KR100541996B1 - A dignosis method of insulation of electric apparatus - Google Patents

A dignosis method of insulation of electric apparatus Download PDF

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KR100541996B1
KR100541996B1 KR1020040032330A KR20040032330A KR100541996B1 KR 100541996 B1 KR100541996 B1 KR 100541996B1 KR 1020040032330 A KR1020040032330 A KR 1020040032330A KR 20040032330 A KR20040032330 A KR 20040032330A KR 100541996 B1 KR100541996 B1 KR 100541996B1
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measurement
diagnostic
item
insulation
items
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KR20050018577A (en
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미키신스케
오카자와히로시
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미쓰비시덴키 가부시키가이샤
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N17/00Investigating resistance of materials to the weather, to corrosion, or to light
    • G01N17/008Monitoring fouling
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00Investigating or analyzing materials by the use of thermal means
    • G01N25/20Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
    • G01N25/22Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on combustion or catalytic oxidation, e.g. of components of gas mixtures
    • G01N25/28Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on combustion or catalytic oxidation, e.g. of components of gas mixtures the rise in temperature of the gases resulting from combustion being measured directly
    • G01N25/30Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on combustion or catalytic oxidation, e.g. of components of gas mixtures the rise in temperature of the gases resulting from combustion being measured directly using electric temperature-responsive elements
    • G01N25/32Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on combustion or catalytic oxidation, e.g. of components of gas mixtures the rise in temperature of the gases resulting from combustion being measured directly using electric temperature-responsive elements using thermoelectric elements
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electro-chemical, or magnetic means
    • G01N27/002Investigating or analysing materials by the use of electric, electro-chemical, or magnetic means by investigating the work function voltage
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02Column chromatography
    • G01N30/86Signal analysis
    • G01N30/8603Signal analysis with integration or differentiation
    • G01N2030/862Other mathematical operations for data preprocessing

Abstract

The present invention provides a method for diagnosing insulation of an electrical device which can be measured without being influenced by an external environment during measurement, and the obtained diagnostic data can be corrected for any external environment.
To this end, the present invention selects a diagnostic item and a plurality of measurement items that correlate with the diagnostic item, and the diagnostic item and the measurement data are based on the diagnostic item taken from the insulation sample and the measurement data of each measurement item. In the measurement object insulation to display the correlation as a correlation diagram (S11), display the relationship between the diagnostic item and the external environmental factors (S12), and insulate and measure each measurement item. One diagnostic measurement data is displayed as one indicator using the MT method, and the numerical value of the corresponding diagnostic item is read out from the correlation chart (S13) prepared in advance (S13), and the relationship between the read numerical value and external environmental factors is shown in the characteristic diagram. The curves are plotted using a, or a characteristic equation to obtain a correction value of the diagnostic item considering the influence of external environmental factors (S14).
Diagnostic data, correlations, diagnostic items, measurement data, environmental factors, correction values, insulation

Description

Diagnosis method of electrical equipment {A DIGNOSIS METHOD OF INSULATION OF ELECTRIC APPARATUS}

1 is a flowchart showing a method for diagnosing insulation of an electric device according to a first embodiment.

2 is a flowchart for selecting measurement items of an insulation diagnosis method of an electric apparatus according to the first embodiment.

3 is a factor effect diagram for determining the validity of a measurement item of an insulation diagnosis method of an electric apparatus according to a first embodiment.

4 is a correlation diagram showing the correlation between the display resistance value and the distance of Maharanobis in the insulation diagnosis method of the electric apparatus according to the first embodiment.

Fig. 5 is a characteristic curve diagram showing the relationship between humidity and surface resistance of the insulation diagnosis method of the electric apparatus according to the first embodiment.

6 is a view for explaining a method of using a characteristic curve of an insulation diagnosis method for an electric apparatus according to the first embodiment.

7 is a diagram illustrating a life expectancy by the insulation diagnosis method of the electric apparatus according to the first embodiment.

FIG. 8 is a diagram showing an electrical equivalent circuit of an insulator of the insulation diagnosis method of the electric apparatus according to the second embodiment.

* Explanation of symbols for main parts of the drawings

Reference Signs List 1 conductive part 2 conductive part 3 insulator

The present invention relates to a method for diagnosing deterioration of performance due to years of use of an insulator used in an electrical apparatus.

