JP5840342B2 - Insulation degradation diagnosis method for insulation materials - Google Patents

Description

  The present invention relates to a method for diagnosing insulation deterioration of an insulating material used for electrical equipment and the like.

  As is well known, power facilities are important facilities that support social infrastructure, and long-term stable operation is required. For that purpose, it is necessary to grasp the deterioration state of the equipment and to carry out maintenance and update systematically. By the way, the insulating material used for the conductor support of an electric power equipment, a barrier, etc. deteriorates insulation characteristics due to aging deterioration of the material itself and adhesion of dust and gas floating in the installation environment. However, since this deterioration of the insulation characteristics causes the equipment to stop due to the occurrence of discharge and tracking, the insulating material is a target of equipment deterioration diagnosis.

In particular, the effect of the installation environment on the deterioration of insulating materials is not only due to contamination due to dust and gas adhesion, but also in environments where there are environmental factors that react with the components of the insulating material, it significantly exceeds normal aging deterioration. Degradation progresses at high speed. For example, in an insulating material used as calcium filler for an inorganic filler, when calcium carbonate reacts with chlorine-based gas, nitrogen oxide gas, or the like, calcium chloride or calcium nitrate is formed on the surface of the insulating material. Since these substances inhale and deliquesce even at low humidity of 40% RH or less, the surface of the insulating material is dewed and leakage current flows even under low humidity conditions, and the insulation is destroyed and the equipment is stopped.
Therefore, in order to diagnose the deterioration state of the equipment and the remaining life, it is important to grasp the influence of the installation environment on the material deterioration in addition to the material deterioration over time.

  Patent Document 1 has been proposed as a conventional technique for diagnosing deterioration of an insulating material. In Patent Document 1, the surface of the organic resin material is irradiated with at least two types of monochromatic light having different wavelengths, the absorbance difference or absorbance ratio of reflected light at each wavelength is calculated, and the deterioration degree and reflection of the resin obtained in advance are calculated. It is disclosed that deterioration of a resin material is determined based on a master curve with a light absorbance difference or absorbance ratio. The invention disclosed in Patent Document 1 is a technique for grasping the deterioration state of the resin material surface. However, as described above, there are environmental factors that greatly accelerate deterioration depending on the installation environment. Therefore, in order to diagnose deterioration, it is necessary to grasp the environmental influence. In the invention disclosed in Patent Document 1, It is difficult to understand the environmental impact.

  Patent Document 2 has been proposed as a method for diagnosing deterioration of an insulating material in consideration of environmental influences. In Patent Document 2, data of measurement items having a strong correlation with diagnostic items (insulation resistance, partial discharge, tan δ, etc.) are represented by one index called Mahalanobis distance by MT method, and a master curve with the diagnostic items is created in advance. deep. When the diagnostic item is insulation resistance, a master curve with a value of 20 ° C. and 50% RH is created. The insulation to be diagnosed is measured, the Mahalanobis distance is calculated, and the insulation resistance value at 20 ° C. and 50% RH is read from the master curve. From this value, the insulation resistance under a desired temperature and humidity condition is obtained and diagnosed by a temperature and humidity correction formula using a Gaussian distribution function. This method considers both the deterioration of the material itself and the influence of the installation environment. However, 20 ° C. and 50% RH is a temperature and humidity condition in which a difference in deterioration appears only slightly, except when the above-described reaction alteration of calcium carbonate occurs. The humidity dependency of the material shows the humidity dependency that varies depending on the combination of the deterioration of the material itself, the amount of dust adhering to the surface of the material, and the type and amount of gas components adsorbed to the dust. Deterioration conditions that cannot be corrected appear.

Japanese Patent No. 3860846 Japanese Patent No. 4112430

  The present invention has been made in consideration of such circumstances, and is based on a multivariate analysis of the installation environment factors including temperature and humidity, taking into account both the deterioration of the material itself and the influence of the installation environment factor on the deterioration of the material. An object of the present invention is to provide a non-destructive method for diagnosing deterioration of an insulating material that can accurately estimate the surface insulation resistance of the insulating material in various deterioration states by estimating the insulating characteristics.

  In the insulation material deterioration diagnosis method according to the present invention, a change in insulation characteristics of an insulation material, which is a criterion for insulation deterioration, and a plurality of material characteristics and insulation materials correlated with the change in the insulation characteristics are installed. Organizing the relationship of atmospheric environmental factors by multivariate analysis, pre-establishing the estimation formula of the insulating characteristics of the insulating material, and measuring the material characteristics and atmospheric environmental factors of the insulating material at the time of deterioration diagnosis, The method includes a step of estimating an insulating property of the insulating material by the estimation formula, and a step of diagnosing a deterioration state of the insulating material by the estimated insulating property.

