JP2010243224A - Method for diagnosing deterioration of heat-resistant polyester varnish - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely diagnose the deterioration of heat-resistant polyester varnish using a very small amount of a sample. <P>SOLUTION: In a method for diagnosing the degree of deterioration of the heat-resistant polyester varnish on the basis of the peaks of a total ion chromatogram (TIC) obtained by measuring the heat-resistant polyester varnish by a pyrolytic GC-MS method, the peak increased by the deterioration of the heat-resistant polyester varnish in the peaks of TIC serves as a deterioration peak and the peak not depending on the deterioration of the heat-resistant polyester varnish in the peak of TIC serves as a fundamental peak. The diagnosis of the degree of deterioration of the heat-resistant polyester varnish is performed on the basis of a peak area ratio obtained by dividing the area of the deterioration peak by the area of the fundamental peak. When the degrees of deterioration of the heat-resistant polyester vanish are measured with respect to samples different in the degree of deterioration by the pyrolytic GC-MS method and a conventional deterioration diagnosing method (e.g., weight reduction ratio) to prepare a master curve being a correlation between the measuring results, the degree of deterioration of the heat-resistant polyester varnish is more precisely measured. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a deterioration diagnosis technique of a heat-resistant polyester varnish used in electrical equipment. The present invention relates to a technique for measuring a peak area that increases due to deterioration of an insulating material by a pyrolysis GC-MS method and diagnosing the degree of deterioration of the insulating material based on the peak area.

  Polyester resins typified by polymer insulating materials have good heat resistance, electrical properties, mechanical strength, adhesiveness and workability (fluidity), and have been used for a long time. During processing, the resin has good fluidity, so the glass tape wound around the stator coil conductor of a rotating machine such as a water turbine generator is impregnated with the resin, or wound around a stationary equipment conductor such as a H-type impregnated mold type dry transformer. Cellulose-based insulating paper is impregnated with resin and used for electrical insulation retention.

  The heat resistance classification of polyester varnish, which is an insulating material applied to Class H impregnated mold type dry transformers for stationary equipment, is Class H, and the standard is JIS C-4003 or MIL E-917D, and the maximum allowable temperature Is defined as 180 ° C. The molecular structure of a general heat resistant polyester varnish is shown in FIG.

  As an insulation diagnosis method for electrical equipment such as a H-type impregnated mold type dry transformer, a method based on an electrical characteristic test (various withstand voltage tests, partial discharge measurement, etc.) is generally used.

  As a life criterion as a method for diagnosing deterioration of a polyester resin applied to a rotating machine, IEC Pub. In 216 “Guide for determining the heat resistance characteristics of an electrically insulating material”, the recommended life reference point of the material is a mass reduction rate of 5%. Therefore, when this life criterion is applied to a rotating machine, a mass reduction rate of 5% or more is defined as a life zone classification, a safety zone is a mass reduction rate of 3% or less, and a warning zone is a mass reduction rate of 3% to 5%. Provisional judgment criteria are established.

  Thus, although the deterioration diagnosis method for insulating materials has been established, as shown in Patent Document 1, the correlation between the conventional deterioration diagnosis method established from the viewpoint of convenience and practicality and other diagnosis methods can be obtained. Therefore, the deterioration diagnosis of the insulating material is performed by simple measurement. Moreover, as shown in Patent Document 2, there is also a method of performing deterioration diagnosis by detecting and quantifying a decomposition product generated by deterioration.

JP 2005-338045 A JP 2003-107075 A

  Since the insulating material used for the stationary equipment is different from that used for the rotating machine, the provisional judgment standard of the rotating machine described in the above-mentioned prior art is directly applied to the H type impregnated mold type dry transformer of the stationary machine. Not applicable to.

  In addition, the current life prediction of the Class H impregnated mold-type dry transformer is predicted in units of about 10 years in the electrical characteristics test. With this method, the state when the electrical characteristics test is carried out can be grasped. There are problems such as poor accuracy of prediction and lack of reliability.

