JP2014052356A - Deterioration diagnosis method and device for insulation material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation deterioration diagnosis method and a device capable of easily diagnosing a contamination state of an insulation material and a deterioration state of the insulation material itself on the spot.SOLUTION: A deterioration diagnosis device 10 includes an insulation resistance measurement section 11 which measures secular change of an insulation resistance by applying a DC voltage to the insulation material to be diagnosed; an approximation curve calculation section 12 which finds a power approximation curve R=A×t(A, B: constant) and an exponent approximation curve R=C×exp (Dt) (C, D: constant) from the relation between the insulation resistance and a measurement time; and a deterioration diagnosis section 13 which determines a contamination state of the insulation material by comparing the value of the constant D of the exponent approximation curve with a determination threshold and diagnoses a deterioration state of the insulation material itself by comparing the value of the constant B of the power approximation curve with a determination threshold.

Description

  Embodiments described herein relate generally to a deterioration diagnosis method and apparatus for diagnosing a deterioration state of an insulating material used in electric power equipment or the like.

  Electric power facilities are important facilities that support social infrastructure, and long-term stable operation is required. However, an insulating material used for a conductor support or a barrier of a power facility may deteriorate in insulation property due to aging of the material itself, adhesion of dust or gas floating in the installation environment, and the like. When the insulating property of the insulating material is lowered, discharge or tracking is generated. Therefore, the lowered insulating property of the insulating material causes the facility to stop.

  In addition, the deterioration of the insulating material based on the installation environment is influenced not only by the contamination due to the adhesion of dust or gas but also by environmental factors that react with the components of the insulating material. In particular, in an environment where there are environmental factors that react with the components of the insulating material, the insulating material may deteriorate at a rate that exceeds normal aging. For example, in an insulating material using calcium carbonate as an inorganic filler, when the calcium carbonate reacts with a chlorine-based gas or a nitrogen oxide gas, calcium chloride or calcium nitrate is formed on the surface of the insulating material. These substances such as calcium chloride or calcium nitrate deliquesce by inhaling moisture even at a low humidity of 40% RH or less. Therefore, when calcium chloride or calcium nitrate is formed on the surface of the insulating material, the surface of the insulating material may condense, leakage current will flow, insulation may be destroyed, and the equipment may be shut down even under low humidity conditions. it is conceivable that.

  Further, when the insulating material is fouled and ionic substances are adhered, moisture is absorbed to generate a micro discharge, resulting in deterioration of insulation, and finally dielectric breakdown. When the minute discharge starts, the surface of the insulating material rapidly deteriorates. Therefore, in the deterioration diagnosis of the insulating material, it is necessary to detect the adhesion amount of the ionic substance and also detect the deterioration state of the insulating material itself.

  In the conventional deterioration diagnosis method, the amount of ionic substances attached is measured by ion analysis. Moreover, as an example for grasping the deterioration state of the insulating material itself, the color difference, reflectance, glossiness, etc. of the surface are measured, and these results are analyzed by the T (Taguchi) method which is multivariate analysis. The surface insulation resistance at temperature and humidity is estimated.

  However, in the above method, on-site measurement cannot be performed for ion analysis, and it takes time until analysis because it is performed after taking it back to a predetermined analysis place.

  In the degradation diagnosis using the conventional T method, the color difference, reflectance, and glossiness of the surface are measured as degradation indicators of the insulating material itself, but it is understood that the degradation does not progress to some extent depending on the original color tone of the material. In some cases, deterioration could not be reflected in the measurement results with high sensitivity.

  Furthermore, the deterioration of the insulating material itself has a correlation with the wettability of the material surface, but the wettability can be grasped by dropping water onto the material surface and measuring the contact angle from the shape measurement of the water droplet. However, the contact angle can be measured on a horizontal plane, but measurement on a vertical plane is difficult because water droplets cannot be held.

  For this reason, there is a demand for an evaluation method that can easily determine the contamination state of the insulating material and the deterioration of the insulating material itself on site.

JP 2011-27596 A

  An object of the embodiment of the present invention is to provide an insulation deterioration diagnosis method and apparatus capable of diagnosing a fouling state of an insulating material and a deterioration state of the insulating material itself on site.