  Multivariate relationship between insulation characteristics of insulation materials that are criteria for insulation deterioration, for example, surface insulation resistance, material characteristics of multiple insulation materials that correlate with changes in surface insulation resistance, and atmospheric environmental factors where insulation is installed The estimation formula of the surface insulation resistance of the insulating material is prepared in advance by organizing by the analysis method T (Taguchi) or TS (Taguchi Schmid).

The material properties to be measured are, for example, color difference L *, color difference a * (red-green), color difference b * (yellow-blue), blue reflectance, red reflectance, glossiness (incident angle 20 °), glossiness (incident). Properties that change with deterioration of the material, such as 60 °), glossiness (incident angle 85 °), surface roughness, wettability (contact angle), and the like are selected. As the atmospheric environmental factors, the degree of contamination of the material surface, chlorine ions, nitrate ions, sulfate ions, sodium ions, ammonium ions, etc., and the temperature, humidity, etc. of the installation environment are selected.
Items to be selected vary depending on the type of material. For example, when the initial color tone of the material is red and gray, the color tone change due to deterioration is different, and the surface characteristics correlated with the insulation resistance are different.

  In order to create an estimation formula, we collect a wide range of material data, covering the assumed degradation forms, and the degree of degradation from new to life, and create an estimation formula for insulation resistance from that data using the T or TS method. , Narrow down factors that have a large effect on improving estimation accuracy. If the data to be analyzed by the T method or the TS method is biased in deterioration only by the field collection product, the data of the simulated deterioration product created in the laboratory is also added. Simulated fouling products are gas-testing devices that are immersed in various fouling solutions to impart fouling to the surface of heat-degraded products simulating the deterioration of the materials themselves created by changing the heat deterioration conditions, or by attaching dust to the surface. Create materials with various gases adsorbed inside and add data.

Next, in the deterioration diagnosis, the material properties and atmospheric environment factors of the insulating material narrowed down when the estimation formula is created are measured, and the surface insulation resistance value of the insulating material is calculated by the estimation formula. FIG. 4 shows an example of remaining life diagnosis steps. Hereinafter, this step will be described.
First, after confirming the type of insulating material to be diagnosed (see (1)), the insulation resistance (V1) of the insulating material is measured (see (2)). Thereafter, as shown in (3), environmental factors (x1, x2,...) Such as the degree of contamination of the material surface and chlorine ions are measured. Further, after the material surface is wiped, the material surface characteristics (x11, x12,...) Are measured.

Next, the above (1) is input to the diagnostic apparatus, and a material-specific estimation formula prepared in advance is selected. Thereafter, the insulation resistance (V1) from (2) above, the environmental factors (x1, x2,...) From (3) above, and the material surface characteristics (x11, x12,...) From (4) above are further installed. Enter the maximum temperature and humidity of the environment (customer-provided information) into the selected material-specific estimation formula in the diagnostic device (see (5)).
Next, calculate the insulation resistance (V2) of the insulation material under the current temperature and humidity (see (6)) using the estimation formula for each material in (5) above, and the actually measured insulation resistance (V1) and By comparing, the validity of the estimation formula for each material is confirmed (shown in the ellipse on the right side of (2) in FIG. 4). Next, the insulation resistance value (V3) of the highest temperature and humidity (for example, the rainy season) assumed in the installation environment is calculated (see (7)). Further, the time until the lifetime threshold is determined based on the insulation resistance value (V3) in (6) (see (8)).

  Many of the equipment troubles caused by the insulation deterioration of the insulating material are during the rainy season when the humidity may exceed 90% RH. Accordingly, the remaining life is the time until the insulation resistance at high humidity reaches the life threshold set for each facility (FIG. 5). In FIG. 5, the remaining life diagnosis condition is the maximum temperature and humidity of the installation environment. The insulation resistance at high humidity can be obtained by calculating the temperature / humidity calculated above with the conditions assumed during the rainy season.

  When the humidity dependence curve of the insulation characteristic change is created, the curve is often in the vicinity of a certain humidity due to the deterioration state or fouling state of the material, and if the estimation formula is created in the entire humidity range, the estimation accuracy is deteriorated. In that case, the estimation accuracy is improved by creating an estimation equation in each humidity range before and after the inflection point of the humidity dependence curve of the insulation resistance. Since the humidity dependence may vary depending on the type of insulator (combination of base material and filler), the inflection point is confirmed for each material, and the humidity range for creating the estimation formula is determined.