Insulators used in electrical equipment such as water distribution facilities deteriorate with years of use due to the surrounding environment, electrical and mechanical stress, etc. For example, many methods are known, such as insulation resistance measurement, partial discharge measurement, leakage current measurement, decomposition gas measurement, and tan-delta measurement. Classification by measurement method includes measurement of destruction of an object, measurement of nondestructive measurement, measurement of direct contact of a measuring device with an insulator, measurement of noncontact, measurement of the operation state of an electrical device, and measurement of a stationary state. have. In such various diagnostic methods, the optimal method for the electric equipment is appropriately selected to diagnose deterioration of the insulation. As a specific conventional technique of such an insulation diagnosis, for example, the surface electrical resistance of the solid insulation material used for the main circuit portion constituting the water distribution facility, or the material equivalent to the solid insulation material provided in the main circuit portion. The first step of measuring the surface electrical resistance of the sensor unit, the surface electrical resistivity measured by the relative humidity of the surface electrical resistivity measurement environment measured at each time corresponding to the actual use time or actual use time of the power distribution equipment in advance. A second step of creating a humidity dependent reference curve based on the basis of the second step, and a comparison of the surface electrical resistivity measured in the first step with the humidity dependent reference curve to determine the life of the power distribution equipment, or to calculate the remaining life of the water distribution equipment. a third step, and that the threshold value of the lifetime is determined at a constant value, such as "80% RH the surface electrical resistivity is 10 9 Ω at the" There are life diagnosis of the power distribution is disclosed [for example, Japanese Patent Laid-Open 2003-9316 No. (second page, FIG. 1 and 2) reference.

In the insulation diagnosis method of the above-described conventional electrical equipment, since the surface resistivity of the insulation is measured at the site where the electrical equipment to be diagnosed is installed, the noise due to the external environment such as the humidity level is high during the measurement. It is easy to be influenced by, and the reliability of the measured data may be lowered, and the measurement result is corrected according to the humidity-dependent reference curve. However, since the reliability of the reference data is low, there is a problem that accurate diagnosis cannot be made. .

In addition, in order to perform electrical measurements such as surface resistivity locally, there is a problem that the measurement operation requires proficiency and expertise, and that no one can easily perform the measurement.

In addition, since the threshold value is made constant regardless of the type and shape of the insulator and the operating environment (applied voltage, etc.), it may not be suitable for the actual condition of the insulator to be diagnosed. In the case of a large change, it may occur that the service cannot be used before the number of years specified by the threshold, and even if the number of years specified by the threshold has elapsed, it may occur without any problem.

The present invention has been made to solve the above problems, and can be easily measured in the field without being affected by the external environment at the time of measurement, and the insulation of the electric device having improved diagnostic accuracy by comprehensively determining the cause of deterioration. The purpose is to provide a diagnostic method.

It is also an object of the present invention to provide a method for diagnosing insulation of electrical equipment that can logically obtain a threshold value and objectively measure a life with good accuracy.

Insulation diagnostic method of an electrical device according to the present invention, the diagnostic items for diagnosing the deterioration of the insulating material used in the electrical equipment, and a plurality of measurement items that correlate with the diagnostic items are selected, the insulation of new and used products The measurement data of the diagnostic items is collected from the sample under a certain environment, the measurement data is collected for each measurement item under a normal environment, and the measurement data of each measurement item is collected using the MT (Maharanobis Taguchi System) method. The first step of creating a correlation diagram showing the correlation between the measurement data of one of the indicators and the diagnostic item, and the relationship between the diagnostic item and the external environmental factors affecting the diagnostic item are displayed. In the second step of preparing a characteristic diagram or a characteristic expression, and the measurement target insulation material for insulation diagnosis, the diagnostic measurement data measured for each measurement item is M. The third step of displaying the value of the diagnostic item corresponding to the one indicator by using the T method and reading the numerical value of the diagnostic item corresponding to the one indicator from the correlation diagram prepared in the first step, and the characteristics prepared in advance in the second step. Using the diagram or the characteristic formula, draw a characteristic curve indicating the relationship between the numerical value of the diagnostic item obtained in the third step and the external environmental factor, and obtain the correction value of the diagnostic item at the time of insulation diagnosis considering the influence of the external environmental factor. And a fourth step, wherein the deterioration state of the insulator is diagnosed using the correction value.

(First embodiment)

The present invention is to determine the diagnostic items in consideration of the external environment (temperature, humidity, external noise, etc.) of the type of insulation to be diagnosed in the insulation degradation diagnosis of the electrical equipment, the correlation with the diagnostic items is strong, and By selecting a plurality of measurement items that can be easily measured in a short time without being affected, and comprehensively judging based on the results of these measurements, accurate deterioration diagnosis is carried out, and logically derived thresholds are used for "lifetime" or It is to measure the "residual life".