  Therefore, in such an electrical property test, material deterioration (deterioration) due to a chemical structural change of the insulating material itself due to deterioration of the properties of the reinforcing member or heating, etc. is not known, so there is actually no problem in the electrical property test. Nevertheless, there are cases that lead to accidents.

  Accordingly, an object of the present invention is to provide a method for accurately diagnosing deterioration of a heat-resistant polyester varnish.

  The heat-resistant polyester varnish deterioration diagnostic method of the present invention that achieves the above-mentioned object is characterized in that the heat-resistant polyester varnish is measured by a pyrolysis GC-MS method, and the heat-resistant polyester varnish is based on the peak of the total ion chromatogram obtained by the measurement. This is a method of diagnosing the degree of deterioration of the slag. Among the peaks, a peak that increases due to deterioration of the heat-resistant polyester varnish is defined as a deterioration peak, and among the peaks, a peak that does not depend on deterioration of the heat-resistant polyester varnish is defined as a basic peak, and an area of the deterioration peak is defined as the basic peak. The degree of deterioration of the heat-resistant polyester varnish is diagnosed based on the peak area ratio divided by the area.

  Therefore, according to the above invention, the heat-resistant polyester varnish deterioration diagnosis can be performed accurately by collecting a small amount of sample.

TIC (total ion chromatogram) of heat-resistant polyester varnish. (A) Mass spectrum of peak component (peak of 10 minutes) which is a decomposition product of heat resistant polyester varnish, (b) Mass spectrum of standard database (benzoic acid). The decomposition | disassembly schematic diagram of a heat resistant polyester varnish. (A) TIC of heat-resistant polyester varnish not deteriorated, (b) TIC of heat-resistant polyester varnish deteriorated. The relationship figure of a peak area ratio and mass reduction rate. Structural formula of heat-resistant polyester varnish.

  The present invention is a heat resistance used in a stationary type H-impregnated mold type dry transformer using a pyrolysis gas chromatograph mass spectrometer (Pyrolysis-Gas Chromatography-Mass Spectrometry, hereinafter abbreviated as pyrolysis GC-MS apparatus). Is used to diagnose deterioration of the conductive polyester varnish.

  The measurement principle of this pyrolysis GC-MS method will be described. A sample such as a polymer material is heated in a heating furnace in an inert gas atmosphere, and a gas desorbed from the sample is introduced into a gas chromatograph. Then, the decomposition gas separated into each component by the separation column in this gas chromatograph enters the mass spectrometer, and the organic substance which is the generated gas becomes an ionic state by the electron impact ionization method (EI method), and the inside of the quadrupole rod The mass is distributed with and the mass is detected with a photomultiplier tube.

  FIG. 1 shows a total ion chromatogram (hereinafter abbreviated as TIC) of a heat-resistant polyester varnish measured using a pyrolysis GC-MS method.

The measurement apparatus and measurement conditions used for the measurement by the pyrolysis GC-MS method are shown.
Measuring device / gas chromatograph mass spectrometer (Shimadzu Corporation)
GC-MS equipment (Gas Chromatography-Mass Spectrometer)
QP-2010 [Data processing software: GC-MS solution Ver. 2.20]
・ Pyrolysis device (Frontier Lab Co., Ltd.)
D-SP (Double-Shot Pyrolzer) apparatus PY-2020iD type measurement condition gas chromatograph (GC)
-Column oven temperature: 50 ° C. (3 min) → [10 ° C./min]→250° C. (5 min)
・ Vaporization chamber temperature: 330 ℃
-Ion source temperature: 200 ° C, injection mode: split-Control mode: pressure control, carrier gas pressure: 100 kPa
Total flow rate: 89.3 ml / min, column flow rate: 1.69 ml / min
-Linear velocity: 47.2 cm / sec, purge flow rate: 3 ml / min
Split ratio: 71.5 to 1.0
Detector / detection mode: EI (Electron Impact), detector voltage: 0.8 kV
Mass detection / measurement mode: scan, measurement time [start to end]: 0.1 min to 28 min
Mass range: 35 m / z to 500 m / z, measurement interval: 0.5 sec
・ Scanning speed: 1000
Sample input amount / weight: approx. 50 μm
FIG. 2A shows the result of mass spectral analysis of the peak component of the decomposition product detected at about 10 minutes in the TIC shown in FIG.