  The purpose of the surface roughness, color difference, reflectance, glossiness, and the like, which are the material characteristics of the insulating material, is to measure the discoloration of the material due to aging and the roughened surface. Instead of these characteristic measurements, it is also possible to obtain a color image of the surface of the insulating material and create an estimation formula using the color information as an estimation factor. It is possible to obtain deterioration information on the surface of the material comprehensively with a digital camera or the like.

According to the present invention, the surface insulation resistance in various deterioration states can be arbitrarily determined by considering both the deterioration of the material itself and the deterioration of the installation environment factor and adding the temperature and humidity of the installation environment to the estimation factor. It can be obtained under temperature and humidity conditions. The system of the estimation formula can be improved by separately creating the estimation formula in the region around the humidity where the humidity dependence curve of the insulation resistance is arranged.
Also, the insulation resistance can be estimated in the same manner even if the color image information obtained by an inexpensive digital camera is used without using a special measuring instrument such as a color difference meter or a reflectance meter.
As described above, by obtaining the estimation formula in advance, it is possible to provide a method for diagnosing the deterioration of an insulating material that can be easily and non-destructively performed on site.

The characteristic view which showed the temperature-humidity dependence of the surface insulation resistance of the unsaturated polyester resin with which the hydrated alumina was filled. The correlation diagram which shows the correlation of the predicted value of the insulation resistance and the true value which were created by analyzing all the data of humidity 50% RH or more by TS method. The correlation diagram which shows the correlation with the predicted value of the insulation resistance and the true value which were created by analyzing the data of the humidity 75% RH or more where the humidity dependency of the insulation resistance changed by the TS method. The block diagram which shows the remaining life diagnosis step until it determines the time from the insulating material of a diagnostic object to a lifetime threshold value. The conceptual diagram for calculating | requiring the remaining life of the insulation material of a diagnostic object.

Next, an insulation deterioration diagnosis method for an insulating material according to an embodiment of the present invention will be described with reference to the drawings. Note that the present embodiment is not limited to the following description.
(Embodiment)
(1) First, the relationship between the change in the insulation characteristics of the insulation material, which is a criterion for insulation deterioration, and the relationship between the material characteristics of the plurality of insulation materials and the atmospheric environmental factors in which the insulation materials are installed. Are arranged by multivariate analysis, and an estimation formula of the insulating property of the insulating material is created in advance.

  First, data for creating a formula for predicting the surface insulation resistance of an insulating material by the T method or the TS method is collected. As the material characteristics of the insulating material to be measured, for example, color difference L *, color difference a *, color difference b *, blue reflectance, red reflectance, gloss (incident angle 20 °), gloss (incident angle 60 °), gloss Characteristics that change with deterioration of the material such as degree (incident angle 85 °), surface roughness, wettability (contact angle), and the like are selected. The atmospheric environment factor measures the degree of contamination of the material surface, chlorine ions, nitrate ions, sulfate ions, sodium ions, ammonium ions, and the temperature and humidity of the installation environment. At the stage of creating the prediction formula, items that improve the estimation accuracy are narrowed down, so data is collected over a wide range.

  If there is a bias in the deterioration of the field-collected products alone, data on the simulated deteriorated products created in the laboratory is also added. Simulated fouling products are gas-testing devices that are immersed in various fouling solutions to impart fouling to the surface of heat-degraded products simulating the deterioration of the materials themselves created by changing the heat deterioration conditions, or by attaching dust to the surface. The material which made the material which adsorb | sucked various gas in the inside and gave the pollution is measured, and it is left to stand in a constant temperature and humidity chamber, and the temperature-humidity characteristic of insulation resistance is measured.

  Next, the measured data is organized by the T (Taguchi) method or the TS (Taguchi Schmidt) method, which is a multivariate analysis technique, and an estimation formula for the surface insulation resistance of the insulating material is created. Here, if there is a degradation mode that was not included when the estimation formula was formulated, the estimation accuracy deteriorates. Therefore, in order to create an estimation equation, it is important to collect a wide range of material data covering a range of assumed deterioration and a degree of deterioration from a new product to a life product.

  FIG. 1 is a characteristic diagram showing the temperature and humidity dependence of the surface insulation resistance of an unsaturated polyester resin filled with hydrated alumina. In FIG. 1, line a shows the relationship between humidity and surface insulation resistance due to an insulating plate that deteriorates by heating at 160 ° C., and line b shows the relationship between humidity and surface insulation resistance by an insulating plate that deteriorates by heating at 180 ° C. Line c shows the relationship between the humidity due to the insulating plate damaged by heat deterioration at 160 ° C. and the surface insulation resistance, and line d shows the relationship between the humidity due to the insulating plate damaged by heat deterioration at 180 ° C. and the surface insulation resistance. . From FIG. 1, it is clear that the humidity dependency changes in the vicinity of 75% at the deterioration and fouling level of the material.