  In order to achieve the above-described object, the method for diagnosing deterioration of an insulating material according to an embodiment of the present invention measures a change in insulation resistance with time by applying a DC voltage to the insulating material to be diagnosed, and measures the insulation resistance and measurement. Diagnose the contamination state of the insulating material from the constant of the exponential approximation curve when the relationship with time is approximated by an exponential equation, and the constant of the power approximation curve when the relationship between the insulation resistance and measurement time is approximated by a power equation From this, the deterioration state of the insulating material is diagnosed.

In addition, in a method for diagnosing deterioration of an insulating material according to another embodiment of the present invention, a DC voltage is applied to an insulating material to be diagnosed to measure a change in the insulation resistance with time, and the relationship between the insulation resistance R and the measurement time t. A power approximation curve R = A × t ^B is approximated by a power equation (A and B are constants), and constant B is used as a deterioration index of the insulating material itself, and a plurality of evaluation items including constant B are used. Using the T method, which is a variable analysis, to obtain an insulation resistance estimation formula, and from the estimated insulation resistance value at the time of diagnosis obtained by substituting the measurement conditions at the time of diagnosis into the insulation resistance estimation formula, and the initial insulation resistance value A life estimation curve is created, and the remaining life is obtained from the intersection of the life estimation curve and a life threshold value obtained in advance for each material.

In order to achieve the above-mentioned object, an insulation material deterioration diagnosis apparatus according to an embodiment of the present invention is an insulation resistance measurement unit that measures a change in insulation resistance with time by applying a DC voltage to an insulation material to be diagnosed. Approximate curve calculation for obtaining a power approximation curve R = A × t ^B (A and B are constants) and an exponential approximation curve R = C × exp (Dt) (C and D are constants) from the relationship between insulation resistance and measurement time And the value of the constant D of the exponential approximation curve is compared with a determination threshold value to diagnose the contamination state of the insulating material, and the value of the constant B of the power approximation curve is compared with a determination threshold value to compare the value of the insulating material itself. A deterioration diagnosis unit for diagnosing the deterioration state.

Furthermore, the insulation material deterioration diagnosis apparatus according to another embodiment of the present invention uses a constant B in a power approximation curve R = A × t ^B in which the relationship between the insulation resistance R and the measurement time t is approximated by a power equation. As an indicator of deterioration, an evaluation item measuring unit that measures evaluation items of a plurality of insulating materials including the constant B, and insulation resistance estimation obtained for each material in advance by the T method that is multivariate analysis using the evaluation items By substituting the measured value of the evaluation item into the estimation equation database for each material in which equations are stored, and the insulation resistance estimation equation, the insulation resistance estimation value is calculated under the condition that the insulating material at the time of diagnosis is assumed in the installation environment. Insulation resistance estimated value calculation unit, life threshold database for each material storing life threshold values of insulation resistance for each material calculated in advance, insulation resistance value in the initial state and the calculated insulation resistance under the same conditions as in the diagnosis Create a lifetime estimation curve and a value, characterized in that and a remaining service life estimation portion for determining the remaining life from the intersection of the said life estimation curve and the material-specific insulation resistance life threshold value.

It is a graph which shows a time-dependent change of the surface insulation resistance of an insulating material. It is a block diagram which shows the structure of the deterioration diagnosis apparatus of the insulating material which concerns on 1st Embodiment. It is a flowchart which shows the procedure of the degradation diagnosis method of the insulating material which concerns on 1st Embodiment. It is a block diagram which shows the structure of the deterioration diagnosis apparatus of the insulating material which concerns on 2nd Embodiment. It is a flowchart which shows the procedure of the degradation diagnosis method of the insulating material which concerns on 2nd Embodiment. It is a graph explaining the remaining life estimation method in the deterioration diagnosis method of the insulating material which concerns on 2nd Embodiment.

  Embodiments of the present invention will be specifically described below with reference to the drawings. In each of the following embodiments, for example, diagnosis is made on insulating materials (specifically, polyester resin, epoxy resin, phenol resin, etc.) used in various power equipment or power equipment such as power receiving equipment, substation equipment, and switchgear. It will be explained as a target.