  FIG. 2 (b) is a mass spectrum of a standard database (benzoic acid).

  From the mass spectra shown in FIGS. 2 (a) and 2 (b), it can be determined that the decomposition product of the heat-resistant polyester varnish is benzoic acid. Therefore, the decomposition mechanism of the heat-resistant polyester varnish will be described with reference to FIG.

  In the molecular structure of the main skeleton of the heat-resistant polyester varnish shown in FIG. 3, the C—C bond and the C—O bond having a weak molecular bonding force are broken by thermal decomposition (dotted line portion in FIG. 3). One hydrogen is added to the oxygen part of the ester bond of the generated decomposition product, and a decomposition product (benzoic acid) resulting from the main skeleton of the heat-resistant polyester varnish is generated.

  A method for determining the degree of deterioration will be described with reference to FIGS.

  The heat-resistant polyester varnish not deteriorated and the heat-resistant polyester varnish deteriorated are measured by a pyrolysis GC-MS method to obtain TIC (FIG. 4 (a), FIG. 4 (b)). Then, the obtained TICs are compared.

  As indicated by an arrow in the TIC in FIG. 4B, in the deteriorated heat-resistant polyester varnish, a peak that increases depending on the degree of deterioration is detected in about 7 minutes. This peak is defined as a degradation peak. The degradation peak increases due to the degradation, as is clear as compared with the heat-resistant polyester varnish that is not degraded (FIG. 4A).

  Further, a peak due to the main skeleton detected at about 10 minutes as a peak of TIC common to both the heat-resistant polyester varnish not deteriorated and the heat-resistant polyester varnish deteriorated is set as a basic peak.

  At the time of measurement by the pyrolysis GC-MS method, the sample is weighed with a balance and about 50 μg is put. It is very difficult to sample a sample on the order of μg and weigh it in a measurement sample container.

  In view of this, in the peak indicated by TIC, a peak whose peak intensity increases with deterioration is defined as a degradation peak, and a peak that does not depend on degradation is defined as a reference peak. Then, the peak area ratio is calculated by dividing the deterioration peak area based on the deterioration peak by the reference peak area based on the reference peak.

  That is, if the sampling weight is made constant, the degradation peak area value increases with degradation. On the other hand, since the basic peak has a correlation with the sampled weight, even if the sampled weight is constant, the basic peak area does not change. Therefore, by comparing and evaluating each sample with the peak area ratio calculated by dividing the degradation peak area by the basic peak area, the sampling weight can be corrected, so that a measurement result independent of the sample weight can be obtained. it can.

  The degree of deterioration of the heat-resistant polyester varnish is evaluated based on the peak area ratio.

  First, the heat-resistant polyester varnish was subjected to a thermal accelerated deterioration test in a hot air circulation type thermostatic chamber at a constant temperature of 220 ° C. The thermal accelerated degradation test time was taken out of the sample in the thermostatic chamber every 1h, 24h, 72h, 120h, 240h, and 480h, and the mass reduction rate was measured. Table 1 shows the measurement result of the mass reduction rate of the sample by the thermal accelerated deterioration test.

  Moreover, the sample of the thermal accelerated deterioration test was measured by the pyrolysis GC-MS method. Each sample was weighed into a sample container with a balance of about 50 μg. This sample container was placed in a pyrolysis furnace in a helium atmosphere, and the temperature in the furnace was heated to 600 ° C., and pyrolysis gas generated from the sample was measured.

  The peak area ratio obtained by dividing the degradation peak area by the basic peak area was calculated from TIC, which is the measurement result of the pyrolysis gas by the pyrolysis GC-MS method.

  And the correlation of mass reduction rate and peak area ratio was plotted, and the master curve shown in FIG. 5 was obtained.

  As a temporary life determination, IEC Pub. In 216 “Guide for determining the heat resistance characteristics of an electrically insulating material”, the recommended life reference point of the material is a mass reduction rate of 5%. This is the recommended life reference point for rotating machines.

