JP2000081401A - Deterioration diagnostic method for organic insulating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deterioration diagnostic method capable of accurate deterioration diagnosis of an organic insulation material with a plurality of peaks in measured values of a loss tangent without effects of a thickness and shape of a piece being measured and of a difference in resin content, for example. SOLUTION: This deterioration diagnostic method for an organic insulation material used for the insulation of electrical machinery and apparatus determines a degree of deterioration of a sample being measured, by preparing a master curve from a relation of a storage-to-loss elastic modulus ratio (a loss tangent) to a degree of deterioration of a model sample containing an organic insulation material, computing a temperature characteristic of the loss tangent of the sample being measured that contains an organic insulation material, and plotting on the master curve a peak temperature appearing on the highest temperature side of temperature characteristic peaks of the loss tangent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a rotating machine, a generator,
The present invention relates to a method for diagnosing deterioration of an organic insulating material used in electrical equipment such as a transformer.

[0002]

2. Description of the Related Art The life of an organic insulating material used for an electric device governs the life of the electric device. Such a method for detecting thermal deterioration of insulating resin of electric equipment is disclosed in Japanese Patent Publication No. 3-50
No. 977 discloses this.

In the above-mentioned method, a sample of the same material as the substance to be measured is deteriorated at various temperatures, a change in dynamic viscoelastic properties due to the deterioration of the sample is obtained, and the deterioration based on the Arrhenius velocity response equation is plotted on one axis. Take the conversion time of the function of temperature and aging time, take the dynamic viscoelastic properties on the other axis, plot the change in dynamic viscoelastic properties at the various temperatures on the coordinates represented by the two axes A master curve is determined, and the degree of deterioration of the actual operating device is detected by comparing the dynamic viscoelastic characteristics of a substance collected from the actual operating device with the master curve.

[0004]

However, in the above prior art, the peak value greatly changes depending on the thickness, shape, and resin content of the piece to be measured, and therefore, such a material as a polyethylene terephthalate (PET) film material is used. In some cases, the determination was erroneous unless the test piece had a uniform thickness.

[0005] In addition, since the insulating layer of an electric device has a thickness, as the aging progresses, the degree of deterioration differs between the surface layer and the inner layer of the insulating layer due to the influence of heat conduction and cooling. Further, when a finish varnish or the like is overcoated on the surface of the insulating layer at the time of overhaul or the like, the degree of deterioration differs between the surface layer and the inner layer.

Accordingly, in a test piece taken from an electric device having an insulating layer in which the degree of deterioration differs between the surface layer and the inner layer, the peak of the temperature dispersion characteristic of the loss tangent corresponds to each layer. More than one often appears. As described above, in the case where a plurality of peaks appear, there is a problem in that the above-described related art cannot accurately determine deterioration.

An object of the present invention is to measure the thickness and shape of a piece to be measured,
In order to provide a method for diagnosing deterioration of an organic insulating material, which is not affected by a difference in resin content and the like, and which correctly diagnoses deterioration of an insulating material of an electrical device having a plurality of loss tangent peaks of a measured piece. is there.

[0008]

The gist of the present invention to achieve the above object is as follows.

[1] A method for diagnosing deterioration of an organic insulating material used for insulating electrical equipment, comprising: a ratio (loss) of a storage elastic modulus and a loss elastic modulus to a degree of deterioration of a model sample containing the organic insulating material. Tangent) is determined in advance to create a master curve, the temperature characteristic of the loss tangent of the sample to be measured including the organic insulating material is determined, and the highest temperature side of the temperature characteristic peak of the loss tangent is determined. A method of diagnosing deterioration of an organic insulating material, wherein the degree of deterioration of a sample to be measured is determined by plotting a temperature of a peak appearing on the master curve.

[2] The method for diagnosing deterioration of an organic insulating material as described above, wherein the remaining life of the sample to be measured is determined from the obtained degree of deterioration of the sample to be measured and the life of the model sample obtained in advance.