1 is a flowchart showing a procedure of an insulation diagnosis method of an electric apparatus according to the first embodiment. Hereinafter, the procedure of invention is demonstrated according to FIG.

First, as a first step, a diagnostic item for determining deterioration of insulation performance of an electric device to be diagnosed is selected, and a plurality of measurement items having a strong correlation with the diagnostic item are selected.

Briefly explain why diagnostic items and multiple measures are used for insulation diagnosis. The deterioration of an insulator varies greatly depending on the kind of the insulator, the use environment, and the external environment. Therefore, as the diagnostic item for this insulator, for example, if the electrical measurement is selected from the items such as "partial discharge", "surface resistance", "tanδ", and "leakage current", it is best to measure these locally. It is not easy to accept the influence of external noise. Therefore, a plurality of items which are the cause of deterioration of the diagnostic item, or which have a strong correlation and can be easily measured locally are extracted, and this is used as a measurement item. For example, when "partial discharge" is a diagnostic item, "gloss", "surface erosion degree" and "decomposition gas amount" are selected as measurement items. By directly measuring the selected measurement item, the original diagnosis item is determined indirectly and comprehensively from a plurality of measurement items.

Then, a large number of insulator samples of new and used articles (for example, deteriorated articles that have been used by users for several years) are prepared. From these insulator samples, measurement data are collected by measuring the diagnostic items under a constant environment (for example, a temperature of 20 ° C., a humidity of 50% or less, which is referred to as a reference environment). Also, measurement data is collected for each measurement item from the sample. Then, for each sample, the measurement data of each measurement item is used as a single indicator (Maharanobis) using the Mahalanobis Taguchi system method (hereinafter referred to as MT method), which is well known in the field of quality engineering. Distance), and a correlation diagram (refer to FIG. 4, described later in detail) indicating the correlation between the measurement result of one of the indicators and the diagnostic item is prepared, and the correlation is represented by one line. A master curve is obtained (S11). In this correlation chart, the numerical value on the horizontal axis indicating the diagnostic item value is the value in the reference environment.

Next, as a second step, a characteristic diagram (see Fig. 5, which will be described in detail later) or a characteristic expression indicating the relationship between the diagnostic item and the external environmental factors affecting the same is prepared and prepared (S12). The external environmental factor herein refers to an environmental item that is taken as a reference environment when the data of the diagnostic item is collected in the first step, and the temperature and humidity in the above example. However, drawing a characteristic diagram for each of a number of external environmental factors for a large number of diagnostic items requires a great deal of effort, especially if a large external environmental factor (eg, humidity) can be identified. Seeing the connection is practically enough.

The method of making the characteristic diagram is to prepare a plurality of insulator samples (which do not need to be the same as the insulator samples in the first stage), prepare samples with different degrees of deterioration due to accelerated deterioration, and parameterize external environmental factors for each of these samples. Measure the diagnostic items with (parameter), and display the measurement results as graphs, for example, where the horizontal axis is the magnitude of external environmental factors and the vertical axis is the measurement value of the diagnostic item. In this way, a plurality of characteristic curves are obtained by using the external environmental factors of diagnostic items having different degrees of deterioration as parameters.

In addition, the characteristic curve may be formulated, and the characteristic curve may be created using the formula (specific examples will be described later).

Steps 1 through 2 above are preparations to be prepared in advance before insulation diagnosis of the electric device to be diagnosed in the field.

Next, the third step will be described. This is then measured and diagnosed for insulation diagnostics in real life. First, the measurement data for diagnosis is collected for each measurement item for the measurement target insulation of the electric equipment to be diagnosed. In addition to the measurement items, the insulation is usually measured directly in the blackout state, or a sample is taken from the insulation to measure the sample. The measurement result is one index using the MT method. Next, using the master curve of the correlation chart created in the first step, the numerical value of the diagnostic item corresponding to one index is read (S13). Since the numerical value of the diagnostic item read out here is a value in a reference environment as mentioned above, the measurement result in a fixed environment can be obtained without being influenced by the local external environmental factor at the time of a measurement.

Next, as a fourth step, the relationship between the external environmental factor and the diagnostic item, based on the numerical value (value in the reference environment) obtained in the third step, using the characteristic diagram created in the second step or the characteristic expression. Create a characteristic curve indicating (specific method of production will be described later).

This characteristic curve is a characteristic curve parameterized by external environmental factors (eg, humidity) of the diagnostic item at the point of measurement at the site. Therefore, for example, if the external environmental factor is set to humidity, the value of the diagnostic item at both humidity 0% and humidity 100% can be read from this characteristic curve (S15).