  The increase in the mass reduction rate due to thermal decomposition of the heat-resistant polyester varnish, which is an insulating material used in the H-impregnated mold-type dry transformer, has rapidly increased from about 7%.

  Therefore, a provisional judgment standard is established with a mass reduction rate of 7% or more, which is 2% higher than the recommended life standard for rotating machines, as a life area classification, a safety area of less than 5%, and a warning area of 5% to 7%. Deterioration degree determination may be performed.

  Samples to be used for determining the degree of deterioration are obtained by scraping several mg from the mold part during periodic inspection of the H-type impregnated mold type dry transformer that is actually operating in the field, and then applying the heat-resistant polyester varnish to the shaved part. Apply and dry to repair.

  This collected sample is measured by the pyrolysis GC-MS method, the peak area ratio is calculated, and the deterioration rate of the heat-resistant polyester varnish can be determined by obtaining the mass reduction rate in light of the master curve in FIG. it can.

  As described above, according to the heat-resistant polyester varnish deterioration diagnosis method according to the present invention, it is possible to diagnose deterioration of heat-resistant polyester varnish used in heavy electrical equipment by collecting a very small amount of sample. . Since deterioration diagnosis can be performed with a very small amount of sample, the amount of sample collected from the device is very small, and the degree of damage to the device is greatly reduced.

  In addition, when the insulating materials for deterioration diagnosis are different, the deterioration degree of different insulating materials can be determined by creating a deterioration determination master curve in advance. The degradation determination master curve can be created in a few days by the pyrolysis GC-MS method if there is a sample subjected to a thermal accelerated degradation test of the insulating material.

  In the deterioration diagnosis, a master curve serving as an index can be created by a thermal acceleration deterioration test as shown in the examples. Then, samples are taken from heat-resistant polyester varnishes used in heavy electrical equipment rotating machines, dry transformers, high voltage switchboards, etc., and peak area ratios and conventional methods (for example, weight reduction rate or tensile strength, bending strength) If a master curve that correlates with the measured value obtained by measurement or the like is created, deterioration diagnosis and remaining life estimation can be performed more accurately.

  The present invention is not limited to the above-described embodiments, and conventional degradation measurement methods for correlating with measurement conditions and the peak area ratio of TIC can be appropriately selected. In particular, the measurement object is not limited to the heat-resistant polyester varnish, and if there is a peak that increases due to deterioration, deterioration diagnosis can be performed by a pyrolysis GC-MS method.

Claims (4)

In the method of measuring the heat-resistant polyester varnish by pyrolysis GC-MS method and diagnosing the degree of deterioration of the heat-resistant polyester varnish based on the peak of the total ion chromatogram obtained by the measurement,
Among the peaks, the peak that increases due to the deterioration of the heat-resistant polyester varnish is a degradation peak,
Among the peaks, a peak that does not depend on deterioration of the heat-resistant polyester varnish is a basic peak,
A method for diagnosing deterioration of a heat-resistant polyester varnish, comprising diagnosing the degree of deterioration of the heat-resistant polyester varnish based on a peak area ratio obtained by dividing the area of the deterioration peak by the area of the basic peak. The method for diagnosing deterioration of a heat-resistant polyester varnish according to claim 1, wherein the deterioration degree of the heat-resistant polyester varnish is diagnosed by correlating the peak area ratio with a mass reduction rate, tensile strength or bending strength. Regularly collect heat-resistant polyester varnishes used in rotating machines, dry-type transformers, and high-voltage switchboards for heavy electrical equipment,
3. The heat-resistant polyester varnish deterioration diagnosis method according to claim 2, wherein a correlation between the peak area ratio and mass reduction rate, tensile strength or bending strength is taken for each of the collected heat-resistant polyester varnishes. When diagnosing the degree of deterioration of the heat-resistant polyester varnish by correlating the peak area ratio and the mass reduction rate,
4. The heat-resistant polyester varnish according to claim 2, wherein when the mass reduction rate is 7% or more, the heat-resistant polyester varnish is determined to be in a lifetime region unsuitable for use due to deterioration. 5. Degradation diagnosis method.

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