According to the present invention, even for a test piece having a plurality of peaks of the loss tangent, the degree of deterioration is determined at the temperature of the peak that appears at the highest temperature among the plurality of peaks. The deterioration of the insulating resin can be diagnosed more accurately than before, without being affected by the difference in the content.

Further, the obtained degree of deterioration of the sample to be measured is
The remaining life of the insulating resin can be obtained more accurately than before, based on the life of the model sample obtained in advance.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have examined in detail the relationship between the degree of deterioration of an insulating resin and the temperature dependence of the loss tangent of the dynamic viscoelastic properties. When a plurality of peaks appear, if the degree of deterioration is diagnosed using the temperature of the peak on the highest temperature side of those peaks, accurate measurement is possible regardless of the thickness, shape, and resin content of the test piece. It has been found that deterioration diagnosis can be performed.

The method of diagnosing deterioration of the present invention will be described in the case of a rotating machine by using the insulating resin used therein. In performing the deterioration diagnosis of the insulating resin of the present embodiment, a diagnosis master curve is prepared in advance. FIG. 5 shows an example of the diagnostic master curve.

The diagnostic master curve shown in FIG. 5 is obtained by performing an accelerated deterioration test on a model sample using the same material as the insulating resin whose deterioration degree is to be determined at four temperatures (indicated by four dots in FIG. 5). In this example, the activation energy of deterioration is calculated based on the chemical reaction kinetics, the conversion time is used as a parameter of the degree of deterioration, and the relationship between the peak value of the loss tangent (tan δ) and the maximum temperature is shown.

In this embodiment, a diagnostic master curve was prepared in advance using a model sample obtained by applying a finishing varnish made of an opaque epoxy resin containing a black pigment used for a piece to be measured to a glass cloth tape. In this model sample, since the maximum peak temperature of tan δ is 150 ° C., the life point θ ₀ is determined to be 8 × 10 ⁹ (h).

As described in Japanese Patent Publication No. 3-50977, the degree of deterioration is generally represented by a conversion time θ which is a function of temperature and time based on the Arrhenius law.
In this conversion time θ, even if the materials have various deterioration histories, the same degree of deterioration means that the conversion times θ are equal. The above conversion time θ is defined by [Equation 1].

[0018]

Equation 1 θ = t × exp (−ΔE / RT) (Equation 1) where ΔE is the apparent activation energy (J /
mol), R is a gas constant (J / K / mol), T is the absolute temperature of degradation (K), and t is the degradation time (h).

ΔE can be easily calculated from an Arrhenius plot. Furthermore, assuming that the conversion time at the life point of the material determined in advance is θ ₀ , the difference Δθ from the conversion time θ obtained from the actual measurement becomes the conversion time corresponding to the remaining life, and serves as a scale of deterioration degree diagnosis. That is, Δθ (= θ ₀ −θ) is represented by [Equation 2].

[0020]

[Expression 2] Δθ = (t ₀ −t) × exp (−ΔE / RT _t ) (Equation 2) From the above expression, if the average operating temperature condition (T _t ) after time t is determined, the remaining life Δt ( = t ₀ -t) can be obtained.

FIG. 1 shows a method for diagnosing deterioration of an insulating resin according to this embodiment.
This will be described using the flow of FIG.

(1) First, a piece to be measured is sampled from the insulating portion at the coil end of the rotating machine stator. The sample to be measured is collected from the coil end part because the same resin as the insulating resin used for the insulating part in the initial stage of manufacturing is used for the coil end part. This is because the change is equivalent and the insulating portion is not damaged by sampling.

Therefore, if the insulating portion is not damaged by the sampling, a glass cloth tape to which a lead wire is bound may be used other than the coil end portion.
With such a part, diagnosis can be performed even on an existing actual machine to which no monitor material for evaluation is attached.

(2) Next, the temperature dependence of the dynamic viscoelastic properties of the sample to be measured is measured.