As described above, according to the first to fourth steps, since the judgment is made based on a plurality of measurement items having a strong correlation with the diagnosis item, the diagnosis item can be determined in multiple ways, and regardless of the external environmental factors at the time of measurement. Since the characteristic curve of the diagnostic item value having external environmental factors as a parameter is obtained, the diagnostic item value corresponding to any external environmental value is obtained, and it is possible to accurately grasp the deterioration state of the insulation.

Based on the above results, a method of accurately performing life diagnosis will be described. First, prepare a lifespan scale that shows the correlation between the diagnostic item and the number of years of use (the number of years), and the initial value of the diagnostic item (that is, the value when it is new), and the value measured in the first step. Plot the diagnostic item value of the measurement time point obtained in step 4, connect the two points to the deterioration tendency line, and estimate the life at the intersection of the deterioration tendency line and the threshold line for the diagnostic item previously obtained (S15). In other words, the elapsed years from the new time point to the intersection point are the lifespan, and the elapsed years from the measurement time point to the intersection point are assumed to be the remaining life time (see Fig. 7, details will be described later).

As described above, according to this method, the life can be estimated by using the diagnostic item value at any external environment value at the time of measurement, and thus, life estimation that predicts various external environments is possible.

Next, a specific diagnosis method will be described, taking the case where the insulation diagnosis method of the electric equipment as described above is applied to the insulation diagnosis of the power distribution equipment.

The main types of insulators used in water distribution facilities are polyester resin insulators, epoxy resin insulators, and phenol resin insulators. Degradation processes of these insulators include fouling of the surface of the insulator, moisture absorption, lowering of the insulation resistance, increased leakage current, and dry bands due to Joule heat (micro dry gaps generated when the surface of the insulator is wet). gap)] → generation of scintillation discharges (creepage microdischarges) → generation and development of tracking discharges (local discharges) by carbonization of the surface Became evident. Therefore, it is known that it is effective to measure and judge the surface resistance of an insulator as a degradation diagnostic item.

First, as a first step, diagnostic items and measurement items are selected. The diagnostic item is " surface resistance value of the insulator " which is effective for determining the deterioration of the insulator as described above. However, electrical measurements such as surface resistance are susceptible to external environmental noise such as humidity. For example, even when the same insulation is degraded to the same degree, there is a measurement error of at least 5 digits if the humidity is different. Therefore, it is less likely to receive noise from the external environment, and it is decided to directly measure the cause of deterioration which is the cause of the change of the surface resistance, and it has a strong correlation with the surface resistance as a measurement item in consideration of the ease of measurement in the field. "Ion amount" and "Color difference gloss amount" which were chemical measurement items were selected. Types of ions include nitrate ions, sulfate ions, chlorine ions, sodium ions, fluorine ions, and the like, and color (brightness), color (yellow) and the like also in terms of color difference. If the strength of the correlation with the insulation to be measured is known in advance, it can be selected appropriately. In this embodiment, the optimal item was selected from each item by the following method.

FIG. 2 is a flowchart for selecting a measurement item from the measurement item candidate, and FIG. 3 is a factor effect diagram for determining the validity of the measurement item (described with reference to the drawings). In Fig. 2, 15 items, such as color, gloss, component (hydrocarbon, etc.) and ion deposition amount, were selected as candidates for a plurality of measurement items that are considered to be correlated with the surface resistance value as the diagnosis item (S21). The items listed in the horizontal axis of Fig. 3 are candidates for measurement.

Next, the degree (effectiveness) of the effect of using and not using the item for each of those items using a sample of the insulator is displayed as the SN ratio using the MT method (S22). In Fig. 3, for each item candidate, the SN ratio is displayed on the vertical axis with " yes " when the item is used for diagnosis and " no " It turns out that the effect in the case of "Y" is remarkable as the difference is larger in the lower right.

Next, an invalid measurement item candidate is excluded, and an item having a significant effect is again extracted from the valid measurement item candidates, and this is selected as a measurement item (S23). Based on FIG. 3, three items of colors (yellow), nitrate ions, and sulfate ions having high SN ratios were extracted and selected as measurement items.

In addition, the correlation is confirmed by the selected measurement item. If the correlation is not sufficient, another measurement item candidate is extracted, and the operations of S21 to S23 are performed again. It goes without saying that the method of judging the validity from this SN ratio and finding the measurement candidate is also applied to the above examples.

According to the operation of determining the measurement item based on the SN ratio as described above, the measurement item can be extracted objectively, and the main deterioration factor can be elucidated.