First, a calculation example of an approximate curve of insulation resistance, which is a premise of the deterioration diagnosis method of the present embodiment, will be described.
(Insulation resistance of insulation material)
FIG. 1 is a graph showing the change over time of the surface insulation resistance of the insulating material when a DC voltage is applied. The measurement voltage is a DC voltage of tens to thousands of volts. Since the insulation resistance changes with time, the value after 60 seconds is usually adopted as the value of the insulation resistance. In this embodiment, it is 60 seconds, but the measurement time may be further increased. On the other hand, the measurement time of several tens of seconds or less is not desirable because the rate of change is large.

  In FIG. 1, measurement 1 is the result of measuring the insulation resistance of an insulating material used in the field under conditions of temperature 20 ° C. and humidity 65% RH, and measurement 2 is measured under conditions of temperature 20 ° C. and humidity 80% RH. It is a result. Measurement 3 is the result of measuring the insulation resistance under the conditions of a temperature of 20 ° C. and a humidity of 65% RH after cleaning the surface fouling material of measurement 1 and measurement 2 with pure water and drying. Measurement 4 is the result of measuring the surface fouling materials of the insulating materials of Measurement 1 and Measurement 2 with pure water and drying them, and measuring under conditions of a temperature of 20 ° C. and a humidity of 80% RH.

(Approximate curve)
Next, a power approximate curve R ₁ = A × t ^B obtained by approximating the relationship between the measured insulation resistance and time (t) by a power equation, and an exponent approximate curve R ₂ = C × exp (Dt) approximated by an exponential equation And correlation coefficients r1 and r2 of the respective approximate curves are obtained. Here, A, B, C, and D are constants. Table 1 shows the correlation coefficient r1 of the power approximation curve, the correlation coefficient r2 of the exponent approximation curve, the constant B of the power approximation curve, and the constant D of the exponent approximation curve.

  From past measurement data, it can be seen that the time-dependent change in insulation resistance matches the exponential approximation curve when the surface becomes wet due to fouling, and the power approximation curve matches well when it is clean and free from moisture. Yes. Measurement 1 and Measurement 2 have the same surface fouling but different measurement atmospheres. Under the high humidity condition, the correlation coefficient of the exponential approximation curve is larger than the correlation coefficient of the power approximation in Measurement 2 which absorbs moisture due to fouling. Further, even in the measurement under the same high humidity condition, in the measurement 4 in which the insulating material whose surface contamination was cleaned was measured, the surface was not contaminated even in a high humidity atmosphere, so the moisture was not absorbed, and the correlation coefficient of the power approximation curve was better. Get higher. However, when only the correlation coefficient is compared, it is soiled but the measurement condition is low humidity (Measurement 1). Since there is no moisture adsorption on the surface, the correlation coefficient becomes larger in the power approximation curve.

(Relationship between constant D and surface fouling state)
Therefore, as a result of investigating the relationship between the constant D of the exponential approximation curve and the surface contamination state, it was found that the constant D can detect the contamination state without being affected by the measured humidity. Table 1 shows the value of the constant D of the exponential approximation curve. It can be seen that the value of the constant D becomes negative when the surface is cleaned. Although the threshold for detecting fouling differs depending on the material, as shown in Table 2, for epoxy resin, the fouling degree (equivalent salt content) is 0.03 mg / cm ² , which is the upper limit of light fouling in the fouling category. As a result of the measurement, the constant D was 0.001 or more. Therefore, when D exceeds 0.001, it is a fouling state that affects the insulation characteristics (more than the medium fouling in Table 2). I can judge.

(Relationship between the constant B and the deterioration state of the insulating material itself)
Further, as a constant capable of detecting the deterioration of the insulating material itself, as a result of investigating the relationship between the power approximation curve constant reflecting the insulation resistance characteristic in the solid state and the insulating material having a different deterioration state, the correlation with the constant B is It was found that the deterioration of the material itself progressed as the value of B became negative. As for the epoxy resin, it can be determined that the value of B is deteriorated when it is −0.1 or less. Therefore, since the materials described in Table 1 are B> −0.1, there is no deterioration of the materials themselves.

[First Embodiment]
(Simple deterioration diagnosis method)
FIG. 2 shows the configuration of the insulation material deterioration diagnosis apparatus according to the present embodiment.