(3) From the temperature dependence of the dynamic viscoelastic properties of the test piece, the temperature dependence of the loss tangent (tan δ), which is the ratio between the storage modulus and the loss modulus, is determined.

(4) Among the peaks that appear in the temperature dependence of the loss tangent (tan δ), the temperature of the peak that appears at the highest temperature is determined.

(5) The above temperature is applied to a diagnostic master curve (FIG. 5) to determine the degree of deterioration of the measured object (time conversion θ).
Ask for.

Further, when the remaining life of the insulating material is obtained, (6) the degree of deterioration (time conversion θ) obtained by using the above-mentioned [Equation 2] and the life point (time The remaining life (Δt) is determined from the converted θ ₀ ) and the average operating temperature condition (T _t ).

Next, a description will be given of a comparative example of a diagnosis of deterioration of the insulating resin according to the present embodiment with a conventional diagnosis.

[Diagnosis Example 1] A description will be given of an example of deterioration diagnosis for the test pieces A to E having different sizes, shapes, and thicknesses collected from the same coil end portion.

A plurality of strips to be measured (glass cloth tape samples 1) each having a size of about 5 mm × 15 mm as shown in FIG. 3 were collected from the coil end portion of the rotating machine. Each of these test pieces is curved,
The shapes and thicknesses were different, the dispersion was large, and the application state of the insulating resin was not uniform.

Using these test pieces, a tensile vibration test using sinusoidal distortion (frequency: 10 Hz, displacement: 1 μm)
And the dynamic viscoelastic properties [temperature dependence of storage (dynamic) modulus, loss modulus and loss tangent (tan δ)] were measured in an air atmosphere.

Although the measurement conditions are not limited to those described above, it is desirable that the measurement conditions are the same as those when the diagnostic master curve was created. In addition, a glass cloth tape, an insulating resin, and a finish varnish are used for the measured piece. An opaque epoxy resin containing a black pigment is used for the finishing varnish, and therefore, it was impossible to evaluate the degree of optical deterioration of the insulating resin.

FIG. 2 shows the measurement results of the dynamic viscoelastic characteristics of five pieces (A to E) having different shapes, thicknesses, and the like.

The five test pieces have the same thermal history, that is,
Although the deterioration is the same, the measurement results are not the same and vary.

As described above, the test pieces taken from the actual machine have different thicknesses, shapes, and resin contents, so that even if the materials have the same thermal history, the storage elasticity of the dynamic viscoelasticity characteristics The temperature dispersion characteristics of the loss tangent (tan δ), which is the ratio between the modulus and the loss elastic modulus, vary as shown in FIGS.

If the temperature of the peak value of tan δ of the test pieces A to E is applied to the diagnostic master curve (FIG. 5) or the degree of deterioration is obtained from the maximum peak value as in the prior art, the degree of deterioration varies. It is not possible to correctly diagnose the original degree of deterioration of the insulating resin used for the insulating portion at the beginning.

On the other hand, in the present invention, since the judgment is made based on the peak temperature at the highest temperature, almost the same result (83 ° C.) is obtained from FIG. 2 for each sample, and is applied to the diagnosis master curve in FIG. And the time conversion θ of the original degree of deterioration of the insulating resin used for the insulating portion in the early stage of manufacturing.
= 8 × 10 to ¹¹ (h).

[Diagnosis Example 2] Next, the test pieces F, having different thicknesses of the finishing varnish, obtained from the coils of the rotating machine,
An example in which the degree of deterioration is diagnosed for G and H will be described.

FIG. 4 shows the tan δ temperature dispersion characteristics of the test pieces F, G, and H. The pieces to be measured F, G, and H were obtained from a coil of a rotating machine in which the surface of a base varnish of an insulating portion was overcoated with a finish varnish.