Subsequently, a plurality of new samples of the same insulator as the measurement target insulator and the used product having different service periods are prepared, and the samples are measured for three items of color (yellow), nitrate ion amount and sulfate ion amount. A color measures the density | concentration of yellow, for example with a simple colorimeter. For each ion amount, the concentration of ions transferred to the ion test paper is measured using, for example, an ion test paper and a high sensitivity reflective photometer. Color and ion amount are hardly affected by temperature or humidity and can be measured at room temperature. Next, the surface resistance value is measured using the same sample as above, but the surface resistance value is greatly influenced by humidity, so for example, a noise shield room which shuts out noise from an external environment. Measured under the constant environment (reference environment) such as temperature of 20 ° C. and humidity of 50%. Next, using the MT method, the color and the two kinds of ions measured above are obtained as one index (distance of Maharanobis), and the correlation between the surface resistance value and the distance of Maharanobis as shown in FIG. It is represented by a correlation diagram showing the sex, and a master curve is obtained. In FIG. 4, a plurality of groups in the lower right corner display a new product, and indicate that the difference between the new product and the deterioration is increasing as the distance of Maharanobis increases. Knowing the distance of Mahalanobis, the surface resistance can be known from the master curve. The surface resistance obtained here is a value in a reference environment.

Next, as a second step, work is performed to see the influence of humidity as the external environment affecting the surface resistance, that is, the dependency of humidity on the surface resistance. The surface resistance changes greatly with humidity even with the same deteriorated product. In the case of using color and ion as the measurement items, temperature is not influenced. Therefore, temperature is not considered.

First, a plurality of insulator samples are prepared. At room temperature, for example, the samples exposed to the vapor of aqueous nitric acid solution at different periods, such as 1 day and 2 days, were dried, and then gradually changed to 20 ° C. and 5% to 95% humidity at room temperature at each time point. Measure the surface resistance at. 5 is a characteristic curve showing the relationship between humidity and surface resistance. The dotted lines in the figure are curves obtained from the measurement results, and the measurement results are plotted and smoothly connected. A denotes a new curve, and B, C, D, and E and the lower curves are characteristic curves of the insulation having a higher degree of deterioration. It can be seen that as the deterioration proceeds, the humidity becomes more susceptible to influence.

In the production of the characteristic curve, when a large number of samples having different degrees of deterioration are prepared, a large number of curves having different degrees of deterioration are obtained, resulting in fine characteristic curves. However, as the number of samples increases, more time and effort are required for data collection. Therefore, if the curve can be formulated, any surface resistance can be easily compensated for humidity. Since the characteristic curve obtained in the measurement is similar to a part of the normal distribution curve as shown in Fig. 5, the curve is fitted by a Gaussian distribution function, and the Gaussian distribution curve is used. A technique for formulating is disclosed in Japanese Patent Laid-Open No. 2003-9316. Therefore, using this technique, the characteristic curve shown using the characteristic formula modified by the Gaussian distribution function is shown by the solid line of FIG. a to e are characteristic curves obtained from characteristic equations corresponding to characteristic curves A to E obtained from actual measurements. By using this characteristic formula, if one point of surface resistance value whose humidity is specified can be known, a characteristic curve can be shown, and the surface resistance value of arbitrary humidity can be read easily. The above steps are preparations prior to the actual diagnosis.

Next, as a third step, three items of color (yellow), amount of nitrate and amount of sulfate are measured from the surface deposits of the object to be measured at the site where the water distribution facility for diagnosis is installed. A color measures the density | concentration of yellow, for example with a simple colorimeter. For each ion amount, the concentration of ions transferred to the ion test paper is measured using, for example, an ion test paper and a high sensitivity reflective photometer. The measured color and the amount of two ions are taken as one index (distance of Maharanobis) using the MT method. Then, the surface resistance value for the Mahalanobis distance is read from the master curve of the correlation chart prepared in the first step. The resistance is a value at 50% humidity. In other words, by the steps up to this point, the surface resistance of the temperature of 20 ° C. and the humidity of 50% can always be obtained from the insulator to be measured locally regardless of the measurement conditions. Therefore, when diagnosing the tendency of deterioration from the measurement result measured in time series, the measurement result can be used as it is without the need for correction.

Next, humidity correction is performed as a fourth step. 6 is a view for explaining a method of using a characteristic curve. In the third step, the surface resistance obtained from the correlation diagram is plotted (point P) on a line with a humidity of 50% in the figure. In the case of using a characteristic curve prepared in advance, when the point P lies on the curve, the curve is a humidity dependent curve of the surface resistance of the insulation measured. If it does not lie on a curve, the curve which newly passes through the point P may be created from the distance of the vertical curve of the point P.

