratio based on FT-IR measurement. FIG. 6 is a spectrum pattern by FT-IR, and the absorbance ratio is determined by dividing the absorption spectrum (1710 cm −1) of the organic acid in this analysis result by the polyester absorption spectrum (1740 −1). As shown in FIG. 4, this absorbance ratio varies depending on the PCT time. It is 0.38 at 8 hours within the healthy time, 0.60 at 48 hours as the update plan creation time, and 1 at 96 hours or more as the life time. The degree of deterioration can be determined by measuring this absorbance ratio.

FIG. 5 shows an embodiment in which the progress of the degree of deterioration is further determined by measuring the pH value.
Samples can be collected at the time of pH measurement by washing the actual machine surface with pure water, collecting about 2 g of the actual insulating material and performing ultrasonic cleaning, and measuring a small amount of surface insulating material of about 0.5 g. There is a method of shaving off, etc., but in particular, a method of collecting about 2 g of an insulating material and performing ultrasonic cleaning is optimal.
As is apparent from FIG. 5, the pH value measured in this way is 6.7 for the PCT 8 hours within the healthy time, 6.5 for the update plan creation time 48 hours, and 96 for the life time. The time is 6.1, and it is possible to determine the progress state of the degree of deterioration also by the pH value.

As described above, according to the present invention, since the relationship between the degree of hydrolysis and the dielectric strength is clarified, the degree of hydrolysis degradation can be grasped and the residual strength can be estimated from the relationship with the dielectric strength. It becomes. Even in such life estimation, it is desired to perform measurement efficiently according to conditions.
FIG. 8 is a comparison of the time required for examination and accuracy in the hydrolysis investigation in the above-described four examples, and shows the judgment items in the investigation items and the time required.
That is, the inspection for the presence or absence of white precipitates in the appearance inspection took 10 minutes. For pH <7, 60 minutes, FT-IR was 180 minutes, and IC was 300 minutes. Therefore, when examining the progress of the deterioration degree, it is of course possible to make a judgment by measuring each item shown in FIG. 8, but considering the time, cost, and accuracy, a plurality of simple and efficient methods can be used. The degree of hydrolysis degradation can be grasped by executing the survey items.

FIG. 5 is a diagram illustrating a dielectric breakdown voltage test for creating a criterion of the present invention. The result figure of the surface observation deposit size which shows the Example of this invention. The result figure of the organic acid production | generation density | concentration which shows the Example of this invention. The result figure of 1710 / 1740m-1 absorbance ratio which shows the Example of this invention. FIG. 5 is a result diagram of pH values showing examples of the present invention. The spectrum pattern figure by FT-IR. FIG. 3 is a determination reference diagram used in the present invention. Relationship diagram between survey items and required time. Correlation diagram of conventional insulation diagnosis items and deterioration phenomenon.

Explanation of symbols

PCT ... Pressure cooker test
FT-IR ... Fourier transform infrared spectroscopy analyzer
IC ... Ion chromatography
BVD ... Breakdown voltage test

Claims (9)

Using polyester resin as the material to be tested, and diagnosing the degree of insulation deterioration from the amount of hydrolysis product of the material to be tested by an accelerated test,
While measuring the size of the white precipitate deposited on the surface of the material to be tested with respect to the accelerated test time, a criterion is prepared in advance based on the relationship between the retention rate and time by the dielectric breakdown voltage test. A method for diagnosing insulation deterioration of electrical equipment, characterized in that the degree of progress of insulation deterioration is determined based on the size of the precipitate. When the maximum diameter of the precipitate is 0.02 mm or less, the degree of deterioration is small. When the maximum diameter of the precipitate is 0.02 to 0.1 mm, the degree of deterioration is medium. When the maximum diameter of the precipitate is 0.1 mm or more, the degree of deterioration is large. The insulation deterioration diagnosis method for electrical equipment according to claim 1. Using polyester resin as the material to be tested, and diagnosing the degree of insulation deterioration from the amount of hydrolysis product of the material to be tested by an accelerated test,
The organic acid generation concentration per unit sample (mg / L) with respect to the accelerated test time is measured by IC, and a determination criterion is created in advance based on the relationship between the retention rate and time in the dielectric breakdown voltage test. A method for diagnosing insulation deterioration of electrical equipment, wherein the degree of progress of insulation deterioration is determined based on an organic acid concentration (mg / L) measured originally. If the measured organic acid amount (mg / L) is 0.15 or less, the degree of deterioration is small, the organic acid amount 0.15 to 1.0 is judged to be a deterioration degree, and if the organic acid amount is 1.0 or more, the degree of deterioration is judged to be high. The insulation deterioration diagnosis method for electrical equipment according to claim 3. Using polyester resin as the material to be tested, and diagnosing the degree of insulation deterioration from the amount of hydrolysis product of the material to be tested by an accelerated test,
Obtain the absorbance ratio of the material to be tested based on the measurement results in the FT-IR, obtain the absorbance ratio with respect to the accelerated test time, and create a criterion based on the relationship between retention rate and time in the dielectric breakdown voltage test in advance. A method for diagnosing insulation deterioration of electrical equipment, wherein the degree of progress of insulation deterioration is determined based on the magnitude of the absorbance ratio measured on the basis of the determination criteria. The absorbance ratio is obtained by dividing the organic acid absorption spectrum 1710 cm −1 by the polyester absorption spectrum 1740 cm −1. When this value is 0.37 or less, the degree of deterioration is small, and the absorbance ratio 0.37 to 0.6 is deteriorated. 6. The method for diagnosing electrical equipment insulation deterioration according to claim 5, wherein the degree of deterioration is determined to be large when the absorbance ratio is 0.6 or more. Using polyester resin as the material to be tested, and diagnosing the degree of insulation deterioration from the amount of hydrolysis product of the material to be tested by an accelerated test,
The pH value of the material to be tested with respect to the accelerated test time is measured, and a criterion is prepared in advance based on the relationship between the retention rate and the time in the dielectric breakdown voltage test, and the pH value measured based on the criterion is used. A method for diagnosing insulation deterioration of electrical equipment, wherein the degree of progress of insulation deterioration is determined. 8. The degree of deterioration is judged to be low when the pH value is 6.7 or less, while the degree of deterioration is pH 6.7 to 6.5, and when the pH value is 6.5 or more, the degree of deterioration is high. Of insulation deterioration diagnosis of electrical equipment. Using polyester resin as the material to be tested, and diagnosing the degree of insulation deterioration from the amount of hydrolysis product of the material to be tested by an accelerated test,
The progress of insulation degradation is determined by a combination of any number of the size of the surface precipitate of the material to be tested with respect to the accelerated test time, the organic acid generation concentration per unit sample, the absorbance ratio, and the pH value. The insulation deterioration diagnosis method for electrical equipment according to claim 1 to 8.

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