These tan δ temperature dispersion characteristics have two peaks. The peak at T1 (around 78 ° C.) on the low temperature side is attributable to the overcoated varnish. T2 on high temperature side
The peak at (around 130 ° C.) is attributable to the base varnish applied during manufacture. From FIG. 4, the test pieces F, G, and H all have the same thermal history, but their peak values are that the test piece A is larger on the T2 side and the test pieces B and C are larger on the T1 side. I understand. This difference in peak value is due to the thickness of the overcoated varnish.

The temperature of the maximum peak value of tan δ of the test piece F is on the T2 side. When the temperature T2 is applied to the diagnostic master curve (FIG. 5) as in the conventional case, the conversion time θ is 4 × 10 to ⁹
, And it is determined that the deterioration has progressed considerably.

On the other hand, in the test pieces G and H, their tan δ
Will be diagnosed using the temperature (T1 side) of the maximum peak value of the measurement result. As a result, the conversion time θ of the test pieces G and H is 5 ×
10 to ¹¹ , which means that there is not much deterioration.

In this embodiment, since the determination is made based on the peak temperature that appears on the highest temperature side of each of the test pieces, the test pieces F and
G and H are both determined on the T2 side, and the converted time θ is 4 × 10 to ⁹ so that the original degree of deterioration of the insulating portion of the coil can be known.

According to the present embodiment, the test piece is not affected by differences in thickness, shape, and resin content of the test piece, and has two or more peaks in the temperature dispersion characteristic of tan δ. , The degree of deterioration can be accurately diagnosed.

[0046]

According to the present invention, even for a test piece having a plurality of loss tangent peaks, the degree of deterioration is obtained based on the temperature of the peak that appears at the highest temperature from the plurality of peaks. The diagnosis can be made more accurately than before.

In addition, the deterioration of the insulating resin can be diagnosed more accurately than the conventional method without being affected by the difference in the thickness and the shape of the piece to be measured, the resin content, and the like. Can be determined accurately.

[Brief description of the drawings]

FIG. 1 is a flowchart of a method for diagnosing deterioration of an insulating resin according to an embodiment of the present invention.

FIG. 2 shows pieces A to be measured having different thicknesses, shapes, and resin contents.
5 is a graph showing a temperature dispersion characteristic of tan δ of E.

FIG. 3 is a schematic diagram showing a shape of a piece to be measured.

FIG. 4 shows tan δ of a test piece coated with a finish varnish.
3 is a graph showing the temperature dispersion characteristics of the sample.

FIG. 5 is a graph showing a diagnostic master curve of a model sample.

[Explanation of symbols]

 1: Glass cloth tape sample.

Continuing from the front page (72) Inventor Yuzo Ito 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd. Hitachi Research Laboratory, Ltd. (72) Inventor Minokichi Miura 1-6-6 Kanda Nishikicho, Chiyoda-ku, Tokyo Hitachi Building Systems Co., Ltd. (72) Inventor Masateru Nakano 1-6-6 Kandanishikicho, Chiyoda-ku, Tokyo F-term in Hitachi Building Systems Co., Ltd. (Reference) 2G015 AA05 AA07 AA13 AA14 AA18 AA19 CA07 CA20 2G016 BA00 BC02 2G040 AA05 AB20 BA02 BA27 CA02 CA13 CA22 DA02 EB02 EC09 HA05 HA11 HA16 HA18

Claims (2)

[Claims] 1. A method for diagnosing deterioration of an organic insulating material used for insulating electrical equipment, comprising: a ratio of a storage elastic modulus and a loss elastic modulus to a deterioration degree of a model sample containing the organic insulating material (loss tangent). ) Is determined in advance, and a master curve is created. The temperature characteristic of the loss tangent of the sample to be measured including the organic insulating material is determined. A method for diagnosing deterioration of an organic insulating material, wherein the temperature of a peak that appears is plotted on the master curve to determine the degree of deterioration of the sample to be measured. 2. The deterioration of the organic insulating material according to claim 1, wherein the remaining life of the measured sample is determined from the determined degree of deterioration of the measured sample and the life of the model sample determined in advance. Diagnostic method.