By using the above-described characteristic formula, it is not necessary to prepare the characteristic diagram in advance, and it is possible to draw a curve by the characteristic formula by the Gaussian distribution function based on the surface resistance of the point P. The curve becomes the humidity dependent curve of the surface resistance obtained by the measurement. As shown by the thick arrow in the figure, if the surface resistance value at 50% of humidity is 11 (log?), A humidity-dependent curve like the one shown in bold in the equation is obtained based on this value. Therefore, the surface resistance value at the time of measurement in arbitrary humidity can be known.

Next, the lifetime is measured based on the result. 7 is a life expectancy estimate by the method for diagnosing insulation of all appliances according to the present embodiment. The life estimate is written as: The vertical axis is the surface resistance (measured in logarithmic scale), the horizontal axis is the number of years of use (elapsed years), and the new insulation resistance is plotted on the vertical axis at the left end (point). Next, the surface resistance value of 50% of humidity read from the correlation diagram in the third step is plotted (point b). In addition, a value at an arbitrary humidity, which is a criterion for estimating the lifetime, is obtained from the characteristic curve obtained in the fourth step and plotted (dot). The point I is always at 50% humidity, so a constant diagnosis is possible regardless of the climate, for example when looking at trends compared to values at other measurement points. For example, if the humidity is set to a value of 100% humidity, the service life described below can be determined under the most stringent conditions. Usually, it is practical to set the humidity at the time of rainy season and typhoon. Next, when a straight line is connected by connecting the point value and the point point, this line becomes the deterioration tendency line of the insulation to be measured.

In addition, in the case of performing the life estimation on a regular basis, the deterioration tendency coincided with the actual state can be seen by drawing the deterioration tendency line starting from the last result.

Next, in order to estimate the lifetime, the threshold value of the surface resistance value set in advance is drawn in parallel on the horizontal axis. For example, the threshold value may be determined based on a rule, derived from a past example, or calculated by a formula obtained in the second embodiment described later. The service life corresponding to the intersection point of this critical line and the deterioration tendency line (point d) is estimated as the lifetime. Therefore, the estimated remaining life can be obtained by drawing the number of years from the life to the point of time. In addition, the reason why the degradation tendency line is rapidly lowered to the right side than in FIG. 7 is that the deterioration progresses rapidly thereafter, and the probability of reaching ground faults and short circuits increases rapidly.

As described above, according to the invention according to the first embodiment, it is possible to obtain diagnostic data in a constant environment excluding the influence of noise from the external environment, and to parameterize the external environment factors regardless of the external environment factors at the time of measurement. Since the characteristic curve of the diagnostic item value is obtained, the measured item value corresponding to an arbitrary external environment value is obtained, and it is possible to accurately grasp the deterioration state of the insulation.

Moreover, since it judges by the selected several measurement item which correlates with a diagnosis item, it is possible to make a decision multifaceted about a diagnosis item, and the measurement precision improves.

In the case of estimating the lifetime using the measurement result, the diagnostic item value in any external environment value can be used, and thus life estimation in which various external environments are predicted is possible.

In addition, to obtain a correction value using the external environmental factors as parameters from the measurement results, it is possible to easily create an external environmental factor dependency curve based on the measurement results by using the characteristic formula.

(2nd Example).

The insulation diagnostic method for an electric machine according to the second embodiment is characterized by theoretically obtaining a threshold value according to the life estimation. Until the measurement data is acquired from the insulation of the electrical equipment to be diagnosed, the surface resistance value is read using the correlation chart, the humidity dependence curve is calculated by the calibration curve, and the deterioration trend line is obtained from the life estimation diagram to estimate the life. Since it is the same as the first embodiment, detailed description thereof will be omitted. The threshold value according to the present embodiment is obtained as follows.

8 is a view showing an electrical equivalent circuit of an insulator of an electric apparatus according to a second embodiment of the present invention. As shown in the figure, an insulator 3 made of, for example, an epoxy resin mold is provided between the conductive portion 1 and the conductive portion 2 to insulate and support them. Although the shape of the insulator used in the electric equipment varies widely, the drawings are schematically shown for the purpose of description (to be described later).

Next, the calculation method of a threshold value is demonstrated. The insulating side distance of the insulator 3 is L, and the applied voltage between the conductive parts 1, 2 is V.

The capacitance per unit length of the insulator 3 is set to C1 to Cn, and the surface resistance is set to R1 to Rn. Strictly, the internal insulation resistance (R) of the insulator (3) also needs to be considered, but at commercial frequency (50/60 Hz), the inductance of the insulator (3) is dominant in capacitance (R >> 1 / C, where C Is the capacitance of the full length of the insulator 3), and is ignored.