(Deterioration diagnosis device)
The degradation diagnosis apparatus 10 includes an insulation resistance measurement unit 11 that measures an insulation resistance of a target insulation material, an approximate curve calculation unit 12 that obtains an approximate curve from measurement time and insulation resistance, and constants and materials in the obtained approximate curve. Deterioration diagnosis unit 13 for diagnosing the degree of deterioration based on the threshold value of the material, deterioration determination threshold value database 14 for each material storing data relating to the deterioration determination threshold value for each material, and the degree of contamination and the amount of nitrate ions per unit area (mg / Cm ² ) to measure the ion analyzer 15.

(Deterioration diagnosis method)
Next, a procedure for performing a simple deterioration diagnosis on site using the deterioration diagnosis apparatus 10 having the above-described configuration will be described with reference to FIG.

First, the insulation resistance measurement unit 11 acquires data on the change in insulation resistance over time for 60 seconds (step S11). Next, the approximate curve calculation unit 12 obtains a power approximate curve R ₁ = A × t ^B of the measurement time and the insulation resistance (step S12). Further, an exponential approximate curve R ₂ = C × exp (Dt) of measurement time and insulation resistance is obtained (step S13).

Next, the deterioration diagnosis unit 13 compares the value of the constant D of the exponential approximation curve R ₂ = C × exp (Dt) with the threshold value data for each material stored in the deterioration determination threshold value database 14 for each material. Diagnose deterioration. For example, in the case of an epoxy resin, the threshold value data is 0.001 as described above. Therefore, the deterioration diagnosis unit 13 determines whether the value of the constant D is less than 0.001 (step S14). If it is less than 001 (Yes in step S14), it is diagnosed that it is not soiled (step S15). On the other hand, if the constant D is 0.001 or more (No in step S14), it is diagnosed that it is soiled (step S16).

  Here, even if it is diagnosed that the material is soiled, if the material itself is not deteriorated, it can be recovered if cleaning is sufficiently performed. Even if the material itself is deteriorated, even if it is cleaned, contamination and deterioration of the material proceed immediately due to discharge. Therefore, it is necessary to quantitatively determine the remaining life by precise diagnosis.

  Therefore, for the material diagnosed as having fouling in step S16, the deterioration diagnosis unit 13 determines deterioration of the material itself based on the threshold values in the material-specific deterioration determination threshold value database 14 (step S17). In determining the deterioration, in the case of an epoxy resin, it is determined whether or not the value of the constant B exceeds −0.1 (step S17). If it exceeds −0.1 (Yes in step S17), It is diagnosed that there is no deterioration of the insulating material itself (step S18). On the other hand, when the constant B is −0.1 or less (No in step S17), it is diagnosed that the insulating material itself is deteriorated (step S19).

If it is determined in step S18 that the material itself is not deteriorated, the ion analyzer 15 measures the degree of contamination and the amount of nitrate ions (mg / cm ² ) per unit area attached (step S20). It has been found that the ratio of the nitrate ion amount to the pollution degree of the normal environment is 0.1 to 0.2 as an empirical value of measurement data for many years. If the ratio of the nitrate ion amount to the degree of contamination exceeds 0.2 in step S21 (Yes in step S21), it is evaluated that there is a sign of discharge, that is, the discharge has started, and precise diagnosis is performed in step S22. . On the other hand, when the ratio of the nitrate ion amount to the degree of fouling is 0.2 or less (No in step S21), the countermeasure is terminated by carrying out cleaning or the like.

  If it is diagnosed in step S19 that the insulating material itself has deteriorated, the deterioration proceeds due to discharge or the like, and there is a high possibility that the life will be near. Therefore, a precise diagnosis is performed in step S22.

(effect)
According to the present embodiment, it is possible to easily diagnose the contamination state of the insulating material and the deterioration state of the insulating material itself on site before the dielectric breakdown due to discharge.

[Second Embodiment]
(Precise deterioration diagnosis method)
FIG. 4 shows the configuration of the insulation material deterioration diagnosis apparatus according to the present embodiment.

(Deterioration diagnosis device)
The degradation diagnosis apparatus 20 includes an insulation resistance measurement unit 11 that measures an insulation resistance of a target insulation material, an approximate curve calculation unit 12 that obtains an approximate curve from the measurement time and the insulation resistance, and an evaluation item that is predetermined for the diagnosis target. The evaluation item measuring unit 21 for measuring (the evaluation item when the insulation resistance estimation formula by the T method is created), the insulation resistance estimated value calculating unit 22 for calculating the estimated value of the insulation resistance, and the estimation formula for each material obtained in advance Material-specific estimation formula database 23 for storing data, life estimation curve creating unit 24 for creating a life estimation curve, remaining life determination unit 25 for determining the remaining life, and data for each material for storing pre-calculated life threshold values for each material The life threshold value database 26 is configured.