FIG. 2 shows the correlation between the predicted value and true value of the insulation resistance created by analyzing all data with a humidity of 50% RH or higher by the TS method (however, the vertical axis represents log [insulation resistance]. ). In the case of FIG. 2, the correlation coefficient R ² = 0.48 and the correlation is low, and the prediction accuracy is poor. FIG. 3 shows the correlation between the predicted value of the insulation resistance and the true value created by analyzing the data of 75% RH or higher where the humidity dependency of the insulation resistance is changed by the TS method (however, the vertical axis is the horizontal axis) Indicates log [insulation resistance]. In the case of FIG. 3, the correlation coefficient R ² = 0.86 is high, and the prediction accuracy of the estimation formula is improved.

(2) Next, at the time of deterioration diagnosis, the material characteristics and atmospheric environment factors of the insulating material are measured, and the insulating characteristics of the insulating material are estimated by the estimation formula. Subsequently, the deterioration state of the insulating material is diagnosed based on the estimated insulating characteristics.
Many of the equipment troubles caused by the insulation deterioration of the insulating material are during the rainy season when the humidity may exceed 90% RH. Therefore, the remaining life is the time until the insulation resistance at high humidity reaches the life threshold set for each facility. The insulation resistance at high humidity is obtained by calculating the temperature / humidity calculated above with the conditions assumed during the rainy season. Therefore, it is desired that the prediction formula of the insulation resistance has high prediction accuracy especially under high humidity conditions. The prediction formula created by the present invention was confirmed to have high prediction accuracy under high humidity conditions. In order to increase the estimation accuracy of the prediction formula, it is effective to perform optimum numerical processing for each measurement item.

  According to the present invention, as described above, the relationship between the change in the insulation characteristics of the insulation material, the material characteristics of the insulation material, and the atmospheric environmental factors in which the insulation material is installed is organized by multivariate analysis, and After preparing the estimation formula of the insulation characteristics in advance, at the time of deterioration diagnosis, measure the material characteristics and atmospheric environmental factors of the insulation material, estimate the insulation characteristics of the insulation material by the estimation formula, and further according to the estimated insulation characteristics By diagnosing the deterioration state of the insulating material, the surface insulation resistance of the insulating material can be accurately estimated in various deterioration states, and the insulating material can be carried out without being destroyed.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

Claims (5)

A change in insulation resistance of an insulation material that is a criterion for insulation deterioration, a material property of the plurality of insulation materials correlated with the change in the insulation resistance, and an atmospheric environmental factor in which the insulation material is installed. A process of organizing relationships of atmospheric environmental factors including multivariate analysis using a T (Taguchi) method or a TS (Taguchi-Schmidt) method, and creating an estimation equation of insulation resistance of the insulating material in advance;
At the time of deterioration diagnosis, the insulation resistance of the insulation material and the atmospheric environmental factors including the material properties and temperature and humidity of the insulation material are measured, and the insulation resistance of the insulation material under the current temperature and humidity is calculated by the estimation formula. Confirming the validity of the estimated equation by comparing with the actually measured insulation resistance;
Calculating an insulation resistance of the insulating material at a maximum temperature and humidity assumed in an installation environment of the insulating material by the estimation formula;
A step of determining a time to a life threshold value based on an insulation resistance of the insulating material at a maximum temperature and humidity assumed in an installation environment of the calculated insulating material. Diagnosis method. 2. The insulation deterioration diagnosis method for an insulating material according to claim 1, wherein the material characteristic of the insulating material is selected based on the kind of the insulating material and the inorganic filler contained in the material. The method for diagnosing insulation deterioration of an insulating material according to claim 1 or 2, wherein the estimation formula for the insulation resistance is created in each humidity range with the humidity at which the humidity dependence curve of the change in insulation resistance changes as a boundary. 4. The insulation deterioration diagnosis method for an insulating material according to claim 3, wherein the boundary of the humidity range for creating each of the estimation equations for the insulation resistance is set for each type of insulating material. The method for diagnosing insulation deterioration of an insulating material according to claim 1, wherein a color image of the surface of the insulating material is acquired instead of measuring the surface roughness, color difference, reflectance, and glossiness which are the material characteristics of the insulating material. .

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