Here, the process from deterioration of the insulator 3 to the formation of tracking on the surface and the breakdown of the insulator can be carried out as described in the first embodiment. Advances such as band formation → scintillation discharge generation → tracking discharge generation and tremor → breakdown of the circuit.

In Fig. 8, the capacitance of the insulator in the dry band is indicated by Cg and the surface resistance by Rg. The impedance Zp per unit length of the part different from the impedance Zd of the dry band part is expressed by equations (1) and (2).

Figure 112004019330295-pat00001

If the impedance of the whole insulator 3 applied is Z, Z = Zd + Zp · n, so that Formula (1) and Formula (2) are substituted into Z to obtain Formula (3).

Figure 112004019330295-pat00002

Here, n is a coefficient in proportion to the insulation side distance L because the number of the insulation side distances L of the insulator 3 is divided by the unit length. Now, when calculating the conditions under which the scintillation discharge occurs on the surface of the insulator 3, the surface resistance Rg of the dry band portion shown in Fig. 8 is sufficiently high, so that the potential share of the surface of the insulator 3 is electrostatic. It is determined by the impedance by the capacitance Cg. Therefore, Z can be approximated by Equation (4) below.

Figure 112004019330295-pat00003

The relationship between the applied voltage V applied to the insulator 3 and the voltage Vg applied to the dry band is given by the following equation (5).

Figure 112004019330295-pat00004

Here, when the condition of the applied voltage V which Vg exceeds the flame start voltage vi is calculated | required, the scintillation discharge generation voltage Vi is calculated by following formula (6).

Figure 112004019330295-pat00005

Cg depends on the length t of the gap of the dryband, and Vi also depends on t. Vi is given by the so-called Passion sparking voltage, and vi of atmospheric air can be approximated by the following equation (7).

Figure 112004019330295-pat00006

In Equation (6), if Rn is left as the left side and the discharge surface resistance (Rs) is obtained, Rs becomes as in Equation (8).

Rs (MΩ) ≒ a × E b / (L × T) ........... (8)

E: rated voltage (KV), L: insulation side distance L (mm), T: insulation length (mm)

In addition, a and b are integers determined from a frequency and a kind of insulator. It was found from equation (8) that the discharge start surface resistance value Rs is inversely proportional to the product of the insulating side distance and the insulating thickness. This discharge start surface resistance value (Rs) indicates that discharge may occur from the material, shape, and use conditions of the insulator. When discharge occurs, ions in the atmospheric environment cause chemical reactions to generate compounds that promote the deterioration of the performance of the insulator. Therefore, the surface resistance value Rs at the start of discharge is set as the threshold value since the breakdown and the evolution of the converter are progressed.

As described above, according to the invention of the second embodiment, since the threshold value is logically obtained from the numerical value of the diagnostic target insulator such as the type of the insulator, the shape used voltage, and the discharge start voltage, an accurate threshold can be obtained objectively. This makes it possible to estimate the correct lifetime and the remaining lifetime.

According to the present invention, a correlation diagram for selecting a plurality of measurement items correlated with a diagnostic item, displaying the measurement values of the plurality of measurement items as one indicator, and displaying a correlation between the measurement values of the diagnostic items, Prepare a characteristic chart or characteristic formula to correct the influence of external environmental factors on the diagnostic items in advance, and display the measured data obtained by measuring a plurality of measurement items as a single indicator, and use the correlation chart and characteristic chart or characteristics as a basis. By using equations to obtain the correction value of the diagnostic items, and using this correction value to diagnose the deterioration of the insulation, it is possible to easily obtain the diagnostic data in a constant environment excluding the influence of noise from the external environment. The diagnostic data in the external environment can be obtained, and the accuracy of the degradation diagnosis is improved.

The present invention is applied to the diagnosis of insulators used in switch gears, which are widely used in chemical companies, electric gas companies, and food companies, for example, to accurately diagnose insulation deterioration conditions, thereby preventing large accidents such as ground faults and short circuits. Can be.