(Precise deterioration diagnosis method)
Next, a procedure for carrying out a precise deterioration diagnosis on site using the deterioration diagnosis apparatus 20 having the above-described configuration will be described.

  In the present embodiment, the constant B of the power approximation curve used for the simple determination in the first embodiment is analyzed by the T (Taguchi) method in addition to the deterioration evaluation items of the insulating material to obtain the insulation resistance estimation formula. is there.

FIG. 5 shows a procedure of the degradation diagnosis method for an insulating material according to the present embodiment.
First, the insulation resistance of the target insulation material is measured by the insulation resistance measurement unit 11 (step S31). Next, the approximate curve calculation unit 12 obtains a power approximate curve R ₁ = A × t ^B from the measurement time and insulation resistance data (step S32).

In addition, a constant B of power approximation curve R ₁ = A × t ^B is used for insulating material evaluation items (temperature, humidity, fouling degree, chlorine ion, nitrate ion, sulfate ion, sodium ion, color difference, reflectance, glossiness, etc.) In addition, an insulation resistance estimation formula is obtained in advance by the T method, and data relating to the insulation resistance estimation formula is stored in the material-specific estimation formula database 23 (step S33).

  Here, the estimation formula is a primary formula of each evaluation item, and is expressed by the following formula. Note that the evaluation items other than the constant B differ depending on the type of material.

Y = C + a.X1 + b.X2 + c.X3 +... + L.X12 + m.X13
Measurement values: X1, X2, ..., X13
Coefficients: C, a, b, c, ... l, m

  Next, the evaluation item measuring unit 21 measures evaluation items predetermined for the diagnosis target including the constant B of the approximate curve (step S34).

  Furthermore, the insulation resistance estimated value calculation unit 22 uses the insulation resistance estimation formula stored in the material-specific estimation formula database 23, and diagnoses under conditions of maximum temperature and maximum humidity (usually temperature and humidity in the rainy season) of the installation environment. An insulation resistance estimated value is calculated by substituting the measured value at the time (step S35).

  Next, the life estimation curve creation unit 24, as shown in FIG. 6, the estimated insulation resistance value under the maximum temperature and maximum humidity conditions (usually the temperature and humidity during the rainy season) at the time of diagnosis, An insulation resistance life estimation curve is created using the initial insulation resistance value of the new material under the same conditions (step S36).

  Further, the remaining life determination unit 25 uses the life estimation curve of the insulation resistance and the life threshold for each material stored in the life threshold database for each material 26, as shown in FIG. The remaining life of the insulating material is obtained from the intersection of (step S37).

(effect)
In the precision degradation diagnosis using the conventional T method, the color difference, reflectance, glossiness, etc. of the surface are measured as degradation indicators of the insulating material itself. However, depending on the original color tone, degradation may be detected with high sensitivity. It may not be reflected, and the accuracy of the remaining life diagnosis result may deteriorate.

  On the other hand, in this embodiment, by adding the constant B of the power approximation curve to the deterioration index of the insulating material itself, a diagnosis result that more accurately reflects the deterioration of the insulating material itself can be obtained.

[Other embodiments]
(1) In the deterioration diagnosis device 20 of the second embodiment, the insulation resistance measurement unit 11 and the approximate curve calculation unit 12 are provided, and the insulation resistance of the insulating material is measured to obtain the power approximate curve R _1. The measurement result by the insulation resistance measurement unit 11 and the approximate curve calculation unit 12 in the deterioration diagnosis apparatus 10 of the first embodiment can be used.

(2) In the deterioration diagnosis device 20 of the second embodiment, the life estimation curve creation unit 24 and the remaining life determination unit 25 are provided separately, but the life estimation curve creation unit 24 is omitted and the remaining life determination unit 25. In addition, the function of the life estimation curve creating unit 24 can be added.