Claims (3)

  1. Diagnosis items for diagnosing deterioration of insulation used in electrical equipment and a plurality of measurement items correlated with the diagnosis items are selected, and measurement data of the diagnosis items under a constant environment from a sample of insulation materials of new and used products. Collecting the measurement data for each of the measurement items in a normal environment, and using the MT (Maharanobis Taguchi system) method to display the measurement data of each measurement item as one indicator, A first step of creating a correlation diagram indicating a correlation between one indicator and measurement data of the diagnostic item;
    A second step of preparing a characteristic diagram or a characteristic expression indicating a relationship between the diagnostic item and an external environmental factor affecting the diagnostic item;
    The diagnostic measurement data measured for each measurement item is displayed as one indicator using the MT method for the insulation object to be insulated and diagnosed, and the numerical value of the diagnostic item corresponding to the one indicator is displayed in the first step. A third step of reading from the correlation diagram created in advance;
    A characteristic curve indicating the relationship between the numerical value of the diagnostic item obtained in the third step and the external environmental factor is prepared by using the characteristic chart or characteristic formula prepared in advance in the second step. A fourth step of acquiring correction values of the diagnostic items at the time of insulation diagnosis considering the influence
    Including,
    Insulation diagnosis method for an electric machine, characterized in that for diagnosing the thermal degradation of the insulation using the correction value.
  2. The method of claim 1,
    The diagnosis of the deterioration situation in the fourth step indicates a correlation between the new value of the diagnostic item measured in the first step, the correction value of the diagnostic item obtained in the fourth step, and the diagnostic item and the number of years elapsed. An insulation diagnostic method for an electric machine, comprising: plotting a deterioration tendency line by plotting a life estimation diagram, and estimating the life from an intersection with a threshold value of the diagnostic item obtained in advance.
  3. The method of claim 2,
    And said threshold value is obtained from a calculation formula prepared on the basis of the discharge generation voltage at which sparks are generated due to deterioration of the insulator.
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Publication number Priority date Publication date Assignee Title
US7327132B2 (en) * 2005-08-15 2008-02-05 University Of Denver Testing procedure for evaluating diffusion and leakage currents in insulators
JP2008180607A (en) * 2007-01-25 2008-08-07 Railway Technical Res Inst Deterioration-evaluating system for article consisting of polymeric material
JP4806668B2 (en) * 2007-09-05 2011-11-02 三菱電機ビルテクノサービス株式会社 Transformer remaining life estimation system
JP5234321B2 (en) * 2008-01-30 2013-07-10 横河電機株式会社 Process-related data display device and process-related data display method
JP5550034B2 (en) * 2008-09-22 2014-07-16 中部電力株式会社 Degradation diagnosis method for polymer materials
JP5293449B2 (en) * 2009-06-24 2013-09-18 三菱電機株式会社 State change detection device
JP5840342B2 (en) * 2009-07-27 2016-01-06 株式会社東芝 Insulation degradation diagnosis method for insulation materials
JP5321904B2 (en) * 2009-08-31 2013-10-23 富士電機株式会社 Remaining life estimation method, maintenance / update plan creation method, remaining life estimation system and maintenance / update plan creation system
JP5722027B2 (en) * 2010-12-28 2015-05-20 株式会社東芝 Insulation material deterioration diagnosis device, deterioration diagnosis method, and deterioration diagnosis program
CN103048260B (en) * 2012-12-29 2015-04-15 南方电网科学研究院有限责任公司 Electrocorrosion acceleration test method for DC porcelain insulator iron cap
JP6334271B2 (en) * 2014-05-30 2018-05-30 株式会社東芝 Remaining life calculation method, deterioration diagnosis method, deterioration diagnosis device, and program
JP5872643B2 (en) * 2014-07-22 2016-03-01 株式会社東芝 Insulation degradation diagnosis method for insulation materials
JP6049792B2 (en) * 2015-03-25 2016-12-21 株式会社東芝 Insulation material deterioration diagnosis device, deterioration diagnosis method, and deterioration diagnosis program
JP2015135348A (en) * 2015-03-25 2015-07-27 株式会社東芝 Insulating material remaining life estimation apparatus, insulating material remaining life estimation method, and insulating material remaining life estimation program
CN105277822B (en) * 2015-09-17 2018-06-12 广西电网有限责任公司电力科学研究院 A kind of artificial accelerated aging test method for GIS disc insulators
JP6460003B2 (en) * 2016-02-15 2019-01-30 三菱電機株式会社 Diagnosis method of electrical equipment
CN105891427B (en) * 2016-06-08 2019-05-31 深圳市欧瑞博电子有限公司 Sensor life-time monitoring method and device based on cloud computing
WO2020105557A1 (en) * 2018-11-20 2020-05-28 三菱電機プラントエンジニアリング株式会社 Method for assessing remaining life of rotating electrical machine and device for assessing remaining life of rotating electrical machine
WO2020165961A1 (en) * 2019-02-13 2020-08-20 三菱電機株式会社 Method and device for diagnosing remaining life of electric device

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* Cited by examiner, † Cited by third party
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