(3) Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Degradation diagnostic apparatus 11 ... Insulation resistance measurement part 12 ... Approximate curve calculation part 13 ... Degradation diagnosis part 14 ... Degradation threshold database 15 classified by material 15 ... Ion analysis part 20 ... Degradation diagnosis apparatus 21 ... Evaluation item measurement part 22 ... Insulation resistance Estimated value calculation unit 23 ... Material-specific estimation formula database 24 ... Life estimation curve creation unit 25 ... Remaining life determination unit 26 ... Material-specific life threshold database

Claims (7)

  Measure the change in insulation resistance over time by applying a DC voltage to the insulation material to be diagnosed, and the contamination of the insulation material from the constant of the exponential approximation curve when the relationship between the insulation resistance and measurement time is approximated by an exponential equation A method for diagnosing deterioration of an insulating material, comprising: diagnosing the state of deterioration and diagnosing a deterioration state of the insulating material from a constant of a power approximation curve when the relation between the insulation resistance and the measurement time is approximated by a power equation.   An exponential approximation curve R = C × exp (Dt) is obtained by approximating the relationship between the insulation resistance R and the measurement time t with an exponential equation (C and D are constants), and the value of the constant D exceeds the threshold set for each material. 2. The method for diagnosing deterioration of an insulating material according to claim 1, wherein the surface of the insulating material is diagnosed as being fouled in the event of failure. A power approximation curve R = A × t ^B obtained by approximating the relationship between the insulation resistance R and the measurement time t with a power equation is obtained (A and B are constants), and the value of the constant B is less than the threshold set for each material. 2. The method for diagnosing deterioration of an insulating material according to claim 1, wherein the diagnosing that the insulating material itself has deteriorated is diagnosed. ^{3. The} amount of nitrate ions per unit area (mg / cm ² ) is measured, and when the ratio of the amount of nitrate ions to the degree of fouling exceeds a predetermined value, it is evaluated that there is an indication of discharge. Deterioration diagnosis method for insulating materials. A DC voltage is applied to the insulation material to be diagnosed to measure the change in insulation resistance with time, and a power approximation curve R = A × t ^B is obtained by approximating the relationship between the insulation resistance R and the measurement time t by a power equation (A , B are constants), the constant B is a deterioration index of the insulating material itself, and an insulation resistance estimation formula is obtained by the T method which is multivariate analysis using a plurality of evaluation items including the constant B, and the insulation resistance estimation formula A life estimation curve is created from the estimated insulation resistance value at diagnosis and the initial insulation resistance value obtained by substituting the measurement conditions at the time of diagnosis with respect to the life estimation curve and the life previously determined for each material. A method for diagnosing deterioration of an insulating material, characterized in that a remaining life is obtained from an intersection with a threshold value. An insulation resistance measurement unit that measures a change in insulation resistance with time by applying a DC voltage to the insulation material to be diagnosed;
An approximate curve calculation unit for obtaining a power approximate curve R = A × t ^B (A and B are constants) and an exponential approximate curve R = C × exp (Dt) (C and D are constants) from the relationship between insulation resistance and measurement time; ,
The value of constant D of the exponential approximation curve is compared with a determination threshold value to diagnose the contamination state of the insulating material, and the value of constant B of the power approximation curve is compared with a determination threshold value to determine the deterioration state of the insulating material itself. A deterioration diagnosis unit to diagnose,
A deterioration diagnosis apparatus for insulating materials, comprising: The constant B in the power approximation curve R = A × t ^B, which approximates the relationship between the insulation resistance R and the measurement time t by a power equation, is used as the degradation index of the insulating material itself, and evaluation items for a plurality of insulating materials including the constant B are as follows. An evaluation item measuring unit to be measured;
An estimation formula database classified by material in which an insulation resistance estimation formula obtained for each material in advance by the T method which is multivariate analysis using the evaluation items is stored;
An insulation resistance estimated value calculation unit that calculates an insulation resistance estimated value in a condition that the insulating material at the time of diagnosis is assumed in an installation environment by substituting the measured value of the evaluation item into the insulation resistance estimation formula;
A life threshold database for each material storing a life threshold value of insulation resistance for each material calculated in advance;
A life estimation curve is created from the initial insulation resistance value and the calculated insulation resistance estimated value under the same conditions as the diagnosis, and the remaining life is calculated from the intersection of the life estimation curve and the life threshold value of the insulation resistance for each material. A remaining life estimation unit for obtaining
A deterioration diagnosis apparatus for insulating materials, comprising:

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